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.     

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.     

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.     

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     

检测时与智力关系的研究述评

检测时是信息加工速度的重要指标,它与一般智力测验分数之间存在着稳定的相关,两者之间的相关常被解释为智力个体差异的认知或生理学的基础。文章介绍了检测时与智商之间的相关研究。讨论了研究者对检测时和智力之间相关本质的几种理论解释。同时,总结了从生物学和发展的角度对检测时与智力之间相关的本质理解的研究。在此基础上,文章分了检测时与智力之间关系研究中存在的问题和未来的研究方向     

SOME COMMENTS ON CULTURE FAIR TESTS1

An attempt has been made in this paper to show that culture fair tests have some problems associated with them. These tests should be examined and reviewed closely before being used and should not be regarded as the answer to testing the culturally disadvantaged. The following points were made in this paper: Culture fair tests measure different psychological functions. Culture fair tests today measure such functions as spatial visualization, abstract reasoning, perceptual speed, etc. Culture fair tests vary considerably in format. Some are pencil and paper tests, some are performance tests. Some use verbal instructions, others do not. There are many test parameters along which culture fair tests now vary. Some evidence suggests that culture fair tests possibly increase the differential between the culturally disadvantaged and the more advantaged population. Use of these tests may not be in the best interests of minority groups. It is not yet definite about the kind of items on which culturally disadvantaged people perform poorer. Some evidence suggests that they do better on verbal items and worst on perceptual items, which is in contrast to the assumption of most proponents of culture-fair tests. The validity of culture fair tests has not been shown to be better than more traditional tests. In contrast, some research even indicates that they do not show relationships as high. What is to be done, if anything, about the test differentials between the culturally disadvantaged and the majority population? Some individuals (Lorge, 1964; Coffman, 1964) agree that the elimination of group differences on tests is futile and argue that the real task at hand is a realistic attempt to study the behavioral significance of test differences. In essence, this is an all out attempt to collect validation information. Does a particular score for a black have the same behavioral implications of a higher (or lower) test score for a white? Are there criterion differences that are related to test differences? Do differential validities exist for various subgroups? Are the standard errors of estimates different for different groups? This approach is essentially what has been pursued by individuals investigating the “moderating” effects of subgrouping by race and/or socio-economic factors. The investigation of test differences within and between subgroups is called for. In my opinion, attempting to mask test differentials by using culture fair tests may in actuality have a reverse effect than what was intended. Test differentials may actually increase, making it more difficult for culturally disadvantaged individuals to be selected into schools, jobs, etc. Clearly, the construction of culture fair tests is not the only answer to testing the disadvantaged.     

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.     

Examining neurochemical determinants of inspection time: Development of a biological model

Inspection time (IT), an information-processing correlate of psychometric intelligence, has been extensively studied. Previous research has shown that IT is a reliable correlate of psychometric intelligence across different developmental periods, mirroring developmental trends of fluid intelligence. Despite this extensive previous literature, very little is known about the biological basis of IT. In the present review, we discuss recent results from our laboratories examining the neurochemical determinants of IT. In this review, we outline the significance of several studies in which performance on the IT task is measured before and after modulating key human central nervous system (CNS) neurotransmitters and receptor systems (e.g., cholinergic, serotonergic, noradrenergic, and dopaminergic systems). The results of these studies indicate a primarily cholinergic basis for IT, although other aspects of psychometric intelligence may have serotonergic and dopaminergic determinants in addition to a cholinergic basis. The results are consistent with data reporting cholinergic depletion and impaired IT performance in dementia of the Alzheimer's type (DAT). Speculatively, we propose that compounds that enhance the release of the neurotransmitter acetylcholine (Ach) will improve IT and the variance that IT shares with IQ test performance.     

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.     

Biological factors and psychometric intelligence: a review.

Results from a synthesis of correlations between psychometric intelligence and two physical traits, head size and body size, are reported. Within-family studies are reviewed for evidence of pleiotropy, the effect of a single genetic factor on two traits. Studies are also reviewed to determine whether prenatal effects bias twin studies, leading to underestimates of genetic influence. An N-weighted mean partial correlation (controlling height) of .10 between intelligence and head size was found. Using a method developed by Van Valen (1974), the correlation of intelligence and brain size was estimated as .29 based on all the intelligence/head-size studies of adults and adolescents, and .44 based on studies measuring intelligence with IQ tests. The N-weighted mean partial correlations (controlling age) of intelligence and height were .18 for children and .22 for adults. The within-family studies indicated that pleiotropy may contribute to the correlation of intelligence with head size and to the correlation of intelligence with body size. Prenatal effects are not an important source of bias in twin studies or for heritability estimates based on them.     

Visual,auditory and reaction time approaches to the measurement of speed of information processing and individual differences in intelligence

A battery of tachistoscopic, auditory, reaction time and microcomputer-generated measures of speed of information processing (inspection time, IT) were administered to 96 college students aged between 18 and 22 yr. In addition, each S was given a battery of tests designed to provide independent evaluations of right- and left-hemispheric functioning. Criterion measures included a verbal (Vocabulary) and a nonverbal (Block Design) measure of intelligence. Results revealed a general processing speed factor in addition to task-specific sources of variability. Moreover, the IT tasks loaded on the same second-order factor as did the traditional measures of intelligence and aptitude. The findings support the theoretical view that processing speed may be a general factor in individual differences in performance on complex intellectual solving tasks. An important objective for future work in this area is to seperate and evaluate the common and specific sources of variability on IT tasks.     

Working memory and intelligence: the same or different constructs?

Several investigators have claimed over the past decade that working memory (WM) and general intelligence (g) are identical, or nearly identical, constructs, from an individual-differences perspective. Although memory measures are commonly included in intelligence tests, and memory abilities are included in theories of intelligence, the identity between WM and intelligence has not been evaluated comprehensively. The authors conducted a meta-analysis of 86 samples that relate WM to intelligence. The average correlation between true-score estimates of WM and g is substantially less than unity (p=.479). The authors also focus on the distinction between short-term memory and WM with respect to intelligence with a supplemental meta-analysis. The authors discuss how consideration of psychometric and theoretical perspectives better informs the discussion of WM-intelligence relations.     

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.     

Intelligence and maturity: meta-analytic evidence for the incremental and discriminant validity of Loevinger's measure of ego development

This review examined whether Loevinger's measure of personality (ego) development is equivalent to the measurement of intelligence. The authors conducted a meta-analysis of 52 correlations between ego level scores and intelligence test scores (retrieved from 42 studies involving 5,648 participants). The weighted average correlation between ego level and intelligence ranged from.20 to.34, depending on the intellectual ability assessed (e.g., verbal intelligence). Adjusting for measurement unreliability increased these values only minimally. The authors also reviewed 16 studies that examined the association between ego level and various criterion variables (e.g., aggressive behavior) after statistically controlling for the effects of intelligence. Ninety-four percent of the tests revealed significant relations between ego level and criterion variables after controlling for intelligence, indicating that ego development and intelligence are not interchangeable constructs. These findings do not support recent speculations concerning the limited value of stage models of maturity, social development, and moral reasoning.     

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.     

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.     

The comparability of intelligence test results: Group- and individual-level comparisons of seven intelligence tests

A significant body of research has demonstrated that IQs obtained from different intelligence tests substantially correlate at the group level. Yet, there is minimal research investigating whether different intelligence tests yield comparable results for individuals. Examining this issue is paramount given that high-stakes decisions are based on individual test results. Consequently, we investigated whether seven current and widely used intelligence tests yielded comparable results for individuals between the ages of 4–20 years. Results mostly indicated substantial correlations between tests, although several significant mean differences at the group level were identified. Results associated with individual-level comparability indicated that the interpretation of exact IQ scores cannot be empirically supported, as the 95% confidence intervals could not be reliably replicated with different intelligence tests. Similar patterns also appeared for the individual-level comparability of nonverbal and verbal intelligence factor scores. Furthermore, the nominal level of intelligence systematically predicted IQ differences between tests, with above- and below-average IQ scores associated with larger differences as compared to average IQ scores. Analyses based on continuous data confirmed that differences appeared to increase toward the above-average IQ score range. These findings are critical as these are the ranges in which diagnostic questions most often arise in practice. Implications for test interpretation and test construction are discussed.     

大学生情绪智力与感恩的交叉滞后分析

以修订后的情绪智力量表(EIS)中文版、青少年感恩量表（AGS）为研究工具,对1所普通高校的 406名大一至大三学生进行为期5个月的追踪,考察大学生情绪智力和感恩的发展变化,以及情绪智力与感恩之间的关系。结果发现：（1）大学生的情绪智力相对稳定,感恩存在一定的发展变化;（2）情绪智力与感恩之间呈显著正相关;（3）交叉滞后回归分析结果表明,前测的情绪智力可以显著预测后测的感恩,而前测的感恩不能显著预测后测的情绪智力。     

Reaction time and intelligence: A replicated study

Two samples of adult subjects of reasonably average intelligence were given IQ tests and a series of RT tests using 0, 1, 2, and 3 bits of information in a Hick paradigm. Both series showed negative correlation between IQ on the one hand, and RT and σRT, on the other, confirming earlier work. On the other hand, there was no evidence of correlation between the Hick slope and IQ, and the correlation between IQ and RT of σRT did not increase from 1 to 3 bits of information. It was found that the Hick paradigm did not apply to some 20% of the samples, and that the exclusion of these nonconformists increased the correlation between IQ and RT/σRT.