Sex differences in the perception of tactile simultaneity

A tactile simultaneity task was used to investigate the effects of sex on s imultaneity thresholds. Participants were required to judge whether pairs o f tactile stimuli delivered unimanually or bimanually were simultaneous. Un imanual stimulation delivered stimuli to the same cerebral hemisphere, whil e bimanual stimulation resulted in the delivery of one stimulus to each hem isphere, therefore requiring interhemispheric transmission before judging s imultaneity. The data of 114 right-handed participants were analysed. Femal es (N = 56) perceived simultaneity at longer intervals than males (N = 58) when bimanual stimulation was received. Furthermore, males had shorter inte rhemispheric transmission times (10.9 ms) than those of females (15.0 ms). The results also provided some support for the predictions of the Hemispher ic Equivalence Model of temporal processing since bimanual simultaneity thr esholds were longer than unimanual; and unimanual stimulation of the left v s right hand did not differ. An advantage for stimulation of right hand fir st (vs left first) in the bimanual condition was small (2.7 ms), and was th e only prediction of the Left Hemisphere Specialisation Model to receive su pport. A modification of the Equivalence Model which allows for a slight le ft hemispheric advantage is proposed.