A sex difference in interference between identity and expression judgments with static but not dynamic faces

Facial motion cues facilitate identity and expression processing (Pilz, Thornton, & Bulthoff, 2006). To explore this dynamic advantage, we used Garner's speeded classification task (Garner, 1976) to investigate whether adding dynamic cues alters the interactions between the processing of identity and expression. We also examined whether facial motion affected women and men differently, given that women show an advantage for several aspects of static face processing (McClure, 2000). Participants made speeded identity or expression judgments while the irrelevant cue was held constant or varied. Significant interference occurred with both tasks when static stimuli were used (as in Ganel & Goshen-Gottstein, 2004), but interference was minimal with dynamic displays. This suggests that adult viewers are either better able to selectively attend to relevant cues, or better able to integrate multiple facial cues, when viewing moving as opposed to static faces. These gains, however, come with a cost in processing time. Only women showed asymmetrical interference with static faces, with variations in identity affecting expression judgments more than the opposite. This finding may reflect sex differences in global-local processing biases (Godard & Fiori, 2012). Our findings stress the importance of using dynamic displays and of considering sex distributions when characterizing typical face processing mechanisms.