Inspection time and the mental age deviation hypothesis

The ‘g’-loading of the inspection time (IT) measure was tested by applying Spitz's mental age (MA) deviation model to a sample of non-retarded adolescents and children. An MA 8 and MA 11 group, each composed of below-average, average and above-average intelligence Ss, were compared on an IT task in which latency of responses was also recorded. Results showed that IT related to MA but not to IQ. By contrast, the latency of responding in the IT differentiated Ss by IQ, but not MA, with above-average IQ Ss exhibiting longer response latencies. It was concluded that response latency exhibited a higher ‘g’-loading than did IT.     

Not so F.A.S.T., Dr. Vickers!

Vickers and his co-workers have recently reported studies with a “frequency accrual speed test” (FAST) that was devised to assess individuals' speed or efficiency of sampling of sensory input. According to Vickers, the FAST overcomes some of the limitations of the inspection time (IT) task, a psychophysical measure that has moderate correlations with IQ scores. After several experiments, Vickers concluded that speed of sensory processing is unimportant in FAST (and IT) differences. After a critical review of the FAST's theoretical basis and empirical results, we argue that the FAST is not appropriately described as an equivalent or alternative to IT, and that results from FAST studies are not generalizable to IT. The FAST involves a substantial memory load. Moreover, no studies to date have used appropriate stimulus parameters to allow Vickers' claim that speed of processing is unimportant in FAST (and IT) variance. The FAST, we suggest, has moderate correlations with IQ-type test because it is a complex, high-level task that is poorly parameterized. Specific hypotheses are formulated based on our understanding of the nature of the FAST. For those who wish to understand the information processing bases of higher order abilities the IT task (also devised by Vickers) continues to afford a better focus of study.     

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     

Implicit learning differences: a question of developmental level?

A. S. Reber's (1992) proposition that the implicit learning system should demonstrate invariance of intellectual level (IQ) was examined by comparing 20 children with intellectual disability (mean mental age [MA] = approximately 5.8 years) with 20 intellectually gifted children (mean MA = approximately 12.4 years) of similar chronological age (CA; approximately 9.5 years). Implicit learning was assessed using a task involving covariation of 2 incidental cues. Explicit learning was assessed using a task of similar logical structure. Contrary to the IQ-invariance proposition, implicit learning as well as explicit learning varied with intellectual level. A secondary aim was to distinguish the contributions of CA, IQ, and MA to implicit learning. This was done by combining the samples of children in the present study with 2 samples of younger and older children of average ability from a study by M. Maybery, M. Taylor, and A. O'Brien-Malone (1995). Analyses showed that MA is critical to implicit learning.     

Inspection time and intelligence in 7-yr-old children: A follow-up

Remeasures of inspection time (IT) were obtained from 30 of the 47 children reported in Nettelbeck and Young (Personality and Individual Differences, 10, 605–614, 1989). Ages ranged from 7 yr–0 months to 7–11 and Full Scale IQ (WISC-R) ranged from 93 to 142 (mean = 116.5 SD = 12.2). Correlations between IT and the WISC-R subtests, scales and factors used in the earlier study were generally statistically significant: and similar to those found earlier. The correlation between IT and Full Scale IQ was — 0.49, with those children whose IQs were below the median score of 116 again contributing more to this outcome. Similarly, the IT-IQ correlation was higher among children showing less well-directed attention in the IT task. Once again IT correlated better with Verbal IQ, supporting the hypothesis that IT is better associated with more general intellectual functioning than with specific cognitive abilities. Cross-lagged panel correlations between IT and IQ were —0.40, whether predicting IQ from IT or the reverse. Thus, there was no evidence for a causal relationship between these variables, although both may reflect a common cognitive ability factor.     

A follow-up developmental study of hypothesis behavior among mentally retarded and nonretarded children

To clarify the roles of IQ and mental age (MA) in hypothesis behavior, MA-matched subjects at three levels of IQ (70, 100, and 130) and three levels of MA ($\text{5}\text{1}\text{2}\text{, 7}\text{1}\text{2}\text{,}\text{and}\text{9}\text{1}\text{2}\text{years}$) received blank-trial discrimination learning problems using procedures designed to discourage position-oriented responding. With position responding discouraged, earlier findings were contradicted in that no hypothesis measure showed a main effect of IQ. This suggest that previously reported IQ group differences in hypothesis behavior may not reflect cognitive deficits inherently linked to low IQ, but instead may reflect the influence of specific methodological factors. The finding and interpretation are consistent with Zigler's (American Journal of Mental Deficiency, 1969, 73, 536–556) “developmental” theory of retardation and inconsistent with the general “difference” position. In additional findings, the predictions that subjects at all three MA levels would use hypotheses, and that retarded children from special-education classes would use hypotheses more often than retarded children “mainstreamed” in classes for the nonretarded were confirmed.     

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.     

Spontaneous private speech and performance on a delayed match-to-sample task

Spontaneous private speech samples were obtained from 65 kindergarten children (mean age 70.3 months) from one suburban (n = 36) and one city (n = 29) school as they worked alone on a delayed match-to-sample (DMS) task with three levels of difficulty (2, 10, and 30 sec delays). As expected increases in DMS delay intervals produced decreased performance and increases in private speech. The expected increased positive relationship between task relevant private speech and performance for longer delays was found in city children but not suburban children. Since mean IQ scores were significantly different for the two groups this variable was further examined in post hoc analyses and discussed along with socio-economic status as possible explanations for the observed school-sample differences. A within-subject comparison for all children showed the percentage of speaking trials correct at 30-sec delay to be significantly greater than the percentage of nonspeaking trials correct. The effect of one experimenter modeled trial on a subsequent 10 trials at 30-sec delay was to increase speech and performance and to show a stronger relationship between speech and performance than for premodeling trials. These exploratory findings with a relatively simple two color matching task suggest further explorations of spontaneous private speech as a way of studying internalization of self regulatory cognitive strategies.     

Visual backward masking in retardates and normals

Educable adolescent male retardates were compared with normal males of equal CA and equal MA on a visual backward masking task. Significantly shorter interstimulus intervals were required to induce a masking effect in the equal-CA group than in the retarded and equal-MA groups, who did not differ from each other. Speed of visual processing is a function of MA. It is related to CA in normals. and to IQ when retardates are compared with equal-CA normals.     

Effects of varying post-KR intervals upon children' motor performance

An experiment using post-KR interval methodology was designed to investigate the developmental relationship of age and processing speed regarding performance on a ballistic linear slide task. The hypothesis drawn from the developmental literature was that, given a short time for processing information, younger children should perform less efficiently than older children and adults. However, an increase in processing time should result in performances being more similar. Subjects in the experiment were 90 female children equally divided among 7 and 11-yr-olds and adults. Within age, subjects were randomly assigned to one of three post-KR interval groups: 3, 6, and 12 sec. Conclusions support the processing deficits hypotheses of Chi (1976): given enough time to process KR, the children's performance was not significantly different from the performance of adults.     

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.     

Intelligence Measurement by Computerized Information Processing using Inspection Time

A computer program was used to investigate the correlation of IQ with inspection time (IT). The program was written as a space game and was presented to 122 fourth-, fifth-, and sixth-grade children. The results were then compared to known Otis-Lennon IQ scores. The correlation was moderately high (.79), most subjects scoring within one stanine of the Otis IQ. Not included in the correlation sample were 23 children of the same grade and age level who were classified by school officials as having reading and language difficulties. All of these children scored significantly higher in IT and teacher evaluation than they did on the SAT vocabulary test and the Otis IQ. IT is a useful alternative to the more traditional measures of IQ. In addition, the computerized approach used in this study overcame many of its criticisms.     

Meta-analysis of the relationship between intelligence and inspection time

This study replicated and extended Kranzler and Jensen's [Intelligence 13 (1989) 329] meta-analysis of the relationship between inspection time (IT) and intelligence (IQ). Separate meta-analyses were conducted on obtained correlations (r's) between IT and general IQ for the total sample and for studies using samples of adults and children. Two new meta-analyses were also conducted. The first compared the IT–IQ r between visual and auditory IT; the second compared the r between strategy users and nonusers. For the total sample (N>4100), the r was −.51 after correction for artifactual effects (−.30 prior to correction). No statistically significant difference was observed between the mean corrected r of −.51 for adults and −.44 for children. The mean corrected r for visual and auditory IT measures were −.49 and −.58, respectively, suggesting that the relationship between IT and IQ is comparable across type of IT task. The mean corrected r of −.77 for strategy nonusers was statistically significantly higher than the r of −.60 for strategy users. Implications of these findings for future research are discussed.     

Early electro-cortical correlates of inspection time task performance

The concept of general intelligence (g) summarizes the well established finding that scores on separate cognitive tasks are positively correlated, indicating a trait common to many aspects of information processing. Inspection time is a well-established correlate of IQ, where those of a higher IQ can correctly identify a briefly presented stimulus with a greater level of accuracy than those of a lower IQ. This study used two age-matched samples, selected on the basis of their scores on Raven's Advanced Progressive Matrices from the undergraduate population of Bangor University. In order to address the confound of inspection time and IQ of previous ITT-ERP research, each participant of the presented study performed an IT task with the same five levels of stimulus duration while undergoing 64-channel EEG recording. The high IQ group made significantly fewer errors at each level of stimulus duration and exhibited a significantly larger N1 response. N1 latency and other ERP components did not distinguish the two IQ groups. Given the specificity of ERP group differences to the N1, the results of the present study suggest that the link between IT performance and g is attributable to individual differences in directing attention to a spatial region.     

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.     

Long-term learning in dyslexic children

There is now extensive evidence that the learning processes of dyslexic children show some abnormalities, generally consistent with failure to completely automatise skills. Two studies are reported in which a group of adolescent dyslexic children and a group of normal children matched for age and IQ undertook long-term training on a keyboard spatial task and a choice reaction task respectively. It was concluded that, following extended training, the dyslexic children had normal “strength” of automatisation (as assessed by resistance to unlearning, by ease of relearning after one year, and by dual task performance) but that their initial and their final performance (as assessed by speed and accuracy) were impaired. The results are consistent with the hypothesis that dyslexic children suffer from cerebellar deficit.     

The Rorschach and structured tests of perception as indices of intellectual development in mentally retarded and nonretarded children

In a study of the developmental significance of certain perceptual activities, the Rorschach and four structured tests of perception were administered to five groups of children at various CA, MA, and IQ levels. All three Rorschach measures were significantly related to MA, as were all four of the structured tests. The Childrens' Embedded Figures Test was the best predictor of MA; it accounted for 52% of the variance, while the six remaining measures yielded nonsignificant increments to a multiple regression equation. In a factor analysis the four structured tests loaded on one factor (51% of total variance), while the three Rorschach variables loaded on a second (17%); MA loaded on both (.669 and .447, respectively). In an additional finding, Zigler's “developmental” hypothesis that level of development and not IQ determines cognitive competence, received partial support from 13 of 14 statistical tests.     

Cognitive processes in children's reading and attention: The role of working memory,divided attention,and response inhibition

Children experiencing attention difficulties have documented cognitive deficits in working memory (WM), response inhibition and dual tasks. Recent evidence suggests however that these same cognitive processes are also closely associated with reading acquisition. This paper therefore explores whether these variables predicted attention difficulties or reading among 123 children with and without significant attention problems sampled from the school population. Children were screened using current WM and attention task measures. Three factors explained variance in WM and attention tasks. Response inhibition tasks loaded mainly with central executive measures, but a dual processing task loaded with the visual‐spatial WM measures. Phonological loop measures loaded independently of attention measures. After controls for age, IQ and attention‐group membership, phonological loop and ‘central processing’ measures both predicted reading ability. A ‘visual memory/dual‐task’ factor predicted attention group membership after controls for age, IQ and reading ability. Results thus suggest that some of the processes previously assumed to be predictive of attention problems may reflect processes involved in reading acquisition. Visual memory and dual‐task functioning are, however, purer indices of cognitive difficulty in children experiencing attention problems.     

Reversing the speed–IQ correlation: Intra-individual variability and attentional control in the inspection time paradigm

Elementary cognitive tasks (ECTs) are simple tasks involving basic cognitive processes for which speed of performance typically correlates with IQ. Inspection time (IT) has the strongest IQ correlations and is considered critical evidence for neural speed underlying individual differences in intelligence. However, results from Bors et al. [Bors, D.A., Stokes, T.L., Forrin, B. & Hodder, S.L., (1999). Inspection Time and Intelligence: Practice, strategies, and attention. Intelligence, 27, 111–129.] suggest task consistency may underlie this shared variance. One possibility is that performance consistency reflects attentional mechanisms, as previous research has shown relationships between attentional control and cognitive performance. In study 1, participants were administered the Raven's Advanced Progressive Matrices and performed an alternative version of the IT task to measure individual trial-by-trial consistency expressed as the standard deviation of IT (ITSD). The alternative procedure yielded IT–IQ correlations similar to those obtained in previous studies and ITSD accounted for the IT–IQ variance. A second experiment tested whether ITSD measures attentional control, as participants simultaneously performed the IT task and an attention-demanding verbalization task. Under these conditions, high IQ participants performed worse on IT. These results suggest IT performance may reflect individual differences in attentional control and that this variable may account for the variance shared between IT and IQ.     

8—12岁超常与常态儿童的检测时比较

研究者采用两种视觉检测时任务,比较了8至12岁超常和常态儿童的检测时发展变化特点。结果发现：随着年龄的增长,超常组和常态组儿童的检测时都呈现出逐步减小的趋势,并且对于不同任务的检测时,两组儿童的发展速度不同,但均未表现出性别差异;在不同的年龄段和检测时任务中,超常组儿童的检测时均显著地快于常态组儿童。通过对两组儿童的检测时发展速率的比较还发现,儿童的检测时发展基本上不受学校知识或经验的影响。另外,两组儿童的检测时和智力测验分数之间都有中等程度的负相关。