Sex differences in the perception of tactile simultaneity

A tactile simultaneity task was used to investigate the effects of sex on simultaneity thresholds. Participants were required to judge whether pairs of tactile stimuli delivered unimanually or bimanually were simultaneous. Unimanual stimulation delivered stimuli to the same cerebral hemisphere, while bimanual stimulation resulted in the delivery of one stimulus to each hemisphere, therefore requiring interhemispheric transmission before judging simultaneity. The data of 114 right-handed participants were analysed. Females (N = 56) perceived simultaneity at longer intervals than males (N = 58) when bimanual stimulation was received. Furthermore, males had shorter interhemispheric transmission times (10.9 ms) than those of females (15.0 ms). The results also provided some support for the predictions of the Hemispheric Equivalence Model of temporal processing since bimanual simultaneity thresholds were longer than unimanual; and unimanual stimulation of the left vs right hand did not differ. An advantage for stimulation of right hand first (vs left first) in the bimanual condition was small (2.7 ms), and was the only prediction of the Left Hemisphere Specialisation Model to receive support. A modification of the Equivalence Model which allows for a slight left hemispheric advantage is proposed.