Brain Advance Access published online on May 18, 2009
Brain, doi:10.1093/brain/awp067
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Not on the face alone: perception of contextualized face expressions in Huntington's disease
1 Department of Psychology, Hebrew University of Jerusalem, Jerusalem, Israel 2 The Rotman Research Institute, Baycrest, Ontario, Canada 3 Center for Neural Computation, Hebrew University of Jerusalem, Jerusalem, Israel 4 University of Toronto, Ontario, Canada 5 North York General Hospital, Toronto, Ontario, Canada
Correspondence to:
Hillel Aviezer, Department of Psychology, Hebrew University of Jerusalem, Jerusalem, 91905, Israel E-mail: hillel.aviezer{at}mail.huji.ac.il
Numerous studies have demonstrated that Huntington's disease mutation-carriers have deficient explicit recognition of isolated facial expressions. There are no studies, however, which have investigated the recognition of facial expressions embedded within an emotional body and scene context. Real life facial expressions are typically embedded in contexts which may dramatically change the emotion recognized in the face. Moreover, a recent study showed that the magnitude of the contextual bias is modulated by the similarity between the actual expression of the presented face and the facial expression that would typically fit the context, e.g. disgust faces are more similar to anger than to sadness faces and, consequently, are more strongly influenced by contexts expressing anger than by contexts expressing sadness. Since context effects on facial expression perception are not explicitly controlled, their pattern serves as an implicit measure of the processing of facial expressions. In this study we took advantage of the face-in-context design to compare explicit recognition of face-expressions by Huntington's disease mutation-carriers, with evidence for processing the expressions deriving from implicit measures. In an initial experiment we presented a group of 21 Huntington's disease mutation-carriers with standard tests of face-expression recognition. Relative to controls, they displayed deficits in recognizing disgust and anger faces despite intact recognition of these emotions from non-facial images. In a subsequent experiment, we embedded the disgust faces on images of people conveying sadness and anger as expressed by body language and additional paraphernalia. In addition, sadness and anger faces were embedded on context images conveying disgust. In both cases participants were instructed to categorize the facial expressions, ignoring the context. Despite the deficient explicit recognition of isolated disgust and anger faces, the perception of the emotions expressed by the faces was affected by context in Huntington's disease mutation-carriers in a similar manner as in control participants. Specifically, they displayed the same sensitivity to face–context pairings. These findings suggest that, despite their impaired explicit recognition of facial expressions, Huntington's disease mutation-carriers display relatively preserved processing of the same facial configurations when embedded in context. The results also show intact utilization of the information elicited by contextual cues about faces expressing disgust even when the actually presented face expresses a different emotion. Overall, our findings shed light on the nature of the deficit in facial expression recognition in Huntington's disease mutation-carriers as well as underscore the importance of context in emotion perception.
Key Words: context effects; facial expressions; Huntington's disease mutation-carriers; implicit and explicit processing
Abbreviations: HDMC, Huntington's disease mutation carrier
Received March 26, 2008. Revised December 19, 2008. Accepted February 19, 2009.