Abstract
Binocular rivalry (BR) is the conscious alternation between two images that are presented to each eye. BR experiments using face stimuli have focused on the influence of emotions by often presenting 2D black and white photos or simplistic, unnatural cartoons of faces; findings from such studies have primarily determined that positive facial expressions dominate (i.e., are perceived longer) over negative ones. While the significance of emotion during rivalry has been meticulously studied, the global significance of the entire face (i.e., identity) carrying the emotion has scarcely been touched upon. To determine whether identity also influences BR face perception, or whether emotion is the paramount factor affecting a face stimulus' dominance, six 3D, realistic faces, with varying skin tone, gender, and facial features, expressing one of three emotions (happy, neutral, or sad) were created using a random face generator software (FaceGen Modeller). Different identities expressing identical emotions, identical identities expressing identical emotions, and identical identities expressing different emotions were all rivaled against one another, as five human subjects reported which stimulus (comprising of both emotion and identity) were perceived throughout the stimuli's presentation. As anticipated, positive expressions were found to dominate over negative ones when expressed by the same identity (p<1.24x10-22, Kolmogorov-Smirnov [KS]). Also, when comparing the dominance durations of rivaling different identities expressing the same emotion, identity was found not to have a significant effect on alternation rates (p>0.6019,KS). Interestingly, however, the strong dominance effect of positive expressions became disputable upon setting different identities to rival. Comparisons of dominance durations for each emotion when rivaled with identical identities versus with different identities exhibited significant differences (p<0.0358,KS), indicating an effect of identity on the percept of emotions. Overall, while emotion appears to play a much greater role in the percept of faces than identity, a significant interaction exists between the two.
Meeting abstract presented at VSS 2014