EVANSTON, Ill. --- Reading the face of a person who is trying to conceal fear or other emotions is tricky business, according to a new Northwestern University study of electrical activity in the brain.
Though such microexpressions as a brief flash of fear are unlikely to be consciously noticed, they still get picked up by the brain and make their way through the visual system. The effect can alter perception and the way other people are treated or judged, the study concludes.
Even though our study subjects were not aware that they were viewing subliminal emotional expressions, their brain activity was altered within 200 milliseconds, said Ken Paller, co-investigator of the study and professor of psychology in the Weinberg College of Arts and Sciences at Northwestern. As a result, the ratings of facial expressions they did see were biased.
In other words, sometimes when it seems like you are acting on the vagaries of instinct, your brain is actually responding to real information about others that bubbles just beneath your consciousness.
The study included tests to determine whether study volunteers had a tendency to experience anxiety, particularly in social situations. Those who tended to be socially anxious had the strongest brain response to subliminal expressions of fear.
The findings have direct implications for understanding psychiatric disorders such as phobia, obsessive-compulsive disorder and generalized anxiety disorder, said Wen Li, lead author of the study and postdoctoral fellow at Northwesterns Feinberg School of Medicine.
Neural and Behavioral Evidence for Affective Priming from Unconsciously Perceived Emotional Facial Expressions and the Influence of Trait Anxiety, will be published in an upcoming issue of the Journal of Cognitive Neuroscience. Besides Li and Paller, the studys co-authors include Stephan Boehm, currently at the University of Wales at Bangor, and Richard Zinbarg, a
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Contact: Pat Vaughan Tremmel
p-tremmel@northwestern.edu
847-491-4892
Northwestern University
31-Jul-2007