IS THERE A SEX DIFFERENCE IN HUMAN LATERALITY .2. AN EXHAUSTIVE SURVEY OF VISUAL LATERALITY STUDIES FROM 6 NEUROPSYCHOLOGY JOURNALS

The contents of six neuropsychology journals (98 volumes, 368 issues) were screened to identify visual half-field (VHF) experiments. Of the 516 experiments identified, 42% provided information about sex differe nces. Sixty-eight experiments yielded a total of 92 sex differences, 2 3 of which met stringent criteria for sex differences in laterality. O f the 20 sex differences satisfying stringent criteria and lending the mselves to interpretation in terms of the differential lateralization hypothesis, 17 supported the hypothesis of greater hemispheric special ization in males than in females. The 17 confirmatory outcomes represe nt 7.8% of the informative experiments. When less stringent criteria w ere invoked, 27 outcomes (12.3% of the informative experiments) were f ound to be consistent with the differential lateralization hypothesis. Six findings were contrary to the hypothesis. The results, which clos ely resemble results for auditory laterality studies, are compatible w ith a population-level sex difference that accounts for 1 to 2% of the variance in laterality.