ACCURACY IN THE FREQUENCY ACCRUAL SPEED TEST (FAST), INSPECTION TIME AND PSYCHOMETRIC INTELLIGENCE IN A SAMPLE OF PRIMARY-SCHOOL CHILDREN

This study tested 28 primary school children, using six subtests of th e WISC-R, an inspection time (IT) task, and a frequency accrual speed test (FAST) procedure, proposed by Vickers (Personality and Individual Differences, 19, 863-879, 1995) as a measure of mental speed. Perform ance in the FAST task was stable and reliable across sessions, and sho wed good correlations with full-scale IQ, both overall and for each se ssion. Contrary to a simple mental speed assumption, however, the data showed clear recency effects. Estimates of IT, averaged over sessions , showed a moderate correlation with IQ, but decreased significantly a nd showed only low reliability across sessions. The latter result appe ared to be due to an increase over sessions in the use of apparent mov ement strategies. Subjects who did not use an apparent movement strate gy showed higher IT-IQ correlations. Although FAST and IT scores were not correlated for the group as a whole, when strategy users were excl uded the FAST-IT correlation was significant for session 1. The result s are discussed in terms of alternative interpretations of accuracy in the FAST task as a measure of mental speed, as determined by retroact ive stimulus attenuation and as an index of working-memory capacity.