Hemispheric effects on emotional perception with the Thatcher illusion

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Psychology , facial perception , emotion , happiness , Thatcher illusion , brain hemispheres , Student Showcase of Research & Engagement 2018
Milligan, Megan
The Thatcher Illusion occurs when a face with an inverted mouth and eyes is turned upside down and distortion is no longer noticed. As a pilot study, faces of six emotions (happiness, surprise, disgust, anger, fear, sadness) were selected from Eckman and Friesan's "Unmasking the Face." Faces were presented at 0 or 180 degrees on the right or left of slides for 0.25 seconds. A fixation dot was centered on each slide. Participants identified the emotion of 176 faces and happiness was most identifiable. In the present study, happy faces (one male and one female) were used. Of sixty-four faces, half were distorted using the Thatcher Illusion. All were presented in the right or left visual fields at various angles (0, 15, 45, 90, 105, 135, 150, 180) for 0.20 seconds. A fixation dot was centered on each slide. Participants rated the happiness of each face from 0 (none) to 10 (extreme). Tentative results indicate that normal faces are perceived as happier than distorted faces. Distorted faces at angles lower than 45 appear to be less happy. The goal is to assess hemispheric effects on emotional perception as well as locate the angle where the Thatcher Illusion is noticed.