Changes in hemispheric advantage during familiarization with facial stimuli: Influence of sex and handedness

Photographs of faces were tachistoscopically presented in a recognition paradigm consisting of four Blocks of 24 trials. Previous research using this paradigm with female right-handers formed the basis for the dynamic shift model which was proposed to account for changes in visual field advantage during familiarization with complex visuospatial stimuli, as well as the relationship between those changes and proficiency. This model attributes the pattern of changes in hemispheric advantage as reflecting a sequence of global-analytic-integrative information processing strategies. The present research was intended to determine the effects of sex and handedness on the results predicted by the dynamic shift model.; It was hypothesized that differences in cerebral functional asymmetry between the subject groups would be reflected in their performance on this face recognition task. To assess degree and direction of verbal and visuospatial lateralization, subjects were tachistoscopically presented with letter identification and dot localization tasks.; Face recognition results for female right-handers were consistent with previous data. While the four sex and handedness subject groups tended to shift direction of visual field advantage during testing, the nature of these shifts and their relationship to proficiency were differentially effected by these variables. Among right-handers, proficiency was also dependent on the direction of the visual field advantage used on the first Block of trials.; For females, an initial left visual field advantage was optimal for overall task accuracy, whereas for males, an initial right visual field advantage maximized proficiency. Among left-handers, direction of initial visual field advantage did not significantly affect task accuracy.; Cognitive strategy differences were suggested to account for certain sex effects on face recognition performance. Handedness effects were hypothesized to reflect greater relative efficiency of either hemisphere to process the faces utilizing more than one type of information processing strategy.; Results of the two lateral asymmetry tasks were consistent with existing evidence indicating males and right-handers to have greater functional asymmetry than females and left-handers. Hypotheses relating degree and direction of cerebral lateralization with performance on the face recognition task were offered. Further direct testing of these hypotheses is suggested by the present findings.