Difference scores: A caveat illustrated with neuropsychological measures

Relationships among preferred minus non-preferred hand difference scores from four neuropsychological sensorimotor tests were evaluated in Community (N= 121), Prison Inmate (N = 350), and Psychiatric Inpatient (N = 398) samples. Across the three samples, the average absolute off-diagonal correlations among the four difference scores ranged from .07 to .13, and the squared multiple correlations (used to predict any difference score from the other three) did not exceed .07. Based on the determinant of the correlation matrix (i.e., |R|), the null hypothesis of complete independence was rejected in only the Prison Inmate sample (p < .001), however, departure from the null hypothesis was negligible (i.e., |R| = .94, expected value under the null = .98). Preferred/non-preferred hand ratio scores were very highly correlated with the difference scores and consequently analyses of the ratio scores yielded results that were comparable to those obtained for the difference scores. Results indicate that the four difference scores or four ratio scores measure little in common and therefore cannot corroborate each other. In general, it would be prudent to exercise considerable caution when using difference scores or ratio scores obtained from non-independent measures, either singly or in combination.     

Structural Solutions to Social Dilemmas: A Field Study on Commuters’ Willingness to Fund Improvements in Public Transit1

The present field study examined commuters’(N= 152) willingness to fund improvements in public transit. Consistent with Samuelson's (1993; Samuelson & Messick, 1995) multiattribute evaluation model of structural change in social dilemmas, support for the transit plan was higher when it was perceived to be (a) effective at reducing congestion and pollution, (b) personally beneficial, and (c) fair in terms of taxes and benefits. Also consistent with predictions, these relationships were moderated by individual differences in social value orientation (MClintock, 1968) and the consideration of future consequences (CFC; Strathman, Gleicher, Boninger, & Edwards, 1994). Prosocials responded more to the perceived fairness of the plan, while proselfs responded more to the plan's effectiveness in reducing congestion. Low CFCs responded more to the plan's personal benefits and effectiveness in reducing congestion, while high CFCs responded more to the plan's effectiveness in reducing pollution.     

Seemingly anomalous full scale IQ scores on the WAIS-III and the WISC-III

The Canadian and American WISC-III and the American WAIS-III standardization data were used to investigate the prevalence of “seemingly anomalous” Full Scale IQ (FSIQ) scores for all possible Verbal and Performance sums of scale score combinations. It was found that 6% of FSIQ scores in these three samples were seemingly anomalous (i.e., fell outside of their associated VIQ/PIQ intervals). Interestingly, the anomalous FSIQ scores were more prevalent at the extremes of the FSIQ distribution, and did not occur when the VIQ/PIQ interval was greater than 12. Additionally, anomalous FSIQ scores were generally further from the center of the FSIQ distribution than were the associated VIQ and PIQ scores. Also, when the VIQ/PIQ interval contained FSIQ (the non-anomalous case), FSIQ tended to be located distally in the half-segment of the VIQ/PIQ interval furthest from the center of the FSIQ distribution. A statistical explanation for the findings is provided. Portions of this paper were presented March 3, 2000 at the 14th Annual Joseph R. Royce Research Conference, Department of Psychology, University of Alberta, Edmonton, Alberta. An erratum to this article is available at .     

Beat It! Music Overloads Novice Dancers

Together with melody, harmony, and timbre, rhythm and beat provide temporal structure for movement timing. Such musical features may act as cues to the phrasing and dynamics of a dance choreographed to the music. Novice dancers (N = 54) learned to criterion a novel 32‐s dance‐pop routine, either to full music or to the rhythm of that music. At test, participants recalled the dance to the same music, rhythm, new music, and in silence. If musical features aid memory, then full music during learning and test should result in superior dance recall, whereas if rhythm alone aids memory, then rhythm during learning and test should result in superior recall. The presence of a rhythm accompaniment during learning provided a significantly greater memory advantage for the recall of dance‐pop steps than full music. After learning to full music, silence at test enhanced recall. Findings are discussed in terms of entrainment and cognitive load. Copyright © 2014 John Wiley & Sons, Ltd.