Face Processing Patterns of Persons with Asperger Syndrome : an Eye Tracking Study

Sammanfattning: One of the main diagnostic criteria for Asperger Syndrome is a severe social impairment (American Psychiatric Association [DSM-IV-TR] 2000), something that has often been connected to a more specific impairment in facial recognition. However, the main diagnostic tool (the DSM-IV-TR) has received much criticism during later years and is soon to be revised (Woodbury-Smith & Volkmar 2009). Among other things, many researchers claim that the diagnosis should be complemented with a sliding scale of severity (Ring, Woodbury-Smith, Watson, Wheelright & Baron-Cohen 2008). The use of facial information is central in the social interaction of humans, evident in the special patterns of visual scanning that people employ for facial stimuli (Yarbus 1967). Because of that, this symptom of Asperger Syndrome has become a high research priority. The impairment in facial recognition has been connected to a bias towards detail based processing (McPartland, Webb, Keehn & Dawson 2010). A recent study also connects this to an unusually high visual acuity, which could result in a disposition to focus on small facial features. In the present study. facial stimuli were prepared to provoke memory conjunction errors. This type of memory error means that a person erroneously claims to recognize a face assembled by pieces of previously shown stimuli. If a person is more prone to do so, that would imply that he or she is more focused on details than on configural information (Danielsson 2006). Two groups were tested, one consisting of non-diagnosed adults and one of adults diagnosed with Asperger Syndrome. A test for visual acuity was administered, which was followed by a series of facial recognition tasks. Responses in the latter part were given with a computer mouse, and eye fixations were recorded using a head mounted eye-tracking device. Three hypotheses were formulated. First, persons with AS were expected to perform more poorly in all facial recognition tasks. Second, persons with AS were expected to make more conjunction errors than test group subjects. Finally, persons with AS were expected to display a mean visual acuity significantly higher than that of the test group. However, no significant differences emerged between the groups in relation to either of the hypotheses, and results could not be referred to flaws in the experimental setup. Therefore, these results are taken to display the heterogeneity of the Asperger Syndrome population, and possibly the importance of early training measures to compensate for social impairments.