Sex differences in functional cerebral asymmetries in a repeated measures design

The aim of the present study was to analyze whether task repetitions which art: an inevitable part of repeated measures designs might induce performance alterations specific for gender and hemisphere. Male and female subjects conducted twice a lexical decision, a polygon recognition, and a face discrimination task as a visual half field paradigm with the two experimental sessions repeated by 2 weeks. The results show that only in female subjects can a session effect for the lexical decision and the polygon recognition task be demonstrated which is hemisphere specific. Thus, repeated measures designs seem to have a gender- and hemisphere-specific effects of their own which could confound with other variables under study. (C) 1999 Academic Press.