Stimulus and sex differences in performance of mental rotation: evidence from event-related potentials.

We examined stimulus and sex differences in reaction time (RT) and event-related potentials (ERPs) during mental rotation of letters and abstract designs (PMA figures). RTs replicated stimulus and angle effects found in previous studies, but no sex differences were found for either set of stimuli. ERP latency data showed women began stimulus evaluation earlier, and PMA rotations began later over smaller angles, whereas letter rotations began later over larger angles. ERP amplitude data replicated hemisphere, electrode, and angle effects found in earlier studies. Amplitude measures also showed greater involvement of anterior cortical areas for evaluation of letter figures and posterior right temporal lobe for PMA figures, and greater positivity of women's waveforms than men's over late evaluation and early rotation components.