INDIVIDUAL-DIFFERENCES IN THE PREVIOUS TRIAL EFFECT

Behavioral laterality effects are believed to reflect hemispheric spec ialization for the task and are sensitive to individual differences, i ncluding handedness, sex and menstrual stage. But the laterality effec t in a behavioral experiment with discrete trials also reflects module - and hemisphere specific momentum effects across trials. Are these pr evious trial effects also sensitive to individual differences? We repe l? the results of three lateralized lexical decision experiments that manipulated the handedness, biological sex and menstrual stage. We ana lyzed accuracy and speed of responses on the current trial as a functi on of the correctness of the previous trial, the wordness of the previ ous target and the visual hemifield of the previous target. Sex, menst rual stage and handedness all interacted with previous trial variables . Males were more sensitive to previous trial variables than were fema les; females during menses were more sensitive than during the midlute al stage; right-handers were more sensitive than were left-handers. Th us, handedness, sex and menstrual stage all modulate previous trial ef fects but do so in different ways.