Reliability of non-verbal laterality effects in the visual modality.
The present experiment investigated the reliability and magnitude of laterality effects in a non-verbal task in the visual modality. The use of a bilateral discrimination task in which participants indicated whether a centrally presented probe stimulus matched either of the bilaterally presented targets was presumed to provide control over attention deployment. This led to the prediction that a reliable left visual field advantage (LVFA) would be obtained. A total of 40 right-handed undergraduate students completed the bilateral discrimination task twice in a test-retest design. Although relatively large test-retest correlations suggested that the laterality effect was quite reliable, a significant LVFA was obtained in the first testing session, and a right visual field advantage in the second one. This finding parallels results obtained in previous work with non-verbal tasks and supports the notion that practice affects the direction of laterality effects. The discussion examines alternative explanations with emphasis on practice effects and possible attentional factors. A possible shift in the bivariate distribution of laterality scores is used as a tentative explanation of the apparent contradiction between the high test-retest reliability and the shift in laterality with practice.
Voyer
Daniel
D
Department of Psychology, University of New Brunswick, Bag Service #45444, Fredericton, NB, Canada E3B 6E4. voyer@unb.ca
D000293:Adolescent; D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D009633:Nonverbal Communication; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014794:Visual Fields; D014796:Visual Perception