Individual Differences In Performance Research Articles

The Cognitive Aging of Episodic Memory: A View Based on the Event-Related Brain Potential

A cardinal feature of older-adult cognition is a decline, relative to the young, in the encoding and retrieval of personally relevant events, i.e., episodic memory (EM). A consensus holds that familiarity, a relatively automatic feeling of knowing that can support recognition-memory judgments, is preserved with aging. By contrast, recollection, which requires the effortful, strategic recovery of contextual detail, declines as we age. Over the last decade, event-related brain potential (ERPs) have become increasingly important tools in the study of the aging of EM, because a few, well-researched EM effects have been associated with the cognitive processes thought to underlie successful EM performance. EM effects are operationalized by subtracting the ERPs elicited by correctly rejected, new items from those to correctly recognized, old items. Although highly controversial, the mid-frontal effect (a positive component between ∼300 and 500 ms, maximal at fronto-central scalp sites) is thought to reflect familiarity-based recognition. A positivity between ∼500 and 800 ms, maximal at left-parietal scalp, has been labeled the left-parietal EM effect. A wealth of evidence suggests that this brain activity reflects recollection-based retrieval. Here, I review the ERP evidence in support of the hypothesis that familiarity is maintained while recollection is compromised in older relative to young adults. I consider the possibility that the inconsistency in findings may be due to individual differences in performance, executive function, and quality of life indices, such as socio-economic status.

Exposure to the self-face facilitates identification of dynamic facial expressions: influences on individual differences.

A growing literature suggests that the self-face is involved in processing the facial expressions of others. The authors experimentally activated self-face representations to assess its effects on the recognition of dynamically emerging facial expressions of others. They exposed participants to videos of either their own faces (self-face prime) or faces of others (nonself-face prime) prior to a facial expression judgment task. Their results show that experimentally activating self-face representations results in earlier recognition of dynamically emerging facial expression. As a group, participants in the self-face prime condition recognized expressions earlier (when less affective perceptual information was available) compared to participants in the nonself-face prime condition. There were individual differences in performance, such that poorer expression identification was associated with higher autism traits (in this neurocognitively healthy sample). However, when randomized into the self-face prime condition, participants with high autism traits performed as well as those with low autism traits. Taken together, these data suggest that the ability to recognize facial expressions in others is linked with the internal representations of our own faces.

Speechreading Development in Deaf and Hearing Children: Introducing the Test of Child Speechreading

In this article, the authors describe the development of a new instrument, the Test of Child Speechreading (ToCS), which was specifically designed for use with deaf and hearing children. Speechreading is a skill that is required for deaf children to access the language of the hearing community. ToCS is a deaf-friendly, computer-based test that measures child speechreading (silent lipreading) at 3 psycholinguistic levels: (a) Words, (b) Sentences, and (c) Short Stories. The aims of the study were to standardize the ToCS with deaf and hearing children and to investigate the effects of hearing status, age, and linguistic complexity on speechreading ability. Eighty-six severely and profoundly deaf children and 91 hearing children participated. All children were between the ages of 5 and 14 years. The deaf children were from a range of language and communication backgrounds, and their preferred mode of communication varied. Speechreading skills significantly improved with age for both groups of children. There was no effect of hearing status on speechreading ability, and children from both groups showed similar performance across all subtests of the ToCS. The ToCS is a valid and reliable assessment of speechreading ability in school-age children that can be used to measure individual differences in performance in speechreading ability.

Are age-related changes in cognitive function driven by age-related changes in sensory processing?

Although there has been keen interest in the association among measures of sensory function and cognitive function for many years, in general, measures of sensory function have been confined to one or two senses and measures of threshold sensitivity (acuity). In this study, rigorous psychophysical measures of threshold sensitivity, temporal gap detection, temporal order identification, and temporal masking have been obtained, in hearing, vision, and touch. In addition, all subjects completed 15 subtests of the Wechsler Adult Intelligence Scale, 3rd edition (WAIS–III). Data were obtained from 245 adults (18–87 years old) for the WAIS–III and for 40 measures of threshold sensitivity and temporal processing. The focus in this report is on individual differences in performance for the entire data set. Principal-components (PC) factor analysis reduced the 40 psychophysical measures to eight correlated factors, which were reduced further to a single global sensory processing factor. Similarly, PC factor analysis of the 15 WAIS–III scores resulted in three correlated factors that were further reduced to a single global cognitive function factor. Age, global sensory processing, and global cognitive function were all moderately and significantly correlated with one another. However, paired partial correlations, controlling for the third of these three measures, revealed that the moderate correlation between age and global cognitive function went to zero when global sensory processing was controlled for; the other two partial correlations remained intact. Structural models confirmed this result. These analyses suggest that the long-standing observation of age-related changes in cognitive function may be mediated by age-related changes in global sensory processing.

Fractionating Human Intelligence

What makes one person more intellectually able than another? Can the entire distribution of human intelligence be accounted for by just one general factor? Is intelligence supported by a single neural system? Here, we provide a perspective on human intelligence that takes into account how general abilities or "factors" reflect the functional organization of the brain. By comparing factor models of individual differences in performance with factor models of brain functional organization, we demonstrate that different components of intelligence havetheir analogs in distinct brain networks. Using simulations based on neuroimaging data, we show that the higher-order factor "g" is accounted for by cognitive tasks corecruiting multiple networks. Finally, we confirm the independence of these components of intelligence by dissociating them using questionnaire variables. We propose that intelligence is an emergent property of anatomically distinct cognitive systems, each of which has its own capacity.

Domain-specific and domain-general constraints on word and sequence learning

The relative influences of language-related and memory-related constraints on the learning of novel words and sequences were examined by comparing individual differences in performance of children with and without specific deficits in either language or working memory. Children recalled lists of words in a Hebbian learning protocol in which occasional lists repeated, yielding improved recall over the course of the task on the repeated lists. The task involved presentation of pictures of common nouns followed immediately by equivalent presentations of the spoken names. The same participants also completed a paired-associate learning task involving word-picture and nonword-picture pairs. Hebbian learning was observed for all groups. Domain-general working memory constrained immediate recall, whereas language abilities impacted recall in the auditory modality only. In addition, working memory constrained paired-associate learning generally, whereas language abilities disproportionately impacted novel word learning. Overall, all of the learning tasks were highly correlated with domain-general working memory. The learning of nonwords was additionally related to general intelligence, phonological short-term memory, language abilities, and implicit learning. The results suggest that distinct associations between language- and memory-related mechanisms support learning of familiar and unfamiliar phonological forms and sequences.

Multidisciplinary Concepts in Ergonomic Design and Individual Differences in Performance

The purpose of this panel is to discuss controversial concepts and ideas on individual differences and capacities which should be included in HWH designs. Novel designs necessitate a broad interaction among psychology, physiology, sociology, biomechanics, emerging current health care needs and functional design as an integration of the individual differences within human capabilities and daily necessities. In this session we acknowledge the multidisciplinarity of ergonomic design and the significance of individual differences. We also ask the following questions:

Neural Correlates of Individual Performance Differences in Resolving Perceptual Conflict

Attentional mechanisms are a crucial prerequisite to organize behavior. Most situations may be characterized by a ‘competition’ between salient, but irrelevant stimuli and less salient, relevant stimuli. In such situations top-down and bottom-up mechanisms interact with each other. In the present fMRI study, we examined how interindividual differences in resolving situations of perceptual conflict are reflected in brain networks mediating attentional selection. Doing so, we employed a change detection task in which subjects had to detect luminance changes in the presence and absence of competing distractors. The results show that good performers presented increased activation in the orbitofrontal cortex (BA 11), anterior cingulate (BA 25), inferior parietal lobule (BA 40) and visual areas V2 and V3 but decreased activation in BA 39. This suggests that areas mediating top-down attentional control are stronger activated in this group. Increased activity in visual areas reflects distinct neuronal enhancement relating to selective attentional mechanisms in order to solve the perceptual conflict. Opposed to good performers, brain areas activated by poor performers comprised the left inferior parietal lobule (BA 39) and fronto-parietal and visual regions were continuously deactivated, suggesting that poor performers perceive stronger conflict than good performers. Moreover, the suppression of neural activation in visual areas might indicate a strategy of poor performers to inhibit the processing of the irrelevant non-target feature. These results indicate that high sensitivity in perceptual areas and increased attentional control led to less conflict in stimulus processing and consequently to higher performance in competitive attentional selection.

Using finite mixture of GLMs to explore variability in children's flexibility in a task-switching paradigm

The present study illustrates the usefulness of finite mixture of generalized linear models (GLMs) to examine variability in cognitive strategies during childhood. More precisely, it addresses this variability in set-shifting situations where task-goal updating is endogenously driven. In a task-switching paradigm 5–6-year-olds had to switch between color- and shape-matching rules as a function of a predetermined, predictable task sequence. A finite mixture of GLMs was fitted to explore individual differences in performance. The statistical model revealed five response profiles, defined by accuracy and response times. These response profiles likely correspond to different cognitive strategies with varying efficiency and differential relations to working memory capacity (assessed by backward digit span). These results illustrate the heuristic value of statistical modeling to reveal the behavioral and cognitive variability in the temporal dynamics of children's cognitive functioning.

Brain networks subserving fixed versus performance-adjusted delay stop trials in a stop signal task

The stop signal task is a widely used tool for assessing inhibitory motor control. Two main task variants exist: (1) a fixed delay version, where all volunteers complete the same trials, resulting in performance differences due to individual variation in inhibitory capacity, and (2) a performance-adjusted version that uses a tracking algorithm to equate performance and task difficulty across subjects, leading to ∼50% successful inhibition for every participant. Our aim was to investigate commonalities, mean differences and between-subject variability in brain activation for successful response inhibition between the performance-adjusted and fixed delay version. We conducted a functional magnetic resonance imaging (fMRI) study in 18 healthy individuals, using a within-subject, within-task design where both adjusting and fixed delay trials were analysed separately. Conjunction analyses identified a network of areas involved in successful response inhibition in both task versions. In comparing the fixed and performance-adjusted versions, we found no significant differences between delay conditions during successful inhibition. While activation measures in the inhibitory networks of both delay variants were highly comparable, the neural responses to fixed delay trials were more variable across participants. This suggests that performance-adjusted stop signal tasks may be more suitable for studies in which the performance differences need to be controlled for, such as for developmental or clinical studies. Fixed delay stop signal tasks may be more appropriate in studies assessing the neural basis of individual differences in performance, such as studies of personality traits or genetic associations.

Influences of Sentence Length and Syntactic Complexity on the Speech Motor Control of Children Who Stutter

To investigate the potential effects of increased sentence length and syntactic complexity on the speech motor control of children who stutter (CWS). Participants repeated sentences of varied length and syntactic complexity. Kinematic measures of articulatory coordination variability and movement duration during perceptually fluent speech were analyzed for 16 CWS and 16 typically developing children (CTD) between 4 and 6 years of age. Behavioral data from a larger pool of children were also examined. For both groups, articulatory coordination variability increased with sentence length. For syntactically simple sentences, CWS had higher coordination variability than CTD. There was no group difference in coordination variability for complex sentences. Coordination variability increased significantly with complexity for CTD, whereas that of CWS remained at the high level demonstrated for simple sentences. There was a trend for higher overall coordination variability in CWS compared with CTD. For both groups, movement duration was greater for syntactically complex, as compared with simple, sentences. Results indicate more variable speech motor coordination during fluent speech production in many CWS as compared with CTD. Disproportionate effects of length and complexity on coordination variability and duration were not found for CWS. Considerable individual differences in performance were observed.

Morphometric gray matter differences of the medial frontal cortex influence the social Simon effect

Interacting with others plays a fundamental role in human life. Although several brain regions have recently been associated with complex cognitive control processes, surprisingly little is known about the structural correlates underlying cognitive control processes involved in social interactions. In the present study we used gray matter voxel-based morphometry (VBM) to investigate structural brain correlates of individual performance differences in a social Simon task. Here, two people share a Simon task, which requires each participant to respond to only one of two possible stimuli, rendering the paradigm a go-nogo task, so that a Simon effect - known as the Social Simon Effect (SSE) - is observable across both participants. Using a whole brain approach, we found that inter-individual differences in the SSE are negatively correlated with gray matter (GM) volume of the medial frontal cortex (MFC). The present data indicate that individuals with larger MFC GM volume were those with better conflict resolution in a social Simon task and vice versa. This brain-behavior relationship between cognitive control processes and individual GM volume differences might help to improve our understanding of social interactions in joint task performance.

Spontaneous neural activity predicts individual differences in performance

We each have particular strengths—some of us are good at math and others are good at language—that vary from one person to another. Less appreciated is the fact that individual differences also extend to performing what appear on the surface to be simple perceptual tasks, like learning to detect one visual form among an array of visually similar forms (1, 2). Neurophysiological studies in awake monkeys and functional MRI (fMRI) studies in humans have provided considerable information about the neural changes that accompany visual perceptual learning—including that learning is highly specific to the retinotopic location of the trained stimulus—making it an ideal model system for studying cortical plasticity (3). Typically, there is also a large amount of intersubject performance variability, making it an ideal model for exploring the neural correlates of individual differences. However, other than good learners showing greater neural activity during the first learning trials than poor learners (2), little is known about the neural underpinnings of individual differences in perceptual learning. In PNAS, Baldassarre et al. (4) present a unique approach to this topic by evaluating the relationship between visual perceptual learning and slowly (<0.1 Hz) fluctuating, spontaneous neural activity recorded during an fMRI resting-state scan 1–2 days before learning.

Word Recognition for Temporally and Spectrally Distorted Materials

The purpose of Experiment 1 was to measure word recognition in younger adults with normal hearing when speech or babble was temporally or spectrally distorted. In Experiment 2, older listeners with near-normal hearing and with hearing loss (for pure tones) were tested to evaluate their susceptibility to changes in speech level and distortion types. The results across groups and listening conditions were compared to assess the extent to which the effects of the distortions on word recognition resembled the effects of age-related differences in auditory processing or pure-tone hearing loss. In Experiment 1, word recognition was measured in 16 younger adults with normal hearing using Northwestern University Auditory Test No. 6 words in quiet and the Words-in-Noise test distorted by temporal jittering, spectral smearing, or combined jittering and smearing. Another 16 younger adults were evaluated in four conditions using the Words-in-Noise test in combinations of unaltered or jittered speech and unaltered or jittered babble. In Experiment 2, word recognition in quiet and in babble was measured in 72 older adults with near-normal hearing and 72 older adults with hearing loss in four conditions: unaltered, jittered, smeared, and combined jittering and smearing. For the listeners in Experiment 1, word recognition was poorer in the distorted conditions compared with the unaltered condition. The signal to noise ratio at 50% correct word recognition was 4.6 dB for the unaltered condition, 6.3 dB for the jittered, 6.8 dB for the smeared, 6.9 dB for the double-jitter, and 8.2 dB for the combined jitter-smear conditions. Jittering both the babble and speech signals did not significantly reduce performance compared with jittering only the speech. In Experiment 2, the older listeners with near-normal hearing and hearing loss performed best in the unaltered condition, followed by the jitter and smear conditions, with the poorest performance in the combined jitter-smear condition in both quiet and noise. Overall, listeners with near-normal hearing performed better than listeners with hearing loss by ~30% in quiet and ~6 dB in noise. In the quiet distorted conditions, when the level of the speech was increased, performance improved for the hearing loss group, but decreased for the older group with near-normal hearing. Recognition performance of younger listeners in the jitter-smear condition and the performance of older listeners with near-normal hearing in the unaltered conditions were similar. Likewise, the performance of older listeners with near-normal hearing in the jitter-smear condition and the performance of older listeners with hearing loss in the unaltered conditions were similar. The present experiments advance our understanding regarding how spectral or temporal distortions of the fine structure of speech affect word recognition in older listeners with and without clinically significant hearing loss. The Speech Intelligibility Index was able to predict group differences, but not the effects of distortion. Individual differences in performance were similar across all distortion conditions with both age and hearing loss being implicated. The speech materials needed to be both spectrally and temporally distorted to mimic the effects of age-related differences in auditory processing and hearing loss.

How reliable is the attentional blink? Examining the relationships within and between attentional blink tasks over time

When the second of two targets is presented temporally close (within 500ms) to the first target in rapid serial visual presentation, accuracy for reporting the second target is markedly diminished-an attentional blink (AB). The AB has become a well-studied phenomenon, and multiple different versions of the AB are currently in use. However, little is known about the stability of individual performance on the AB. The current study examined the reliability of two different versions of the AB task (a task-switch and no-task-switch version) within session, and over the period of 7-10days, in order to examine performance stability. In addition to testing the reliability, we also examined the relationship between both versions of our AB tasks. Both versions of the AB were shown to be reliable within session, and over time, suggesting that performance is quite stable on this task. In addition, performance on the two different AB tasks was significantly correlated within and across sessions, suggesting that the AB phenomenon is being accurately captured by versions of the AB that include a task-switch. These findings are important given the recent interest in individual differences in performance on the AB.

Normative benchmarks are useful for studying individual differences in reasoning

AbstractWe applaud many aspects of Elqayam &amp; Evans' (E&amp;E's) call for a descriptivist research programme in studying reasoning. Nevertheless, we contend that normative benchmarks are vital for understanding individual differences in performance. We argue that the presence of normative responses to particular problems by certain individuals should inspire researchers to look for converging evidence for analytic processing that may have a normative basis.

The functional fidelity of individual differences research: the case for context-matching

Applying basic research on individual differences in performance requires a kind of ‘functional fidelity’. That is, the laboratory environment must elicit individual differences in cognition and emotion similar to those seen in the operational setting. Studies of conventional personality traits and performance often lack this functional fidelity. Four research directions for enhancing functional fidelity are proposed. First, a greater focus on simulated operational tasks that require cognitive skills is requisite. Second, contexts relevant to specific personality traits, such as social demands, may be simulated in the laboratory. Third, traits linked to a specific performance context, such as vehicle driving, may be developed and validated. Fourth, psychophysiological responses to tasks that reproduce operational cognitive demands may be used as predictors, as exemplified in recent studies of vigilance. Enhancements to functional fidelity will assist human factors practitioners in accommodating the role of individual differences in operator selection, diagnostic monitoring and augmented cognition.

Dimensions of Judgment: Factor Analysis of Individual Differences

ABSTRACTIn this paper, we explore a pattern of individual differences in performance on judgment tasks. One hundred participants completed a battery of standard judgment tasks, including multiple cue judgment and tasks based on the “heuristics and biases” and problem‐solving literature. Participants also completed tests of fluid and crystallized intelligence, forward digit span memory, and multiple cue probability learning. Confirmatory factor analyses indicated a two‐factor structure underlying performance on these tasks and tests. The two moderately correlated factors reflected a distinction between tasks requiring accurate judgments based on multiple cues (correspondence tasks) and those requiring coherent judgments (coherence tasks), in which probabilities are compared and combined. Measures of fluid and crystallized intelligence and forward digit span memory were correlated with both factors but were more associated with correspondence than with coherence. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Spatial cognition through the keyhole: how studying a real-world domain can inform basic science--and vice versa.

This paper discusses spatial cognition in the domain of minimally invasive surgery. It draws on studies from this domain to shed light on a range of spatial cognitive processes and to consider individual differences in performance. In relation to modeling, the aim is to identify potential opportunities for characterizing the complex interplay between perception, action, and cognition, and to consider how theoretical models of the relevant processes might prove valuable for addressing applied questions about surgical performance and training.

Moving Beyond the Mean in Studies of Mental Chronometry

Although it is widely recognized that response time (RT) distributions are almost always positively skewed and that mathematical psychologists have developed straightforward procedures for capturing characteristics of RT distributions, researchers continue to rely primarily on mean performance, which can be misleading for such data. We review simple procedures for capturing characteristics of underlying RT distributions and show how such procedures have recently been useful to better understand effects from standard cognitive experimental paradigms and individual differences in performance. These well-studied procedures for understanding RT distributions indicate that effects in means can be produced by (a) shifts of RT distributions, (b) stretching of slow tails of RT distributions, or (c) some combination. Importantly, effects in means can actually be obscured by opposing influences on the modal and tail portions of RT distributions. Such disparate patterns demand novel theoretical interpretations.