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A System for Relational Reasoning in Human Prefrontal Cortex
Abstract
The integration of multiple relations between mental representations is critical for higher level cognition. For both deductive- and inductive-reasoning tasks, patients with prefrontal damage exhibited a selective and catastrophic deficit in the integration of relations, whereas patients with anterior temporal lobe damage, matched for overall IQ but with intact prefrontal cortex, exhibited normal relational integration. In contrast, prefrontal patients performed more accurately than temporal patients on tests of both episodic memory and semantic knowledge. These double dissociations suggest that integration of relations is a specific source of cognitive complexity for which intact prefrontal cortex is essential. The integration of relations may be the fundamental common factor linking the diverse abilities that depend on prefrontal function, such as planning, problem solving, and fluid intelligence.
... Moreover, it remains unclear which subprocess of analogical reasoning is most strongly supported by the rlPFC. Generally, the rlPFC is speculated to be the brain region supporting analogy mapping given its role in reflective transfer (Anderson & Fincham, 2014) and relational integration (Christoff, Keramatian, Gordon, Smith, & Mädler, 2009;Green, Fugelsang, Kraemer, Shamosh, & Dunbar, 2006;Waltz et al., 1999). Nonetheless, Krawczyk, McClelland, Donovan, Tillman, and Maguire (2010) and Volle et al. (2010) both found that the rlPFC was more active during the encoding phase than during the mapping phase; Davis, Goldwater, & Giron, (2017), otherwise, noticed that rlPFC was highly active when learning a new relation for solving the problem but would not stay active if relations involved in subsequent problems remained unchanged. ...
... Nevertheless, we regard the role of the left rlPFC in syntactic analogy as universal rather than specific to analogical mapping because we did not find significant correlations between its activation and the difficulty ratings of any subprocesses, which seems to challenge the common assumption that the rlPFC is central to the mapping subprocess of analogical reasoning but not to other subprocesses Green et al., 2006;Waltz et al., 1999). In their recent review of brain research on analogical reasoning, Parsons and Davies (2022) also pointed out that no conclusive evidence has been found regarding the role of the rlPFC during analogical mapping. ...
... First, the left pMFG activation pattern found in the current study confirms that the left dlPFC is important to analogical access and analogical mapping, which demand efficient memory retrieval. Second, the left aMFG activation pattern suggests that the task-general function of the rlPFC in relational integration (Hobeika et al., 2016;Waltz et al., 1999) is more likely to permeate the whole process of analogical reasoning than to influence only one or two subprocesses. Third, the closer MNI peak of syntactic analogy found in the present study to that of semantic analogy than to that of visuospatial analogy found in the previous study ( Wendelken et al., 2012) again reflects the domain sensitivity of the aMFG as a result of different kinds of first-order inputs; that is, the left ventrolateral pFC, which processes semantics (Binder et al., 2009), and the left posterior inferior frontal gyrus, which processes syntax (Matchin & Hickok, 2020), are both ventral to the left superior frontal sulcus, which processes visuospatial information (Sala et al., 2003). ...
Analogical reasoning is central to thought and learning. However, previous neuroscience studies have focused mainly on neural substrates for visuospatial and semantic analogies. There has not yet been research on the neural correlates of analogical reasoning on syntactic patterns generated by the syntactic rules, a key feature of human language faculty. The present investigation took an initial step to address this paucity. Twenty-four participants, whose brain activity was monitored by fMRI, engaged in first-order and second-order relational judgments of syntactic patterns as well as simple and complex working memory tasks. After scanning, participants rated the difficulty of each step during analogical reasoning; these ratings were related to signal intensities in activated regions of interest using Spearman correlation analyses. After prior research, differences in activation levels during second-order and first-order relational judgments were taken as evidence of analogical reasoning. These analyses showed that analogical reasoning on syntactic patterns recruited brain regions consistent with those supporting visuospatial and semantic analogies, including the anterior and posterior parts of the left middle frontal gyrus, anatomically corresponding to the left rostrolateral pFC and the left dorsolateral pFC. The correlation results further revealed that the posterior middle frontal gyrus might be involved in analogical access and mapping with syntactic patterns. Our study is the first to investigate the process of analogical reasoning on syntactic patterns at the neurobiological level and provide evidence of the specific functional roles of related regions during subprocesses of analogical reasoning.
... Relational integration refers to considering multiple attributes simultaneously to formulate new relations to solve problems (Klaus Oberauer et al., 2008;Waltz et al., 1999). Relational integration has been proven to predict general intelligence, especially reasoning ability (Buehner et al., 2005(Buehner et al., , 2006Oberauer et al., 2000Oberauer et al., , 2003Oberauer et al., , 2008Süß et al., 2002;Wilhelm et al., 2013). ...
... Neuroimaging studies have shown that the relational complexity effect on number series task modulated the fronto-parietal network (Jia et al., 2011(Jia et al., , 2015Liang et al., 2016;Xiao et al., 2014;Yang et al., 2009;Zhong et al., 2011), in which hierarchical problems especially recruited the fronto-prefrontal cortex (FPC, BA 10) (Xiao et al., 2014). Also, hierarchical problems have been widely demonstrated to engage in relational integration underlying relational reasoning tasks (Crescentini et al., 2011;Krawczyk et al., 2011;Waltz et al., 1999;Wendelken et al., 2017). ...
... Relational integration was defined as considering multiple relations or features to formulate the new structure (Halford et al., 1998;Krawczyk et al., 2011;Waltz et al., 1999;Wendelken et al., 2017) and was operationalized to monitor relational changes (Oberauer et al., 2000(Oberauer et al., , 2003(Oberauer et al., , 2005(Oberauer et al., , 2008Süß et al., 2002). Since inductive reasoning required self-generating hypotheses about numerical relations, successful acquisition of the hidden rules seemed to be equated to relational integration. ...
As relational integration performance can be used to predict reasoning ability, the present study aimed to provide electrophysiological evidence for numerical inductive reasoning. Number series with two levels of relational complexity were utilized, including simple and hierarchical problems (such as “15–16‐17” versus “15–16‐18”). Two tasks were adopted: a relational integration task that required to determine whether the numerical relations were changed across numbers; a number series task that required to determine whether a hidden rule was acquired (Experiment 1) or to predict the subsequent number (Experiment 2), whose phases were divided as rule searching, rule discovery, and rule following. The event‐related potential (ERP) results of both experiments indicated that, in contrast to simple problems, hierarchical problems triggered enhanced N400 and late negative component (LNC), reflecting numerical fact retrieval, and generalizing novel hypotheses about the hidden rules by integrating adjacent numerical relations, respectively; relational integration showed similar N400 and LNC activation patterns to rule discovery (Experiment 1) or rule searching (Experiment 2). Additionally, the N400 and LNC elicited by relational integration showed strong positive correlations and even were able to predict the ones triggered by rule discovery (Experiment 1) or rule searching (Experiment 2). Therefore, the results supported the role of relational integration in numerical inductive reasoning and thereby in intelligence. In the first report to use identical numerical series to compare numerical inductive reasoning to relational integration, we observed that the N400 and LNC effects on relational integration not only exhibited similar patterns to those on rule acquisition but were also positively correlated with and able to predict rule acquisition. This supports the role of relational integration in intelligence.
... The frontal cortex includes the motor cortex (that contains primary motor, premotor, and supplementary motor areas), Broca's area, the lateral prefrontal cortex (LPFC), and the ventromedial prefrontal cortex (vmPFC). Vol. 4 | No. 2 | Fall 2020 3 in and controlled by the lateral prefrontal cortex (LPFC) (Christoff and Gabrieli 2000;Waltz et al. 1999;Duncan, Burgess, and Emslie 1995;A. Luria 2012;Fuster 2008;Baker et al. 1996), and voluntary talking initiated in and controlled by the Broca's area (Friederici 2011). ...
... Voluntary imagination paralysis is, however, easily revealed in special tests. Affected individuals commonly exhibit a selective and catastrophic deficit in matrix reasoning tasks requiring mental integration of multiple objects (Waltz et al. 1999 figure 2, the Tower of London test (Shallice 1982), and the mental two-digit number multiplication (Zago et al. 2001). Similarly, individuals with voluntary imagination paralysis have difficulty combining objects in a sentence: they show dramatically reduced ability to understand spatial prepositions ("draw a triangle above a circle"), time prepositions ("give me the ranch after you give me the screwdriver"), as well as passive ("the boy was defeated by the girl"), comparative ("the boy is shorter than the girl"), and recursive sentences ("John lives under Mary, who lives under Steve") (Dragoy 2017). ...
... Aphasia, however, is translated from Greek as "speechless" and these patients have normal articulate speech. Furthermore, as pointed out above, patients commonly exhibit a related deficit in nonverbal tasks requiring voluntary imagination (Waltz et al. 1999;Shallice 1982;Zago et al. 2001). Thus, their condition is better described as voluntary imagination paralysis. ...
A vivid and bizarre dream conjures up a myriad of novel mental images. The same exact images can be created volitionally when awake. The neurological mechanisms of these two processes are different. Voluntary combination of mental objects is mediated by the lateral prefrontal cortex (LPFC) and patients with damage to the LPFC often lose this ability. Conversely, the combination of mental objects into novel images during dreaming does not depend on the LPFC: LPFC is inactive during sleep and patients whose LPFC is damaged do not notice a change in their dreams. Paradoxically, few scientists are aware of the difference between mechanisms of imagery during dreaming and waking. Furthermore, neither colloquial English nor scientific jargon have an established way to report on the origin of a conjured up mental image: the term “imagination” is regularly used to describe any experience generated internally whether voluntarily (in waking) or involuntarily (in dreaming). Failing to distinguish between voluntary and involuntary imagination leads to confusion in developmental psychology, neurolinguistics, and paleoanthropology. Comprehensive understanding of the distinction between voluntary and involuntary imagination will help develop better therapy for children with language delay, contribute to clearer understanding of the uniqueness of human language, and enable a more productive discussion of the evolutionary origin of human language.
... What makes human thinking so special? A longstanding proposal [1] is that a core capacity is a high-level form of relational reasoning closely linked to the functions of the prefrontal cortex -what in this paper we refer to as the Late System, specific to humans. This type of reasoning has two basic prerequisites: the ability to form explicit representations of relations between entities, and the ability to make inferences by integrating multiple relations and comparing relations across domains. ...
... before B, so A must have happened before C). A very similar limitation -an inability to reorder comparative relations based on their inherent meaning, separate from their overt order of presentation -has been observed in tests of transitive inference administered to human frontal patients [1]. ...
... This contrast corresponds to a shift from reliance on fluid intelligence (based on the Late System) to crystalized intelligence (based on compiled linguistic knowledge). It is notable that those frontal patients who exhibit severe deficits in relational reasoning with novel problems are sometimes relatively unimpaired in their use of language [1], which is itself an inherently relational system. Comprehension of metaphors -a type of nonliteral language -appears to draw upon multiple systems [43 ,44]. ...
We review recent theoretical and empirical work on the emergence of relational reasoning, drawing connections among the fields of comparative psychology, developmental psychology, cognitive neuroscience, cognitive science, and machine learning. Relational learning appears to involve multiple systems: a suite of Early Systems that are available to human infants and are shared to some extent with nonhuman animals; and a Late System that emerges in humans only, at approximately age three years. The Late System supports reasoning with explicit role-governed relations, and is closely tied to the functions of a frontoparietal network in the human brain. Recent work in cognitive science and machine learning suggests that humans (and perhaps machines) may acquire abstract relations from nonrelational inputs by means of processes that enable re-representation.
... Tasks that have been used previously to measure working memory capacity (Lee et al., 2007;Metzler-Baddeley et al., 2017;St Clair-Thompson & Gathercole, 2006), and high-order components of executive function (i.e., planning and reasoning ability ;Corbett et al., 2015;Metzler-Baddeley et al., 2017). The following descriptions of these high-order components include: planning, responsible for modelling and anticipating the consequences of action before executing goals (Kaller et al., 2008;Unterrainer & Owen, 2006); and reasoning, requiring the ability to draw relationships between disparate or dissimilar phenomena, manipulate working memory and extract information from past and current information in order to achieve an outcome (Goswami et al., 1998;Krawczyk et al., 2008;Waltz et al., 1999). Given the variety of decision rules available, and the lack of consensus over the methods most appropriate for PCA (Crawford & Koopman, 1979;Hakstian et al., 1982), we utilised a four-fold approach as follows: parallel analysis (Horn, 1965), Kaiser criterion (>1; Kaiser, 1960), Cattell's scree plots were inspected (Cattell, 1952) and the interpretability of the statistical output was considered (Fabrigar et al., 1999). ...
... On the other hand, Reasoning ability necessitates the capability to establish connections between disparate or dissimilar phenomena. This process entails the manipulation of working memory and the extraction of pertinent information from historical and current data to achieve desired outcomes (Goswami et al., 1998;Krawczyk et al., 2008;Waltz et al., 1999). Latent variables were then produced by regressing task scores onto the rotated component matrix (Table 1). ...
Two experiments aimed to determine whether working memory capacity (WMC) and high‐order executive functions predict drown detection performance and maintenance under heightened task demands. Experiment 1 ( n = 111) found a positive correlation between enhanced performance scores and higher WMC, while executive function showed no comparable association. Experiment 2 ( n = 28) individuals with elevated WMC demonstrated an ability to detect a greater number of drowning events over an extended period overall, relative to their lower scoring counterparts. However, this heightened capacity did not necessarily prevent the presence of vigilance decrement, but enabled lifeguards to perform more effectively under conditions of increased bather numbers. Our findings highlight that lifeguards have a measurable underlying process that may systematically discriminate lifeguards of varying degrees of experience and detection performance. This offers a new avenue for future lifeguarding research.
... The ability to reason requires maintenance and manipulation of mental representations and the ability to understand relationships between objects. In particular, the ability to understand and integrate multiple (versus single) dimensional representations appears to be a marker of increasingly sophisticated reasoning ability, differentiating humans from non-human primates (Waltz et al. 1999) and marking developmental change over the human lifespan (Crone et al. 2009). A host of critical and complex mental processes involved in day-to-day life rely on reasoning ability, including problem solving, planning, execution of complex activities, and inferences (Krawczyk 2012). ...
... Neuropsychological and neuroimaging studies point to the prefrontal cortex as a central neural substrate of reasoning. Performance on MR and RPM is sensitive to functioning of prefrontal cortex, including medial and lateral regions, as well as the posterior parietal cortex (Bugg et al. 2006;Waltz et al. 1999). In particular, the anterior dorsolateral prefrontal cortex (dlPFC) has been shown to be activated by reasoning and problem-solving tasks (Prabhakaran et al. 1997). ...
Reasoning requires the ability to manipulate mental representations and understand relationships between objects. There is a paucity of research regarding the functional connections between multiple brain areas that may interact during commonly used reasoning tasks. The present study aimed to examine functional activation and connectivity of frontoparietal regions during a Matrix Decision Making Task, completed by twenty-one right-handed healthy participants while undergoing fMRI. Voxel-wise whole brain analysis of neural response to the task revealed activation spanning dorsal and lateral prefrontal, occipital, and parietal regions. Utilizing Group Iterative Multiple Model Estimation, a data-driven approach that estimates the presence and direction of connectivity between specific ROIs, connectivity between prefrontal and sensory processing regions were revealed. Moreover, the magnitude of connectivity strength between the left precentral gyrus and left dorsal cingulate (dACC) was positively correlated with MR behavioral performance. Taken together, results are consistent with earlier work demonstrating involvement of regions comprising the central executive network in relational reasoning. These data expand existing knowledge regarding communication of key brain regions during the task and demonstrate that understanding how key brain regions are interconnected can effectively predict the quality of behavioral output.
... Therefore, for establishing a performance at least over chance more trials would be required compared with a discrimination between probabilities of 1 and 0. This trend has been shown in humans, where learning the association of pvalues such as 0.75, 0.57, 0.43, and 0.25 with particular stimuli requires at least 50 trials until reaching asymptotic levels. This learning is impaired in patients with amnesia, which suggests the involvement of memory in learning probabilities (Waltz et al., 1999). This finding would be consistent with previous research showing deficits in memory caused by brain damage impairing TI in humans (Waltz et al., 1999;Vartiani et al., 2009;Waechter et al., 2012). ...
... This learning is impaired in patients with amnesia, which suggests the involvement of memory in learning probabilities (Waltz et al., 1999). This finding would be consistent with previous research showing deficits in memory caused by brain damage impairing TI in humans (Waltz et al., 1999;Vartiani et al., 2009;Waechter et al., 2012). Consequently, the complexity of the task can overload memory resources impeding TI. ...
In the basic verbal task from Piaget, when a relation of the form if A > B and B > C is given, a logical inference A > C is expected. This process is called transitive inference (TI). The adapted version for animals involves the presentation of a simultaneous discrimination between stimuli pairs. In this way, when A+B−, B+C−, C+D−, D+E− is trained, a B>D preference is expected, assuming that if A>B>C>D>E, then B>D. This effect has been widely reported using several procedures and different species. In the current experiment TI was evaluated employing probabilistic reinforcement. Thus, for the positive stimuli a .7 probability was administered and for the negative stimuli a .3 probability was administered. Under this arrangement the relation A>B>C>D>E is still allowed, but TI becomes more difficult. Five pigeons (Columba Livia) were exposed to the mentioned arrangement. Only one pigeon reached the criterion in C+D− discrimination, whereas the remaining did not. Only the one who successfully solved C+D− was capable of learning TI, whereas the others were not. Additionally, it was found that correct response ratios did not predict BD performance. Consequently, probabilistic reinforcement disrupted TI, but some positional ordering was retained in the test. The results suggest that TI might be affected by associative strength but also by the positional ordering of the stimuli. The discussion addresses the two main accounts of TI: the associative account and the ordinal representation account.
... It was hypothesized that the mechanism of PFS involves LPFC-controlled synchronization of object-encoding neuronal ensembles (objectNE) in the posterior cortex mediated via the frontoposterior connections (the Neuronal Ensembles Synchronization hypothesis or NES) [6,14,16]. Patients with damage to the LPFC [17], or the frontoposterior fibers [7], or to the temporal-parietal-occipital junction [18] (where objectNEs are encoded) often experience PFS paralysis. ...
... The neurological mechanisms of these two processes are different [13]. Voluntary combination of mental objects is mediated by the LPFC and patients with damage to the LPFC often lose this ability [17,[23][24][25][26][27]. Conversely, the combination of mental objects into novel images during dreaming does not depend on the LPFC: LPFC is inactive during sleep [28,29] and patients whose LPFC is damaged do not notice a change in their dreams [30]. ...
Children with autism often have difficulties in imaginative play, Theory of Mind, and playing out different scenarios in their minds. Research shows that the root of these problems may be the voluntary imagination network that involves the lateral prefrontal cortex and its long frontoposterior connections to the temporal-parietal-occipital area. Previously disconnected visuospatial issues (stimulus overselectivity and tunnel vision) and language issues (lack of comprehension of spatial prepositions and complex recursive sentences) may be explained by the same voluntary imagination deficit. This review highlights the new insights into the mechanism of voluntary imagination, its difference from involuntary imagination, and its unusually strong critical period. Clearer developmental terminology and a better understanding of voluntary imagination have the potential to facilitate communication between therapists and parents, and improve therapy outcomes in children.
... Conventionally, executive functions include inhibition and attention, working memory, and cognitive flexibility-all mediated by the LPFC [41]. PFS, defined as the process of juxtaposing multiple mental visuospatial objects, is also mediated by the LPFC [42][43][44][45][46][47]. PFS, however, is hypothesized to be mediated by a mechanism separate from other executive functions-the synchronization of object-encoding neuronal ensembles (objectNEs), whereby the LPFC phase-shifts the firing of two or more objectNEs; the synchronously firing objectNEs are perceived as a novel hybrid object (the Neuronal Ensembles Synchronization hypothesis or NES) [1,48,49]. ...
... To conduct PFS and to synchronize the objectNEs encoded in the posterior cortex (temporal, parietal, and occipital cortices), the LPFC relies on its frontoposterior connections, such as arcuate fasciculus and superior longitudinal fasciculus. Patients with damage to any component of this circuit-the LPFC [43], or the frontoposterior fibers [6], or the temporal-parietal-occipital junction [76]-often lose access to the full extent of PFS. Fuster calls their condition "prefrontal aphasia" [46] and Luria "semantic aphasia" [77]. ...
Prefrontal synthesis (PFS) is defined as the ability to juxtapose mental visuospatial objects at will. Paralysis of PFS may be responsible for the lack of comprehension of spatial prepositions, semantically-reversible sentences, and recursive sentences observed in 30 to 40% of individuals with autism spectrum disorder (ASD). In this report we present data from a three-year-long clinical trial of 6454 ASD children age 2 to 12 years, which were administered a PFS-targeting intervention. Tablet-based verbal and nonverbal exercises emphasizing mental-juxtaposition-of-objects were organized into an application called Mental Imagery Therapy for Autism (MITA). The test group included participants who completed more than one thousand exercises and made no more than one error per exercise. The control group was selected from the rest of participants by a matching procedure. Each test group participant was matched to the control group participant by age, gender, expressive language, receptive language, sociability, cognitive awareness, and health score at first evaluation using propensity score analysis. The test group showed a 2.2-fold improvement in receptive language score vs. control group (p < 0.0001) and a 1.4-fold improvement in expressive language (p = 0.0144). No statistically significant change was detected in other subscales not targeted by the exercises. These findings show that language acquisition improves after training PFS and that a further investigation of the PFS-targeting intervention in a randomized controlled study is warranted.
... A possible factor to explain the beginner groups' reliance on a search-based strategy is their development of and access to knowledge suitable for the higher order executive functions of planning and reasoning. Together, these functions enable the formation of mental representations, which relate relevant information and assist in representing the problem and goal state and anticipating the effect of any actions performed (Unterrainer and Owen, 2006;Waltz et al., 1999). Such functions are essential for security screening and the formation of situational problem-solving knowledge, which enables more-experienced screeners to engage in problem solving activities that generate valuable information to support decision making (Swann et al., 2020). ...
Airport security screening is a visual inspection task comprising search and decision. Problem solving is used to support decision making. However, it is not well understood. This study investigated how airport security screeners employ problem solving during x-ray screening, and how strategies change with experience. Thirty-nine professional security screeners were observed performing x-ray screening in the field at an Australian International Airport. Video and eye-tracking data were collected and analysed to explore activity phases and problem-solving strategies. Less-experienced screeners performed more problem solving and preferred problem-solving strategies that rely on visual examination without decision support or that defer decision making, compared to more-experienced screeners, who performed efficient and independent strategies. Findings also show that screeners need more time to develop problem-solving skills than visual scanning skills. Screeners would benefit from problem-solving support tools and intensified training and mentorship within the first six months of experience to advance problem-solving competencies.
... If this ability is learnable, then formal schooling might well be relevant to it, as proposed by Vygotsky (1934) and others. However, there is considerable evidence that it is only when multiple relations need to be taken into account that a strong correlation with g emerges (Duncan et al., 2020;Waltz et al., 1999). In this context, it is worth noting that our hidden single task does require human subjects to consider multiple relationships-specifically the positional relationships between several instances of a candidate digit (the target or the distractor) and the empty non-target cells in the target house-in order to perform the task correctly, and there is evidence that human participants have more difficulty solving cells in Sudoku puzzles that require more relationships to be taken into account. ...
We investigate human adults’ ability to learn an abstract reasoning task quickly and to generalize outside of the range of training examples. Using a task based on a solution strategy in Sudoku, we provide Sudoku-naive participants with a brief instructional tutorial with explanatory feedback using a narrow range of training examples. We find that most participants who master the task do so within 10 practice trials and generalize well to puzzles outside of the training range. We also find that most of those who master the task can describe a valid solution strategy, and such participants perform better on transfer puzzles than those whose strategy descriptions are vague or incomplete. Interestingly, fewer than half of our human participants were successful in acquiring a valid solution strategy, and this ability is associated with completion of high school algebra and geometry. We consider the implications of these findings for understanding human systematic reasoning, as well as the challenges these findings pose for building computational models that capture all aspects of our findings, and we point toward a role for learning from instructions and explanations to support rapid learning and generalization.
... However, there is also the possibility that the prefrontal regions responsible for problem-solving may deteriorate if they are not utilized (Peter et al., 2020;Takahata et al., 2018). For example, impairments in problem-solving (Jobson et al., 2021;Waltz et al., 1999) (Bailey, 2007), and mental health (Marx et al., 1992;Testa & Pantelis, 2009). At the societal level, a population with reduced problem-solving capacity may even impact a country's gross domestic product (Dickerson, 2006). ...
Background: Chat generative retrained transformer (ChatGPT) represents a groundbreaking advancement in Artificial Intelligence (AI-chatbot) technology, utilizing transformer algorithms to enhance natural language processing and facilitating their use for addressing specific tasks. These AI chatbots can respond to questions by generating verbal instructions similar to those a person would provide during the problem-solving process. Aim: ChatGPT has become the fastest growing software in terms of user adoption in history, leading to an anticipated widespread use of this technology in the general population. Current literature is predominantly focused on the functional aspects of these technologies, but the field has not yet explored hypotheses on how these AI chatbots could impact the evolutionary aspects of human cognitive development. Thesis: The “neuronal recycling hypothesis” posits that the brain undergoes structural transformation by incorporating new cultural tools into “neural niches,” consequently altering individual cognition. In the case of technological tools, it has been established that they reduce the cognitive demand needed to solve tasks through a process called “cognitive offloading.” In this theoretical article, three hypotheses were proposed via forward inference about how algorithms such as ChatGPT and similar models may influence the cognitive processes and structures of upcoming generations. Conclusions: By forecasting the neurocognitive effects of these technologies, educational and political communities can anticipate future scenarios and formulate strategic plans to either mitigate or enhance the cognitive influence that these factors may have on the general population.
... The prefrontal activation for two-operation problems accords with a proposal that the prefrontal cortex plays a critical role when reasoning demands integrating two or more relations (Waltz et al., 1999). Patients with a frontal variant of fronto-temporal dementia, where hypometabolism was initially localized in the prefrontal cortex, had impaired performance only on two-relation verbal and spatial problems. ...
Brain activation was examined using functional magnetic resonance imaging during mathematical problem solving in 7 young healthy participants. Problems were selected from the Necessary Arithmetic Operations Test (NAOT; R. B. Ekstrom, J. W. French, H. H. Harman, & D. Dermen, 1976). Participants solved 3 types of problems: 2-operation problems requiring mathematical reasoning and text processing, 1-operation problems requiring text processing but minimal mathematical reasoning, and 0-operation problems requiring minimal text processing and controlling sensorimotor demands of the NAOT problems. Two-operation problems yielded major activations in bilateral frontal regions similar to those found in other problem-solving tasks, indicating that the processes mediated by these regions subserve many forms of reasoning. Findings suggest a dissociation in mathematical problem solving between reasoning, mediated by frontal cortex, and text processing, mediated by temporal cortex.
... These theoretical considerations have subsequently been validated with experimental observations, as individuals with damage to their prefrontal lobes demonstrate selective deficits to their relational reasoning ability. 49 Subjects with prefrontal lobe damage iScience Article exhibited no decrements to episodic memory or semantic knowledge, whereas subjects with intact prefrontal cortex (but damage to anterior temporal regions) showed no deficits to their analogical reasoning ability. This suggests the PFC is essential for the type of relational processing required by analogies. ...
Human language without analogy is like a zebra without stripes. The ability to understand analogies, or to engage in relational reasoning, has been argued to be an important distinction between the cognitive abilities of human and non-human animals. Current studies have failed to robustly show that animals can perform more complex, relational discriminations, in part because such tests rely on linguistic or symbolic experiences, and therefore are not suitable for evaluating analogical reasoning in animals. We report on a methodological approach allowing for direct comparisons of analogical reasoning ability across species. We show that human participants spontaneously make analogical discriminations with minimal verbal instructions, and that the ability to reason analogically is affected by analogical complexity. Furthermore, performance on our task correlated with participants’ fluid intelligence scores. These results show the nuance of analogical reasoning abilities by humans, and provide a means of robustly comparing this capacity across species.
... Complex human thinking and reasoning is a recent evolutionary arrival. The primate brain evolved to interact with objects in space rather than interact with complex logic structures, so a great deal of the cerebral cortex is devoted to visuospatial and motor processing (Byrne and Johnson-Laird, 1989;Waltz et al., 1999;Byrne et al., 2007;Kravitz et al., 2011). According to a prominent account in cognitive science-mental model theory (MMT)-human reasoning and problem-solving co-opts previously evolved neural machinery for visuospatial and motor processing to internally represent and manipulate information (Johnson-Laird, 1980, 2010Tversky, 1991;Wai et al., 2009). ...
Introduction
Reasoning is a complex form of human cognition whose nature has long been debated. While a number of neurocognitive mechanisms for deductive reasoning have been offered, one of the most prominent accounts is Mental Model Theory (MMT). According to MMT, humans are able to manipulate and represent information for reasoning and problem solving by leveraging the brain’s evolved visuospatial resources. Thus, when solving deductive reasoning problems, reasoners build “mental models” of the essential pieces of information conveyed in the premises, with their relations to each other represented spatially—even when the information contained within a reasoning problem is not intrinsically spatial. Crucially, taking a spatially-based approach, such as building mental models, supports higher accuracy on deductive reasoning problems. However, no study has empirically tested whether explicitly training this mental modeling ability leads to improved deductive reasoning performance.
Method
Therefore, we designed the Mental Models Training App, a cognitive training mobile application which requires participants to complete increasingly difficult reasoning problems while using an external mental modeling tool. In this preregistered study (https://osf.io/4b7kn), we conducted a between-subjects experiment (N = 301) which compared the Mental Models Training App to 3 distinct control conditions in order to examine which specific components (if any) of the training were causally responsible for improved reasoning performance.
Results
Results demonstrate that, when compared to a passive control condition, the Mental Models Training App led to improvements in adults’ verbal deductive reasoning performance both during and after the training intervention. However, contrary to our preregistered hypotheses, the training-induced improvements were not significantly larger than the effects of the active control conditions—one which included adaptive practice of the reasoning problems, and one which included adaptive practice as well as a spatial alphabetization control task.
Discussion
Therefore, while the present results demonstrate the ability of the Mental Models Training App to enhance verbal deductive reasoning, they do not support the hypothesis that directly training participants mental modeling ability yields improved performance beyond the effects of adaptive practice of reasoning. Future research should examine the long-term effects of repeated usage of the Mental Models Training App, as well as transfer effects to other forms of reasoning. Finally, we present the Mental Models Training App as a free mobile application available on the Apple App store (https://apps.apple.com/us/app/mental-models-training/id1664939931), in the hope that this translational research may be utilized by the general public to improve their reasoning ability.
... PFS is neurologically different from other key components of mental imagery, such as dreaming and simple memory recall. Unlike dreaming, which is not controlled by the LPFC and occurs spontaneously (Braun et al., 1997;Solms, 1997), PFS is completely dependent on an intact LPFC (Baker et al., 1996;Christoff & Gabrieli, 2000;Duncan et al., 1995;Fuster, 2008;Luria, 2012;Waltz et al., 1999). Furthermore, simple memory recall differs from PFS as well, as it involves the recall of a single object encoded at some point in the past, whereas PFS also involves the combination of two or more objects from memory into a novel scene Vyshedskiy & Dunn 2015). ...
Prefrontal synthesis (PFS) is a component of constructive imagination. It is defined as the process of mentally juxtaposing objects into novel combinations. For example, to comprehend the instruction “put the cat under the dog and above the monkey,” it is necessary to use PFS in order to correctly determine the spatial arrangement of the cat, dog, and monkey with relation to one another. The acquisition of PFS hinges on the use of combinatorial language during early childhood development. Accordingly, children with developmental delays exhibit a deficit in PFS, and frequent assessments are recommended for such individuals. In 2018, we developed the Mental Synthesis Evaluation Checklist (MSEC), a parent-reported evaluation designed to assess PFS and combinatorial language comprehension. In this manuscript we use MSEC to identify differences in combinatorial language acquisition between ASD (N = 29,138) and neurotypical (N = 111) children. Results emphasize the utility of the MSEC in distinguishing language deficits in ASD from typical development as early as 2 years of age (p < 0.0001).
... Complementing behavior, the present models also make a set of population-level neural activity predictions ( Table 4, columns 3-5). These predictions are most immediately relevant to neural data from brain regions previously linked to relational inference and/or WM, most notably prefrontal cortex (PFC) and hippocampus [133,134,135,136,137,138,139], both required for TI performance [61,140]. Importantly, testing the predictions we have established has the potential to provide insight not only into how the brain implements TI, but also how these brain regions contribute to the ability to perform other cognitive tasks, particularly those involving WM and relational inference. ...
The ability to make inferences using abstract rules and relations has long been understood to be a hallmark of human intelligence, as evidenced in logic, mathematics, and language. Intriguingly, modern work in animal cognition has established that this ability is evolutionarily widespread, indicating an ancient and possibly foun-dational role in natural intelligence. Despite this importance, it remains an open question how inference using abstract rules is implemented in the brain — possibly due to a lack of competing hypotheses at the level of collective neural activity and of behavior. Here we report the generation and analysis of a collection of neural networks (NNs) that perform transitive inference (TI), a classical cognitive task that requires inference of a single abstract relation between novel combinations of inputs (if A > B and B > C, then A > C). We found that NNs generated using standard training methods (i) generalize fully (i.e. to all novel combinations of inputs), (ii) generalize when inference requires working memory (WM), a capacity thought to be essential for inference in living subjects, (iii) express multiple emergent behaviors long documented in humans and animals, in addition to novel behaviors not previously studied, and (iv) adopt different solutions that yield alternative predictions for both behavior and collective neural activity. Further, a subset of NNs expressed a “subtractive” solution that was characterized in neural activity space by a simple dynamical pattern (an oscillation) and geometric arrangement (ordered collinearity). Together, these findings show how collective neural activity can accomplish generalization according to an abstract rule, and provide a series of testable hypotheses not previously established in the study of TI. More broadly, these findings suggest new ways to understand how neural systems realize abstract rules and relations.
... This result further supports the view that the cognitive processes implemented within areas identified as core to deductive reasoning cannot be reduced to merely reflecting increased working memory demands, and might rather be integral to "identify[ing] and represent[ing] the overall structure of the proof necessary to solve a deductive problem" p. 1113). Indeed, anterior prefrontal cortex has been previously associated with processes such as relational complexity (Halford et al., 1998Robin & Holyoak, 1995;Waltz et al., 1999), and BA10 in particular has been found to activate in response to tasks requiring relational integration, keeping track of and integrating multiple related variables and sub-operations, and the handling of branching subtasks (Charron & Koechlin, 2010;Christoff et al., 2001;De Pisapia & Braver, 2008;Koechlin, Basso, Pietrini, Panzer, & Grafman, 1999b;Kroger et al., 2002;Ramnani & Owen, 2004), all of which are analogous to the kinds of processes that may be involved in evaluating deductive inferences. Similarly, previous research has associated medial BA8 with processes such as executive control, the choosing and coordinating of subgoals, and resolving competition between rules to transform a problem from one state into another (Fletcher & Henson, 2001;Koechlin, Corrado, Pietrini, & Grafman, 2000;Posner & Dehaene, 1994;Volz, Schubotz, & Cramon, 2005). ...
Deductive reasoning has been an object of investigation in psychology for almost a century now. Yet, key questions remain unanswered. These include (but are not limited to) the relationship between deductive reasoning and other psychological processes (such as language and memory), the identity of the neurological structures that are core to the deductive process, the source of the hierarchical structures on which deduction depends, whether deduction is a modular or domain-general process, and what the source is of the facilitation that is frequently observed when deductive
problems are framed in different ways. In order to address these questions, this thesis will present three experiments that shed light on different aspects of deduction. Study 1 is an fMRI study which replicates prior findings regarding the relationship between language and deductionandreveals a new dissociationbetween deduction and working memory. Study 2, a neuromodulation study, is a logical extension of the findings regarding deduction and language from Study 1 and other prior studies. Here, a form of transcranial magnetic stimulation (TMS) is used to manipulate brain function in order to establish a causaldissociation between brain areas that support language and those believed to support deduction, specifically with regard to the hierarchical frameworks on which both language and deduction depend. Finally, in Study 3, a large online study is used to test the Social Exchange Theory of facilitated performance on the Wason Card selection Task on a more diverse sample than has been the case in the past, especially with regard to the cues that have been suggested to trigger the underlying cognitive “modules.” This study also tests the relationship between facilitation on the Wason Task and a number of individual differences, revealing novel associations with personality traits and with psychopathology. Together, these three studies provide a clearer picture of how deductive reasoning, one of our most distinctively human capacities, is situated amongst our other cognitive abilities.
... PFS is neurologically different from other key components of mental imagery, such as dreaming and simple memory recall. Unlike dreaming, which is not controlled by the LPFC and occurs spontaneously (Braun et al., 1997;Solms, 1997), PFS is completely dependent on an intact LPFC (Baker et al., 1996;Christoff & Gabrieli, 2000;Duncan et al., 1995;Fuster, 2008;Luria, 2012;Waltz et al., 1999). Furthermore, simple memory recall differs from PFS as well, as it involves the recall of a single object encoded at some point in the past, whereas PFS involves the recollection and novel combination of two or more objects encoded in one's memory Vyshedskiy & Dunn, 2015). ...
Prefrontal synthesis (PFS) is a component of constructive imagination. It is defined as the process of mentally juxtaposing objects into novel combinations. For example, to comprehend the instruction “put the cat under the dog and above the monkey,” it is necessary to use PFS in order to correctly determine the spatial arrangement of the cat, dog, and monkey with relation to one another. The acquisition of PFS hinges on the use of combinatorial language during early development in childhood. Accordingly, children with developmental delays exhibit a deficit in PFS, and frequent assessments are recommended for these individuals. In 2018, we developed the Mental Synthesis Evaluation Checklist (MSEC), a parent-reported evaluation designed to assess PFS and combinatorial language comprehension. In this manuscript we use MSEC to identify differences in combinatorial language acquisition between ASD (N=29138) and neurotypical (N=111) children. Results confirm the utility of the MSEC in distinguishing language deficits in ASD from typical development as early as 2 years of age (p<0.0001).
... For example, weapon : gun considered alone could map to either mammal : dog or dog : beagle, because all of these pairs instantiate the superordinate-of relation. As we will show in an experiment reported below, humans can reliably solve such analogy problems; a comparable requirement to integrate multiple relations arises in many other relational reasoning paradigms, such as transitive inference (Halford, Bain, et al., 1998;Waltz et al., 1999). To resolve ambiguity in local mappings, a reliable analogy model must assess relation similarities and integrate across relations based on mapping constraints. ...
The human ability to flexibly reason using analogies with domain-general content depends on mechanisms for identifying relations between concepts, and for mapping concepts and their relations across analogs. Building on a recent model of how semantic relations can be learned from nonrelational word embeddings, we present a new computational model of mapping between two analogs. The model adopts a Bayesian framework for probabilistic graph matching, operating on semantic relation networks constructed from distributed representations of individual concepts and of relations between concepts. Through comparisons of model predictions with human performance in a novel mapping task requiring integration of multiple relations, as well as in several classic studies, we demonstrate that the model accounts for a broad range of phenomena involving analogical mapping by both adults and children. We also show the potential for extending the model to deal with analog retrieval. Our approach demonstrates that human-like analogical mapping can emerge from comparison mechanisms applied to rich semantic representations of individual concepts and relations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
... Relational integration may be a basic common factor that connects various abilities that depend on prefrontal function, including problem-solving, for which an intact prefrontal cortex is essential. 48 The present study indicates that the integrity of the frontal lobe is relatively preserved in MCI but not in mild AD as a lower performance was observed only in the mild AD group. This suggests that obvious frontal lobe damage would not be observed and inductive reasoning/problem-solving is preserved in the MCI stage. ...
Aim:
MATRICS Consensus Cognitive Battery was developed by the National Institute of Mental Health to establish acceptance criteria for measuring cognitive changes in schizophrenia and can be used to assess cognitive functions in other psychiatric disorders. We used a Japanese version of MATRICS Consensus Cognitive Battery to explore the changes in multiple cognitive functions in patients with mild cognitive impairment and mild Alzheimer's disease.
Methods:
We administered the Japanese version of MATRICS Consensus Cognitive Battery to 11 patients with mild cognitive impairment (MCI), 11 patients with Alzheimer's disease, and 27 healthy controls. All Japanese versions of MATRICS Consensus Cognitive Battery domain scores were converted to t-scores using sample means and standard deviations and were compared for significant performance differences among healthy control, MCI, and mild Alzheimer's disease groups.
Results:
Compared with healthy controls, patients with MCI and mild Alzheimer's disease demonstrated the same degree of impairment to processing speed, verbal learning, and visual learning. Reasoning and problem-solving showed significant impairments only in mild Alzheimer's disease. Verbal and visual abilities in working memory showed different performances in the MCI and mild Alzheimer's disease groups, with the Alzheimer's disease group demonstrating significantly more deficits in these domains. No significant difference was found among the groups in attention/vigilance and social cognition.
Conclusions:
The Japanese version of MATRICS Consensus Cognitive Battery can be used to elucidate the characteristics of cognitive dysfunction of normal aging, MCI, and mild dementia in clinical practice.
... Studies in neurobiology and brain imaging have identified a distinction between fluid and crystallized intelligence (Blair, 2006;Horn & McArdle, 2007), which show the former to be associated with the brain's prefrontal cortex. Waltz et al. (1999) find that damage to the prefrontal cortex appears to have little effect on crystallized intelligence. PV say the differential rate of change for the two types of intelligence could be due to improved nutrition and health care (Lynn, 2009b), disease containment (Eppig et al., 2010;Van Panhuis et al., 2013), and reductions in environmental risks (for example, lead poisoning (Kaufman et al., 2014) and air pollution (Chay & Greenstone, 2003). ...
Policymakers, conceptualized here as principals, disagree as to whether US student performance has changed over the past half century. To inform conversations, agents administered seven million psychometrically linked tests in math (m) and reading (rd) in 160 survey waves to national probability samples of cohorts born between 1954 and 2007. Estimated change in standard deviations (sd) per decade varies by agent (m: –0.10sd to 0.27sd, rd: –0.02sd to 0.12sd). Consistent with Flynn effects, median trends show larger gains in m (0.19sd) than in rd (0.04sd), though rates of progress for cohorts born since 1990 have increased in rd but slowed in m. Greater progress is shown by students tested at younger ages (m: 0.31sd, rd: 0.08sd) than when tested in middle years of schooling (m: 0.17sd, rd: 0.03sd) or toward the end of schooling (m: 0.06sd, rd: 0.02sd). Young white students progress more slowly (m: 0.28sd, rd: 0.09sd) than Asian (m: 46sd, rd: 0.28sd), black (m: 0.36sd, rd: 0.19sd), and Hispanic (m: 0.29sd, rd: 0.13sd) students. These ethnic differences generally attenuate as students age. Young students in the bottom quartile of the SES distribution show greater progress than those in the top quartile (difference in m: 0.08sd, in rd: 0.15sd), but the reverse is true for older students. Moderators likely include not only changes in families and schools but also improvements in nutrition, health care, and protection from contagious diseases and environmental risks. International data suggest that subject and age differentials may be due to moderators more general than just the United States.
... Thus, it is a non-verbal task that requires reasoning about and the integration of multiple dimensions of concern. It is often considered a test of fluid intelligence (Raven, 2000), meaning the application of reasoning to solve novel problems not based on prior knowledge, and a test of relational reasoning (Waltz et al., 1999), or the consideration of multiple relations simultaneously. We used advanced rather than more basic matrices from the test to provide a test of complex reasoning. ...
The popularity of remote work and a norm of constant connectivity have made text-based computer-mediated communication (tCMC) such as email inevitable for many organizational tasks. This could be worsening communicators’ performance on their later work. Specifically, drawing on media synchronicity theory (Dennis & Valacich, 1999), we propose that using tCMC for convergence processes—resolving ambiguity and conflicting interpretations to form shared understandings—is more difficult than using face-to-face communication. We use conservation of resources (COR) theory to argue this greater communication difficulty could dampen motivation maintenance for subsequent tasks, which, in turn, is likely to hamper knowledge work tasks that require complex reasoning. Supporting this line of reasoning, four experimental studies show causal effects of using tCMC (relative to in-person interaction) for tasks dependent on convergence processes on motivation maintenance and later complex reasoning tasks. A fifth study using an experience sampling design shows day-to-day changes in tCMC use influence depletion and downstream motivation maintenance for individuals whose jobs require complex problem solving. Together, these five studies indicate using text-based communication media has lasting effects on communicators beyond the communication task itself. These studies raise new questions about the pervasive use of email and other forms of text-based communication in organizations for individuals’ motivation and effectiveness.
... Voluntary combination of mental objects is mediated by the lateral prefrontal cortex (LPFC), and patients with damage to the LPFC or its extended connections to the rear part of the brain often lose this ability (Waltz et al. 1999;Dragoy, Akinina, and Dronkers 2017). Conversely, the combination of mental objects into novel images while dreaming does not depend on the LPFC: LPFC is inactive during sleep (Braun et al. 1997;Siclari et al. 2017), and patients whose LPFC is damaged do not notice a change in their dreams (Solms 1997). ...
A mythopoetic paradigm or perspective sees the world primarily as a dramatic story of competing personal intentions, rather than a system of objective impersonal laws. Asma (2017) argued that our contemporary imaginative cognition is evolutionarily conserved-it has structural and functional similarities to premodern Homo sapiens’s cognition. This article will (i) outline the essential features of mythopoetic cognition or adaptive imagination, (ii) delineate the adaptive sociocultural advantages of mythopoetic cognition, (iii) explain the phylogenetic and ontogenetic mechanisms that give rise to human mythopoetic mind (i.e., genetically endowed simulation and associational systems that underwrite diverse symbolic systems), (iv) show how mythopoetic cognition challenges contemporary trends in cognitive science and philosophy, and (v) recognize and outline empirical approaches for a new cognitive science of the imagination.
... Working memory (WM) allows us to hold information actively in mind (Baddeley and Hitch 1974;Baddeley 1983;Baddeley 1992) and supports multiple facets of complex behavior including the ability to learn about and comprehend the world around us and to perform numerical calculations and reasoning tasks (Waltz et al. 1999;Geary et al. 2004;Gathercole et al. 2019). It also provides the workspace in which naturally occurring spontaneous thoughts emerge, especially those with social episodic features (Teasdale et al. 1993;Teasdale et al. 1995;Smallwood et al. 2009;Smallwood et al. 2013;Turnbull, Wang, Schooler, et al. 2019;Turnbull, Wang, Murphy, et al. 2019). ...
Working memory (WM) allows goal-relevant information to be encoded and maintained in mind, even when the contents of WM are incongruent with the immediate environment. While regions of heteromodal cortex are important for WM, the neural mechanisms that relate to individual differences in the encoding and maintenance of goal-relevant information remain unclear. Here, we used behavioural correlates of two large-scale heteromodal networks at rest, the default mode (DMN) and frontoparietal (FPN) networks, to understand their contributions to distinct features of WM. We assessed each individual’s ability to resist distracting information during the encoding and maintenance phases of a visual WM task. Individuals with stronger connectivity of DMN with medial visual and retrosplenial cortex were less affected by encoding distraction. Conversely, weaker connectivity of both DMN and FPN with visual regions was associated with better WM performance when target information was no longer in the environment and distractors were presented in the maintenance phase. Our study suggests that stronger coupling between heteromodal cortex and visual-spatial regions supports WM encoding by reducing the influence of concurrently-presented distractors, while weaker visual coupling is associated with better maintenance of goal-relevant information because it relates to the capacity to ignore task-irrelevant changes in the environment.
... Classical ability theories distinguish fluid and crystallized skills. Research on brain structures and functions supports this classical distinction into fluid and crystallized skills (Nisbett et al., 2012;Waltz et al., 1999). Fluid skills, such as reasoning, are required to solve novel problems by drawing inferences or identifying relations. ...
This study aims to investigate how test scores from PIAAC (Programme for the International Assessment of Adult Competencies) can be interpreted, by comparing the PIAAC competencies literacy and numeracy to reasoning and perceptual speed. Dimensionality analyses supported, that the PIAAC competencies can be separated into a common factor overlapping with reasoning and perceptual speed, and domain-specific factors. For the common and specific factors, relations to other variables were analyzed. The nested factor for PIAAC literacy was as expected unrelated to age, positively related to learning opportunities during one’s lifetime, and positively related to literacy skill use. The nested factor for PIAAC numeracy was also as expected unrelated to age, against expectation unrelated to learning opportunities during one’s lifetime, and as expected positively related to numeracy skill use. Results support the validity of the intended test score interpretation for PIAAC literacy, while results for PIAAC numeracy were less clear.
... Another proposal suggests that a general process of abstraction may be a key factor contributing towards the frontal lobes' role in fluid intelligence (Krawczyk, McClelland, & Donovan, 2011;Waltz et al., 1999). In keeping with this, we found that, in comparison to healthy controls, frontal patients were impaired on several AH4-1 variables and had significantly poorer scores on Raven's APM. ...
The frontal lobes are thought to make a fundamental contribution to fluid intelligence. However, evidence that fluid intelligence is impaired following focal frontal lobe lesions is surprisingly sparse and based on non-verbal tests of fluid intelligence. We investigated performance on Part 1 of the Alice Heim 4 (AH4–1), a verbal test of fluid intelligence, in a sample of 35 patients with focal, unilateral, left or right, frontal brain tumours and 54 healthy controls. We analysed the following variables: overall number of correct AH4–1 answers, overall AH4–1 accuracy and accuracy on four selected categories of AH4–1 questions that assess abilities previously linked to the frontal lobes, namely: synonyms, verbal analogies, numerical series and multistage calculations. We found several significant frontal effects. Thus, in comparison to healthy controls, frontal patients had a significantly lower overall number of AH4–1 answers, had significantly lower overall AH4–1 accuracy and had significantly poorer performance on verbal analogies and multistage calculations. We also found several significant lateralised left frontal effects. Thus, in comparison to healthy controls, left, but not right, frontal patents had significantly lower overall AH4–1 accuracy and poorer performance on synonyms, numerical series and multistage calculation questions. This suggests that the left frontal lobe plays a critical role in AH4–1 performance. Moreover, left frontal patients had significantly lower overall AH4–1 accuracy and poorer performance on multistage calculations than right frontal patients. These results suggest that a left lateralised frontal network is critically involved in some aspects of fluid intelligence and, in particular, multistage calculations.
... PFS is mediated by the LPFC [38][39][40][41][42][43] . It was hypothesized that to conduct PFS, the LPFC synchronizes object-encoding neuronal ensembles (objectNEs) in the posterior cortex (temporal, parietal, and occipital cortices) using the frontoposterior connections, such as arcuate fasciculus and superior longitudinal fasciculus (the Neuronal Ensembles Synchronization hypothesis or NES) 1,44,45 . ...
Imagination exercises administered by caregivers were investigated in a three-year-long observational trial of 3,540 children with autism aged 2-12 years. Tablet-based verbal and nonverbal exercises modeled on language therapy and emphasizing mental-juxtaposition-of-objects were organized into an application called Mental Imagery Therapy for Autism (MITA). MITA-exposed children were matched to the ‘Treatment-as-Usual’ participants (TaU, N=5,222) by age, gender, language, sociability, cognitive awareness, health, and ASD severity at baseline. Both younger (2-5 years-of-age) and older children (5-12 YOA) in MITA and TaU groups improved their symptoms over time, but younger MITA-exposed children showed 2.3-fold improvement in language score at the end of the trial vs. TaU group. There was no difference between MITA and TaU in the older children group, supporting Lenneberg’s critical period hypothesis.
... ; https://doi.org/10.1101/041368 doi: bioRxiv preprint and structure (Waltz et al., 1999;Woolgar et al., 2010), grey matter indices (Kievit et al., 2014;Stuss et al., 2003) or additional WM metrics such as MD and AD (Tamnes et al., 2012) to obtain a more complete picture. ...
Fluid intelligence is a crucial cognitive ability that predicts key life outcomes across the lifespan. Strong empirical links exist between fluid intelligence and processing speed on the one hand, and white matter integrity and processing speed on the other. We propose a watershed model that integrates these three explanatory levels in a principled manner in a single statistical model, with processing speed and white matter figuring as intermediate endophenotypes. We fit this model in a large (N=555) adult lifespan cohort from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) using multiple measures of processing speed, white matter health and fluid intelligence. The model fit the data well, outperforming competing models and providing evidence for a many-to-one mapping between white matter integrity, processing speed and fluid intelligence. The model can be naturally extended to integrate other cognitive domains, endophenotypes and genotypes.
... According to our analysis, linguistic isolates performed well in all tests that did not involve the LPFC control of the posterior cortex, showed decreasing scores in tests that involved greater recruitment of the posterior cortex by the LPFC, and failed in tests that involved the greatest recruitment of posterior cortex necessary for mental synthesis of multiple objects. This performance pattern is in line with observations in late first-language learners [14][15][16]41 , individuals with nonverbal ASD 42 , as well as in patients with LPFC damage who are often unable to correctly answer questions that require integration of modifiers, mental rotation and modification of an object's location in space, as well as mental synthesis of several objects [43][44][45][46][47] . ...
We analyzed all published reports of individuals not exposed to syntactic language until puberty: two feral children, who grew up without hearing any language, and eight deaf linguistic isolates, who grew up communicating to their families using homesign or kitchensign, a system of gestures which allows them to communicate simple commands but lacks much in the way of syntax. A common observation in these individuals is the lifelong difficulty understanding syntax and spatial prepositions, even after many years of rehabilitation. This debilitating condition stands in stark contrast to linguistic isolates’ performance on memory as well as semantic tests: they could easily remember hundreds of newly learned words and identify previously seen objects by name. The lack of syntactic language comprehension in linguistic isolates may stem from inability to understand words and/or grammar or inability to mentally synthesize known objects into novel configurations. We have previously shown that purposeful construction of novel mental images is the function of the lateral prefrontal cortex (LPFC) ability to dynamically control posterior cortex neurons ¹ . Here we have ranked all tests performed on linguistic isolates by their reliance on the LPFC control of the posterior cortex: a) the amount of posterior cortex territory that needs to be recruited by the LPFC and b) the number of disparate objects that have to be combined together by the LPFC in order to answer the test question. According to our analysis, linguistic isolates performed well in all tests that did not involve the LPFC control of the posterior cortex, showed decreasing scores in tests that involved greater recruitment of the posterior cortex by the LPFC, and failed in tests that involved greatest recruitment of posterior cortex necessary for mental synthesis of multiple objects. This pattern is consistent with inadequate frontoposterior connections in linguistic isolates. We discuss implications of these findings for the importance of early syntactic language exposure in formation of frontoposterior connections.
... Mental synthesis is neurologically different from other key components of imagery, such as simple memory recall and dreaming. Unlike dreaming, which is spontaneous and not controlled by the LPFC 4,5 , mental synthesis is controlled by and completely dependent on an intact LPFC [6][7][8][9][10][11] . Unlike simple memory recall, which involves the recall of a single object encoded at some point in the past, mental synthesis involves combination of two or more objects stored in memory 2,3 . ...
Background: Mental synthesis is the conscious purposeful process of synthesizing a novel mental image from objects stored in memory. In our everyday use of language, we rely on mental synthesis to communicate an infinite number of images with a finite number of words. In typical children, the timeline of mental synthesis acquisition is highly correlated with an increasing vocabulary. Children with ASD, on the other hand, may learn hundreds of words but never acquire mental synthesis. In these individuals, tests assessing vocabulary comprehension may fail to demonstrate the profound deficit in mental synthesis and the resulting inability to understand flexible syntax and spatial prepositions. Objective: We developed a 20-question parent-reported evaluation tool designed to quantitatively assess mental synthesis ability and to serve as a complimentary scale for Autism Treatment Evaluation Checklist (ATEC). Results: Internal reliability was good (Cronbach’s alpha > .9), and the MSEC exhibited adequate test-retest reliability after a three- and nine-months follow up period. The MSEC results positively correlated with the ATEC communication subscale, providing support for construct validity. Moreover, MSEC scores were significantly different for children of different ASD severity levels confirming the known groups validity. Conclusions: This study represents the first step toward the development of an instrument to measure mental synthesis in children with ASD. Although the current empirical evaluation demonstrated strong evidence of excellent psychometric properties, such as validity and reliability, additional studies should be performed to replicate these findings.
Relational cognition—the ability to infer relationships that generalize to novel combinations of objects—is fundamental to human and animal intelligence. Despite this importance, it remains unclear how relational cognition is implemented in the brain due in part to a lack of hypotheses and predictions at the levels of collective neural activity and behavior. Here we discovered, analyzed, and experimentally tested neural networks (NNs) that perform transitive inference (TI), a classic relational task (if A > B and B > C, then A > C). We found NNs that (i) generalized perfectly, despite lacking overt transitive structure prior to training, (ii) generalized when the task required working memory (WM), a capacity thought to be essential to inference in the brain, (iii) emergently expressed behaviors long observed in living subjects, in addition to a novel order-dependent behavior, and (iv) expressed different task solutions yielding alternative behavioral and neural predictions. Further, in a large-scale experiment, we found that human subjects performing WM-based TI showed behavior inconsistent with a class of NNs that characteristically expressed an intuitive task solution. These findings provide neural insights into a classical relational ability, with wider implications for how the brain realizes relational cognition.
The human brain is distinguished by its ability to perform explicit logical reasoning like transitive inference. This study investigated the functional role of the inferior parietal cortex in transitive inference with functional MRI. Participants viewed premises describing abstract relations among items. They accurately recalled the relationship between old pairs of items, effectively inferred the relationship between new pairs of items, and discriminated between true and false relationships for new pairs. First, the inferior parietal cortex, but not the hippocampus or lateral prefrontal cortex, was associated with transitive inference. The inferior parietal activity and functional connectivity were modulated by inference (new versus old pairs) and discrimination (true versus false pairs). Moreover, the new/old and true/false pairs were decodable from the inferior parietal representation. Second, the inferior parietal cortex represented an integrated relational structure (ordered and directed series). The inferior parietal activity was modulated by serial position (larger end versus center pairs). The inferior parietal representation was modulated by symbolic distance (adjacent versus distant pairs) and direction (preceding versus following pairs). It suggests that the inferior parietal cortex may flexibly integrate observed relations into a relational structure and use the relational structure to infer unobserved relations and discriminate between true and false relations.
Aging comes with declines in episodic memory. Memory decline is accompanied by structural and functional alterations within key brain regions, including the hippocampus and lateral prefrontal cortex, as well as their affiliated default and frontoparietal control networks. Most studies have examined how structural or functional differences relate to memory independently. Here we implemented a multimodal, multivariate approach to investigate how interactions between individual differences in structural integrity and functional connectivity relate to episodic memory performance in healthy aging. In a sample of younger ( N = 111; mean age, 22.11 years) and older ( N = 78; mean age, 67.29 years) adults, we analyzed structural MRI and multiecho resting-state fMRI data. Participants completed measures of list recall (free recall of words from a list), associative memory (cued recall of paired words), and source memory (cued recall of the trial type, or the sensory modality in which a word was presented). The findings revealed that greater structural integrity of the posterior hippocampus and middle frontal gyrus were linked with a pattern of increased within-network connectivity, which together were related to better associative and source memory in older adulthood. Critically, older adults displayed better memory performance in the context of decreased hippocampal volumes when structural differences were accompanied by functional reorganization. This functional reorganization was characterized by a pruning of connections between the hippocampus and the limbic and frontoparietal control networks. Our work provides insight into the neural mechanisms that underlie age-related compensation, revealing that the functional architecture associated with better memory performance in healthy aging is tied to the structural integrity of the hippocampus and prefrontal cortex.
Most task spaces require a hierarchical structure, where decisions on one level are contingent on previous decisions made on one or more higher levels. While it is a truism that increasing the number of hierarchical levels makes it harder to solve a given task, the exact nature of this "number-of-levels" effect is not clear. On the one hand, processing costs might be strictly "local," incurred only when higher-level settings need to be updated, while otherwise lower-level decisions are insulated from the presence of higher-level settings (local updating costs with ballistic control). On the other hand, maintaining and integrating more complex hierarchical structures could require overall greater representational resources, negatively affecting each individual decision within the represented task space (global integration/maintenance costs). Further, navigation through hierarchical structures can be guided either through prompts in the environment (cue-based), or through sequential plans (serial-order based), with potentially distinct maintenance and updating demands. In two experiments, we assessed performance as a function of hierarchical level and format (serial-order vs. cue-based). Model comparisons showed that the pattern of costs in the serial-order format was consistent with a global maintenance/integration account. In contrast, in the cue-based format, costs arose at updating points and when one additional relevant level beyond the current decision was relevant, while additional levels produced no further costs. This overall constellation of costs can be explained by assuming that each decision requires checking the immediately relevant higher-level context for that decision. For cue-based control, this context involves the "next-level-up" rule, whereas in the serial-order format, each trial requires updating of the current position within the sequence, which in turn requires integration across all relevant hierarchical levels.
Humans learn internal models of the world that support planning and generalization in complex environments. Yet it remains unclear how such internal models are represented and learned in the brain. We approach this question using theory-based reinforcement learning, a strong form of model-based reinforcement learning in which the model is a kind of intuitive theory. We analyzed fMRI data from human participants learning to play Atari-style games. We found evidence of theory representations in prefrontal cortex and of theory updating in prefrontal cortex, occipital cortex, and fusiform gyrus. Theory updates coincided with transient strengthening of theory representations. Effective connectivity during theory updating suggests that information flows from prefrontal theory-coding regions to posterior theory-updating regions. Together, our results are consistent with a neural architecture in which top-down theory representations originating in prefrontal regions shape sensory predictions in visual areas, where factored theory prediction errors are computed and trigger bottom-up updates of the theory.
Despite advances in neuroscience, the mechanisms by which human brain resolve optical image formation through relational reasoning remain unclear, particularly its relationships with task difficulty. Therefore, this study explores the underlying brain dynamics involved in optical image formation tasks at various difficulty levels, including those with a single convex lens and a single mirror. Compared to single convex lens relational reasoning with high task difficulty, the single mirror relational reasoning exhibited significantly higher response accuracy and shorter latency. As compared to single mirror tasks, single convex tasks exhibited greater frontal midline theta augmentation and right parietal alpha suppression during phase I and earlier phase II, and augmentation of frontal midline theta, right parietal-occipital alpha, and left mu alpha suppression during late phase II. Moreover, the frontal midline theta power in late phase II predicts the likelihood of solving single convex tasks the best, while the parietal alpha power in phase I is most predictive. In addition, frontal midline theta power exhibited stronger synchronization with right parietal alpha, right occipital alpha, and mu alpha power when solving single convex tasks than single mirror tasks. In summary, having stronger brain dynamics and coordination is vital for achieving optical image formation with greater difficulty.
Related research has shown that collaborating with Intelligent Virtual Agents (IVAs) embodied in Augmented Reality (AR) or Virtual Reality (VR) can improve task performance and reduce task load. Human cognition and behaviors are controlled by brain activities, which can be captured and reflected by Electroencephalogram (EEG) signals. However, little research has been done to understand users’ cognition and behaviors using EEG while interacting with IVAs embodied in AR and VR environments. In this paper, we investigate the impact of the virtual agent’s multimodal communication in VR on users’ EEG signals as measured by alpha band power. We develop a desert survival game where the participants make decisions collaboratively with the virtual agent in VR. We evaluate three different communication methods based on a within-subject pilot study: 1) a Voice-only Agent, 2) an Embodied Agent with speech and gaze, and 3) a Gestural Agent with a gesture pointing at the object while talking about it. No significant difference was found in the EEG alpha band power. However, the alpha band ERD/ERS calculated around the moment when the virtual agent started speaking indicated providing a virtual body for the sudden speech could avoid the abrupt attentional demand when the agent started speaking. Moreover, a sudden gesture coupled with the speech induced more attentional demands, even though the speech was matched with the virtual body. This work is the first to explore the impact of IVAs’ interaction methods in VR on users’ brain activity, and our findings contribute to the IVAs interaction design.
Did the boy bite the cat or was it the other way around? When processing a sentence with several objects, one has to establish ‘who did what to whom’. When a sentence cannot be interpreted by recalling an image from memory, we rely on the special type of voluntary constructive imagination called Prefrontal synthesis (PFS). PFS is defined as the ability to juxtapose mental visuospatial objects at will. We hypothesised that PFS has fundamental importance for language acquisition. To test this hypothesis, we designed a PFS-targeting intervention and administered it to 6,454 children with language deficiencies (age 2 to 12 years). The results from the three-year-long study demonstrated that children who engaged with the PFS intervention showed 2.2-fold improvement in combinatorial language comprehension compared to children with similar initial evaluations. These findings suggest that language can be improved by training the PFS and exposes the importance of the visuospatial component of language. This manuscript reflects on the experimental findings from the point of view of human language evolution. When used as a proxy for evolutionary language acquisition, the study results suggest a dichotomy of language evolution, with its speech component and its visuospatial component developing in parallel. The study highlights the radical idea that evolutionary acquisition of language was driven primarily by improvements of voluntary imagination rather than by improvements in the speech apparatus.
Analogical reasoning is a core facet of higher cognition in humans. Creating analogies as we navigate the environment helps us learn. Analogies involve reframing novel encounters using knowledge of familiar, relationally similar contexts stored in memory. When an analogy links a novel encounter with a familiar context, it can aid in problem solving. Reasoning by analogy is a complex process that is mediated by multiple brain regions and mechanisms. Several advanced computational architectures have been developed to simulate how these brain processes give rise to analogical reasoning, like the "learning with inferences and schema abstraction" architecture and the Companion architecture. To obtain this power to simulate human reasoning, theses architectures assume that various computational "subprocesses" comprise analogical reasoning, such as analogical access, mapping, inference, and schema induction, consistent with the structure-mapping framework proposed decades ago. However, little is known about how these subprocesses relate to actual brain processes. While some work in neuroscience has linked analogical reasoning to regions of brain prefrontal cortex, more research is needed to investigate the wide array of specific neural hypotheses generated by the computational architectures. In the current article, we review the association between historically important computational architectures of analogy and empirical studies in neuroscience. In particular, we focus on evidence for a frontoparietal brain network underlying analogical reasoning and the degree to which brain mechanisms mirror the computational subprocesses. We also offer a general vantage on the current- and future-states of neuroscience research in this domain and provide some recommendations for future neuroimaging studies.
Human memory is prone to memory errors and distortion. Evidence from studies on cognitive functions in bilinguals indicates that they might be prone to different types of memory errors compared to monolinguals; however, the effect of language in false memories is still understudied. Source monitoring processes required for proper memory functioning, presumably, rely on inhibitory control, which is also heavily utilized by bilinguals. Moreover, it is suggested that thinking in a second language leads to more systematic and deliberate reasoning. All these results lead to expect that bilinguals are more analytical when processing information in their second language overcoming some memory errors depending on the language of information. To test this hypothesis, we run a classical misinformation experiment with an explicit source monitoring task with a sample of Russian–English bilinguals. The language of the misinformation presentation did not affect the degree of the misinformation effect between the Russian and English languages. Source monitoring demonstrated an overall higher accuracy for attributions to the English source over the Russian source. Furthermore, analysis on incorrect source attributions showed that when participants misattributed the sources of false information (English or Russian narrative), they favored the Russian source over the not presented condition. Taken together, these results imply that high proficiency in the second language does not affect misinformation and that information processing and memory monitoring in bilinguals can differ depending on the language of the information, which seems to lead to some memory errors and not others.
Analogical reasoning, e.g. inferring that teacher is to chalk as mechanic is to wrench, plays a fundamental role in human cognition. However, whether brain activity patterns of individual words are encoded in a way that could facilitate analogical reasoning is unclear. Recent advances in computational linguistics have shown that information about analogical problems can be accessed by simple addition and subtraction of word embeddings (e.g., wrench = mechanic + chalk – teacher). Critically, this property emerges in artificial neural networks that were not trained to produce analogies but instead were trained to produce general-purpose semantic representations. Here, we test whether such emergent property can be observed in representations in human brains, as well as in artificial neural networks. fMRI activation patterns were recorded while participants viewed isolated words but did not perform analogical reasoning tasks. Analogy relations were constructed from word pairs that were categorically or thematically related, and we tested whether the predicted fMRI pattern calculated with simple arithmetic was more correlated with the pattern of the target word than other words. We observed that the predicted fMRI patterns contain information not only about the identity of the target word but also its category and theme (e.g., teaching-related). In summary, this study demonstrated that information about analogy questions can be reliably accessed with the addition and subtraction of fMRI patterns, and that, similar to word embeddings, this property holds for task-general patterns elicited when participants were not explicitly told to perform analogical reasoning.
This textbook is a systematic and straightforward introduction to the interdisciplinary study of creativity. Each chapter is written by one or more of the world's experts and features the latest research developments, alongside foundational knowledge. Each chapter also includes an introduction, key terms, and critical thought questions to promote active learning. Topics and authors have been selected to represent a comprehensive and balanced overview. Any reader will come away with a deeper understanding of how creativity is studied – and how they can improve their own creativity.
In their 2016 Psych Science article, Matthews, Lewis and Hubbard leveled a challenge against the prevailing theory that fractions – as opposed to whole numbers – are incompatible with humans’ primitive nonsymbolic number sense. Their ratio processing system (RPS) account holds that humans possess a primitive system that confers the ability to process nonysmbolic ratio magnitudes (Jacob, Vallentin, & Nieder, 2012; Lewis, Matthews, & Hubbard, 2016). Perhaps the most striking finding from Matthews et al. was that ratio processing ability predicted symbolic fractions knowledge and algebraic competence.
The purpose of the current study was to replicate Matthews et al.’s novel results and to extend the study by including a control measure of fluid intelligence and an additional nonsymbolic magnitude format as predictors of multiple symbolic math outcomes. Ninety-nine college students completed three comparison tasks deciding which of two nonsymbolic ratios was numerically larger along with three simple magnitude comparison tasks in corresponding formats that served as controls. The formats included were lines, circles, and dots.
We found that RPS acuity predicted fractions knowledge for three university math placement exam subtests when controlling for simple magnitude acuities and inhibitory control. However, this predictive power of the RPS measure appeared to stem primarily from acuity of the line-ratio format, and that predictive power was attenuated with the inclusion of fluid intelligence. These findings may help refine theories positing the RPS as a domain-specific foundation for building fractional knowledge and related higher mathematics.
The opening line in Aristotle’s Metaphysics asserts that “humans desire to understand”, establishing understanding as the defining characteristic of the human mind and human species. What is understanding and what role does it play in cognition, what advantages does it confer, what brain mechanisms are involved? The Webster’s Dictionary defines understanding as “apprehending general relations in a multitude of particulars.” A proposal discussed in this chapter defines understanding as a form of active inference in self-adaptive systems seeking to expand their inference domains while minimizing metabolic costs incurred in the expansions. Under the same proposal, understanding is viewed as an advanced adaptive mechanism involving self-directed construction of mental models establishing relations between domain entities. Understanding complements learning and serves to overcome the inertia of learned behavior when conditions are unfamiliar or deviate from those experienced in the past. While learning is common across all animals, understanding is unique to the human species. This chapter will unpack these notions, focusing on different facets of understanding. The proposal formulates hypotheses regarding the underlying neuronal mechanisms, attempting to assess their plausibility and reconcile them with the recent ideas and findings concerning brain functional architecture.
The prefrontal cortex (PFC) is critical for elaborating and controlling goal-directed actions. It may be seen as a buffer space between perception and action where past experiences and prospective thoughts can be mentally represented and manipulated, allowing for decision-making and action selection based on mental deliberation. Fundamental processes such as attention, working memory, inhibition, set-shifting, motivation, and behavioral control mediate this general principle of functioning. The PFC also allows for higher-order functions that are particularly developed in humans, such as planning, abstraction, reasoning, creativity, and social cognition. In this second chapter, we detail the body of evidence that supports the involvement of the PFC in higher-order functions and how these functions are altered and assessed in neurological conditions affecting the PFC.
There is an overwhelming archeological and genetic evidence that modern speech apparatus was acquired by hominins by 600,000 years ago. On the other hand, artifacts signifying modern imagination, such as (1) composite figurative arts, (2) bone needles with an eye, (3) construction of dwellings, and (4) elaborate burials arose not earlier than 70,000 years ago. It remains unclear (1) why there was a long gap between acquisition of modern speech apparatus and modern imagination, (2) what triggered the acquisition of modern imagination 70,000 years ago, and (3) what role language might have played in this process. Our research into evolutionary origin of modern imagination has been driven by the observation of a temporal limit for the development of a particular component of imagination. Modern children not exposed to recursive language in early childhood never acquire the type of active constructive imagination called Prefrontal Synthesis (PFS). Unlike vocabulary and grammar acquisition, which can be learned throughout one’s lifetime, there is a strong critical period for the development of PFS and individuals not exposed to recursive language in early childhood can never acquire PFS as adults. Their language will always lack understanding of spatial prepositions and recursion that depend on the PFS ability. In a similar manner, early hominins would not have been able to learn recursive language as adults and, therefore, would not be able to teach recursive language to their children. Thus, the existence of a strong critical period for PFS acquisition creates an evolutionary barrier for behavioral modernity. An evolutionary mathematical model suggests that a synergistic confluence of three events (1) a genetic mutation that extended the critical period by slowing down the prefrontal cortex development simultaneously in two or more children, (2) invention of recursive elements of language, such as spatial prepositions, by these children and (3) their dialogic communications using these recursive elements, resulted in concurrent conversion of a non-recursive communication system of their parents to recursive language and acquisition of PFS around 70,000 years ago.
Several computational models suggest that the hippocampal complex plays a key role in the establishment of new memories, but over time the storage of such memories becomes independent of this region. In support of such models, the authors demonstrate that patients with semantic dementia, who have relative sparing of the hippocampal complex, show a pattern of preserved recent memories and impaired distant memories. In a group study that used the Autobiographical Memory Interview, amnesic patients with Alzheimer's disease showed the more typical temporally graded loss (poor recall of recent memories), whereas patients with semantic dementia showed the reverse pattern. In a single-case study, using the Galton-Crovitz test, a patient with semantic dementia was significantly better at producing autobiographical memories from the most recent 5 years. By contrast, controls provided similarly detailed memories across all time periods back to childhood.
Three chimpanzees with a history of conditional and numeric token training spontaneously matched relations between relations under conditions of nondifferential reinforcement. Heretofore, this conceptual ability was demonstrated only in language-trained chimpanzees. The performance levels of the language-naive animals in this study, however, were equivalent to those of a 4th animal—Sarah—whose history included language training and analogical problem solving. There was no evidence that associative factors mediated successful performance in any of the animals. Prior claims of a profound disparity between language-trained and language-naive chimpanzees apparently can be attributed to prior experience with arbitrary tokens consistently associated with abstract relations and not language per se.
Chunking by pigeons was demonstrated by comparing performance on different types of lists. Experiment 1 showed that Groups II and IV (who learned lists in which colors and achromatic geometric forms were segregated: A → B → C → D′ → E′ and A → B → C → D → E′, respectively) executed lists more rapidly than did Group I (who learned a homogeneous list of colors: A → B → C → D → E) or Groups II and III (who learned lists consisting of unsegregated colors and forms: A → B′ → C → D′ → E and A → B → C′ → D → E, respectively). Experiment 2 showed that Groups II and IV tolerated interruptions of the list better than did Groups I, III, and V. The accuracy of responding of Groups I, III, and V decreased as a function of the duration of the interruption and the point in the sequence at which it occurred. The performance of Group II was unaffected by interruptions; Group IV was minimally affected. These results indicate that Groups II and IV organized their lists as ordered chunks.
Investigated developmental changes in performance on cognitive and memory tests purported to reflect frontal lobe functioning in 52 normal children and adolescents, including 17 children aged 7–8 yrs, 17 children aged 9–12 yrs, and 18 adolescents aged 13–15 yrs. The tests included measures of verbal and design fluency, memory, problem solving and concept formation, and response modulation. With the exception of Delayed Alternation (a problem solving task), developmental changes were confirmed on all of the tests. Several measures of cognition and organization of memory showed major gains in adolescents as compared with 9–12 yr olds. A principal components analysis revealed a 3-factor solution, including a semantic association/concept formation factor, a freedom from perseveration factor, and a planning/strategy factor. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The neuroanatomical region that has most prominently altered with the advancing cognitive competency of the human is the prefrontal cortex, particularly the rostral extreme. While the prefrontal cortex does not appear to contain the neural networks that carry out cognitive activities, the management of these high level manipulations, so uniquely characteristic of the human, appears dependent upon the prefrontal cortex.
Recent research suggests 2 principal processes are assessed in many neuropsychological tests of prefrontal functioning: the ability to keep transient information on-line (working memory) and the ability to inhibit prepotent, but incorrect, responses. The current studies examined the hypothesis that taxing working memory beyond some threshold can result in decreased inhibition, resembling the errors committed by patients with prefrontal dysfunctions. Across 3 studies, 70 nonpatient subjects were tested on the antisaccade (AS) task (D. Guitton et al, 1985)—a task sensitive to inhibitory deficits. Subjects were required to look in the opposite direction of a flashed cue, inhibiting the reflexive tendency to saccade to the cue. Subjects performed concurrent tasks that varied working-memory load. The results indicated that conditions with the highest working-memory load produced inhibitory errors comparable to patients with prefrontal dysfunctions. The findings are discussed in terms of the interaction between working memory and the inhibition of prepotent responses. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This article describes an integrated theory of analogical access and mapping, instantiated in a computational model called
LISA (Learning and Inference with Schemas and Analogies). LISA represents predicates and objects as distributed patterns of activation that are dynamically bound into propositional structures, thereby achieving both the flexibility of a connectionist system and the structure sensitivity of a symbolic system. The model treats access and mapping as types of guided pattern classification, differing only in that mapping is augmented by a capacity to learn new correspondences. The resulting model simulates a wide range of empirical findings concerning human analogical access and mapping. LISA also has a number of inherent limitations, including capacity limits, that arise in human reasoning and suggests a specific computational account of these limitations. Extensions of this approach also account for analogical inference and schema induction. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Investigated the information-processing demands of transitive inference problems with a probe reaction-time (RT) secondary task. Two versions of a primary task were used: the standard 3-term inference problem and a matched verification task that did not require premise integration. In the 1st 2 experiments, with a total of 40 undergraduates, the premise and target-matching components of the primary task were presented sequentially. Results indicate that for the transitive inference task, probe RT was especially slow when the probe occurred during the 2nd premise phase, but no such effect was found with the matched verification task. This implies that premise integration imposed an increased load on processing resources. A 3rd experiment with 10 undergraduates showed that the processing demand associated with premise integration also occurred with simultaneous presentation. Other variations in problem form (e.g., premise markedness, negation, and pivot search) did not influence probe RT, although they are known to affect solution time. It is concluded that solution time and measures of processing load may be independent. (39 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Five experiments investigated transitive inference by chimpanzees. In the initial experiment, 3 5–6 yr old female chimpanzees (Sadie, Luvie, and Jessie) received training with pairs of adjacent stimuli from a 5-stimulus series—E, D, C, B, A—each having a successively smaller amount of food. When the Ss were tested on the novel nonadjacent pair, BD, Jessie chose inconsistently between B and D, Luvie chose inconsistently in an initial test but chose D consistently in a 2nd test, and Sadie chose D consistently. In Exp IB, Sadie received training with 5 adjacent pairs, then during a test with novel nonadjacent pairs, BE and CE, provided further evidence of transitive inference by choosing E consistently. Exps IIA and IIB examined the effects on nonadjacent pair performance of manipulation of the linear order of stimuli in a series based on relative food values. The presence of a low and a high end point in the series A and F, respectively, was crucial for transitive inference in the BD, BE, and CE pairs. Exp III used a double-blind procedure to demonstrate that elimination of social cues by the trainer did not affect Sadie's test performance on nonadjacent pairs. Data suggests that language is not a necessary condition for transitive inference, and that integration theories better account for it than do nonintegration theories. (15 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
An individual has a theory of mind if he imputes mental states to himself and others. A system of inferences of this kind is properly viewed as a theory because such states are not directly observable, and the system can be used to make predictions about the behavior of others. As to the mental states the chimpanzee may infer, consider those inferred by our own species, for example, purpose or intention, as well as knowledge, belief, thinking, doubt, guessing, pretending, liking, and so forth. To determine whether or not the chimpanzee infers states of this kind, we showed an adult chimpanzee a series of videotaped scenes of a human actor struggling with a variety of problems. Some problems were simple, involving inaccessible food – bananas vertically or horizontally out of reach, behind a box, and so forth – as in the original Kohler problems; others were more complex, involving an actor unable to extricate himself from a locked cage, shivering because of a malfunctioning heater, or unable to play a phonograph because it was unplugged. With each videotape the chimpanzee was given several photographs, one a solution to the problem, such as a stick for the inaccessible bananas, a key for the locked up actor, a lit wick for the malfunctioning heater. The chimpanzee's consistent choice of the correct photographs can be understood by assuming that the animal recognized the videotape as representing a problem, understood the actor's purpose, and chose alternatives compatible with that purpose.
We report five patients with a stereotyped clinical syndrome characterized by fluent dysphasia with severe anomia, reduced vocabulary and prominent impairment of single-word comprehension, progressing to a stage of virtually complete dissolution of the semantic components of language. A marked reduction in the ability to generate exemplars from restricted semantic categories (e.g. animals, vehicles, etc.) was a consistent and early feature. Tests of semantic memory demonstrated a radically impoverished knowledge about a range of living and man-made items. In contrast, phonology and grammar of spoken language were largely preserved, as was comprehension of complex syntactic commands. Reading showed a pattern of surface dyslexia. Autobiographical and day-to-day (episodic) memory were relatively retained. Non-verbal memory, perceptual and visuospatial abilities were also strikingly preserved. In some cases, behavioural and personality changes may supervene; one patient developed features of the Kluver-Bucy Syndrome. Radiological investigations have shown marked focal temporal atrophy in all five patients, and functional imaging by single positron emission tomography and positron emission tomography (one case) have implicated the dominant temporal lobe in all five. In the older literature, such cases would have been subsumed under the rubric of Pick's disease. Others have been included in series with progressive aphasia. We propose the term semantic dementia, first coined by Snowden et al. (1989), to designate this clinical syndrome.
The cognitive processes in a widely used, nonverbal test of analytic intelligence, the Raven Progressive Matrices Test (Raven, 1962), are analyzed in terms of which processes distinguish between higher scoring and lower scoring subjects and which processes are common to all subjects and all items on the test. The analysis is based on detailed performance characteristics, such as verbal protocols, eye-fixation patterns, and errors. The theory is expressed as a pair of computer simulation models that perform like the median or best college students in the sample. The processing characteristic common to all subjects is an incremental, reiterative strategy for encoding and inducing the regularities in each problem. The processes that distinguish among individuals are primarily the ability to induce abstract relations and the ability to dynamically manage a large set of problem-solving goals in working memory.
The frontal eye field (FEF) and superior colliculus (SC) are thought to form two parallel systems for generating saccadic eye movements. The SC is thought classically to mediate reflex-like orienting movements. Thus it can be hypothesized that the FEF exerts a higher level control on a visual grasp reflex. To test this hypothesis we have studied the saccades of patients who have had discrete unilateral removals of frontal lobe tissue for the relief of intractable epilepsy. The responses of these patients were compared to those of normal subjects and patients with unilateral temporal lobe removals. Two tasks were used. In the first task the subject was instructed to look in the direction of a visual cue that appeared unexpectedly 12 degrees to the left or right of a central fixation point (FP), in order to identify a patterned target that appeared 200 ms or more later. In the second "anti-saccade" task the subject was required to look not at the location of the cue but in the opposite direction, an equal distance from FP where after 200 ms or more the patterned target appeared. Three major observations have emerged from the present study. Most frontal patients, with lesions involving both the dorsolateral and mesial cortex had long term difficulties in suppressing disallowed glances to visual stimuli that suddenly appeared in peripheral vision. In such patients, saccades that were eventually directed away from the cue and towards the target were nearly always triggered by the appearance of the target itself irrespective of whether or not the "anti-saccade" was preceded by a disallowed glance. Those eye movements away from the cue were only rarely generated spontaneously across the blank screen during the cue-target time interval. The latency of these visually-triggered saccades was very short (80-140 ms) compared to that of the correct saccades (170-200 ms) to the cue when the cue and target were on the same side, thereby suggesting that the structures removed in these patients normally trigger saccades after considerable computations have already been performed. The results support the view that the frontal lobes, particularly the dorsolateral region which contains the FEF and possibly the supplementary motor area contribute to the generation of complex saccadic eye-movement behaviour. More specifically, they appear to aid in suppressing unwanted reflex-like oculomotor activity and in triggering the appropriate volitional movements when the goal for the movement is known but not yet visible.
The concept of working memory is central to theories of human cognition because working memory is essential to such human skills as language comprehension and deductive reasoning. Working memory is thought to be composed of two parts, a set of buffers that temporarily store information in either a phonological or visuospatial form, and a central executive responsible for various computations such as mental arithmetic. Although most data on working memory come from behavioural studies of normal and brain-injured humans, there is evidence about its physiological basis from invasive studies of monkeys. Here we report positron emission tomography (PET) studies of regional cerebral blood flow in normal humans that reveal activation in right-hemisphere prefrontal, occipital, parietal and premotor cortices accompanying spatial working memory processes. These results begin to uncover the circuitry of a working memory system in humans.
The cognitive and behavioral functions of the frontal lobes have been of great interest to neuroscientists, neurologists, psychologists and psychiatrists. Recent technical advances have made it possible to trace their neuroanatomical connections more precisely and to conduct evoked potential and neuroimaging studies in patients. This book presents a broad and authoritative synthesis of research progress in this field. It encompasses neuroanatomical studies; experiments involving temporal organization and working memory tasks in non-human primates; clinical studies of patients following frontal lobe excisions for intractable epilepsy; metabolic imaging in schizophrenia and affective disorder; neurobehavioral studies of patients with dementia, frontal lobe tumors, and head injuries; magnetic resonance imaging methods for studying human frontal lobe anatomy; theoretical approaches to describing frontal lobe functions; and rehabilitation of patients with frontal lobe damage including their core problem of diminished awareness. Written by a distinguished group of neuroscientists, psychologists and clinicians, Frontal Lobe Function and Dysfunction provides the best current source of information on this region of the brain and its role in cognition, behavior and clinical disorders.
Several computational models suggest that the hippocampal complex plays a key role in the establishment of new memories, but over time the storage of such memories becomes independent of this region. In support of such models, the authors demonstrate that patients with semantic dementia, who have relative sparing of the hippocampal complex, show a pattern of preserved recent memories and impaired distant memories. In a group study that used the Autobiographical Memory Interview, amnesic patients with Alzheimer's disease showed the more typical temporally graded loss (poor recall of recent memories), whereas patients with semantic dementia showed the reverse pattern. In a single-case study, using the Galton-Crovitz test, a patient with semantic dementia was significantly better at producing autobiographical memories from the most recent 5 years. By contrast, controls provided similarly detailed memories across all time periods back to childhood.
This article describes an integrated theory of analogical access and mapping, instantiated in a computational model called LISA (Learning and Inference with Schemas and Analogies). LISA represents predicates and objects as distributed patterns of activation that are dynamically bound into propositional structures, thereby achieving both the flexibility of a connectionist system and the structure sensitivity of a symbolic system. The model treats access and mapping as types of guided pattern classification, differing only in that mapping is augmented by a capacity to learn new correspondences. The resulting model simulates a wide range of empirical findings concerning human analogical access and mapping. LISA also has a number of inherent limitations, including capacity limits, that arise in human reasoning and suggests a specific computational account of these limitations. Extensions of this approach also account for analogical inference and schema induction.
Frontotemporal dementia is a dementia syndrome with diverse clinical characteristics. Based upon clinical parameters and single photon emission computed tomography, we identified 47 frontotemporal dementia subjects. In 10 of these 47 the primary site of brain dysfunction was anterior temporal and orbital-frontal with other frontal regions relatively spared. In this temporal lobe variant (TLV) of frontotemporal dementia, five of the subjects had more severe left-sided, and five had more right-sided, hypoperfusion. The clinical, neuropsychological and neuropsychiatric features of predominantly left-sided (LTLV) and right-sided (RTLV) TLV subjects are discussed and contrasted with more frontal presentations of frontotemporal dementia. In LTLV, aphasia was usually the first and most severe clinical abnormality RTLV patients presented with behavioural disorders characterized by irritability, impulsiveness, bizarre alterations in dress, limited and fixed ideas, decreased facial expression and increased visual alertness. These findings suggest that: (i) frontotemporal dementia is clinically heterogeneous with bitemporal and inferior frontal lobe dysfunction contributing to the clinical presentation; (ii) behavioural disturbance and aphasia are the most prominent features of predominantly temporal subtypes of frontotemporal dementia; (iii) the right and left anterior temporal regions may mediate different behavioural functions. The results of this study suggests that TLV offers a valuable source of information concerning the behavioural disorders seen with combined anterior temporal and inferior frontal lobe dysfunction.
The term working memory refers to a brain system that provides temporary storage and manipulation of the information necessary
for such complex cognitive tasks as language comprehension, learning, and reasoning. This definition has evolved from the
concept of a unitary short-term memory system. Working memory has been found to require the simultaneous storage and processing
of information. It can be divided into the following three subcomponents: (i) the central executive, which is assumed to be
an attentional-controlling system, is important in skills such as chess playing and is particularly susceptible to the effects
of Alzheimer's disease; and two slave systems, namely (ii) the visuospatial sketch pad, which manipulates visual images and
(iii) the phonological loop, which stores and rehearses speech-based information and is necessary for the acquisition of both
native and second-language vocabulary.
Rats were trained to discriminate between boxes covered with distinctive odors There were six stimulus odors, labeled A through F, and the problems learned formed the five premises A+B-, B+C-, C+D-, D+E-, and E+F-Combining the premises, the relative values of the stimuli were A > B > C > D > E > F In two experiments, linear arrangement groups learned these premises with Boxes A through F placed in a linear spatial sequence Nonlinear groups had boxes either randomly changed from one position to another (Experiment I) or placed in a circular arrangement (Experiment 2) Tests of transitive inference between the B and D stimult were carried out in an environment different from that in which premise training took place Only the groups trained with a linear arrangement of boxes showed evidence of transitive inference These findings offer support for a spatial coding hypothesis of transitive inference in animals
Sorting tasks, requiring the subject to respond selectively, first to one aspect of a situation and then to another, have traditionally been regarded as sensitive indicators of brain injury, but there has been little agreement concerning the effects of lesions in different areas of the brain on sorting behavior. Weigl,36 in 1927, found that braininjured patients performed more poorly than normal control subjects on a simple Color-Form sorting task, and he described a patient with bilateral frontal-lobe damage who had particular difficulty in shifting from one sorting principle to another. Goldstein,6 though rejecting any strict localization of intellectual function, also appears to stress the importance of the frontal lobes for spontaneous shifting, and this view has been further emphasized by such workers as Rylander29 and Halstead.9,10 Yet Teuber, Battersby, and Bender,34 studying men with penetrating missile wounds of the brain, found greater deficits on
describe our recent efforts devoted to analyzing the mechanisms employed by cebus monkeys when learning a serial order task / begins with a description of some important characteristics of the serial learning achieved by monkeys / the symbolic distance effect
an exercise in comparative cognition / try to show that although pigeons, like monkeys, can learn four- and five-item series to respectable levels of accuracy, they do so by quite different means
provide an illustration of the possibility of using results from relatively simple tasks to predict species' differences on more complex tasks / closes with some observations regarding the capacity of animals for processing serial pattern, a much more demanding task than dealing with serial order
associative transitivity in monkeys and pigeons / serial learning by pigeons and monkeys [five-item series performance: monkeys versus pigeons, implications for representational competence] / the monkey's knowledge of ordinal position [the associative chain theory, the single-wild-card experiment, the double-wild-card experiment] / a "symbolic" distance effect in monkeys [nature and relevance of the distance effect, the distance-effect experiment] / representation of ordinal information [associative versus inferential transitivity, knowledge or ordinal position in other species] / processing of serial pattern by animals [tonal pattern perception, reward-magnitude pattern perception] (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Discusses the influence of frontal lobe pathology (FLP) on amnesic disorders, drawing from human and animal neuropsychology and from cognitive psychology. Data are reviewed suggesting that amnesic patients with FLP exhibit special deficits on tasks in which performance depends on memory for spatiotemporal information (SI). Similar memory deficits in primates with FLP are discussed. Studies of normal humans suggest that memory for SI is accomplished automatically, and that SI memory deficits due to FLP are not the result of a generalized inability to engage in effortful, resource-demanding processing. It is concluded that amnesia associated with FLP is qualitatively different from amnesia in patients free of frontal signs and that FLP amnesia may thus provide unique insights into normal memory function. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Progressive matrices provide a nonverbal series of tests designed for measuring intelligence. The individual test was standardized on 660 children from Ipswich sampled from those born between 1924 and 1932. Subsequently, 1407 children from the same schools were given group tests. Score values are presented in the form of separate curves for the 5, 10, 25, 50, 75, 90, and 95th percentile points at half-yearly ages from 6 to 14 for the individual test and from 8 to 14 for the group test. The group test also includes percentile values for 3665 male adults. Results are compared with those of the revised Stanford Binet, but no correlations are stated. Case notes show that verbal fluency sometimes influences Binet IQ's, while not influencing matrix test scores. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
An analysis is presented of the relational information needed for premise integration in transitivity and simple serial order tasks. The tasks are divided into those where an ordering decision can be made by considering a single binary relation, and those where two binary relations must be considered. Four experiments are reported, the principal purpose of which is to manipulate the number of relations which must be considered in making decisions about the order of a small set of elements. In every test it was found that preschool children succeeded if decisions could be made by considering one relation, but failed if two relations had to be considered. Children over 5 almost always succeeded in both cases. It is concluded that preschool children cannot integrate relational premise information, and therefore cannot understand transitivity or serial order. This would impose limitations on their understanding of quantification and a number of other concepts. It is also suggested that the amount of information required to make a single decision may be an important factor determining cognitive complexity generally.
The study of patients with excisions from the frontal lobes has revealed specific cognitive deficits that appear against a background of normal functioning on a variety of perceptual and memory tasks, as well as on conventional intelligence tests. These deficits include a reduced output on fluency tasks, faulty regulation of behaviour of external cues, and impaired organization and monitoring of material to be remembered, and of the subject's own responses. Differential effects related to the side of the lesion are less consistently observed after frontal-than after temporal-lobe excisions. Such effects, when they do occur, may depend as much on the demands of the task as on the nature of the test material.
Twenty-six patients with unilateral or bilateral frontal lobe excisions were compared with age and IQ matched controls on a computerized battery of tests of spatial working memory and planning. A computerized test of spatial short term memory capacity revealed no significant impairment in the patients' ability to execute a given sequence of visuo-spatial moves. In contrast, a paradigm designed to assess spatial working memory capacity, revealed significant impairments in the patient group in both possible types of search errors. Furthermore, additional analysis showed that the frontal lobe patients were less efficient than controls in their usage of a strategy for improving performance on this test.Higher level planning was also investigated using a test based on the “Tower of London” problem [Shallice, T. Phil. Trans. R. Soc. Lond. B. 298, 199–209, 1982]. Patients with frontal lobe damage required more moves to complete the problems and a yoked motor control condition revealed that movement times were significantly increased in this group. Taking both of these factors into consideration, initial thinking (planning) time was unimpaired in the patient group although the thinking time subsequent to the first move was significantly prolonged. These data are compared to previous findings from patients with idiopathic Parkinson's disease and are discussed in terms of an impairment of higher cognitive functioning following frontal lobe damage.
Primate Cognition What can we learn from ape behaviour experiments about consciousness? Are apes a model for humans - are they conscious at our level at all? Not finally answered here but a good overview.
Between the ages of 1.5 and 5 years, and again between the ages of 5 and 10 years, a sequence of changes takes place in children's behavior which indicates a fundamental reorganization of their attentional, executive, and self-reflexive processes. In the present article, these changes are summarized, and evidence is adduced to support the claims (1) that these changes are frontally mediated and (2) that the underlying mechanism that generates them is similar to the one that generates the changes in EEG coherence during the same time period. The psychological model that has been hypothesized to explain the cycles of cognitive development (Case, 1992) is then compared to the physiological model that has been proposed to explain cycles of EEG development (Thatcher, 1992). It is shown that the two models are complementary, both in the underlying developmental sequence that they postulate and in the recursive dynamic they propose for producing movement through this sequence. A number of implications and predictions are derived, which follow from the proposition that the two sets of changes are different manifestations of a common underlying process.
A new sorting task designed to isolate and measure specific components of problem-solving ability was administered to four subject groups: patients with focal frontal lobe lesions, patients with both frontal dysfunction and amnesia (Korsakoff's syndrome), patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with frontal lobe lesions and patients with Korsakoff's syndrome were impaired on eight of the nine components of the task. The findings run counter to theories of a single or primary impairment in patients with frontal lobe dysfunction. Rather, the results suggest that a wide spectrum of deficits in abstract thinking, cognitive flexibility, and use of knowledge to regulate behavior contributes to the problem-solving impairment of these patients. Although the (non-Korsakoff) amnesic patients performed similarly to normal subjects on most measures, a finer analysis suggested that successful performance on this complex sorting task, in addition to being strongly dependent upon frontal lobe function, is mildly dependent upon memory function.
Chunking by pigeons was demonstrated by comparing performance on different types of lists. Experiment 1 showed that Groups II and IV (who learned lists in which colors and achromatic geometric forms were segregated: A----B----C----D'----E' and A----B----C----D----E', respectively) executed lists more rapidly than did Group I (who learned a homogeneous list of colors: A----B----C----D----E) or Groups II and III (who learned lists consisting of unsegregated colors and forms: A----B'----C----D'----E and A----B----C'----D----E, respectively). Experiment 2 showed that Groups II and IV tolerated interruptions of the list better than did Groups I, III, and V. The accuracy of responding of Groups I, III, and V decreased as a function of the duration of the interruption and the point in the sequence at which it occurred. The performance of Group II was unaffected by interruptions; Group IV was minimally affected. These results indicate that Groups II and IV organized their lists as ordered chunks.
Word fluency has been shown to be reduced by left frontal lesions. The hypothesis is formulated that this is due to the coincidence of lesions in the left hemisphere entailing verbal deficits generally, and frontal lesions producing deficits in the capacity to suppress habitual behaviour in order to adapt to unusual situations. A test of word fluency and a modification of the Stroop-Test were given to 118 patients with circumscribed cerebral lesions. In the Stroop-Test the patients were faced with an increasing degree of conflict between a usual (verbal) category and an unsual category. The deficit in word fluency after left frontal lesions reported earlier is confirmed. Moreover, with increasing conflict between two categories in the Stroop-Test, left frontal lesions produce an increasing performance deficit as compared with lesions localized elsewhere in the brain. Finally, the correlations between performance in word fluency and in the Stroop-Test are highest in left frontal patients. These results corroborate the hypothesis of the role of the frontal lobe in the adaptation of behaviour to unsual situations, the left frontal lobe being of fundamental importance when verbal factors are involved.
The category theory concept of a commutative diagram is used to construct a model of the way in which symbolic processes are applied to problem solving. The model provides for a relationship between symbolic processes and the problem which depends on structural isomorphism and consistency, but is independent of similarity between symbol elements and problem elements. It is then shown that several different levels of thought can be distinguished within the basic model. More information is needed to assign symbolic processes to a problem in a consistent way with higher-level thought processes than with lower-level processes. These information-processing requirements permit the approximate age of mastery of each level to be predicted, thereby offering an alternate theory of cognitive developmental stages. Two experiments designed to test the theory are reported.
Working memory refers to a system for temporary storage and manipulation of information in the brain, a function critical for a wide range of cognitive operations. It has been proposed that working memory includes a central executive system (CES) to control attention and information flow to and from verbal and spatial short-term memory buffers. Although the prefrontal cortex is activated during both verbal and spatial passive working memory tasks, the brain regions involved in the CES component of working memory have not been identified. We have used functional magnetic resonance imaging (fMRI) to examine brain activation during the concurrent performance of two tasks, which is expected to engage the CES. Activation of the prefrontal cortex was observed when both tasks are performed together, but not when they are performed separately. These results support the view that the prefrontal cortex is involved in human working memory.
Generally positive correlations between different ability tests provide the evidence for a factor of "general intelligence" or Spearman's g. Though a possible neural substrate for g is suggested by executive impairments following frontal lobe lesions, preserved IQs in some frontal patients have been taken as strong evidence against this interpretation. We show that such results depend on how g is measured. Patients with superior IQs on the most clinically popular test--the Wechsler Adult Intelligence Scale--show impairments of 20-60 points on conventionally measured fluid intelligence or novel problem solving. On psychometric grounds, it is fluid intelligence that is most closely related to Spearman's g. The data suggest that g may in large part be a reflection of frontal functions.
We report a formal model of transitive inference based on protocols from experiments on squirrel monkeys solving the 5-term series problem (McGonigle & Chalmers, 1977, 1992). These studies generate databases featuring transitive choice, task transfer (where at first a significant decrement is observed, and later substantial improvement without explicit training), and, finally, a Symbolic Distance Effect (SDE) based on decision-time data. Using a rule-based (production) system, we first established rule stacks at the group, then at the individual level, on the basis of triadic transfer performance first recorded in the McGonigle and Chalmers (1977) study. The models for each subject then accommodated data from the more intensive, later study with the same subjects (McGonigle & Chalmers, 1992). We found the initial model capable of dealing with all choice and reaction-time phenomena reported thus far, with only small changes in a rule search procedure. In common with an independent assay by McGonigle and Chalmers (1992), our model-based reassessment of decision times indicates that a major source of reaction time variation is item prominence in the rule stack rather than interitem (ordinal) distance per se.
The neuropathology of frontal lobe degeneration of non-Alzheimer type was reevaluated on the basis of a new material of 13 cases against the background of experiences from earlier published 16 cases. The salient neuropathological feature was an unspecific neuronal degeneration of superficial cortical layers of the frontal and to some extent the temporal lobes without markers for Alzheimer's, Pick's or Lewy body diseases and there were no indications so far of a prion etiology. The consistency of histopathological features are taken to indicate a disease entity, also identified by other authors. It is tentatively grouped together with progressive and aphasic dementia, similar cases in the literature and possibly also Pick's disease and ALS with dementia.