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.     

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.     

Inspection time: Does it measure intelligence?

The relationship between inspection time (IT) and intelligence id discussed in the context of the more general relationship between measures of mental speed and mental ability. Six issues are raised concerning IT, mental speed and intelligence: the size of the sample that have been studied; the inclusion of mentally-retarded Ss in these samples; the generality of IT; reaction time (RT) correlations with intelligence; IT and timed vs untimed IQ tests; and theoritical implications of the IT/IQ relationship. In the latter section, it is concluded that IT does not fit neatly into models accounting for RT/IQ correlates and that additional research will be required to obtain a better understanding of the nature of its relationship with intelligence.     

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.     

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.     

Ability factors and cognitive processes

Several measures of the speed of information processing were related to ability factors derived from the Cattell-Horn theory of fluid and crystallized intelligence. Ninety-one college students took a battery of paper and pencil tests designed to measure four ability factors: fluid intelligence (Gf), crystallized intelligence (Gc), spatial visualization (Gv), and clerical perceptual speed (CPS). They also performed paper and pencil and computerized versions of three information processing tasks: mental rotations, letter matching, and sentence verification. Correlations among the ability measures, among the information processing measures, and between the two domains were analyzed using confirmatory factor analysis. The four ability factors were found to be largely independent in this college population. Speed of letter-matching and sentence verification were highly correlated, but neither was related to speed of mental rotation. Mental rotation speed was strongly correlated with Gv; letter matching speed was correlated with CPS; and sentence verification speed was correlated with both Gc and CPS.     

Inspection time and the relationship among elementary cognitive tasks, general intelligence, and specific cognitive abilities

The relationship between inspection time (IT) and paper-and-pencil tests of cognitive ability is well documented. However, the extent to which IT relates to cognitive ability through general intelligence or through group factors such as performance has not been fully addressed. Another unresolved issue is whether IT relates to psychometric intelligence independent from other elementary cognitive tasks. The current study examined these issues in a sample of 6–13-year-old twins drawn from the Western Reserve Twin Project (WRTP) (n=568 participants). Analyses suggest that IT and other elementary tasks predict general intelligence. IT also predicts Performance ability while other elementary tasks do not. Furthermore, IT contributes variance to cognitive ability independent from other elementary tasks. These suggest that multiple indices of elementary cognitive ability are necessary to fully understand their relationship with complex psychometric measures.     

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.     

Individual and group differences in intelligence and speed of information processing

A battery of eight different reaction time (RT) tests, measuring the speed with which individuals perform various elementary cognitive processes, and a group test of scholastic aptitude (the Armed Services Vocational Aptitude Battery, ASVAB) were given to 50 black and 56 white male vocational college students. The regression of the general factor scores of the ASVAB on the RT measures yielded a shrunken multiple correlation of 0.465. Although discriminant analyses, when applied separately to the ASVAB subtests and to the RT variables, showed highly comparable overall discrimination (over 70% correct classification) between the black and white groups, factor scores derived from the general factor (labeled ‘speed of information processing’) of the RT battery show only about one-third as large a mean black-white difference as the mean group difference on the general factor scores derived from the ASVAB. Comparisons were also made between the 106 vocational college students and 100 university students of higher average academic aptitude who had previously been tested on the same RT battery (Vernon, 1983a). These groups showed marked differences on the RT variables, the largest differences occuring on the tests that required more complex cognitive processing. The more complex RT tests also correlate most highly with the psychometric measures of ability within each group. The results are consistent with the hypothesis that individual differences and the mean differences between groups in psychometric abilities and scholastic achievement are related to differences in the speed of information processing as measured in elementary cognitive tasks.     

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.     

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.     

Inspection time and IQ: Evidence for a mental speed—ability association

Two studies have tested a theory that individual differences in mental speed constitute an important component of differences in general intelligence by examining patterns of correlation between ‘inspection time’ (IT) and various ability measures assumed to reflect different kinds of speed. The first study was set within the framework of Cattell's theory about the structure of abilities. Results from 30 adult Ss whose IQs (Raven Advanced Progressive Matrices, RAPM) were in the average to above-average range suggested that IT is associated with a broad general ability variable and not with the primary abilities ‘perceptual speed’ or ‘speed of closure’. However, IT was significantly correlated with only a subgroup of those primary abilities that were significantly intercorrelated, and the outcome did not further elucidate the nature of speed as discussed within Cattell's formulation. The second study tested a relationship between IT and a measure of general ‘intellectual speed’, previously described as the major determinant of intellectual differences in a situation where two other critical variables, ‘accuracy’ and ‘continuance’ can exert no influence. It was measured for more than 40 adult Ss, whose IQs (Wechsler Adult Intelligence Scale—Revised) ranged from 81 to 138, and compared with times to produce the correct solution to individual items from the RPM. IT, IQ and solution times were all significantly intercorrelated but, nonetheless, IT and solution times appeared to be substantially reflecting different processes. It is concluded that IT can account for more than the 10% of variance in IQ commonly found to be shared with simple information-processing tasks. The present result of approx. 17% shared variance is probably an underestimate, given the restricted IQ samples used and certain procedural shortcomings. The nature of speed reflected by IT has not been determined and current measurement procedures may be confounded by internal noise.     

抑制和加工速度与液态智力的年老化

研究抑制能力和加工速度在液态智力年老化过程中的相对作用。被试为142名18~85岁健康成年人,完成包括抑制优势反应、加工速度和液态智力共13项测验。分层回归分析显示,抑制能力与年龄相关的特异性变异,在控制简单的速度变量时较控制复杂的速度变量时更大;结构方程分析表明,对液态智力年老化的中介作用,当选取较复杂的速度变量时加工速度的作用更大,而当选取较简单的速度变量时抑制能力的作用更大。研究结果表明,在液态智力的年老化过程中,除了加工速度的作用之外,抑制能力也起重要的中介作用。该结果为认知年老化的抑制理论和执行衰退假说提供了认知行为学研究的证据,并且对加工速度理论作了有益的补充和修正     

Inspection time and IQ in young children

Three studies investigating the relationship between IQ, mental age (MA), chronological age (CA) and inspection time (IT) are reported. Forty-seven children participated: three age groups, 6, 8 and 10 yr, attending a London primary school and with IQs ranging from 75 to 141. The IT task was incorporated into a microcomputer-controlled video game and two measures of IT were obtained from two psychophysical procedures: method of limits and method of constant stimuli. All three studies found that a significant relationship was maintained for Ss over the full age range. Although, in general, IT decreased with increasing CA, bright 6-yr-olds had similar ITs to dull 10-yr-olds. Given that the latter have higher MA than the former and they have had more years experience of school, it is concluded that the IT/IQ relationship is primarily based on fundamental aspects of information processing, such as processing speed, rather than on task sophistication. The two psychophysical procedures produced different estimates of IT. However, it is concluded that using two methods can reduce the noisy effects of variability in responding of children. Reliabilities in the order of r = 0.45 are reported for the task.     

Effects of age and the relationship between response time measures and psychometric intelligence in younger adults

The major goal of the present study was to investigate the potential influence of age on the relationship among performance measures derived from a Hick reaction time task and general intelligence (psychometric g). Participants were 130 male and 130 female younger adults (mean age: 24.6 years) covering a wide range of individual levels of intelligence. Results from structural-equation modelling analyses clearly indicate that there is no evidence for the notion of a general speed factor underlying psychometric g. A much more sufficient model is provided by the assumption that median reaction time (RTmd) and intraindividual variability of reaction time (RTSD), though highly correlated, reflect two distinct sources of variance for psychometric g. While age was negatively associated with RTmd, no such relationship could be established for RTSD.     

Advances in the assessment of cognitive skills using computer-based measurement

The impact of technology in the field of intellectual assessment has, for the most part, been limited to computerized administration and scoring. Anderson’s (2001) theory of intelligence suggests that performance on traditional IQ measures is acquired via two main routes, thinking and dedicated processing systems known as modules. Empirical data used to support this relationship between the speed of basic processing and intellectual functioning have been evidenced primarily by correlations between measures of general intelligence and measures of inspection time (IT). These IT measures allow individuals to make a forced choice discrimination task without a motor component. Because only the time used to cognitively solve the problem is recorded, these responses typically occur in milliseconds. Many theorists (e.g., Burns & Nettelbeck, 2002; Deary, 2000; Jensen, 2006) consider IT to be a more “pure” measure of intelligence, because the influences of verbal skills, memory, and socialization are minimized and results are therefore considered to be more culture-fair. Until relatively recently, IT measurement was restricted to complex and expensive specialized laboratory equipment. This article describes the theoretical background and developmental process of a computer-based IT measure that is easily adaptable to accommodate the needs of the researcher.     

The Roles of Working Memory Updating and Processing Speed in Mediating Age-related Differences in Fluid Intelligence

ABSTRACT

This study was conducted to investigate the relative roles of working memory updating (updating) and processing speed in mediating age-related differences in fluid intelligence. A sample of 142 normal adults between 18 and 85 years of age performed a set of updating, processing speed, and fluid intelligence tasks. Hierarchical regression analyses indicated that the proportion of unique age-related variance in updating measures was related to the complexity of speed measures. There was a larger proportion of unique age-related variance in updating measures after controlling for the variance in simpler speed measures. Moreover, structural equation modeling showed that updating mediated almost all the age-related effects on fluid intelligence. These results suggest that updating, but not speed, is the critical mediator between age and fluid intelligence. In addition, the speed mediation of age-related differences in fluid intelligence as indicated by previous studies is at least partially derived from the executive component of speed measures.     

The relationship between WAIS-R abilities and speed of processing in a word identification task

Matched to the proportions found in the U.K. census data for a range of demographic variables (age, sex, and socioeconomic status) 123 participants were tested on the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and a test of the minimum presentation time required to identify tachistoscopically presented words. The correlations between the sum of the scaled scores for Full, Verbal, and Performance subtests and the log of the identification measures were -0.40, -0.22, and -0.51, respectively. These results are in line with those observed between the WAIS-R measures and standard visual inspection time (IT). Confirmatory factor analysis indicated that a three-factor model of intelligence with Verbal, Performance, and Attention/Concentration factors, and with the identification threshold loaded on the Performance factor alone, represented a better fit to the data than either a single general factor model or a two-factor model with Verbal and Performance factors. These results are in line with findings in the IT literature (Deary, 1993) that speed of information processing is significantly related to performance IQ but not to verbal IQ.     

Age differences in fluid intelligence: contributions of general slowing and frontal decline

The current study examined the contributions of general slowing and frontal decline to age differences in fluid intelligence. Participants aged 20-89 years completed Block Design, Matrix Reasoning, simple reaction time, choice reaction time, Wisconsin Card Sorting, and Tower of London tasks. Age-related declines in fluid intelligence, speed of processing, and frontal function were observed. Hierarchical regression analyses showed that the processing speed and frontal function measures accounted for significant variance in fluid intelligence performance, but there was also a residual effect of age after controlling for each variable individually as well as both variables. An additional analysis showed that the variance in fluid intelligence that was attributable to processing speed was not fully shared with the variance attributable to frontal function. These findings suggest that the age-related decline in fluid intelligence is due to general slowing and frontal decline, as well as other unidentified factors.     

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.