Robert J. Gregory

Reliability of the Finger Tapping Test and a Note on Sex Differences

The reliability of the Finger Tapping Test was investigated in two studies. In the test-retest condition 30 male and 30 female college students were tested twice by the same examiner. In the inter-examiner condition 30 male and 30 female college students were tested once by each of two examiners. Reliability coefficients for the dominant and nondominant hands were high in both studies (about .8), as contrasted with that of the ratio score (about .5), casting doubt on the use of the ratio score to lateralize impairment. Significant sex differences (males about 3 taps faster) were found, calling into question the use of single test interpretation schemes. Slight inter-examiner differences in mean scores were also detected.

A short form of the Category Test for adults.

Proposed a 120-item version of the 208-item Category Test for adults. When the test protocols of 70 diverse Ss including 18 with definite brain impairment were scored for both the standard and short form, a very high degree of correlation (r = .95) was found, which suggests that the two forms are nearly equivalent. The application of cut-off scores (normal vs. brain impaired) resulted in only 3 Ss changing classifications from the standard to the short form, with 2 of those changes in the correct direction. A savings in administration time of about one half was observed.

Left-handedness and spatial reasoning abilities: The deficit hypothesis revisited

Abstract Left-handers with an inverted handwriting posture have been found by Levy and Reid to have relatively bilateral representation of tachistoscopically tested verbal and spatial functions. On the assumption that such bilateral representation is inefficient, it was hypothesized that left-inverted subjects (N = 20) would score lower than left- and right-handers with normal handwriting postures (Ns = 64, 66 respectively) on spatial reasoning. Results were consistent with the hypothesis. Possible alternative explanations and directions for future research are outlined.

Effect of asymptomatic lead exposure on childhood intelligence: A critical review

Abstract Criteria for evaluating studies of asymptomatic lead exposure and childhood intelligence are outlined. When these criteria are applied to nine recent studies on the intellectual consequences of asymptomatic lead exposure, all of the studies are found to have significant deficiencies. The reviewers conclude that the intellectual consequences of asymptomatic lead exposure are simply unknown. Suggestions for improving future research by assessing information processing capacities are offered.

A FORTRAN Computer Program for the Fisher Exact Probability Test

40 and each expected cell frequency is at least 10, this use of chisquare as a test for association is considered justifiable and relatively free of controversy. On the other hand, when the total N is small or any expected cell frequency is less than five the use of chi-square is usually warned against. Recommendations for the borderline case of an expected cell frequency between five and 10 differ, but the details of this issue are not pertinent here. The salient issue is that in such situations of low expected cell frequency the Fisher exact probability test (Fisher, 1934) is always appropriate, and usually recommended as a means of overcoming the pitfalls of chi-square. This test is a method for

The Effects of a Temporary Dysphoric Mood upon Selected WAIS-R Subtests

This study assessed the effect of a temporary dysphoric mood upon selected subtests from the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Male and female college students were assigned randomly to either an audiotape-induced dysphoria condition (n = 34) or a control condition (n = 34). Pretests of intelligence and mood revealed no differences between groups. Both groups were administered Arithmetic, Similarities, Block Design, and Object Assembly from the WAIS-R. Subjects in the temporary dysphoria condition scored significantly lower than did controls on Block Design and Object Assembly. Implications for everyday testing practices are discussed.