Individual differences on speeded cognitive tasks: Comment on Chen,Hale, and Myerson (2007)

Chen, Hale, and Myerson (2007) recently reported a test of the difference engine model (Myerson, Hale, Zheng, Jenkins, & Widaman, 2003). This test evaluated whether the standard deviation (SD) is proportional to the amount of processing—that is, mean reaction time (RT)—in a speeded cognitive task. We show that this evaluation is not a test of the model because its finding is a consequence of relationships in the data. We argue any model structure that produces increasing values of RT as a function of difficulty, with different slopes for different individuals, necessarily produces a correlation between SD and mean RT. We illustrate this with a different model structure—that is, the diffusion model proposed by Ratcliff (1978)—showing that it produces a fan out between fast- and slow-group means and produces the correlation between SD and mean RT that matches the empirical result.     

Working memory and interference: A comment on Jenkins, Myerson, Hale, and Fry (1999)

Jenkins, Myerson, Hale, and Fry (1999) showed that slopes relating complex spans to simple spans were considerably smaller than one, indicating that persons with higher simple spans suffered more interference when the span task was combined with a processing demand. They argued that this finding ruled out accounts of working memory based on interference and/or inhibition of interfering information. We demonstrate that the effect is mainly an artifact from regression to the mean, owing to the low reliability of span scores as used by Jenkins et al. Data from 133 young adults for two verbal and two spatial span tasks show that the slopes relating complex to simple performance are considerably higher for sum scores than for span scores. Furthermore, an adequate test for an interference or an inhibition account of working memory is to predict interference from complex span tasks, not from simple span tasks. Interference effects in the verbal span tasks were negatively correlated with an independent measure of working memory capacity, consistent with the interference/inhibition account.     

Individual differences in performance on elementary cognitive tasks (ECTs): lawful vs. problematic parameters.

Over the past 2 decades, the cognitive-correlates approach has dominated investigations into the nature of intelligence. This research program relies on a number of processing speed parameters (apart from "average performance"). These measures include the slope, intercept, and intraindividual variability of both decision time and movement time. By correlating these measures with established markers of intelligence, researchers postulate theoretical models underlying these information-processing constructs. However, there is a lack of substantive evidence that these phenomena are as robust within the individual as has been proposed. The authors tested the properties of intraindividual parameters by asking participants (N = 179) to perform 10 elementary cognitive tasks (ECTs). Detailed analyses revealed that average performance parameters, extracted from these ECTs, behaved lawfully. However, up to 40% of participants failed to provide acceptable indices of intraindividual model fit. Similarly, intraindividual variability measures appeared less valid than previously suggested. The implications of these findings for cognitive and biological models of intelligence are discussed.     

Individual differences,aging, and IQ in two-choice tasks

The effects of aging and IQ on performance were examined in three two-choice tasks: numerosity discrimination, recognition memory, and lexical decision. The experimental data, accuracy, correct and error response times, and response time distributions, were well explained by Ratcliff’s (1978) diffusion model. The components of processing identified by the model were compared across levels of IQ (ranging from 83 to 146) and age (college students, 60–74, and 75–90 year olds). Declines in performance with age were not significantly different for low compared to high IQ subjects. IQ but not age had large effects on the quality of the evidence that was obtained from a stimulus or memory, that is, the evidence upon which decisions were based. Applying the model to individual subjects, the components of processing identified by the model for individuals correlated across tasks. In addition, the model’s predictions and the data were examined for the “worst performance rule”, the finding that age and IQ have larger effects on slower responses than faster responses.     

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.     

Individual differences in reappraisal ability: Links to reappraisal frequency, well-being, and cognitive control

Reappraisal is generally viewed as an adaptive emotion regulation strategy. Reappraisal frequency has been associated with greater well-being, and reappraisal ability is thought to be composed of several crucial cognitive control processes. However, the relationships among reappraisal ability, reappraisal frequency, well-being, and various cognitive control processes have not yet been determined. In this study, we experimentally examined individual differences in reappraisal ability (RA), and also assessed reappraisal frequency, well-being, and several cognitive control processes. We observed a positive relationship between RA, reappraisal frequency, and well-being. RA was also related positively to working memory capacity and set-shifting costs, and marginally related to abstract reasoning. These findings have important implications for understanding the cognitive components and affective outcomes of RA.     

Individual differences in children's private speech: Consistency across tasks, timepoints, and contexts

Children often talk themselves through their activities. They produce private speech (PS), which is internalized to form inner speech (silent verbal thought). Twenty-five 8-10-year-olds completed four tasks in a laboratory context (Tower of London, digit span, and two measures of spatial IQ). PS production was recorded. Eleven months later, the same participants completed the Tower of London and academic numeracy tasks, again in a laboratory context, as well as numeracy tasks in a classroom context. Rates of PS production and its level of internalization showed large positive correlations across time, tasks, and contexts. The results are interpreted in terms of the psychometric properties of PS production and are taken as evidence for the development of a domain-general system for verbal self-regulation in childhood.     

Individual differences in cognitive style,working memory,and semantic integration

In two experiments subjects classified as being either high or low in field articulation (FA) performed a semantic integration task with high-information load. In Experiment 1, differences in performance between high- and low-FA subjects on an inference and recognition test were obtained when sentences were presented for 5 sec a piece but not when they were presented for 10 sec a piece. In Experiment 2, performance differences between high and low-FA subjects were eliminated by presenting only a specific subset of the sentences for 10 sec a piece. The implications of these results for explanations of FA effects in semantic integration are discussed.     

Multiple,speeded assessments: Initial evidence on subgroup differences and applicant perceptions

Recently, shorter assessments have emerged as potential alternatives for more resourceful traditional selection approaches. Multiple, speeded assessments (MSAs) represent such an alternative. In MSAs, candidates participate in a large number of short (a maximum of 5 min), behavioral simulations in which they face a variety of job situations. Initial psychometric evidence on the validity of MSAs is promising. Yet, validity represents only one piece of evidence. It is not known whether MSAs disadvantage specific subgroups, which may inhibit diversity. There is also no information on candidates' experience of going through an MSA, which is pivotal for the attractiveness of the organization's selection process. Therefore, this study investigates an MSA in terms of subgroup differences (gender and nationality) and applicant perceptions. Master of Business Administration (MBA) students (N = 96) proceeded through 18 short role-plays sampling junior management situations. Score differences between men and women were negligible. Yet, there were large score differences between national citizens and foreigners. There was no evidence for predictive bias for nationality, though. Of the applicant reaction measures, interpersonal treatment perceptions contributed most to overall fairness perceptions. These findings add to the evidence in support of MSAs, while also stressing to remain vigilant for potential score differences among subgroups.     

Individual differences in cognitive control on self-referenced and other-referenced memory

Self-referenced information is better recalled than other-referenced information – a mnemonic advantage known as the “self-reference effect” (SRE). By using a modified version of the “think/no-think” (TNT) paradigm (Anderson & Green, 2001), this study examined the effects of cognitive control on the SRE after the encoding stage. The results indicate that individual differences in personality traits and affective states strongly modulated the SRE after the TNT phase. For individuals high in negative cognitive style, an ironic enhancement of negative self-referenced memory produced a “maladaptive” SRE: better memory for negative self-referenced information than for negative other-referenced information, when trying to suppress that information. Before the TNT phase, instead, the SRE was characterized by the opposite bias. These results indicate that (1) the SRE is strongly affected by cognitive control after encoding, and (2) also in the non-clinical population, dysfunctional cognitive control can transform the SRE into a “maladaptive” memory bias.     

Effects of focusing strategy on speeded classification with grouping,filtering, and condensation tasks

Speeded classification was studied with three tasks varying in the way in which extra stimuli are provided for a single class:grouping, with additional levels on a single relevant dimension;filtering, with additional levels on an irrelevant dimension; andcondensation, with additional levels on a second relevant dimension. (Both relevant dimensions must be processed for correct classification.) For the dimensions used (color and form), filtering was easiest, followed by grouping and condensation. In the latter two cases, asymmetric classifications, in which one class had a single member, eliminated the difficulty of classification. The presumed mechanism is focusing, in which the single stimulus is seen as a positive set and all other stimuli as negative.     

Individual differences in social, cognitive, and morphological aspects of infant pointing

Little is known about the origins of the pointing gesture. We sought to gain insight into its emergence by investigating individual differences in the pointing of 12-month-old infants in two ways. First, we looked at differences in the communicative and interactional uses of pointing and asked how different hand shapes relate to point frequency, accompanying vocalizations, and mothers’ pointing. Second, we looked at differences in social-cognitive skills of point comprehension and imitation and tested whether these were related to infants’ own pointing. Infants’ and mothers’ spontaneous pointing correlated with one another, as did infants’ point production and comprehension. In particular, infants’ index-finger pointing had a profile different from simple whole-hand pointing. It was more frequent, it was more often accompanied by vocalizations, and it correlated more strongly with comprehension of pointing (especially to occluded referents). We conclude that whole-hand and index-finger pointing differ qualitatively and suggest that it is index-finger pointing that first embodies infants’ understanding of communicative intentions.     

Individual differences in cognitive control processes and their relationship to emotion regulation

Cognitive control and emotional control share many similarities, but the specific relationship between these processes is not well understood. This study explored the relationship between three types of cognitive control (working memory updating, response inhibition and set-shifting) and two emotional regulation strategies (expressive suppression and cognitive reappraisal). Corrugator electromyography, behaviour and self-reports of affect were measured as indices of emotion regulation. Results indicate that working memory updating predicted negative affect reduction during reappraisal and during expressive suppression. This study specifically shows that the working memory component of cognitive control is associated with negative affect reduction. Response inhibition and set-shifting were not specifically related to negative affect reduction, but these variables did predict aspects of emotional behaviour and regulation. These results suggest a general role for cognitive control in some aspects of emotion regulation as well as a specific modulatory role for working memory updating in the regulation of negative affect.     

Making strides in modeling individual differences: reply to Leite, Ratcliff, and White (2007)

Leite, Ratcliff, and White (2007) claimed that the diffusion model (Ratcliff, 1978) could simulate the molar patterns in response times (RTs) from the multiple tasks observed by Chen, Hale, and Myerson (2007). We present our own simulations to clarify the underlying mechanisms and show that, as is predicted by the difference engine model (Myerson, Hale, Zheng, Jenkins, & Widaman, 2003), correlations across tasks are the key to the molar patterns in individual RTs. Although the diffusion model and other sequential-sampling models may be able to accommodate patterns of RTs across tasks like those studied by Chen et al., the difference engine is the only current model that actually predicts them.     

Individual differences in hypothetic-deductive reasoning: importance of cognitive skills and flexibility

Recent investigations show that people's differential performance when solving reasoning tasks is due to differences not only at computational level, but also at the rational or intentional level. This study is within the framework of this context and it specifically analyses individual differences in hypothetic-deductive reasoning, taking into account the characteristics associated with the task itself (content and instructions) as well as the individuals' differential characteristics. Two hundred and seventy-six students from the University of Santiago de Compostela participated in this study. Several psychometric tests were administered and participants were requested to solve various reasoning tasks. The results obtained confirm that, in effect, the differences between competent and non-competent reasoners are observed at both the above-mentioned levels: cognitive skills and abilities (algorithmic level) and cognitive flexibility (intentional level).     

Psychopathic personality traits and cognitive dissonance: Individual differences in attitude change

In a study using a classic cognitive dissonance paradigm, 164 undergraduate participants were induced to deceive a fellow student; half were directly instructed to lie whereas the other half were politely requested but not instructed to lie. Participants were assessed for psychopathic traits using the Psychopathic Personality Inventory-Revised: Short Form and the Levenson Self-Report Psychopathy Scale, and for Machiavellianism using the MACH-IV. As predicted, participants low in psychopathic traits exhibited classic cognitive dissonance effects following their lie whereas participants high in psychopathic traits did not. Results for Machiavellianism were nonsignificant. These results indicate that cognitive dissonance effects in an induced compliance paradigm are reduced or eliminated among individuals with high levels of psychopathic traits.     

Paap and Noel revisited: Individual differences in independent word recognition tasks in relation to the dual-task paradigm

Paap and Noel (1991) found that participants' pronunciation latencies were faster for low-frequency irregular words when named under a concurrent high digit memory load than when named under a low load. The effects reported by Paap and Noel have proved difficult to replicate in subsequent studies. The present research suggests that individual differences in word recognition skill relate to who will or will not show these effects. In two experiments, participants were allocated to skill groups on the basis of latency in tasks tapping lexical and sub-lexical reading processes. In both studies, only one group (the "intermediate skilled"), showed evidence of such effects. A combined analysis of the data from Experiments 1 and 2 was carried out. This confirmed and extended the analyses of the individual experiments. The results are discussed in relation to contemporary models of word recognition.