Magnitude of sex differences in visual search varies with target eccentricity

A recent meta-analysis found no support for the popular theory that superior visuospatial ability in males is attributable to their relatively greater hemispheric asymmetry of neural functions. However, the issue of whether differences in hemispheric laterality could account for differences in visual perception between the sexes has not been systematically investigated. Visual search is an ideal task for such an investigation, as target-position can be systematically varied across the visual field allowing for a detailed analysis of how performance varies with visual field and eccentricity. We recruited 539 undergraduate participants (150 male) and administered a visual search task that required them to identify the presence of a uniquely-oriented triangle amongst distractors. Crucially, target location was systematically varied over the visual field across trials. Males displayed both superior accuracy and shorter reaction time when targets were presented in the left visual field, whilst sex differences systematically diminished when the target was located further rightward. These behavioural results are in line with the notion that greater hemispheric asymmetry in males influences task performance to a varying extent across the visual field, and illustrates the importance of considering task parameters and the influence of sex in behavioural research.