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Forty years of experimental psychology in relation to age: Retrospect and prospect
Abstract
Experimental psychological research on performance in relation to age is outlined to show how aims, methods and interests have developed between the pioneering days of the 1940s and the present time. More detailed consideration is then given to the actual and potential applications to studies of aging of the quantitative methods of Information and Signal Detection Theories, and to the importance of taking account not only of correct performance but of the frequency and nature of errors if age changes are to be fully understood. Research in relation to age on continued performance is discussed, including short-term serial effects and the longer terms effects of fatigue, learning and practice, and the need for further research in these areas is emphasised. Guiding principles for future psychological research on aging are briefly urged.
... 3 Em 1946 surge, em Cambridge, o primeiro laboratório dedicado aos problemas do envelhecimento, dirigido por Bartlett. Este laboratório, à semelhança dos trabalhos de Miles, centrava-se no estudo da performance humana com o objectivo de definir quais os tipos de trabalho industrial mais adequados para os trabalhadores menos jovens (Welford, 1976(Welford, , 1986, ou seja, ambos os laboratórios estavam concentrados em avaliar o potencial dos mais velhos para o trabalho, abordando o tema de forma fundamental, isto é, medindo a performance em diferentes idades em tarefas de laboratório supostamente implicadas nas actividades industriais (Welford, 1976(Welford, , 1985a. No entanto, se por um lado os objectivos eram semelhantes, os dois grandes pioneiros no estudo do envelhecimento diferiam quanto aos seus fundamentos teóricos. ...
... final dos anos 50 aos anos 70 : a aversão à investigação aplicada 6 Segundo Welford e Teiger, o desenvolvimento da investigação sobre o envelhecimento parece atingir o seu pico precisamente no final da década de 50, iniciando-se, a partir daqui, uma trajectória marcada por um certo declínio que pode ser explicada por razões, uma vez mais, ligadas ao contexto sócio-demográfico da época. Nesta altura previa-se, em Inglaterra, um excesso de mão-de-obra para os anos 70, o que conduziu ao encorajamento da antecipação das reformas com vista a reduzir o desemprego (Welford, 1986). Além disso, assistia-se também a uma crescente aversão generalizada à investigação aplicada, a qual Welford (1986) explica recorrendo a diferentes causas : i) a conotação militar dos estudos realizados no período do pósguerra, sendo a investigação aplicada vista como negação da liberdade académica ; ii) o facto de a investigação no terreno ser considerada por muitos investigadores mais árdua e menos elegante, exigindo competências de relacionamento interpessoal que nem todos partilham ; iii) a ênfase crescente na teoria, isto é, a insistência na verificação de hipóteses deduzidas de teorias pré-formadas mais do que em deixar a teoria emergir indutivamente dos factos. ...
... Nesta altura previa-se, em Inglaterra, um excesso de mão-de-obra para os anos 70, o que conduziu ao encorajamento da antecipação das reformas com vista a reduzir o desemprego (Welford, 1986). Além disso, assistia-se também a uma crescente aversão generalizada à investigação aplicada, a qual Welford (1986) explica recorrendo a diferentes causas : i) a conotação militar dos estudos realizados no período do pósguerra, sendo a investigação aplicada vista como negação da liberdade académica ; ii) o facto de a investigação no terreno ser considerada por muitos investigadores mais árdua e menos elegante, exigindo competências de relacionamento interpessoal que nem todos partilham ; iii) a ênfase crescente na teoria, isto é, a insistência na verificação de hipóteses deduzidas de teorias pré-formadas mais do que em deixar a teoria emergir indutivamente dos factos. ...
... Em 1946 surge, em Cambridge, o primeiro laboratório dedicado aos problemas do envelhecimento, dirigido por Bartlett. Este laboratório, à semelhança dos trabalhos de Miles, centrava-se no estudo da performance humana com o objectivo de definir quais os tipos de trabalho industrial mais adequados para os trabalhadores menos jovens (Welford, 1976(Welford, , 1986, ou seja, ambos os laboratórios estavam concentrados em avaliar o potencial dos mais velhos para o trabalho, abordando o tema de forma fundamental, isto é, medindo a performance em diferentes idades em tarefas de laboratório supostamente implicadas nas actividades industriais (Welford, 1976(Welford, , 1985a. No entanto, se por um lado os objectivos eram semelhantes, os dois grandes pioneiros no estudo do envelhecimento diferiam quanto aos seus fundamentos teóricos. ...
... Do final dos anos 50 aos anos 70: a aversão à investigação aplicada Segundo Welford e Teiger, o desenvolvimento da investigação sobre o envelhecimento parece atingir o seu pico precisamente no final da década de 50, iniciando-se, a partir daqui, uma trajectória marcada por um certo declínio que pode ser explicada por razões, uma vez mais, ligadas ao contexto sócio-demográfico da época. Nesta altura previa-se, em Inglaterra, um excesso de mão-de-obra para os anos 70, o que conduziu ao encorajamento da antecipação das reformas com vista a reduzir o desemprego (Welford, 1986). Além disso, assistia-se também a uma crescente aversão generalizada à investigação aplicada, a qual Welford (1986) explica recorrendo a diferentes causas: i) a conotação militar dos estudos realizados no período do pósguerra, sendo a investigação aplicada vista como negação da liberdade académica; ii) o facto de a investigação no terreno ser considerada por muitos investigadores mais árdua e menos elegante, exigindo competências de relacionamento interpessoal que nem todos partilham; iii) a ênfase crescente na teoria, isto é, a insistência na verificação de hipóteses deduzidas de teorias pré-formadas mais do que em deixar a teoria emergir indutivamente dos factos. ...
... Além disso, assistia-se também a uma crescente aversão generalizada à investigação aplicada, a qual Welford (1986) explica recorrendo a diferentes causas: i) a conotação militar dos estudos realizados no período do pósguerra, sendo a investigação aplicada vista como negação da liberdade académica; ii) o facto de a investigação no terreno ser considerada por muitos investigadores mais árdua e menos elegante, exigindo competências de relacionamento interpessoal que nem todos partilham; iii) a ênfase crescente na teoria, isto é, a insistência na verificação de hipóteses deduzidas de teorias pré-formadas mais do que em deixar a teoria emergir indutivamente dos factos. O resultado disto ao nível metodológico foi uma alteração nas práticas iniciais em favor do estudo laboratorial de funções isoladas, tendência que deu origem a dois grandes desenvolvimentos, o uso generalizado dos testes psicométricos e dos questionários para comparar grupos de diferentes idades e o início dos estudos longitudinais (Welford, 1986). Mais uma vez, o percurso da investigação sobre o envelhecimento estabelece pontes evidentes com o desenvolvimento da psicologia e com os debates teórico-metodológicos que caracterizaram a evolução e a história da disciplina. ...
The aim of this thematic revision is to draw a possible course for the research history in ageing and work, describing the evolution of studies in this area, since the initial research in the 20´s and their development during the post-war period until today. We attempt to critically reflect on how this evolution occurred; its relations with socio-economic and demographic conditions that characterize each period; and the theoretical and methodological consequences of that evolution, either in the conceptualization of ageing or in research methods that are privileged. In the context of theoretical repercussions the approaches based on the cognitive dimension of ageing will be analysed in more detail, discussing the limits and the arguments that were conducive to the emergence of other traditions more directed towards the influences of context and situation, emphasizing the experience and the individual history of subjects. These approaches correspond to a methodological tradition witch privilege field research, conducted in real contexts, largely developed in work psychology and ergonomic domains. The final part of this text refers to the most recent theoretical orientations which lead to the genesis of a new approach to the study of ageing in their relation with work.
... There is no singular definition of cognitive workload [18]. There are at least two major theoretical approaches to the construct: 1) mental workload may be defined such that a given task's requirements are viewed as an independent, external variable with which the working subjects have to cope more or less efficiently; or 2) mental workload may be defined in terms of an interaction between task requirements and human capabilities or resources [19,20]. In either of these paradigms, the definition of workload involves the "objective" effects of task difficulty on the participant, and the participant's effort involved in maintaining performance. ...
Deployment of portable neuroimaging technologies to operating settings could help assess cognitive states of personnel assigned
to perform critical tasks and thus help improve efficiency and safety of human machine systems. Functional Near Infrared Spectroscopy
(fNIR) is an emerging noninvasive brain imaging technology that relies on optical techniques to detect brain hemodynamics
within the prefrontal cortex in response to sensory, motor, or cognitive activation. Collaborating with the FAA William J.
Hughes Technical Center, fNIR has been used to monitor twenty four certified professional controllers as they manage realistic
Air Traffic Control (ATC) scenarios under typical and emergent conditions. We have implemented a normalization procedure to
estimate cognitive workload levels from fNIR signals during ATC by developing linear regression models that were informed
by the respective participants’ prior n-back data. This normalization can account for oxygenation variance due to inter-personal
physiological differences. Results indicate that fNIR is sensitive task loads during ATC.
... Contrary to common belief, there is a complex relationship between age and productivity (Guest and Shacklock 2005). There is a rich body of research on this topic going back to the Middle Ages; in reality there is no general evidence of an age-related decline, though attributes change with age (Welford 1992Welford , 1986). Deterioration in some functional areas (e.g. ...
This review highlights some of the principal issues and debates surrounding age discrimination at the workplace. Essentially, the existing research in this area can be divided into three broad, although somewhat overlapping, categories. The first explores the underlying causes and consequences of age discrimination at the workplace from one or other theoretical tradition. The second broad body of literature encompasses empirical studies which document the nature and extent of age discrimination, based on the use of official statistics, and/or firm-level survey evidence. The third explores the effects of various governmental initiatives to reduce the incidence of age discrimination and policy options in this area. Even though age discrimination is widely accepted to be prevalent, its causes are rather more contentious. Age discrimination has variously been ascribed to market imperfections, the product of rational choices and the effects of long-term changes in the nature of the economy. Policy interventions may be prompted by economic pressure, demographic changes or cultural shifts, and have involved voluntary codes as well as legislation. Although voluntary codes have generally proved ineffective, the literature indicates that more formal regulations may still have only limited efficacy, underscoring the deeply rooted nature of age discrimination in society. Yes Yes
The main goal of the field of augmented cognition is to research and develop adaptive systems capable of extending the information management capacity of individuals through computing technologies. Augmented cognition research and development is therefore focused on accelerating the production of novel concepts in human-system integration and includes the study of methods for addressing cognitive bottlenecks (e.g., limitations in attention, memory, learning, comprehension, visualization abilities, and decision making) via technologies that assess the user’s cognitive status in real time. A computational interaction employing such novel system concepts monitors the state of the user, through behavioral, psychophysiological, and neurophysiological data acquired from the user in real time, and then adapts or augments the computational interface to significantly improve their performance on the task at hand.
The International Conference on Augmented Cognition (AC), an affiliated conference of the HCI International (HCII) conference, arrived at its 16th edition and encouraged papers from academics, researchers, industry, and professionals, on a broad range of theoretical and applied issues related to augmented cognition and its applications.
The field of augmented cognition has matured over the years to solve enduring issues such as portable, wearable neurosensing technologies and data fusion strategies in operational environments. These innovations coupled with better understanding of brain and behavior, improved measures of brain state change, and improved artificial intelligence algorithms have helped expand the augmented cognition focus areas to rehabilitation, brain-computer interfaces, and training and education. The burgeoning field of human-machine interfaces such as drones and autonomous agents are also benefitting from augmented cognition research.
This volume of the HCII 2022 proceedings is dedicated to this year’s edition of the AC conference and focuses on topics related to understanding human cognition and behavior, brain activity measurement and electroencephalography, human and machine learning, and augmented cognition in extended reality.
Papers of this one volume are included for publication after a minimum of two single-blind reviews from the members of the AC Program Board or, in some cases, from members of the Program Boards of other affiliated conferences. We would like to thank all of them for their invaluable contribution, support, and efforts.
Cognitive workload changes in the assessment of human performance have long been monitored through the use of subjective self-reports, physiological, or neuro-physiological measures. The purpose of this study is to use multi-modal sensors and machine learning (ML) approach as an assessment method and to investigate which set of biometrics serves as the best objective predictor of cognitive workload. Several biometrics, including prefrontal cortex oxygenation changes, heart rate, and respiratory rate, were collected in both 5-screen and 1-screen immersion conditions to induce high and low task load in simulated use of force (UOF) scenarios. These biometrics were then used to train logistic regression and feature mapping classifiers. Performance of these classifiers was assessed through measures of F1-score and accuracy in order to determine which feature set lends itself to the best prediction power. The classifier trained with left anterior medial prefrontal cortex oxygenation changes performed the best out of individual biometrics, with an accuracy of 0.68 and a f1-score of 0.67. The accuracy of this model was marginally improved to 0.69 when heart rate and oxygenation changes from the other prefrontal cortex quadrants were included, however, the f1-score decreased to 0.51. These results suggest that the logistic regression model underfit the data, necessitating an increase of training data set and exploration of alternative ML approaches in order to use these sensor-driven biometrics effectively and reliably to assess cognitive workload.KeywordsHuman performanceTrainingCognitive workloadMachine learningfNIRSHeart rateRespiratory rate
Cognitive workload changes have been studied and utilized as a means of assessment for engagement and learner’s performance during training. Yet, it is unclear how varying levels of simulator immersion affect learner cognitive workload. Wearable sensors allow us to monitor direct physiological changes associated with cognitive workload in real time. This study seeks to utilize multiple physiological and neurological measures: functional near-infrared spectroscopy (fNIRS), eye-tracking, electrodermal activity (EDA), heart rate, and respiratory rate; in order to assess cognitive workload changes during different training conditions. The National Aeronautics and Space Administration’s (NASA) Task Load Index (TLX) and flow state scale questionnaires were additionally used to record self-reported cognitive workload and subjective experience. Nine law enforcement trainees participated in different immersions conditions in a law enforcement use-of-force (UOF) simulator. Results from a low immersion condition were compared to results from a high immersion condition. Preliminary comparison between these two conditions suggests that the Index of Cognitive Activity (ICA) and respiration rate were greater in the low immersion condition. However, a notable increase in the oxygenated hemoglobin of the right anterior medial prefrontal cortex was detected via fNIRS. Heart rate also increased between the two conditions. Traditional questionnaires used to measure cognitive load showed no significance between conditions. Compared to self-report subjective metrics, biometrics such as fNIRS were operationally more effective at smaller sample sizes. Not only do these results show that features associated with trainees’ workload can viably be collected in realistic simulator settings, but they also suggest that increased immersion in law enforcement simulators may have a measurable effect on biometrics associated with cognitive workload.
A battery of cognitive and sensory-motor tests was given to a large number of French railway operatives ranging in age from the 20s to the 50s, and to trainees in their teenage years. The adults were divided into 5-year age ranges each of which was further divided into two levels of attainment in primary education. Declines of performance with age from the early 20s onwards occurred in all tests. It was most marked for tasks requiring complex muscle coordination or secondary memory, and least for digit span and sensory-motor tasks requiring simple responses. Educational attainment showed to greater advantage in the cognitive than in the sensory-motor tests. A factor analysis indicated that, with few exceptions, the factor structure remained constant throughout the adult age ranges and at both educational levels. Performance by the trainees was less in some tests and greater in others than that of adults in their 20s. The data provide a unique factual contribution to knowledge of age changes during the middle years.
It is generally believed that short-term memory (STM) performance decreases from maturity to old age, but the present paper questions the generality of this conclusion. The first experiment reported is a short-term recognition probe study—no significant age differences were found in either acquisition or the rate of forgetting. It is suggested that age decrements in STM are limited to situations where attention is divided at input or where the material must be manipulated during storage. Experiment II confirmed previous findings of minimal age losses in secondary memory word recognition. The results of this second study support the conclusion that there is poorer accessibility to stored verbal material with advancing age.
Studied the mechanisms responsible for practice-related improvement in detection, discrimination, and speeded classification. A 2nd goal was to determine whether there are adult age differences in the magnitude of practice-related improvement on simple perceptual and cognitive skills or in the mechanisms used to achieve that improvement. Eight young adults (ages 19–27 yrs) and 8 older adults (ages 62–73 yrs) performed 4 simple tasks for 51 experimental sessions. On several sessions Ss received qualitatively or quantitatively different stimuli to determine the mechanisms responsible for improvement. A concurrent RT task was performed at 3 periods to assess the level of residual capacity after various amounts of practice. Results are interpreted as suggesting that improvement is due to shifts in the type of information being processed, the identity or sequence of processing operations, and the attention requirements of the task. A model incorporating these mechanisms is proposed, and its application to the data is discussed. Age differences persisted on nearly every performance measure throughout all levels of practice. Moreover, there was little evidence that young and old Ss were qualitatively different in the manner in which they performed the tasks. It is suggested that the major difference between young and old adults on simple perceptual and cognitive tasks is the rate of processing nearly all types of information. (105 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Two experiments, with 34 mentally retarded (MR) 16-33 yr olds (WAIS IQs 43-76) and 34 CA-matched normal controls, investigated whether differences in the way that MR and non-MR monitor and regulate speed and accuracy of responding contribute to the slower and more variable performance of MR Ss on choice RT tasks. In Exp I, most MR Ss detected their errors as efficiently as controls, a finding that excludes the possibility that MR Ss do not monitor accuracy efficiently but achieve comparable levels of accuracy by consistently responding within slow RT bands that minimize likelihood of errors. Exp II showed that while a qualitatively similar trial-by-trial tracking mechanism mediated the performance of both groups, MR Ss were less efficient at constraining RTs within fast but safe bands. Increasing error probabilities at longer RTs suggested that momentary fluctuations in stimulus discriminability and/or attention affected RT variability in MR Ss. The RT patterns for various sequences of correct responses initiated and terminated by errors suggested that the effective past experience guiding trial-by-trial RT adjustments of MR Ss was short and inadequate and that this accounted for much of the remaining RT variability contributing to differences between MR and non-MR Ss. (53 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).
Two experiments were conducted to examine adult age differences in the use of context information. In Experiment 1, the encoding
of contextually influenced semantic features was examined, and the encodings of target words by both young and old adults
were observed to be influenced by semantic information provided by the context. Older adults did make more semantic confusion
errors, however, suggesting less distinctive encoding. Verbal ability also influenced performance, with the difference between
ability groups being similar to that between age groups. In Experiment 2, target words were presented in semantically unrelated contexts, and older adults were found not to encode contextual information
in this situation. It is hypothesized that the older adults' context effects in Experiment 1 were due to automatic activation
of nonspecific word meaning features due to the relation between target and context. When no such familiar context existed,
the older adults were less likely to use context information.
The Handbook of the Psychology of Aging, 6e provides a comprehensive summary and evaluation of recent research on the psychological aspects of aging. The 22 chapters are organized into four divisions: Concepts, Theories, and Methods in the Psychology of Aging; Biological and Social Influences on Aging; Behavioral Processes and Aging; and Complex Behavioral Concepts and Processes in Aging. The 6th edition of the Handbook is considerably changed from the previous edition. Half of the chapters are on new topics and the remaining half are on returning subjects that are entirely new presentations by different authors of new material. Some of the exciting new topics include Contributions of Cognitive Neuroscience to Understanding Behavior and Aging, Everyday Problem Solving and Decision Making, Autobiographical Memory, and Religion and Health Late in Life. The Handbook will be of use to researchers and professional practitioners working with the aged. It is also suitable for use as a textbook for graduate and advanced undergraduate courses on the psychology of aging. The Handbook of the Psychology of Aging, Sixth Edition is part of the Handbooks on Aging series, including Handbook of the Biology of Aging and Handbook of Aging and the Social Sciences, also in their 6th editions.
Longstreth's (1984) critique of Jensen's research on the relationship of IQ to individual differences in visual reaction time (RT), measured in the Hick paradigm, is found to have numerous errors of fact and interpretation, some trivial and some of theoretical importance. Longstreth's narrowly focused and conjectural style of criticism, which peculiarly strains to favor the null hypothesis, unfortunately obscures the essential findings of Jensen's (and others') studies of the RT-IQ relationship. The two main negative verdicts of Longstreth's critique concerning the RT-IQ relationship are refuted by meta-analyses of presently available data. First, not only do individual differences in RT show a significant negative correlation with IQ, but individual differences in the slope of the regression of RT on stimulus set size scaled in bits (i.e., the binary logarithm of the number of potential reaction stimuli) also show a fully significant, albeit low, negative correlation with IQ. Contrary to Longstreth's second negative surmise, meta-analysis also shows that the magnitude of the RT-IQ correlation itself is a linearly increasing (negative) function of stimulus set-size scaled in bits.
Two experiments are reported which applied signal detection measures to recall and compared them with similar measures of recognition. In both experiments there were more correct responses in recognition but also more false ones. As a result, the signal detection measure of discrimination d' was closely similar for both recognition and recall. The difference between recognition and recall could be accounted for by a more stringent criterion for response in the latter. The second experiment showed that, as in previous experiments on psychophysical discrimination, d' rose approximately linearly with the square root of the number of times the stimuli were repeated. The rate of increase was closely similar for recall and recognition. Possible reasons for the differences of criterion between recall and recognition are briefly discussed. The results emphasize the need to take false as well as correct responses into account when studying either recognition or recall.
A survey of practice effects in sensorimotor performance reveals that they are in some cases less and in others greater among older than among younger adults. Indices of age differences and functional relationships between performance and amount of practice are proposed, based on a model derived from signal detection theory. Results in studies of verbal learning have been well accounted for by plotting the normal deviate (z score) corresponding to the probability of a correct response against the square root of the number of previous presentations of the material to be learned. The same relationship has been found to hold for certain sensorimotor tasks where time is controlled and performance is measured in terms of accuracy. The model is extended to cases in which performance is measured in terms of time, with accuracy held constant. In these, time per trial is found to be linearly related to the square root of the total time spent on previous trials. Examples of data from different age groups, treated in terms of the model, are given for both verbal learning and sensorimotor practice effects. In the latter, older subjects tend to improve more slowly than younger in tasks that require the making of movements which are complex, unfamiliar, or not guided by a display. When simple movements directly related to a display are required, older subjects tend to improve as fast or faster than younger. Little is known of the detailed changes in performance that occur during the course of practice, and of how these differ with age.
Presents a collection of experimental reports, descriptions of apparatus, and an analysis of the philosophy involved in the author's study of perception over the last 20 yrs. Topics include studies of perception in simulated space conditions; a case study of a man who, after being blind since infancy, had his sight restored in middle age; a device for reducing atmospheric image interference in telescopes; and a speculative account of brain function in terms of probability and induction. (151/2 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
In a serial learning task given to subjects whose ages ranged from twenty to seventy, a decline in performance showed itself as a loss of speed in the thirties, a loss of accuracy in the forties, and a marked loss of both speed and accuracy in the fifties and sixties. Experiments on recall and reorganization of material verified that older subjects were forgetting more quickly than younger, but that one of their main difficulties was an inability to substitute new reponses in an already mentally formed sequence.
Older subjects were not introducing new learning features but accentuating normal tendencies, such as the repetition of the same error at the same serial position. In so far as subjects learned their repeated errors, final learning involved unlearning, with the often observable phenomenon of the previously learned error serving as the cue for the more recently learned correct response. In terms of schematic concepts of mental functions, serial learning difficulty was not so much the formation of a general “scheme” but its subsequent amendment. Preformed habits influenced both the learning procedure and its results, particularly in the constraints and expectancies which the making of one serial response had upon another.
Sketches the history of research on industrial gerontology in Britain from 1946 onward and views it in relation to gerontological research in other countries. The individual studies were closely integrated with fundamental gerontological research, and were both guided by and helped to formulate leading theoretical ideas. These are briefly discussed under 6 heads: the central locus of the most important age changes; the concept that signal-to-noise ratio in the brain is reduced in old age; the increasing failure by older people to transfer material from short-term to long-term storage and to recover it from long-term store; compensatory relationships between fall of ability to manipulate data in the abstract, and increase of knowledge; slowness as a major cause of accidents among older people; and methodological problems of interpreting industrial statistics regarding age. Future research needs are outlined. (66 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Reports a pilot study of 946 coal miners at 5 collieries which examined factors affecting the age at which men leave coal-face work. Miners are subject to the interactive and cumulative effects of arduous work and environment, heavy pace, and organizational pressures. Against a background of awareness and acceptance of increasing incapacity, the ability to cope diminishes noticeably among men about 45 or over. Leaving the coal-face is an occupational self-selection process. The choice is forced on the older man by recognition of his growing inability to handle occupational pressures; the younger man's decision to leave owes more to his unwillingness to continue such work. It is concluded that some of the attention given to training new workers could profitably be applied to mitigating occupational pressures and thereby lengthening the working life of experienced older men. (58 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This paper is concerned with the human observer's behavior in detecting light signals in a uniform light background. Detection of these signals depends on information transmitted to cortical centers by way of the visual pathways. An analysis is made of the form of this information, and the types of decisions which can be based on information of this form. Based on this analysis, the expected form of data collected in "yes-no' and "forced-choice' psychophysical experiments is defined, and experiments demonstrating the internal consistency of the theory are presented.
The analytical methods of information theory are applied to the data obtained in certain choice-reaction-time experiments. Two types of experiment were performed: (a) a conventional choice-reaction experiment, with various numbers of alternatives up to ten, and with a negligible proportion of errors, and (b) a ten-choice experiment in which the subjects deliberately reduced their reaction time by allowing themselves various proportions of errors.
The principal finding is that the rate of gain of information is, on the average, constant with respect to time, within the duration of one perceptual-motor act, and has a value of the order of five “bits” per second.
The distribution of reaction times among the ten stimuli in the second experiment is shown to be related to the objective uncertainty as to which response will be given to each stimulus. The distribution of reaction times among the responses is also related to the same uncertainty. This is further evidence that information is intimately concerned with reaction time.
Some possible conceptual models of the process are considered, but tests against the data are inconclusive.
Current theories of aging suggest that at least part of the decline in performance on psychophysical tasks, commonly observed
in older subjects, may be the result of their becoming more cautious about sensory decisions. This conclusion has been supported
by experiments in which the criterion index, β, from signal detection theory is shown to be higher (indicating a strict criterion)
for older subjects. A weight-discrimination experiment is reported which failed to replicate the earlier results; older subjects'
criteria were the same or more lax than those of younger controls on that task. The possibility that extreme caution on the
part of older people may be specific to certain classes of task is discussed.
An attempt is made to outline a conceptual framework in which to view the problems of defining and measuring mental work-load. This is treated in terms of the demands made by tasks, the capacities the subject brings to meet these demands, and the strategies he uses to relate the first to the second. Two types of demand are distinguished: the amount of data to be handled at a particular moment, and the amount to be dealt with during a particular period of time. Each type is considered in relation to the main central functions of perception, decision and choice, phasing and coordination of action, memory, and motivation. Capacity, and the effects of various factors upon it, are considered in relation to concepts of signal-to-noise ratio in the central nervous system. Three main types of strategy are outlined: coding and programming, methods of search, and balancing conflicting factors such as speed and accuracy or errors of omission and commission. Skill is discussed in terms of efficiency of strategy and a model is proposed to account for the attainment of skill with experience. Two basic approaches to the measurement of work-load are compared: the synthetic, in which the load imposed by the task as a whole is calculated from the loads imposed by its components; and the analytic, in which the task is studied as a whole, and components are analysed from the whole performance. Chronic stress and emotion are briefly discussed as long-term factors liable to affect work-load.
Recognition memory was studied in young and elderly women by assessing memory strength and response bias using Signal Detection Theory methodology. Young women (mean age 21 years; n = 8) had better recognition memory (d' and d'e) than did elderly women (mean age 71 years; n = 16) but the groups did not differ significantly on correct recognitions (hit rate) or incorrect recognitions (false affirmative rate). Evaluation of response bias indicated that the elderly women adopted a lax response strategy which resulted in an inflated correct recognition rate. The data indicate that, in aging research, evaluation of memory in terms of correct and incorrect recognitions can lead to erroneous interpretations, due to uncontrolled bias effects. Age does adversely influence recognition memory strength suggesting that acquisition and/or storage processes are not invariant with age.
The performance of young (18-22 years) and old adults (55-64 years) on an auditory task was compared using signal detection
procedures. Subjects used a confidence rating scale to report the presence or absence of a 6000 Hz pure tone embedded in gaussian
noise. The tone was set at either 35, 50, or 65 dB SPL. Younger subjects showed perfect sensitivity at all dB levels, and
the sensitivity of older subjects increased as a function of the dB level. Discrimination was then tested at 20 and 30 dB
in another sample of younger subjects. We found that this group tended to respond much less conservatively than the older
group, even though the task was of comparable difficulty.
Twelve elderly and 12 young subjects were tested on a series of experiments with increasing complexity of perceptual-response mapping. As task complexity increased the differential slowing in performance between young and old increased and an age × task complexity interaction was observed. However, with practice this phenomenon disappeared leaving an apparent age lag constant. This slowing was due to increased central processing time rather than peripheral factors.
No major differences in strategies were observed between the groups, though the old subjects tended to be less able to extract critical (useful) features from the display. Stimulus repetitions of a new kind were found where all characteristics of the stimulus (relevant and irrelevant) were important. Repetitions of coding rules rather than of particular signals or responses also facilitated RT. It was also found that later in practice old subjects were making fewer errors than the young, reversing earlier observations.
Data from an eight choice serial reaction time experiment using two different response-stimulus intervals were examined for sequential effects by separating out the mean reaction times for each stimulus following every other stimulus. This analysis revealed differences in performance under the two response-stimulus interval conditions not shown by the conventional partitioning of the reaction times into those for repetitions and for non-repetitions.
A recognition-memory paradigm was used to test two hypotheses, storage and retrieval, which account for the adult age decrement seen in recall. Partial storage was minimized by using items in the recognition list which were similar to the to-be-remembered items. Recognition performance was unaffected by adult age differences, thereby supporting the retrieval hypothesis. However, older persons made a greater number of semantic errors in the recognition test list supporting the storage hypothesis. While the error difference did not affect overall recognition performance, the result does indicate some caution is necessary in interpreting age-recognition interactions.
Three predictions were derived from the assumption that with increased age there is a decrease in the effective signal-to-noise ratio of neural representations of visually presented stimuli. Although the results from manipulations designed to examine the internal consistency of the predictions were quite positive, the predicted age differences failed to appear in two of the three dependent measures. Because the same pattern was found in two independent studies and estimates of measurement reliability and statistical power were moderately high, it was concluded that at least some versions of the neural-noise hypothesis of cognitive changes with age may be untenable and that more effort should be devoted to devising experimentally testable implications of the hypothesis.
Twenty two elderly (mean age 71.23 years) and 22 young adult (mean age 24.76 years) college students were given 2 trials each of a recognition memory task for separate lists of words and nonsense syllables. Measures derived from Signal Detection Theory were used to assess age differences in recognition memory (d') independently of response criterion (L(x)). It was expected that a storage deficit in the elderly would result in relatively less improvement in memory on the second trial, particularly for the nonsense syllables. Younger adults were found to show greater increments in d' on the second trial and to retain more information about each item over trials, but there were no age differences in improvement between words and nonsense syllables. The response criterion results suggested that attitudes toward responding represent a complex interaction of age, type of material, and number of trials. Compared to the younger adults, the elderly set higher criteria with words, and lower criteria with nonsense syllables on the first trial.
Indices of human performance are less clear-cut than analogous measures in the physical sciences for several reasons. Variables which can alter performance include the noise upon which sensory signals are imposed, the bias shown by an observer towards one or another alternative, the use of an optional-stopping strategy for examining sensory input, and the accumulation of statistical information over time concerning the source of the input. The development of a theoretical appreciation of these variables is traced and, on this basis, a measure of the noise, which sets a limit to discriminative capacity, is suggested. The proposed index is simply the standard deviation of the best fitting normal ogive, calculated for the psychometric function obtained in a forced-choice discrimination task by the method of constant stimuli, the discriminanda being presented for 100 ms, in random order, and followed by appropriate backward masking. The index is thus closely related to traditional psychophysical measures, but is distinguished by the detailed specification of conditions under which it should be obtained. Analysis of data from previous experiments gives some indication of the order of magnitude that might be expected from a carefully controlled determination of the measure. In addition, three experiments were carried out to evaluate this suggestion, and to test its underlying rationale. In the first two, observers were required to discriminate, by pressing one of two keys, between two lines of markedly different length, exposed in random order for ten different durations. In the third, stimulus exposure was held constant, while ten different stimulus differences were presented in random order. Results from the first two experiments yielded estimates of minimum inspection time close to 100 ms, and were inconsistent with the view that observers can abandon an optional-stopping procedure of processing sensory information in favour of responding by a deadline. Measures of noise calculated in the third experiment were of the order expected on the proposed rationale, while response latencies were again inconsistent with the notion of deadline responding. Further analysis of the results of the three experiments suggests that measures of inspection time and noise, together with a third index related to the degree of caution exercised by an observer, appear to be stable and consistent descriptors of performance. The wider implications of the successful use of this kind of perceptual index of performance are discussed with reference to the measurement of visual acuity, as a means for detecting effects of environmental stress, and as a conceptual framework for the understanding of individual differences.
Subjects released 1 key with the right hand upon presentation of a red light and another with the left hand when a green light was presented. Each stimulus occurred an equal number of times in a sequence of 40 trials, but the probability that it would do so twice in succession was only .25. The subjects were male volunteers who ranged in age from the 20s through the 70s. Mean response latency increased with age, although variability did not. Stimulus alternations were responded to more rapidly than repetitions by subjects in all age groups, a result consistent with an expectancy theory of choice reaction time. A detailed analysis of the frequency distributions of reaction times suggests that the older individuals' longer latencies reflect impaired psychomotor rather than decision making efficiency.
An experiment on the speed and accuracy of movement is reported in which subjects tapped to-and-fro with a pencil between two targets drawn on paper. The time taken was found to vary approximately, as in previous studies, with the logarithm of the ratio between the distance apart of the targets and their width. However, when speed was related to the actual scatters of shots on the targets instead of to the target widths, the results showed systematic and consistent departures from a linear relationship with the logarithm of the ratio between distance apart and the width of scatter. Two modifications to the formulation are discussed, one of which takes account of possible tremor effects, and the other of the possibility that visual control when ‘homing’ on a target may be slower than the control of movement designed to cover a given distance. Both modifications gave good fits to the observed results, but the second is preferred on grounds of consistency with the findings of other studies.The general pattern of results was followed for subjects in each decade of age from the twenties to the seventies. Performance improved in certain ways from the twenties to the thirties and forties, and thereafter declined with age.
A number of models are outlined which attempt to account for relationships between various bodily, and especially neural, changes and the widespread slowing of performance observed in old age. Muscular and neuromuscular changes can account for some types of slowing, but most types are attributable to central mechanisms. The accumulation of small increments of time in a long chain of cells from sensory input to motor output is shown to be an inadequate explanation. Correlations between reaction time, EEG alpha cycle-time and age are in line with the widespread tendency for increases of reaction time with age to be proportional, but do not take account of errors. A powerful model which does consider both time and errors is derived from the fact that signals from sense organs and within the brain have to be distinguished against a background of random activity ("noise") both in the signals themselves and in the central nervous system, and slowing of performance with age results from a fall in signal-to-noise ratios. This leads in some circumstances to absolute and in others to proportional increases of time taken by older people. Interacting with these factors are tendencies by older people to adopt higher criteria for responding, and to spend more time monitoring their actions. Certain cases in which there is a disproportionate increase with age of time taken appear to occur when memory is involved in holding data temporarily while other data are gathered to arrive at a decision. The several stages of information processing from input to output are affected by slowing with age differently in different tasks, so that detailed study of various aspects of tasks is needed to account for overall effects observed.
An 18-year longitudinal repeat of the mackworth clock vigilance experiment was conducted. Skin potential response latencies
(SPRL) and reaction times were taken from 33 men during the vigilance task. The longitudinal change in this study reproduced
the earlier cross-sectional relationship. The 51 to 69 year olds showed faster reaction times, the 70 to 88 year olds showed
slower reaction times and, the 70 to 88 year olds detected significantly fewer targets than when 18 years younger. It was
found that the greater the reduction in the percentage of targets detected, the greater the increase in reaction time. The
longitudinal change noted in this study reflected previously determined cross-sectional SPRL effect. However, the SPRL outcome
was equivocated by a time-of-measurement effect. It was concluded that at about age 70 years a noticeable reduction in vigilance
performance occurs, and this is accompanied by a reduction in autonomic and central nervous system reactivity.
Ten years ago, it seemed reasonable to summarize two decades of research on the age changes in central mechanisms affecting performance under four main headings: slowing of perception and action, increased disruption of short-term memory by any shift of attention, difficulty in searching material in long-term memory, and difficulty in coping with certain kinds of complexity. Theories under these four headings are reexamined in light of recent findings which imply that older people have a reduced signal-to-noise ratio in the brain but at the same time a spontaneous tendency to adopt strategies which optimize performance. This approach accounts directly for longer times taken in discrimination and some choice reaction tasks, and indirectly for at least some of the greater tendency of older people to monitor their responses. A model is proposed which applies the same approach to memory. In terms of this model, poor performances in both short- and long-term memory are due to failure to transfer items from primary to secondary memory and to the weakness of traces established in long-term memory. The model raises some as yet unanswered questions about the precise manner in which complex relationships between signals and responses are handled.
Fifty-seven males representing groups with median ages of 20, 52, and 63 years were presented with a long sequence of words. Using a four point scale, they judged whether each word was presented for the first ("new") or second ("old") time in the sequence. High and low frequency words and separations of 0 to 64 words between the two presentations of a given word were employed. Analyses of errors confidence judgments and decision times revealed minimal or no age difference when the number of words intervening between successive presentations did not exceed the span of immediate memory. Older subjects' performance declined more rapidly than younger subjects from 3 to 12 second retention intervals, but declined at about the same rate from 12 to 192 second retention intervals. Low frequency words were better remembered by all age groups and there was no interaction between the effects of age and word frequency in any dependent measure.
Forty young adults (18 to 31 years) and 40 older adults (61 to 82 years) participated in a weight discrimination study. The
subject's task was to decide if two weights lifted successively were the same or different and to rate the decision confidence
of each response. The standard weight was 210 grams and the comparison weight was either 210 or 225 grams.
It was found that the younger adults discriminated between the pair of weights better than the older adults and that men discriminated
better than women, but an age by sex interaction was not observed. With regard to d ', much of the age difference rested with
older men being less sensitive than younger men at two of five rating scale categories.
There was a tendency for older adults to set stricter criteria than young adults, but this was seen only when age groups differing
in sensitivity were compared. When matched for sensitivity, age differences in response bias were not found. When shifts in
response bias were observed it was such that young men set higher criteria than old men at the first category of the rating scale and lower criteria at the fifth category.
Emotional and neutral words were used to compare old, middle-aged, and young groups in their recognition memory at two hours and at one week following learning. The old retrieved fewer emotionally charged words than younger groups, while they were equally proficient in the recognition of neutral words. All groups made more correct and more false recognitions of emotional words than of neutral words. Based on discriminability measures, the emotional value of words induced a greater recognition difference at one week than at two hours. The old were less willing to guess than younger persons, adopting high decision criteria especially for emotional words during the two-hour test. The results were interpreted that the elderly are less responsive to emotional words or, alternatively, adopt more stringent recognition criteria for such words.