Differences In Mental Ability Research Articles

Team Cohesion Profiles: Influence on the Development of Mental Skills and Stress Management.

High-level sports competitions involve facing highly challenging situations. Athletes must maintain strong team cohesion with peers, have specific mental abilities, and high-stress control to overcome adversity and report high sports performance. This research aimed to identify team cohesion profiles and examine whether participants differed significantly in their mental abilities and stress management. The sample consisted of 146 promising and talented athletes from the Sports Talent Development of the Provincial Council of Guipúzcoa (Spain) (Mage = 20.08; SD = 4.68), who completed the questionnaire on Psychological Characteristics Related to Sports Performance (CPRD). Cluster analyzes revealed three profiles; (a) profile with low team cohesion; (b) profile with average team cohesion; (c) profile with high team cohesion. Results showed significant differences in mental abilities (i.e., positive self-talk), and marginally significant differences in self-confidence, between the profiles. The best scores were reported in profile (b). In conclusion, the combination of low individualism, high social cohesion, and medium team spirit seems to be the most recommendable for promoting mental abilities and self-confidence in athletes' samples. As practical implications, the programs that train the mental abilities of athletes and control management should consider the importance of team cohesion to obtain improvements in the results of the competitions.

Intrinsic network interactions explain individual differences in mentalizing ability in adolescents

Mentalizing is an important aspect of social cognition and people vary in their ability to mentalize. Despite initial evidence that mentalizing continues to develop throughout adolescence, it is unclear which neural mechanisms underlie individual variability in mentalizing ability in adolescents. Interactions within and between the default-mode network (DMN), frontoparietal network (FPN) and cingulo-opercular/salience network (CO/SN) have been related to inter-individual differences in cognitive processes in both adults and adolescents. Here, we investigated whether intrinsic connectivity within and between these brain networks explained inter-individual differences in affective mentalizing ability in adolescents. Resting-state brain activity was measured using functional MRI and affective mentalizing ability was defined as correct performance on the Reading the Mind in the Eyes test performed outside the scanner. We identified the DMN, FPN and CO/SN, and within and between network connectivity values were submitted to a bootstrapping enhanced penalized multiple regression analysis to predict mentalizing in 66 young adolescents (11–14 years). We showed that stronger connectivity between the DMN and the FPN, together with lower within-network connectivity of the FPN and the CO/SN predicted better mentalizing performance. These novel findings provide insight into the normative developmental trajectory of the neural mechanisms underlying affective mentalizing in early adolescence.

On the Relationship between P3 Latency and Mental Ability as a Function of Increasing Demands in a Selective Attention Task.

The mental speed approach to individual differences in mental ability (MA) is based on the assumption of higher speed of information processing in individuals with higher than those with lower MA. Empirical support of this assumption has been inconsistent when speed was measured by means of the P3 latency in the event-related potential (ERP). The present study investigated the association between MA and P3 latency as a function of task demands on selective attention. For this purpose, 20 men and 90 women performed on a standard continuous performance test (CPT1 condition) as well as on two further task conditions with lower (CPT0) and higher demands (CPT2) on selective attention. MA and P3 latency negatively correlated in the standard CPT, and this negative relationship even increased systematically from the CPT1 to the CPT2 condition but was absent in the CPT0 condition. The present results indicate that task demands on selective attention are decisive to observe the expected shorter P3 latency in individuals with higher compared to those with lower MA.

Decomposing the functional relationship between speed of information processing in the Hick paradigm and mental ability: A fixed-links modeling approach

In his scholarly work, Bob Stelmack insistently reminded that response times represent an index of various cognitive processes that are unlikely to be functionally related to individual differences in mental ability to the same extent. Here, we introduce a fixed-links modeling approach to cope with this so-called impurity problem inherent in virtually all reaction time (RT) measures used within the mental speed approach to intelligence. For this purpose, we decomposed the variance of individual differences in RT obtained with the Hick RT paradigm into an experimental latent variable (LV) representing individual differences in RT associated with the systematically increased number of response alternatives in the Hick task, and a non-experimental LV representing individual differences in RT unrelated to this experimental manipulation. While the experimental LV explained a significant portion of 11.6% of variance in mental ability, the non-experimental LV accounted for only 2.6%. This outcome clearly indicates that, with the Hick RT paradigm, the functional relationship between speed of information processing and mental ability is primarily caused by individual differences in decision latency as a function of the experimentally increased number of response alternatives. Fixed-links modeling proved to be a highly suitable procedure to deal with the impurity problem.

Discounting IQ’s Relevance to Organizational Behavior: The “Somebody Else’s Problem” in Management Education

We hypothesize the existence of a “somebody else’s problem” in management education for the subdiscipline of organizational behavior (OB). The problem regards human intelligence, specifically, the general factor, g. Although g is arguably the most powerful variable in social science, OB educators largely ignore it. To demonstrate the former, we review a vast literature establishing g’s construct validity. To demonstrate the latter, we show that current OB textbooks place far less emphasis on g relative to a popular but less potent predictor of organizational success, emotional intelligence. We also show that when textbooks do reference g, it is often just to offer criticism. Misconceptions about empirical data on intelligence testing, denial that a general factor of intelligence exists, the reality of mean racial differences in mental ability, and the finding that genes play a non-trivial role in causing intelligence, seem to make OB’s treatment of this topic “somebody else’s problem.”

Mental ability, P300, and mismatch negativity: Analysis of frequency and duration discrimination

Individual differences in mental ability (MA) were examined with event-related potentials (ERP). In addition to using an auditory frequency discrimination task, a duration discrimination task was used to elicit P300 and mismatch negativity (MMN) components of the ERP. Frequency and duration P300 latencies explained 9% and 10% of variance of MAB performance scores independently of each other and commonly 28% of variance. The finding that duration P300 latency explained variance of MA independent of that explained by frequency P300 latency, suggests that temporal information processing is partly dissociable from processing of frequency information in its prediction of MA. Duration and frequency MMNs were shown to be indices of discrimination ability and predicted 11% of variance of MAB performance scores. The outcome of the present study not only emphasizes the importance of both mental speed and discrimination ability for MA but also points to the significance of duration- and frequency-related ERP measures for the understanding of underlying brain mechanisms.

Impulsivity, intelligence and P300 wave: An empirical study

The aim of this study was to analyze the relationships among impulsivity, intelligence and P300, a well-known component of the event-related potential widely studied in personality and intelligence research. Eighty-two males completed the Barratt Impulsiveness Scale and the two-subtest form of the Wechsler Abbreviated Scale of Intelligence. A subsample of 45 participants (mean age = 24.4, SD = 4.6) performed a visual oddball task, consisting of a two-letter recognition task, during which psychophysiological data were recorded. Although no significant relationships emerged for P300 latency, overall results suggest that the P300 amplitude was positively related to IQ and negatively related to impulsivity. Those who scored high on impulsivity (high impulsives) had lower P300 amplitudes than low impulsives, but this relationship was not significant when controlling for individual differences in mental ability. The results also showed an inverse relationship between mental ability and impulsivity. That is, high impulsives demonstrated reduced cognitive performance on intelligence testing and it is reflected in their reduced P300 amplitude. These findings are likely due to high impulsives' less efficient ability to inhibit task-irrelevant information or to ignore additional information intake. It was suggested that impulsivity exerts a disadvantageous influence on the performance of tasks (such as those used on intelligence tests) in which exclusive concentration and sustained attention are necessary.

Intelligence and P3 components of the event-related potential elicited during an auditory discrimination task with masking

The relationship between fluid intelligence (indexed by scores on Raven Progressive Matrices) and auditory discrimination ability was examined by recording event-related potentials from 48 women during the performance of an auditory oddball task with backward masking. High ability (HA) subjects exhibited shorter response times, greater response accuracy, larger P3b amplitude and shorter P3b latency to target stimuli than the lower ability (LA) subjects. There were no differences between high and low ability groups for the P3a component of the ERP. Correlation and multiple regression analyses indicated that frontal P3b latency and, to a smaller extent, P3b amplitude are the best predictors of mental ability. These results are consistent with previous studies reporting a relation between intelligence and ERPs and provide further evidence that individual differences in mental ability are reflected in the P3b component, an electrocortical index of the efficiency of stimulus evaluation processes.

Sex differences in mental ability: A proposed means to link them to brain structure and function

Recent work with the 42 mental ability tests administered to participants of the Minnesota Study of Twins Reared Apart (MISTRA) has suggested that there are important dimensions of mental ability that function independently of g. Two of these dimensions, rotation–verbal and focus–diffusion, appear to involve trade-offs: greater residual rotation ability implies less residual verbal ability and vice-versa, and the focus–diffusion dimension functions similarly. These two uncorrelated dimensions also show strong sex differences. Individuals lying at different positions along these dimensions may have brains that differ structurally and/or functionally, leading to differences in the ways they approach mental ability tasks. If so, we should expect a lack of factorial invariance in test scores across groups of individuals lying at different positions on the two dimensions, indicating that the tests do not measure the same constructs in the same ways in the different groups. This study demonstrated such a lack of factorial invariance in each of the three mental ability batteries included in the MISTRA assessment. The Wechsler Adult Intelligence Scale can be scored to correlate .7 with each of the two dimensions. We propose that use of these scores may help to clarify brain-mapping studies relating brain structure and function and to facilitate understanding of sex differences in mental abilities.

Sex differences in mental abilities: g masks the dimensions on which they lie

Empirical data suggest that there is at most a very small sex difference in general mental ability, but men clearly perform better on visuospatial tasks while women clearly perform better on tests of verbal usage and perceptual speed. In this study, we integrated these overall findings with predictions based on the Verbal–Perceptual–Rotation (VPR) model ([Johnson, W., and Bouchard, T. J. (2005a). Constructive replication of the visual–perceptual–image rotation (VPR) model in Thurstone's (1941) battery of 60 tests of mental ability. Intelligence, 33, 417–430.; Johnson, W., and Bouchard, T. J. (2005b). The structure of human intelligence: It's verbal, perceptual, and image rotation (VPR), not fluid and crystallized. Intelligence, 33. 393–416.]) of the structure of mental abilities. We examined the structure of abilities after removing the effects of general intelligence, identifying three underlying dimensions termed rotation–verbal, focus–diffusion, and memory. Substantial sex differences appeared to lie along all three dimensions, with men more likely to be positioned towards the rotation and focus poles of those dimensions, and women displaying generally greater memory. At the level of specific ability tests, there were greater sex differences in residual than full test scores, providing evidence that general intelligence serves as an all-purpose problem solving ability that masks sex differences in more specialized abilities. The residual ability factors we identified showed strong genetic influences comparable to those for full abilities, indicating that the residual abilities have some basis in brain structure and function.

Sex differences in common Marmosets (Callithrix jacchus) in response to an unfamiliar food task.

There is a growing body of information on sex differences in callitrichid behaviour that includes the animals' performance in food tasks. For example, both reproductive and non-reproductive adult females have been found to be more successful than adult males in solving food tasks. In this study ten adult male and ten adult female common marmosets (Callithrix jacchus), housed individually, were tested with an unfamiliar task that involved the extraction of an embedded food. The task was to open a plastic canister that contained a raisin; the open end was covered with parchment paper. Each marmoset was given 15 trials in three blocks of 5 consecutive days. We measured the latency for each animal to open the lid and get the raisin--by one of five strategies that spontaneously emerged. The females learned the task faster and more efficiently than males; all the females opened the canister on day 1, for instance, in contrast to seven of the males on the same day. Females also progressively decreased the time that they took to open the tube. The final latency on day 15, for instance, was significantly shorter for the females. These results are consistent with relevant literature for callitrichids and cannot be accounted for in terms of differences in mental abilities, strength, hand morphology, or energy requirements. Further investigation is necessary to clarify the reasons for these differences.

Differences in Mental Abilities between Musicians and Non-Musicians

Psychometric performance on different aspects of primary mental abilities (verbal comprehension, word fluency, space, closure, perceptual speed, reasoning, number and memory) was compared in 35 adult musicians and non-musicians. Significant differences could not be revealed for either mean full-scale scores or for specific aspects of intelligence, except verbal memory and reasoning. While performance on verbal memory was reliably higher for the musicians than for the non-musicians, non-musicians performed significantly better on all four subscales of Cattell’s Culture Free Intelligence Test, Scale 3. This latter finding is consistent with the assumption that musical talent may be associated more with intuitive rather than logical thinking. Musicians’ superior performance on verbal memory supports the notion that long-term musical training exerts beneficial effects on verbal memory, which is most likely due to changes in cortical organization.

Intelligence and neural transmission time: a brain stem auditory evoked potential analysis

Brain stem auditory evoked potential (BAEP) measures were employed to assess the association of individual differences in mental ability and neural transmission time. The BAEP to brief click stimuli at 72, 80 and 88 dB intensity was recorded from 54 female participants. Overall, low positive correlations between full-scale intelligence (FIQ), as measured by the Multidimensional Aptitude Battery, and BAEP latency were observed, with salient effects at the 80 dB intensity level for wave III, wave V and interpeak latency I–V. The association of higher ability (HA) with longer BAEP latency contradicts the hypothesis of faster neural transmission for HA. Head size was also positively correlated with both mental ability and BAEP latency. An analysis using measures of head width and interpeak latency to calculate nerve conduction velocity (NCV) associated higher verbal intelligence with slower auditory NCV.

Reaction times and intelligence differences: A population-based cohort study

The association between reaction times and psychometric intelligence test scores is a major plank of the information-processing approach to mental ability differences. An important but unavailable datum is the effect size of the correlation in the normal population. Here we describe the associations between scores on a test of general mental ability (Alice Heim 4, AH4) and reaction times using a ‘Hick’-style device. The sample is 900 people aged 56 years who are broadly representative of the Scottish population. AH4 Part I total scores correlated −.31 with simple reaction time, −.49 with four-choice reaction time, and −.26 with intraindividual variability in both reaction time procedures. The correlation between AH4 scores and the difference between simple and four-choice reaction time was −.15. Separate analyses were conducted after partitioning the total group according to sex, educational level, social class grouping, and number of errors on the four-choice reaction time task. None of these factors significantly altered the effect sizes. This is the first report of reaction time and psychometric intelligence in a large, normal sample of the population. It provides a benchmark for other studies and suggests larger effect sizes than the majority of present studies, which are dominated by young student samples.

Racial Differences in IQ Revisited: A Synthesis of Nearly a Century of Research

This article presents a synthesis of arguments disputing the existence of racial-ethnic differences in mental ability, and it challenges the classicist model of “intelligence” on which hereditarian assumptions of racial disparity are based. A review of the literature reveals the following eight major premises held by supporters of this perspective: (a) intelligence is unidimensional and can be represented by a single factor, g; (b) intelligence is fixed within individuals and across generations; (c) IQ tests accurately measure this fixed ability; (d) IQ tests are equally valid across racial, ethnic, and cultural groups; (e) intelligence determines individuals’ professional and social standings; (f) environment plays little role in determining an individual’s intelligence; (g) the intelligence of populations is deteriorating over time; and (h) scores on IQ tests are consistent with classical statistical and measurement theory. Each premise is refuted on the basis of historical, sociological, psychological, and statistical evidence.

Individual differences in cognition: British contributions over a century

Research on individual differences in mental abilities is discussed from three viewpoints: the psychometric structure of ability differences, the predictive validity of mental test scores, and some putative causes of psychometric intelligence differences in terms of psychometric and cognitive components and biological indices. A hierarchical descriptive structure for mental ability differences, as it emerged in the 1980s and 1990s, prominently displays British discoveries and suggestions, especially those of Spearman, Burt and P. E. Vernon from the first half of the 20th century. Galton and Spearman's largely unproductive search for the origins of ability differences has seen new activity since the 1970s, and there are several replicable associations that are yet to be explained. Over the 20th century the emphasis has been on measuring mental ability differences; at its beginning there was an emphasis (largely British) on understanding psychometric intelligence. The new century is likely to see a continuation of this re-emphasis on explaining human ability differences.

Psychometric intelligence differences and brain function.

Psychometric intelligence attracts a converging consensus about its phenotypic structure. Mental ability test scores have proven predictive validity. However, although individual differences in mental abilities can be measured, they are not understood. A long-standing aim of the 'London School' of British psychologists, since Galton and Spearman, is to understand the origins of psychometric intelligence differences in terms of individual differences in brain processes. The history of this research is described, as is the rise in interest since the 1970s. The first problem, met since antiquity, is to discover the relevant levels of brain function. Thus, aspects of brain function that 'explain' psychometric intelligence differences are sought at psychometric, cognitive, psychophysical, physiological, neurochemical and genetic levels. The growing points and dead-ends within each of these levels are identified. Special attention is given to research that crosses levels of description of brain function. Two types of multi-level brain function research are discussed, 'correlational' and 'circumstantial/experimental,' and examples of each are described. Illustrating both approaches, there is a detailed account of research on inspection time that discusses how psychometric intelligence-brain process correlations at one level (psychophysical) may be expanded using event-related potentials, psychopharmacology and functional magnetic resonance imaging.

The Stability of Individual Differences in Mental Ability from Childhood to Old Age: Follow-up of the 1932 Scottish Mental Survey

All Scottish children born in 1921 and attending school on June 1, 1932 ( N=87,498) undertook a validated test of psychometric intelligence, The Moray House Test. We followed up 101 of these people at age 77 and re-administered the same mental ability test. Concurrent validity data are provided for the Moray House Test at age 11 ( n=1,000) and age 77 years ( n=97). The correlation between Moray House Test scores at age 11 and age 77 was 0.63, which adjusted to 0.73 when corrected for attenuation of ability range within the re-tested sample. This, the longest follow-up study of psychometric intelligence reported to date, shows that mental ability differences show substantial stability from childhood to late life.

Do individual differences in speed reflect “global” or “local” differences in mental abilities?

Two centuries of investigation suggest that decision times on simple laboratory tasks can sometimes partially reflect speed of elementary neurophysiological processes. Consequently, findings that decision times on a variety of simple tasks also modestly correlate with scores on intelligence tests have been taken as evidence that individual differences in general fluid ability also reflect individual differences in neurophysiological efficiency. A further questions is whether these differences are “global,” in the sense that they affect all cognitive systems equally, or “local” in the sense that they affect some cognitive systems more than others. A finding that test scores have constant proportional effects on decision times for all cognitive tasks, irrespective of their demands, would suggest a “global” effect, whereas a finding that test scores have different effects on different tasks would suggest local effects. Comparisons by many eminent psychometricians have suggested local specificity of effects. However, when replotted, their published data seem to offer equally strong support for a “global” hypothesis. So does a new analysis of data from 15 different cognitive tasks taken by 93 volunteers with scores on the Cattell Culture Fair test ranging from 11 to 40 points. However, further inspection of these results shows that rather than having equal, scalar effects on all tasks differences in Cattell scores systematically affected performance on some tasks more than on others. This article discusses implications of demonstrations of “local” rather than “global” individual differences for recent models of the relationship between general ability and information processing speed.

The Hoffmann reflex from the flexor pollicis longus of the thumb in left-handed subjects: spinal motor asymmetry and supraspinal facilitation to Cattell's intelligence test.

The spinal motor asymmetry was studied in left-handers. Hand preference was assessed by Geschwind scores (GS), and hand skill by peg moving task, the reflex responses were recorded from the long flexor muscle of the thumb. The H-reflex could be elicited by averaging during cortico-spinal facilitation (voluntary isometric force). The Cattell's Culture Fair Intelligence Test was used to assess the individual differences in mental abilities. H-reflexes were found to be significantly larger on the left than the right side. The amplitude of H-reflex increased linearly with force applied to transducer by the thumb. This facilitation was more pronounced for the left than the right reflexes. Removal of the visual visual input caused facilitation in H-reflex (supraspinal disinhibition). Post-activation potentiation was also observed in H-reflex. There was a positive linear correlation between the degree of left-hand preference (-GSs) and left-hand skill. The correlation for the right-hand skill was not significant. There was a linear correlation between the degree of left-hand preference and the right minus left hand skill. There was an inverse correlation between left-hand skill and H-reflex from left. The correlation for the right side did not reach the 5% significance level. The force-reflex relation did not show any significant change to IQ for the right H-reflex. The left H-reflexes were significantly larger in subjects with high IQ than those with low IQ. The regression line and its slope for the force-reflex relation on the left was found to be higher in subjects with high IQ than those with low IQs. There was a positive linear relationship between IQ and H reflex from left. The correlation for the right side was not as pronounced as that for the left side. The left minus right H reflex was also positive linearly correlated with IQ. These results provide further evidence for the psycho-motor hypothesis (Tan. 1988b) as well as the spinal motor asymmetry to handedness. It was suggested that lateralization of cognitive and motor functions would be essential to create subjects with high psychomotor capacity.