Abstract
When viewing ambiguous figures, individuals can exert selective attentional control over their perceptual reversals (e.g., Strüber & Stadler, 1999). In the current study, we replicated this finding and also found that ambiguous figures containing faces are processed quite differently from those containing objects. Viewers' were able to divide their attention equally between the two face interpretations of Boring's young girl-old woman, and showed a face preference when viewing Rubin's vase-face. When instructed to alternate quickly between competing interpretations, their reversal rates were much quicker for these two figures than for figures containing only objects (Maltese cross, Necker cube), a finding that might reflect greater use of a holistic processing strategy when viewing figures involving faces. This was examined by comparing reversal behaviours for upright and inverted versions of Rubin's vase-face and looking for inversion effects (i.e., alterations in reversal behaviours associated with inversion). Viewers spent more time perceiving the face than the vase interpretation with upright but not inverted stimuli, and made faster reversals with upright than inverted displays. These findings suggest that face inversion influences how we attend to faces, in addition to how we perceive and process them. Describing the perceptual reversal patterns of individuals in the general population allowed us to draw comparisons to behaviours exhibited by individuals with Asperger Syndrome (AS). The group data suggested that these individuals were less affected than neurotypical controls by figure type or stimulus inversion. Examination of individual scores, moreover, revealed that the majority of participants with AS showed atypical reversal patterns, particularly with ambiguous figures containing faces. The majority also showed an atypical rather than a diminished or absent inversion effect. Together, our results show that ambiguous figures can be a valuable tool for examining face processing mechanisms in the general population and other distinct groups of individuals.