Visual reaction time and high-speed ball games

Laboratory measures of visual reaction time suggest that some aspects of high-speed ball games such as cricket are 'impossible' because there is insufficient time for the player to respond to unpredictable movements of the ball. Given the success with which some people perform these supposedly impossible acts, it has been assumed by some commentators that laboratory measures of reaction time are not applicable to skilled performers. An analysis of high-speed film of international cricketers batting on a specially prepared pitch which produced unpredictable movement of the ball is reported, and it is shown that, when batting, highly skilled professional cricketers show reaction times of around 200 ms, times similar to those found in traditional laboratory studies. Furthermore, professional cricketers take roughly as long as casual players to pick up ball flight information from film of bowlers. These two sets of results suggest that the dramatic contrast between the ability of skilled and unskilled sportsmen to act on the basis of visual information does not lie in differences in the speed of operation of the perceptual system. It lies in the organisation of the motor system that uses the output of the perceptual system.     

Inspection time and measured intelligence.

Ten subjects with WAIS Full Scale IQ scores ranging from 119 to 47 were required to discriminate between two lines of markedly different length, exposed in random order for ten different durations, by pressing one of two keys. Estimates of inspection time gamma, the rate at which sensory input is accumulated and passed to subsequent decision processes, were calculated directly from the psychometric functions obtained gamma was found to correlate negatively with subtests contributing to Performance IQ. There was a substantial degree of consistency between estimates of gamma on two different occasions and training did not appear to affect the index, although differences between the two estimates increased as the value of the first estimate increased. Mean overall response latency did not correlate significantly with intelligence and measures obtained from retarded subjects were very like those reported in similar experimental situations utilizing normal subjects. This unexpected finding is interpreted as suggesting that, in this situation, retarded subjects have been prepared to respond on the basis of less evidence than is usually required by intellectually normal subjects.     

Inspection time and its relation to intelligence

Inspection time, defined as the minimum duration for which two different stimuli must be presented if they are to be perceived as different, was measured for both auditory and visual stimuli. The minimum durations were determined by means of a two- alternative forced-choice task for 50 children whose average age was 12 years 2 months. The times were correlated with the children's verbal (Mill-Hill vocabulary) and nonverbal (Raven matrices) intelligence. The Kendall correlation coefficients were ?.3188 and ?.0929 for the auditory and visual inspection times with verbal intelligence, and ?.2322 and ?.2676 for those times with nonverbal intelligence. Auditory and visual inspection times were correlated .1721 with each other. These results do not support earlier claims that inspection time is closely related to conventional measures of intelligence.     

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.     

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.     

Inspection time: Past, present, and future

This paper is a commentary on the other papers in this special issue. A speculative account of inspection time is presented. Inspection time is viewed as an index of a core information-processing ability which has a causal influence on the development of complex intellectual skills.     

Inspection time and everyday functioning: A longitudinal study

We tested whether level and/or changes in inspection time (IT) in an elderly sample (70–85 years at baseline) predicted future independence in everyday functioning, independent from chronological age. Sixty-eight participants were initially assessed on IT and cognitive abilities in 2003, reassessed on IT in 2005, and then completed the Everyday Problems Test, a test of independence in everyday living, in 2008. Controlling for age, lower fluid reasoning at baseline (Raven’s-subset) and slowing IT over 18 months independently predicted poorer everyday functioning in 2008, together accounting for one-third variance. This supports the proposition that IT has utility as a biomarker for less favourable ageing.     

Inspection time and everyday functioning: A longitudinal study

We tested whether level and/or changes in inspection time (IT) in an elderly sample (70–85 years at baseline) predicted future independence in everyday functioning, independent from chronological age. Sixty-eight participants were initially assessed on IT and cognitive abilities in 2003, reassessed on IT in 2005, and then completed the Everyday Problems Test, a test of independence in everyday living, in 2008. Controlling for age, lower fluid reasoning at baseline (Raven’s-subset) and slowing IT over 18 months independently predicted poorer everyday functioning in 2008, together accounting for one-third variance. This supports the proposition that IT has utility as a biomarker for less favourable ageing.     

Inspection time: An index for intelligence?

Recent publicity has been given to reports of high correlations between IQ and “inspection time”, a measure derived from simple discrimination which is assumed to provide an estimate of the time taken by a basic component of the decision process. However, this publicity has not recognised that the inclusion of mentally retarded participants in the experiments concerned may have led to inflated correlations, because of the marked extent to which the performance of retarded subjects is inferior to that of nonretarded subjects. Evidence from the performance of nonretarded subjects in three studies suggests that although speed of decision is related to IQ, the degree of association is smaller than recent publicity has suggested. Inspection time does not appear at present to hold promise as an index from which a “culture-fair” measure of intelligence might be derived.     

Inspection time and response strategies in a choice response task

The effects of varying stimulus duration on two response measures, percentage correct (p_c) and mean reaction time (RT) were investigated in a lights-keys RT task similar to an inspection time (IT) task. One of either N = 2, 4 or 8 lights came on as the stimulus, followed after a range of stimulus exposure durations (D) by all 8, as a backward mask. It was found that p_c was an ogival function of D for all three levels of choice, and that the standard deviations of the best-fitting normal ogives were equal. It is argued that the standard deviation can be taken as a measure of the neural noise, or error-inducing variability introduced by processing the stimulus, and so this result indicated that noise in the choice reaction task is independent of N. The effect of D on RT was as predicted by an optional accumulator model for 7 Ss with RT decreasing as D increased, while another 2 Ss appeared to have adopted a temporal deadline criterion giving RTs independent of D and equal error and correct RTs. The same two response styles were found in a re-analysis of RT data from an IT study. The p_c vs D curves were comparable for both response styles. The accumulator model commonly assumed to underly IT tasks thus does not describe the behaviour of all Ss. Such individual differences in strategic approach to the IT task should be investigated further, since assuming that all Ss use one approach may hide or confound relationships between IT and other measures of individual difference, such as intelligence. Recommendations for better IT measurement techniques are given.     

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.     

Reaction time and short-term memory: Implications of repetition effects for the high-speed exhaustive scan hypothesis

Recognition memory for sub-span digit sequences was investigated using Stern-berg's varied-set RT technique. Two experiments studied memory for sequences containing repetitions (e.g. 9 1 9 3) and observed faster recognition of repeated items. Experiment I also showed serial position effects with faster responding to more recent items. Neither of these effects is predicted by Sternberg's highspeed exhaustive scanning hypothesis. Several alternative hypotheses are considered, including two models based on the concept of trace strength, which appear to merit further investigation.