Process differences and individual differences in some cognitive tasks

This study is based on three distinct elementary cognitive tasks (ECTs) using chronometric techniques: (a) the S. Sternberg memory scan task, (b) a visual scan task which is perfectly analogous to the memory scan, except that the target digit is presented first and the subject must then scan a set of digits and indicate the presence or absence of the target digit in the set, and (c) the Hick paradigm, which involves responding to a visual stimulus (a light going “on”) when the stimulus is one among sets of either 1, 2, 4, or 8 equally probable alternatives. Certain parameters of all three tasks, such as intercept and slope of RT as a function of set size, from which different cognitive processes are inferred, are compared experimentally and correlationally. Subjects were 48 university students, tested and retested on the three tasks in a counterbalanced design on two separate days to obtain the retest reliabilities needed to correct all correlations for attenuation. Subjects were also given Raven's Advanced Progressive Matrices as a measure of psychometric g. Parameters of the ECTs are significantly and, in some cases, quite substantially correlated with g. Virtually all of this correlation is due to the general factor of the various ECTs, rather than to specific processing components (independent of the general factor). The results also indicate that different ECT paradigms (e.g., visual search and memory search tasks) may yield markedly different values in terms of the group means of analogous parameters, indicating different processes, and yet not show independence of the parameters in terms of individual differences; that is, measurements of the different parameters in individuals are perfectly correlated (i.e., disattenuated correlations do not differ significantly from r = 1). This is found for the intercept parameter of visual and memory search. The reverse condition is also found for the other parameters (e.g., slope); that is, their mean values are nearly identical, suggesting the same processes, yet disattenuated correlations between individual differences are relatively low, or even negative, indicating different processes. Although the general factor clearly predominates, it does not completely overwhelm individual differences in various component processes that are distinct from the general factor.     

An investigative biobehavioral approach to sex differences in cognitive functioning

Advances in our biological understanding and control of cognitive functioning have not been matched in the behavioral realm. The bio-behavioral approach outlined in this paper helps to close this bio-behavioral gap by aiming for a taxonomic precision in psychology that is comparable to that in physiology. The approach is applied to the phenomenon of group sex differences, and is illustrated by referring to three sets of recently reported findings: (a) interactive effects of nicotine and sex on the trait of cognitive style; (b) sexually dimorphic cognitive style in rats and the involvement of nitric oxide as a potential physiological mechanism and (c) sexually dimorphic phasic arousal change induced by smoking a cigarette following deprivation.     

The role of individual differences in cognitive training and transfer

Working memory (WM) training has recently become a topic of intense interest and controversy. Although several recent studies have reported near- and far-transfer effects as a result of training WM-related skills, others have failed to show far transfer, suggesting that generalization effects are elusive. Also, many of the earlier intervention attempts have been criticized on methodological grounds. The present study resolves some of the methodological limitations of previous studies and also considers individual differences as potential explanations for the differing transfer effects across studies. We recruited intrinsically motivated participants and assessed their need for cognition (NFC; Cacioppo & Petty Journal of Personality and Social Psychology 42:116–131, 1982) and their implicit theories of intelligence (Dweck, 1999) prior to training. We assessed the efficacy of two WM interventions by comparing participants’ improvements on a battery of fluid intelligence tests against those of an active control group. We observed that transfer to a composite measure of fluid reasoning resulted from both WM interventions. In addition, we uncovered factors that contributed to training success, including motivation, need for cognition, preexisting ability, and implicit theories about intelligence.     

Effect of instructions on elementary cognitive tasks sensitive to individual differences

The effect of instructions on basic cognitive tasks was investigated. In the first study, 60 college students completed both a choice reaction time and a modified match-to-sample task. Students were given either written, non-verbal, or no instructions. Mean level of performance changed across type of instruction for each task. The correlations between the task parameters and a measure of general intelligence also appeared to change across instructional conditions. A second study was conducted with 464 Air Force and National Guard recruits who completed choice reaction time, match-to-sample, tachistoscopic threshold, and probed recall tasks. Approximately half of these subjects received standard written instructions while the others received no instructions. Mean group differences were substantial but decreased with practice. Patterns of individual differences between the instruction and no-instruction conditions varied more with increased task complexity, with greater change occurring in more complex tasks such as probed recall. In sum, instructions have a significant impact on mean performance on basic cognitive tasks and a lesser effect on individual differences.     

Recruitment modeling applied to longitudinal studies of group differences in intelligence

In longitudinal studies data is collected in a series of waves. Each wave after the first suffers from attrition. Therefore it can be difficult to discriminate between changes in sample parameters due to a longitudinal process (e.g. ageing) and changes due to attrition. The problem is particularly vexing if one of the purposes is to compare differences between two or more groups over time, because there may be differential attrition across groups. We refer to this as a recruitment problem, because the sample studied in any wave after the first can be thought of as having been recruited from a preceding wave. We present a mathematical model of the recruitment process. We then apply it to two large longitudinal studies, the British Cohort Survey 1970 and the National Child Development Study (1958), to demonstrate how we can identify effects expected from recruitment alone. As an illustration we show that differential recruitment would predict increasing differences between estimates of men's and women's intelligence as the studied sample ages.     

Temporal stability and individual differences in using assessment information to form overall ratings

Relationships among dimension ratings and between dimension ratings and overall judgments were examined for 719 individuals assessed by four assessor teams. High stability was found, and there was no evidence for stable changes in an assessor's or assessor team's pattern of ratings over time. Parallel analysis and factor comparisons provided support for hypothesized individual differences in the complexity and nature of the dimensionality underlying the assessment ratings. Overall decisions were modeled accurately using a subset of the available dimensions. Use of a common set of predictors produced only a small decline in predictive power over the use of the optimal predictors for each assessor and assessor team. Two factors common to virtually all assessors (leadership and organizing—planning/decision making) consistently contained dimensions identified as important by the regression model. Assessor ratings of dimension importance agree with the regression model to the extent that leadership and organizing/decision making were commonly identified as important. The generality of some laboratory findings regarding decisionmaking strategies and information-processing style is illustrated.     

A research strategy for investigating group differences in a cognitive construct: Application to ageing and executive processes

A strategy involving five distinct phases is proposed as a means of obtaining the most informative evidence about group differences in a particular aspect of cognitive functioning. Perhaps because the phases require different types of analytical methods, most prior research has focused on only a few of the proposed phases. This is unfortunate because each phase provides valuable information about the nature of the relevant construct, and its role in group differences in cognition. The strategy is illustrated with research on adult age differences in executive processes.     

Understanding correlates of change by modeling individual differences in growth

The study of correlates of change is the investigation of systematic individual differences in growth. Our representation of systematic individual differences in growth is built up in two parts: (a) a model for individual growth and, (b) a model for the dependence of parameters in the individual growth models on individual characteristics. First, explicit representations of correlates of change are constructed for various models of individual growth. Second, for the special case of initial status as a correlate of change, properties of collections of growth curves provide new results on the relation between change and initial status. Third, the shortcomings of previous approaches to the assessment of correlates of change are demonstrated. In particular, correlations of residual change measures with exogenous individual characteristics are shown to be poor indicators of systematic individual differences in growth.The research reported here was supported by a grant from The Spencer Foundation to the senior author and by the Study of Stanford and the Schools.     

Computational modeling of individual differences in short term memory search

Modeling of individual or group differences, believed to be a powerful test for computational models, is still rare in current cognitive science. In this paper, we discuss alternative approaches to the computational modeling of both qualitative and quantitative differences among individuals as well as groups of individuals. Then, an example is presented of how accounting for individual differences in short term memory (STM) search can bring us insight into cognitive processes underlying this phenomenon, insight that otherways would be impossible. The two-phase computational model of memory search implements the idea of working memory (WM) focus of attention (FA): due to updating process a few items may be actively kept and easily accessed in ACT-R goal buffer. FA is being scanned serially first, and if the scan result is negative, a parallel chunk retrieval from active part of declarative memory outside the FA may run with certain probability. The model aptly simulates steep decrease in accuracy as well as steep increase in latency for responses to five most recent stimuli. The model also predicts the observed effect of faster negative responses than positive responses to less recent stimuli. Most important, with manipulation to only one of its parameters (i.e., the capacity of FA) our model is able to predict 94% of variance for two groups of participants that differed in latency patterns (i.e., ‘serial-like’ vs. ‘parallel-like’ groups) of the search process.     

Working memory capacity and categorization: individual differences and modeling

Working memory is crucial for many higher-level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization, and modeling in category learning has thus far been largely uninformed by knowledge about people's memory processes. This article reports a large study (N = 113) that related people's working memory capacity (WMC) to their category-learning performance using the 6 problem types of Shepard, Hovland, and Jenkins (1961). Structural equation modeling revealed a strong relationship between WMC and category learning, with a single latent variable accommodating performance on all 6 problems. A model of categorization (the Attention Learning COVEring map, ALCOVE; Kruschke, 1992) was fit to the individual data and a single latent variable was sufficient to capture the variation among associative learning parameters across all problems. The data and modeling suggest that working memory mediates category learning across a broad range of tasks.     

Decision framing: moderating effects of individual differences and cognitive processing

Two studies examined the effect of an individual difference variable, need for cognition (NC), and processing of the options on the occurrence of risky choice framing effects. In Study 1 (N=206), frame interacted with NC and math skill such that no framing effect was observed among those high in both NC and math skill. No effect was found for the processing manipulation of requesting a reason for one's choices. Study 2 (N=257) enhanced the processing of the problems by asking participants to write out the options as they would describe them to a friend. Results showed that frame interacted with NC and depth of processing such that no framing effect was observed among those high in NC who were in the deep processing condition. These findings suggest that NC and depth of processing need to be considered in concert in order to understand their moderating effects on framing. Copyright © 2004 John Wiley & Sons, Ltd.     

Further explorations of perceptual speed abilities in the context of assessment methods, cognitive abilities, and individual differences during skill acquisition

Measures of perceptual speed ability have been shown to be an important part of assessment batteries for predicting performance on tasks and jobs that require a high level of speed and accuracy. However, traditional measures of perceptual speed ability sometimes have limited cost-effectiveness because of the requirements for administration and scoring of paper-and-pencil tests. There have also been concerns about the validity of previous computer approaches to administering perceptual speed tests (e.g., see Mead & Drasgow, 1993). The authors developed two sets of computerized perceptual speed tests, with touch-sensitive monitors, that were designed to parallel several paper-and-pencil tests. The reliability and validity of the tests were explored across three empirical studies (N = 167, 160, and 117, respectively). The final study included two criterion tasks with 4.67 and 10 hours of time-on-task practice, respectively. Results indicated that these new measures provide both high levels of reliability and substantial validity for performance on the two skill-learning tasks. Implications for research and application for computerized perceptual speed tests are discussed.     

Role of individual neurons and neural networks in cognitive functioning of the brain: a new insight

The prevailing concept in modern neuroscience is that neuron networks play a dominant role in the functioning of the nervous system, whereas the role of individual neurons is rather insignificant. This concept suggests that "individuality" of single neurons is primarily determined by their place in a network rather than their intrinsic properties. Here I argue that individual neurons may play an important, if not decisive, role in performing cognitive functions of the brain. This tentative viewpoint is supported by experimental and clinical insights into disorders of cognitive functions and by genetic studies of cognitive abilities and disabilities. The results obtained in these studies indicate that many specific cognitive functions are carried out by groups of highly specialized neurons whose roles in performing these functions are genetically predetermined and their activity could not be substituted by the activity of other neurons. In this context, the main role of neural networks and intercellular interactions is to form dynamic ensembles of neurons involved in performing a given cognitive function.     

Spontaneous individual differences in cognitive performances of young adult rats predict locomotor response to amphetamine

Inter-individual differences in cognitive capacities of young adult rats have largely been ignored. To explore this variability and its neurobiological bases, the relationships between individual differences in working memory and locomotor responses to novelty and to amphetamine were investigated in SD rats. Groups of good and poor learners were isolated, the latter demonstrating a markedly slower learning of the task compared to performant rats, with more perseverations independently to motivational state. They also presented a much higher increase in amphetamine-induced locomotion that remained significant for more than 1h after the injection. These results provide evidence that variability in cognitive capacities can be used to reveal their neurobiological substrates. They open new perspectives to study a possible cognitive origin of addictive behaviors and to investigate the involvement of these inter-individual differences on those observed later in life.     

眼动技术在个体认知能力差异研究中的应用

本文从可能性和可行性两方面介绍和论述了眼动技术在个体认知能力差异研究中的应用。在可能性方面,个体眼动特征具有的良好的重测信度和内部一致性信度;在可行性方面,已有研究利用注视和眼跳相关指标、眼动轨迹和瞳孔直径这三类指标对该问题进行探索,结果均发现这些眼动特征与认知能力之间存在着密切关系。今后研究应继续深入探索两者关系的内在认知和神经机制,并尝试结合人工智能算法开发高信效度的眼动认知测验。     

Motivation towards closure and cognitive processes: An individual differences approach

Two studies (N = 212) examined the relationships between elementary cognitive processes and individual differences in the need for cognitive closure. The results indicated that the need for closure is linked with certain cognitive deficits, specifically a restricted pool of cognitive resources allocated to a current activity. It was also found that these cognitive limitations tend to be compensated for by a particularly efficient process of information-selection from the environment. However, the selection process is costly, thus in a situation of drainage of cognitive resources its effectiveness also drops and the selection advantage of high (vs. low) need for closure individuals is eliminated.     

Motivation towards closure and cognitive processes: An individual differences approach

Two studies (N = 212) examined the relationships between elementary cognitive processes and individual differences in the need for cognitive closure. The results indicated that the need for closure is linked with certain cognitive deficits, specifically a restricted pool of cognitive resources allocated to a current activity. It was also found that these cognitive limitations tend to be compensated for by a particularly efficient process of information-selection from the environment. However, the selection process is costly, thus in a situation of drainage of cognitive resources its effectiveness also drops and the selection advantage of high (vs. low) need for closure individuals is eliminated.     

Individual-differences assessment of the relationship between change in and initial level of adult cognitive functioning

Methodological factors may have been partially responsible for the inconsistency in findings from previous investigations into the relationship between change in, and initial level of, adult cognitive functioning. An alternative data-analytic procedure is proposed and applied to data from 277 men (25-76 years of age at initial testing) over 3 measurement occasions (interwave intervals of 6.7 years). Performances on both the Benton Revised Visual Retention Test (BVRT) and the Wechsler Adult Intelligence Scale (WAIS) Vocabulary subtest were analyzed. The findings demonstrate that the significant negative relationships between change and initial status, found on both tests, were partially a function of measurement error. Once adjustments were made for errors of measurement, the previously significant negative relationship for the BVRT data became significantly positive, whereas for the WAIS the relationship remained significantly negative, although to a lesser degree. The importance of accounting for errors of measurement is discussed.