Is there a sex difference in human laterality? I. An exhaustive survey of auditory laterality studies from six neuropsychology journals.

The entire contents of six neuropsychology journals (98 volumes, 368 issues) were screened to identify auditory laterality experiments. Of the 352 dichotic and monaural listening experiments identified, 40% provided information about sex differences. Among the 49 experiments that yielded at least one significant effect or interaction involving the sex factor, 11 outcomes met stringent criteria for sex differences in laterality. Of those 11 positive outcomes, 9 supported the hypothesis of greater hemispheric specialization in males than in females. The 9 confirmatory outcomes represent 6.4% of the informative experiments. When less stringent criteria were invoked, 21 outcomes (14.9% of the informative experiments) were found to be consistent with the differential lateralization hypothesis. The overall pattern of results is compatible with a weak population-level sex difference in hemispheric specialization.