Testing Predictions from the Hunter-Gatherer Hypothesis — 2: Sex Differences in the Visual Processing of near and Far Space

Abstract

Here, in the second of two linked reports, we focus on sex differences in visual processing. Study 1 presented a time estimation task in virtual space and generated the predicted Space*Sex interaction with men performing significantly better in far than in near space. Study 2 used a laboratory-based puzzle completion task in which participants saw their hands and the puzzle in far or near space. This time women performed significantly better in near than far space. Study 3 simplified the puzzle completion task. Once again the predicted Space*Sex interaction was significant but with both sexes showing significantly different performances: women better in near, men in far space. These findings are compatible with an evolutionary origin as predicted by the hunter-gatherer hypothesis. Far and near space are processed in the ventral and dorsal streams, two cortical regions more widely known as the “what” and “where” visual systems. To those traditional descriptions we suggest adding that the two streams are sex-dimorphic, with the ventral “there” system interacting with far space and favored in men and the dorsal “here” system interacting with near space and favored in women. Future studies of visual systems should consider the impact of sex differences and the spatial location of stimulus presentations.