Interaction of emotional expression and eye gaze: an event related potential study

The current study examined the interaction of emotional expression and eye gaze in order to test the evolutionary theory predicting fearful averted-gaze expressions are prioritized over angry averted-gaze expressions while angry straight-gaze expressions are prioritized over fearful straight-gaze expressions. ERPs were acquired from 22 participants fi tted with 19 electrodes (10-20 international system) in response to four emotions (happy, angry, fearful, neutral) each displaying three gaze-directions (left, straight, right; a total of 12 experimental conditions). Participants viewed trials consisting of a neutral image (700ms) followed by a fi xation cross (500ms) and a target image (1000ms). Six blocks of 112 trials consisted of 96 target faces (8 for each condition) and 16 scrambled faces presented as targets; participants were instructed to press “1” whenever they saw a scrambled face. Repeated Measures ANOVAs were run on mean amplitudes for electrodes 01, 02, T5, and T6 with factors Emotion (happy, angry, fearful, neutral) and Hemisphere (left, right) for each gaze direction (left, straight, right) across three time windows (80-120ms, 120-200ms, 200-400ms). The overall results demonstrated that leftward gaze signifi cantly interacted with expression from 120-200ms while rightward gaze signifi cantly interacted with expression from 200-400ms. Additionally,
fearful faces elicited signifi cantly larger N170 mean amplitudes than angry faces for leftward and straight gazes. The results demonstrate that the interaction of leftward gaze and expression is temporally processed before the interaction of rightward gaze and expression. Further, fearful faces were preferentially processed over angry faces regardless of gaze direction; in opposition to what was predicted by evolutionary theory.