The relationship between speed of information processing and cognitive ability

Speed of information processing as measured by various reaction time and inspection tasks has been shown to correlate with psychometric intelligence, and it has been suggested that general intelligence (g) is determined to some degree by the speed that information is processed. If this is so, then various measures of speed of information processing should correlate substantially with each other, and each should also correlate with a wide range of psychometric tests that load on g. Alternatively, intelligence may be considered to be a multi-faceted complex of partially related abilities with specific abilities being dependent upon specific cognitive processes. If this is the case, it should be possible to discover independent cognitive processes, some of which correlate with one facet or broad ability and some with another. This paper presents three experiments in which the relationship between intellectual ability and four speed of information processing measures was examined. These were rate of memory scanning, rate of retrieval of information from long term memory, speed of stimulus-response mapping and inspection time (IT). Results showed that correlations between IT and most reaction time measures of speed of information processing were low, and that correlations between different versions of IT were negligible. In addition, some cognitive tasks with verbal material (memory scanning rate for digits and Posner letter matching IT) correlated most substantially with Verbal Reasoning whereas non-verbal (two-line) IT consistently correlated with tests loading on g. It was thus suggested that while non-verbal IT may be a measure of a perceptual speed attribute that contributes to mental functioning, other “speed of information processing” parameters may be more specific to a subset of abilities.     

Visual information processing and intelligence

Measures of inspection time (IT) have robust, moderately-sized correlations with IQ-type test scores. However, the reason for the IT-IQ correlation is not understood. Although the original theory asserted that IT performance was based on a single parameter—essentially speed of visual processing—peculiarities of the task have afforded other interpretations of IT differences and the IT-IQ association. In the present report two new visual processing tasks, visual change detection (VCD) and visual movement detection (VMD) are found to be correlated at or above .4 with IT and with non-verbal scores from the Alice Heim 4 test of general intelligence. VCD and VMD, in common with IT, assess the stimulus duration that is required by subjects in order to make an accurate discrimination. VCD and VMD, however, require a broader attentional focus than IT and do not involve backward masking. Measures of contrast sensitivity, a difficult discrimination task in which stimuli are not time-limited, had near-to-zero correlations with other visual processing tasks and with IQ-type test scores. We tested the hypothesis that only the latent trait derived from the speeded visual processing tasks (rather than task-specific features) would correlate with cognitive ability, and this was supported. The present study adds weight to the view that it is the ability to make accurate discriminations in the face of limited stimulus time that causes IT to correlate with psychometric intelligence. The psychological correlates of VCD, in terms of neural circuits that detect “difference” suggest a new line of investigation into the psychobiological bases of human intelligence.     

Ability EI as an intelligence? Associations of the MSCEIT with performance on emotion processing and social tasks and with cognitive ability

Associations among the MSCEIT, a broad-bandwidth measure of ability emotional intelligence (EI), self-report EI, social perception ability, psychometric intelligence and performance on inspection time (IT) tasks, which assessed the speed of processing of emotional and non-emotional information were investigated in two student samples (N=99, 199). The main findings were that MSCEIT scores were unrelated to fluid ability or speed of non-emotional information processing as assessed by IT, but evidence for associations of MSCEIT scores with crystallised ability was found. Positive associations were found between MSCEIT scores, self-report EI and some emotion/social task scores. The results suggest that EI as assessed by the MSCEIT has some properties of an intelligence and is more closely related to crystallised than to fluid ability. The relatively small MSCEIT/g _c correlations suggest that the MSCEIT is not a pure ability measure, although restriction of range in the samples used may also be relevant. More work, and the development of new measures, is required to determine whether performance EI has a fluid component.     

Still no demonstration that g is not unitary: Further comment on Kranzler and Jensen

Because they employed a statistical procedure that was inappropriate for the purpose, Kranzler and Jensen (1991) have not demonstrated that a factor of general intelligence, g, depends on a number of independent processes. It is more parsimonious to interpret their results in terms of a g that is unitary. A factorial reanalysis of their data, including some that they did not present (cross-correlations between psychometric variables and variables from elementary cognitive tasks, or ECTs), shows that many ECT variables, especially those reflecting decision time rather than movement time, have substantial loadings on a second-order general factor. This factor is orthogonal to a second-order factor representing general speed of movement from a “home button” to the response button in ECTs. Possible implications for interpreting g in terms of information-processing efficiency are discussed.     

Placing inspection time, reaction time, and perceptual speed in the broader context of cognitive ability: The VPR model in the Lothian Birth Cohort 1936

The idea that information processing speed is related to cognitive ability has a long history. Much evidence has been amassed in its support, with respect to both individual differences in general intelligence and developmental trajectories. Two so-called elementary cognitive tasks, reaction time and inspection time, have been used to compile this evidence, but most studies have used either one or the other. Relations between speed and fluid intelligence have tended to be stronger than those between speed and crystallized intelligence, but studies testing this have confounded verbal abilities with crystallized intelligence and spatial/perceptual abilities with fluid intelligence. Questions have also been raised regarding whether speed contributes directly to general intelligence or to more specific cognitive abilities to which general intelligence also contributes. We used 18 ability and speed measures in the Lothian Birth Cohort 1936, assessed at approximately age 70, to construct alternative versions of the Verbal-Perceptual-Image Rotation (Johnson & Bouchard, 2005a) model of cognitive ability to test different hypotheses regarding these issues. Though differences in the extents to which our models fit the data were relatively small, they suggested that reaction and inspection time tasks were comparable indicators of information processing speed with respect to general intelligence, that verbal and spatial abilities were similarly related to information processing speed, and that spatial, verbal, and perceptual speed abilities were more directly related to information processing speed than was general intelligence. We discuss the theoretical implications of these results.     

Correlation between inspection time and psychometric abilities: A personal interpretation

More than 25 years of research suggests that the measure inspection time (IT) does capture low-level aspects of cognitive functioning that contribute to human intelligence. However, recent evidence does not support earlier claims that IT estimates the speed of a single mechanism like “sampling input” or “apprehension.” Rather, together with other tasks that employ pattern backward masking to limit the duration for which information is available for processing, IT is probably sensitive both to focused attentional capacities to detect organization and change under severe time constraints and to decision processes, ongoing beyond mask onset, that monitor responding. Among normal young adults, IT is correlated with the broad psychometric factor Gs (“speediness”). This mediates correlation with general intelligence. In this group, IT is not correlated with Gf. However, whether this outcome generalizes to samples of persons with an intellectual disability, to young children, or to elderly persons is not yet known. Psychological processes underpinning IT are currently only speculatively defined, but it should prove possible to unravel these by experimentation. To this end, backward masking procedures are arguably more theoretically tractable than reaction time tasks because they reduce the impact of higher-level cognitive strategies on performance. On this basis, IT may hold promise as a means for developing partial explanations for intelligence in psychological terms. However, whether this is realized depends on identifying the psychological functions that support IT.     

Genetics and general cognitive ability (g)

Two recent articles in this journal made the case for the existence and importance of g and reviewed research on cognitive and psychophysical correlates of psychometric g. This review considers g from a genetic perspective. Multivariate genetic research indicates that g accounts for nearly all of the genetic variance of diverse psychometric cognitive tests (genetic g). Recent research suggests not only that elementary cognitive tasks are genetically linked to psychometric g but also that genetic g pervades these tasks. Contrary to the assumption of modularity that dominates cognitive science, genetic g exists in the mind as well as in psychometric tests.     

Intelligence and reaction times in the Hick, Sternberg and Posner paradigms

The relationship between psychometric intelligence and reaction times (RTs) in three well-known elementary cognitive tasks (Hick simple and choice reaction time task, Sternberg's short-term memory scanning, Posner's letter matching) was studied in a sample of 116 participants. In conformity with other studies mean RTs and intraindividual variabilities (SDs) of RT were correlated significantly with Raven's Advanced Progressive Matrices (APM). On the basis of the mental speed theory the processing measures or component scores (like slopes in the Hick and Sternberg paradigm and the NI-PI measure in the Posner task) should give the most substantial relationships with intelligence. However, as in other previous studies these measures displayed rather low, albeit significant, relationships with intelligence, which was probably due to the low reliability of these parameters. For the Posner paradigm, we proposed alternative approaches to compute an indicator for long-term memory (LTM) access that gave substantial correlations with intelligence. We conclude that LTM access is significantly associated with psychometric intelligence, whereas up to now there has been no unequivocal evidence for a substantial relationship between short-term memory access in the Sternberg task and intelligence.     

Beyond IQ: A latent state-trait analysis of general intelligence, dynamic decision making, and implicit learning

The present study investigated cognitive performance measures beyond IQ. In particular, we investigated the psychometric properties of dynamic decision making variables and implicit learning variables and their relation with general intelligence and professional success. N = 173 employees from different companies and occupational groups completed two standard intelligence tests, two dynamic decision making tasks, and two implicit learning tasks at two measurement occasions each. We used structural equation models to test latent state-trait measurement models and the relation between constructs. The results suggest that dynamic decision making and implicit learning are substantially related with general intelligence. Furthermore, general intelligence is the best predictor for income, social status, and educational attainment. Dynamic decision making can predict supervisor ratings even beyond general intelligence.     

A measure of inspection time in 4‐year‐old children: The Benny Bee IT task

Inspection time (IT) measures speed of information processing without the confounding influence of motor speed. While IT has been found to relate to cognitive abilities in adults and older children, no measure of IT has been validated for use with children younger than 6 years. This study examined the validity of a new measure of IT for preschool children. N=71 4‐year‐old children completed the new IT task and standardized measures of fluid ability, visuospatial ability, and speed of processing. N=50 adults completed the same tasks and, additionally, a standard IT task. Results showed that the new IT task is a stable, reliable measure of IT in 4‐year‐old children. The new task had reasonable concurrent validity with the standard IT task in adults and the relationships between cognitive abilities, particularly general cognitive ability, and IT are sufficiently similar in young children and adults to suggest that the new IT task may be a useful tool for research in populations where IT was previously not measurable.     

Event-related-potential (ERP) correlates of cognitive styles,abilities and aptitudes

Fifty, right-handed males were given 11 psychometric tests of cognitive styles, abilities and aptitudes. Visual (VERP), auditory (AERP) and bimodal (BERP) brain event-related-potential (ERP) amplitudes were recorded from each of these Ss. Canonical and product-moment correlations were computed. These analyses established that VERPs and BERPs elicited in the frontal, temporal, parietal and occipital regions were related to abilities and aptitudes: general aptitude, reading and verbal comprehension and spatial ability; and a cognitive style: field dependence-independence. The results demonstrated the construct validity of ERPs as indicators of individual differences in cognitive characteristics, especially crystallized and fluid intelligence.     

Genetic and Environmental Influences on Two Measures of Speed of Information Processing and their Relation to Psychometric Intelligence: Evidence from the German Observational Study of Adult Twins

Speed of information processing, as measured by reaction times (RTs) in elementary cognitive tasks (ECTs), has been found to be an important correlate of human psychometric intelligence. While the heritability of psychometric intelligence is well understood, we know only a little about genetic and environmental influences on ECT performance, particularly about genetic and environmental contributions to ECT–intelligence relation. These questions were studied by employing two widely used ECTs (Sternberg's memory scanning and Posner's letter-matching task) as well as two psychometric intelligence tests (Advanced Progressive Matrices and Leistungs–Prüf System) in a large sample of 169 monozygotic (MZ) and 131 dizygotic (DZ) twin pairs. As expected, RTs correlated negatively with psychometric intelligence. Moreover, heritability estimates were substantial for both psychometric intelligence and RTs in ECTs. Finally, multivariate genetic analyses suggested that most of the phenotypic correlation between mental speed and intelligence is due to genetic factors.     

智力与心理速度的关系研究述评

目前在智力研究领域出现了一种新的研究趋势,研究者开始关注心理计量学智力与认知或生理心理学变量的相关,考察的重点是心理速度,相应的测量指标主要有检测时（IT）、反应时、ERP或神经传导速度,等等。在运用IT任务进行的ERP研究中发现,ERP波幅和潜伏期的不同往往能够反映出智力上的差异。信息加工速度和神经传导速度均与一般智力因素（g因素）存在较高的相关。上述研究发现促进了智力与心理速度关系的跨学科研究,成为智力研究领域中的热点     

Intelligence and individual differences in becoming neurally efficient

Physiological approaches to human psychometric intelligence have shown a higher neural efficiency (i.e. less cortical activation) during cognitive performance in brighter subjects. The main aim of this study was to explore the relationship between intelligence and cortical activation patterns in the framework of the learning test concept. In 27 participants we assessed the topography and extent of cortical activation by means of event-related desynchronization (ERD) during reasoning tests in a pre-test--training--post-test design and related it to psychometric intelligence (measured by the German Leistungs-Prüf-System, LPS). Significant associations between intelligence and cortical activation patterns were exclusively found at anterior (frontal) recording sites, which corroborates the central role of the frontal lobe for higher-order cognitive functions. The hypothesized negative intelligence-activation correlation was observed only after the training, i.e. in the post-test, but not in the pre-test. More important, the decrease in cortical investment from pre-test to post-test correlated negatively with intelligence, indicating that the higher the subjects' general mental ability the larger the decrease in the amount of cortical activation. These findings suggest intelligence-related individual differences in becoming neurally efficient.     

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.     

Convergence between attention variables and factors of psychometric intelligence in older adults

The purpose of the present study was to examine the hypothesis that individual differences on measures of attention would converge with select factors of psychometric intelligence, especially fluid intelligence and short-term acquisition and retrieval. A sample of 83 elderly adults $\text{(}\text{X}\text{= 71}\text{years}\text{)}$ was administered a battery of 17 psychometric ability tests. Tests were selected to mark four psychometric ability factors (Cattell and Horn's dimensions of fluid and crystallized intelligence, short-term acquisition and retrieval, and perceptual speed). Also, seven tasks representing four aspects of attention—decoding processes, selective attention, attention switching, and concentration—were administered. A confirmatory factor analysis was conducted to examine the relationships among the four psychometric ability factors and 11 variables obtained from the attention tasks. Results were only partially consistent with the hypothesized pattern of convergence. Two attention measures had significant loadings on a fluid-type intelligence factor, and one had a marginally significant loading on a short-term memory factor. In general, the greatest convergence occured between attention variables and the ability factor of Perceptual Speed. Results were discussed with respect to previous research on psychometric abilities and cognitive processes, the theory of fluid-crystallized intelligence, and their implications for understanding intellectual aging.     

The coordination of compensatory tracking and anticipatory timing tasks

Two experiments investigated the presence of a coordination factor in a task consisting of compensatory tracking and anticipatory timing components. The task (Intercept task) resembles a computer game in which a rocket must be aimed and fired to shoot an incoming missile. The studies were designed to determine if a coordinating ability exists above and beyond the abilities needed to perform the component tasks alone. We also investigated the nature of coordination abilities through correlations with other types of coordination tasks and measures of intelligence. Is coordination a general cognitive ability that contributes to performance in a wide range of coordination tasks, or is coordination ability task specific? Multiple regression analyses indicated the existence of a coordination ability in the Intercept task. This coordination ability, however, was shown to be unrelated to the coordination of visual and linguistic processing and to psychometric measures of intelligence as assessed by the Armed Services Vocational Aptitude Battery (ASVAB). Coordination of visual and linguistic processing correlated with a component of the ASVAB measuring perceptual speed. We conclude that, although the ability to integrate separate components of a complex task draws on a coordination ability, this ability is domain specific and thus varies depending on the nature of the component tasks.     

The role of attention in the relationship between inspection time and IQ in children.

This study investigated the possibility that the widely reported relationship between IQ and Inspection Time (IT) in children (e.g. Nettlebeck & Young, 1990) may derive from the involvement of various aspects of attention in both IT and psychometric ability tasks. Forty-nine participants, aged approximately 8–11 years, were given a battery of tests designed to measure different aspects of attention, the Colored Progressive Matrices (CPM) intelligence test and a visual IT test. Analysis using multiple regression indicated that, although attention predicted CPM score, IT was still a significant predictor of CPM score after age and the attention measures had been partialled out, indicating that IT scores account for a unique proportion of the variance in CPM scores. Age and IT were significantly (negatively) correlated. This correlation became non-significant once the attention measures had been removed. These results are discussed in relation to previous studies. After a consideration of a number of methodological criticisms, suggestions for further research are outlined.     

An investigation of the relationship between trait emotional intelligence and emotional task performance

This study examined the relationships between trait emotional intelligence (EI) and tasks involving the recognition of facial expressions of emotion. Two facial expression recognition tasks using the inspection time (IT) paradigm assessed speed of emotional information processing. An unspeeded emotion recognition task was also included, and a symbol IT task was used to assess speed of processing of non-emotional information. It was found that scores on all three emotion-related tasks were strongly intercorrelated, as were scores on the three IT tasks. The two emotional IT scores remained significantly correlated when symbol IT performance was partialled out. This finding, together with the associations between the speeded (IT) and unspeeded face tasks suggests that the association between the emotional IT tasks is not entirely accounted for by general processing speed, and that a general emotion-processing ability also contributes to performance on these tasks. An EI subscale assessing Appraisal of Emotions was significantly correlated with performance on the emotional IT tasks, suggesting that self-reports of emotional perception ability do relate to performance measures.     

Psychometric g and mental processing speed on a semantic verification test

The Semantic Verification Test (SVT) consists of brief, simple statements, which are either true or false, about various arrangements of the letters ABC (e.g. B after A). Mean reaction time (RT) for confirming or disconfirming the various statements varies according to their complexity. In independent studies of university students and Navy recruits, RT and other response latency parameters (intraindividual variability and movement time) from SVT performance show significant correlations of about -0.40 with nonspeeded tests of psychometric g. The mean RTs of adults to the various SVT item types are highly related to the mean error rates on these item types when the SVT is taken by elementary school children as a nonspeeded paper-and-pencil test. RT is correlated with the general cognitive ability factor (g) and not with the test-taking speed factor that is found in speeded paper-and-pencil tests. The degree of correlation between RT and psychometric g does not show any regular relationship to differences in the SVT item-type's complexity or difficulty as indicated by mean RT.