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Sex, Brain, Hands And Cognition

DEVELOPMENTAL REVIEW ARTICLE NO.

16, 261–270 (1996)

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Sex, Brains, Hands, and Spatial Cognition
DIANE F. HALPERN
California State University, San Bernardino The literature that investigates the joint effects of sex, handedness, familial handedness, and spatial experience on the performance of spatial tasks shows numerous significant interactions, but the results are difficult to interpret. Casey has proposed a model that incorporates the biological notion of a ‘‘genetic right-shift factor’’ and participation in visual-spatial activities to produce systematic differences in spatial performance. This model has many strengths including the specific nature of its predictions that have been supported empirically across several different studies and the melding of biological propensities and experience. However, many of the basic assumptions rest on shaky ground, and there is a body of contradictory evidence that 1996 Academic Press, Inc. still remains to be explained.

How can we understand the huge and confusing literature that probes the joint effects of sex, handedness, familial hand use, and spatial experience on the performance of spatial tasks? The research literature on these topics is marred with inconsistent findings, null results, and confusion, in part because of the measurement problems inherent in their assessment, and in part because of the political climate that makes empirical studies of biological influences on cognition immediately suspect if they produce the ‘‘wrong’’ results. Casey (1996) has made a valiant attempt to organize a diverse array of empirical results under a single organizing framework that includes the way that sex, cerebral lateralization, genetic predispositions, and life experiences work together in the development of spatial cognition. Casey’s model is rooted in Annett’s (1985) notion of a genetic ‘‘right-shift factor.’’ The right-shift factor is a single gene, whose dominant allele produces a bias toward right-sided...