Sex differences in cognition: the role of handedness.

Women typically outperform men on episodic memory and verbal fluency tasks, whereas men tend to excel on visuospatial tasks. As the vast majority of individuals are right-handed (RH), sex differences in the cognitive literature reflect laterality-specific patterns for RH individuals. We examined the magnitude of cognitive sex differences as a function of hand dominance in samples of RH and non-RH individuals. Results showed the expected sex differences in the RH group, whereas these differences were unreliable in the non-RH group. These results are discussed in terms of earlier findings of a more bilateral representation of language functions in non-RH men, possibly affecting their visuospatial performance negatively and their verbal performance positively, thereby reducing cognitive sex differences.