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Cognitive precedence for local information in hierarchical stimulus processing by pigeons
Abstract
Four experiments investigated the processing of hierarchical stimuli by pigeons. Using a 4 alternative divided-attention task, 4 pigeons were food-reinforced for accurately identifying letters arranged as either hierarchical global- or local-relevant stimuli or as size-matched filled stimuli. Experiment 1 found that task acquisition was faster with local-relevant than global-relevant stimuli. This difference was not due to letter size. Experiment 2 demonstrated successful transfer to a novel irrelevant letter configuration. Experiments 3 and 4 tested pigeons' responses to conflict probe stimuli composed of equally discriminable relevant letters at each level. These tests revealed that all of the pigeons showed a cognitive precedence for local information early in processing, with the pigeons using different cues to initiate the processing of global information. This local advantage contrasts with previously reported results for humans and pigeons but is similar to that reported for nonhuman primates. Alternatives attempting to reconcile these contrasting comparative results are considered.
... The attentional scope test has been adapted for use in non-human species to evaluate differences in visual processing across animal taxa, including monkeys (22), dogs (23), splitfin fish (24), domestic chicks (25), pigeons (26) and honeybees (27). The methodology involves training animals to select a rewarded image and to avoid selecting an unrewarded or punished image. ...
... Dairy cows in our study were more likely to approach the local image, although it must be noted that approach responses to both global and local images were low. Other studies have also found that animals tend to show a local bias in similar tasks, including in domestic chicks (25), pigeons (26), dogs (29) and several non-human primates (37,38). A local bias may occur if animals have difficulty with processing the overall global arrangement of shapes. ...
... A local bias may occur if animals have difficulty with processing the overall global arrangement of shapes. For instance, this probably requires first identifying the smaller local elements and visually connecting them to form the overall global shape matching the local element (26,39). We verified that cows were able to correctly distinguish the single local elements of the positive and negative images, but we did not present a test for the global elements [see Chiandetti et al. (25) for an example, although this introduces solid lines that have never been viewed before]. ...
A positive mood in humans tends to broaden attentional scope while negative mood narrows it. A similar effect may be present in non-human animals; therefore, attentional scope may be a novel method to assess emotional states in livestock. In this proof-of-concept exploratory study, we examined the attentional scope of dairy cows housed with their calves either full-time, part-time (during daytime only), or with no calf contact (enrolled n = 10 each). Housing conditions were previously verified to induce differences in positive and negative emotional state, where part-time was considered more negative. Cows were trained to approach or avoid hierarchical images on a screen that were consistent in local and global elements (i.e., 13 small circles or crosses arranged in an overall circle or cross). After discrimination learning (>80% correct, over two consecutive days), 14 cows proceeded to test (n = 6 each full-and part-time; n = 2 no-contact, not analyzed). Test images showed inconsistent combinations of global and local elements (i.e., the overall global shape differs from the smaller local elements, such as a global circle composed of smaller local crosses and vice versa). Over two test days, approach responses to global and local images (each presented four times) were recorded. All cows were more likely to approach the local than the global image, especially part-time cows who never approached the global image; this may reflect a narrowed attentional scope in these cows. Full-time cows approached images more often than part-time cows, but overall response rates to global and local images were low, making specific conclusions regarding attentional scope difficult. Different housing conditions have potential to affect attentional scope, and possibly emotional state, of dairy cows, but statistical comparison to no-contact treatment was not possible. Cortisol concentration did not affect responses to images; thus arousal due to treatment or test conditions could not explain test performance. Further work with refined methodology and a larger sample size is required to validate the reliability of attentional scope as an assessment method of emotional state in cattle. Beyond this, the attentional scope test revealed how cattle may process, learn and respond to different visual hierarchical images, which further our understanding of cognitive and visual processes in cattle.
... What might these observations mean with respect to pigeons' visual behavior? When pigeons scrutinize nearby images in an operant chamber using the red field, they engage the tectofugal system, where higher stages (such as MVL) are less prone to global processing than regions in the primate ventral stream (Cavoto and Cook, 2001;Cook and Hagmann, 2012;Cook et al., 2015;Murphy et al., 2015). The primary ecological function of the red field is mainly for the detection of grain against a textured surface ( Figure 1B) to guide bill strikes (Goodale, 1983;Delius and Delius, 2019). ...
Non-human animals tend to solve behavioral tasks using local information. Pigeons are particularly biased toward using the local features of stimuli to guide behavior in small-scale environments. When behavioral tasks are performed in large-scale environments, pigeons are much better global processors of information. The local and global strategies are mediated by two different fovea in the pigeon retina that are associated with the tectofugal and thalamofugal pathways. We discuss the neural mechanisms of pigeons’ bias for local information within the tectofugal pathway, which terminates at an intermediate stage of extracting shape complexity. We also review the evidence suggesting that the thalamofugal pathway participates in global processing in pigeons and is primarily engaged in constructing a spatial representation of the environment in conjunction with the hippocampus.
... For example, density is not visible at the level of the single element, but it emerges when we consider the various elements as a group (Table 1). Humans and other vertebrates generally use global processing for perceiving the world, that is, the tendency to process the overall images of a scene rather than a collection of the separate features which form it [52][53][54]; (but see [55,56]). In a few studies, Avarguès-Weber et al. investigated whether honeybees prioritize global or local information by setting a scene with these two levels in competition [15,46]. ...
For two centuries, visual illusions have attracted the attention of neurobiologists and com- parative psychologists, given the possibility of investigating the complexity of perceptual mechanisms by using relatively simple patterns. Animal models, such as primates, birds, and fish, have played a crucial role in understanding the physiological circuits involved in the susceptibility of visual illusions. However, the comprehension of such mechanisms is still a matter of debate. Despite their different neural architectures, recent studies have shown that some arthropods, primarily Hymenoptera and Diptera, experience illusions similar to those humans do, suggesting that perceptual mechanisms are evolutionarily conserved among species. Here, we review the current state of illusory perception in bees. First, we introduce bees’ visual system and speculate which areas might make them susceptible to illusory scenes. Second, we review the current state of knowledge on misperception in bees (Apidae), focusing on the visual stimuli used in the literature. Finally, we discuss important aspects to be considered before claiming that a species shows higher cognitive ability while equally supporting alternative hypotheses. This growing evidence provides insights into the evolutionary origin of visual mechanisms across species.
When seeing a visual image, humans prioritize the perception of global features, which is followed by the assessment of the local ones. This global precedence has been investigated using hierarchical stimuli that consist of a large, global shape formed by the spatial arrangement of small local shapes. Comparing non-human animals to humans, research on global and local processing has revealed a heterogeneous pattern of results with some species exhibiting a local precedence and others a global one. Many factors have been proposed to influence the global and local processing: internal factors (e.g., age, sex) and external elements or perceptual field variables (e.g., stimulus size, visual angle, eccentricity, sparsity). In this review, studies showing that different non-human species process hierarchical stimuli in the same (global precedence) or reverse (local precedence) direction as humans are first collated. Different ecological, perceptual, and anatomical features that may influence global and local processing are subsequently proposed based on a detailed analysis of these studies. This information is likely to improve our understanding of the mechanisms behind the perceptual organization and visual processing, and could explain the observed differences in hierarchical processing between species.
The cognitive abilities of birds are remarkable: hummingbirds integrate spatial and temporal information about food sources, day-old chicks have a sense of numbers, parrots can make and use tools, and ravens have sophisticated insights in social relationships. This volume describes the full range of avian cognitive abilities, the mechanisms behind such abilities and how they relate to the ecology of the species. Synthesising the latest research in avian cognition, a range of experts in the field provide first-hand insights into experimental procedures, outcomes and theoretical advances, including a discussion of how the findings in birds relate to the cognitive abilities of other species, including humans. The authors cover a range of topics such as spatial cognition, social learning, tool use, perceptual categorization and concept learning, providing the broader context for students and researchers interested in the current state of avian cognition research, its key questions and appropriate experimental approaches.
In humans, contrasting emotional states can lead to a broadening or narrowing of attentional scope. Whether this is also the case in animals has yet to be investigated. If confirmed, measurement of attentional scope has potential as a novel cognitive method of welfare assessment. In this study, we therefore aimed to investigate a test of attentional scope as a measure of emotional state in animals. We did this by inducing four putatively different emotional states in dogs (N = 10), varying in valence (positive, negative) and arousal (high, low), in two different reward contexts (food rewards in Experiment 1, social rewards in Experiment 2) and then assessing dogs’ behavioural responses in a test of attentional scope. We also recorded heart rate variability (HRV) parameters as additional confirmatory affective indicators. In Experiment 1, the dogs showed a narrowing of attentional scope after the induction of both positively valenced emotional states. That dogs were in a positive state was supported by the reduced Standard Deviation of normal-to-normal R-R intervals (SDNN) and the reduced Low Frequency (LF) and Very Low Frequency (VLF) HRV. In Experiment 2, when responses to social rewards were examined, we did not detect any statistically significant differences in attentional scope between the emotional states, but dogs had a slightly narrow attentional scope in the negatively valenced emotional states. The LF tended to be reduced in the high arousal positive treatment. In conclusion, our study provides the first indication that emotional states can also alter attentional scope in animals. The results justify further investigation of this approach for use in animal welfare assessment, although additional studies are needed to refine predictions.
Researchers have studied non-human primate cognition along different paths, including social cognition, planning and causal knowledge, spatial cognition and memory, and gestural communication, as well as comparative studies with humans. This volume describes how primate cognition is studied in labs, zoos, sanctuaries, and in the field, bringing together researchers examining similar issues in all of these settings and showing how each benefits from the others. Readers will discover how lab-based concepts play out in the real world of free primates. This book tackles pressing issues such as replicability, research ethics, and open science. With contributors from a broad range of comparative, cognitive, neuroscience, developmental, ecological, and ethological perspectives, the volume provides a state-of-the-art review pointing to new avenues for integrative research.
In humans, contrasting emotional states can lead to a broadening or narrowing of attentional scope. Whether this is also the case in animals has yet to be investigated. If confirmed, measurement of attentional scope has potential as a novel cognitive method of welfare assessment. In this study, we therefore aimed to validate a test of attentional scope as a measure of emotional state in animals. We did this by inducing four putatively different emotional states in dogs (N = 10), varying in valence (positive, negative) and arousal (high, low), in two different reward contexts (food rewards in Experiment 1, social rewards in Experiment 2) and then assessing dogs’ behavioural responses in a test of attentional scope. We also recorded heart rate variability (HRV) parameters as additional confirmatory affective indicators. In Experiment 1, the dogs showed a narrowing of attentional scope after the induction of both positively valenced emotional states. That dogs were in a positive state was supported by the reduced Standard Deviation of normal-to-normal R-R intervals (SDNN) and the reduced Low Frequency (LF) and Very Low Frequency (VLF) HRV. In Experiment 2, when responses to social rewards were examined, the dogs showed attentional narrowing only in the low arousal negative treatment, while the LF and VLF were reduced in the high arousal positive treatment. In conclusion, our study provides the first indication that emotional states can also alter attentional scope in animals. The results justify further investigation of this approach for use in animal welfare assessment, although further studies are needed to refine predictions.
Several lines of evidence suggest that the pigeon is near-sighted for stimuli located in front of its beak and far-sighted for stimuli located to the sides of its head.
When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: identification of changes becomes extremely difficult, even when changes are large and made repeatedly. Identification is much faster when a verbal cue is provided, showing that poor visibility is not the cause of this difficulty. Identification is also faster for objects mentioned in brief verbal descriptions of the scene. These results support the idea that observers never form a complete, detailed representation of their surroundings. In addition, results also indicate that attention is required to perceive change, and that in the absence of localized motion signals it is guided on the basis of high-level interest.
To see or not to see: The need for attention to perceive changes in scenes. Available from: https://www.researchgate.net/publication/236170014_To_see_or_not_to_see_The_need_for_attention_to_perceive_changes_in_scenes [accessed Jun 15, 2017].
Two experiments investigated texture discrimination in pigeons. In a simultaneous conditional-discrimination procedure, pigeons were reinforced for pecking at a small target region of identically colored form elements embedded in a larger region of distractor elements. These regions differed in either color or shape or differed redundantly in both dimensions. Pigeons readily acquired these discriminations and showed substantial positive discrimination transfer to new displays composed from novel recombinations of training colors and shapes, novel colors and shapes, and novel spatial organizations. The global organization of these displays appeared to be chief property mediating performance. This suggests that pigeons have mechanisms for perceptually grouping regions of similar colors and shapes, and these mechanisms may be similar to the preattentive visual mechanisms proposed for human texture segregation. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Notes that the hypothesis that animals selectively attend developed mainly in explanations of certain conditioning and discrimination learning phenomena. This hypothesis of selective attention is evaluated against a continuity (nonattentional) theory, and most, if not all, facts of simple learning can be accounted for by a nonattentional analysis. Thus, the usefulness of selective attention as an explanatory notion remains in doubt, and few phenomena can be regarded as exemplars of selective attention. In contrast, many examples of selective attention phenomena have been discovered in human information processing experiments. Emphasis in these experiments is on instructional and stimulus variables as they affect steady-state performance rather than response learning. Recent research with animals, modeled on human steady-state tasks, promises to provide similar instances of selective attention effects in performance. (2 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Evaluates a class of models of human information processing made popular by D. E. Broadbent (see 33:5). A brief tachistoscopic display of 1 or 2 single letters, 4-letter common words, or 4-letter nonwords was immediately followed by a masking field along with 2 single-letter response alternatives chosen so as to minimize informational differences among the tasks. Giving 9 Ss response alternatives before the stimulus display as well as after it caused an impairment of performance. Performance on single words was clearly better than performance on single letters. The data suggested that the 1st stages of information processing are done in parallel, but scanning of the resultant highly processed information is done serially. (17 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This research assessed the visual processing of the global and local stimulus features in humans and chimpanzees. In Experiment 1, participants were tested with compound stimuli presented in a visual search task. There was an advantage to process the global stimulus level in humans but not in chimpanzees. The global size and the density of the local elements were manipulated in Experiment 2. Humans showed an overall advantage for processing the global shape. Chimpanzees showed an advantage for processing the local shape in the low-density condition but showed no advantage in the dense conditions. In Experiment 3, chimpanzees showed a global advantage when line segments connected the local elements and a local one when the lines were removed. Together, these results suggest a phylogenetic trend in the way compound stimuli are processed. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
In 3 zero-delay matching-to-sample experiments, 3 Silver King pigeons' performance on element samples (color or angular orientation) was compared with their performance on 4 different compound samples in which color and angular orientation were combined. In Exp I, Ss matched element and compound samples to element tests, which for compound samples varied randomly between the 2 colors and the 2 angular orientations. In Exp II, test stimuli were symbolic and the elements of compound stimuli were presented such that both elements always matched the same test. All Ss showed uniformly high matching accuracy on all sample types. Exp III replicated Exp I except that sample duration was systematically varied. Performance on all sample types was ordered as in Exp I. These differences in performance appeared at all sample durations tested, suggesting that they reflect differences in the way the information is stored, rather than only in the efficiency of the input process. (19 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Two experiments examined the influence of dimensional organization on pigeons' texture perception, using a simultaneous conditional discrimination procedure. Four pigeons were reinforced for pecking at a small group of target colored shape elements randomly located within a larger array of distractor elements. The target and distractor regions of feature displays differed consistently in color or shape, whereas in conjunctive displays these regions were formed by conjunctive mixtures of the 2 dimensions. In Exp 1, pigeons' target-detection accuracy was higher with feature than with conjunctive displays. In Exp 2, pigeons responded more accurately and humans responded more quickly with feature than with 2 variations of conjunctive displays. These results suggest that the early visual mechanisms mediating the perception of dimensional information are similar for both species. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Fagot and Deruelle (1997) demonstrated that, when tested with identical visual stimuli, baboons exhibit an advantage in processing
local features, whereas humans show the “global precedence” effect initially reported by Navon (1977). In the present experiments,
we investigated the cause of this species difference. Humans and baboons performed a visual search task in which the target
differed from the distractors at either the global or the local level. Humans responded more quickly to global than to local
targets, whereas baboons did the opposite (Experiment 1). Human response times (RTs) were independent of display size, for
both local and global processing. Baboon RTs increased linearly with display size, more so for global than for local processing.
The search slope for baboons disappeared for continuous targets (Experiment 2). That effect was not due to variations in stimulus
luminance (Experiment 3). Finally, variations in stimulus density affected global search slopes in baboons but not in humans
(Experiment 4). Overall, results suggest that perceptual grouping operations involved during the processing of hierarchical
stimuli are attention demanding for baboons, but not for humans.
Three experiments examined the effects of changes in retinal locus and locational uncertainty in the processing of hierarchical
stimuli. In Experiment 1, stimuli were presented randomly in the left, center, or right portions of a display. Central presentation
decreased reaction times for identifying small letters presented within a hierarchical stimulus pattern (i.e., local letters)
but not for a single small letter presented alone. In Experiment 2, all stimuli were presented centrally, thus eliminating
the locational uncertainty that existed in Experiment 1. The elimination of locational uncertainty resulted in faster reaction
times (as compared with the central data of Experiment 1) for identifying small letters, whether or not they appeared in a
hierarchical pattern. In Experiment 3, eye movements were monitored and eliminated as a possible source of these effects.
The results are discussed in terms of possible effects of an attentional “spotlight” on hierarchical stimulus processing.
It was also found that the identity of the target letter (i.e., whether it was an H or an S) had a large effect on performance.
Finally, in contrast to earlier findings (Hoffman, 1980; Martin, 1979), the response-time advantage at a given level and the
amount of Stroop-type interference produced at the other level did not always covary, suggesting that these two effects may
reflect the operation of separate mechanisms.