PREATTENTIVE ANALYSIS OF FACIAL EXPRESSIONS OF EMOTION

Some experiments have shown that a face having an expression different from the others in a crowd can be detected in a time that is independent of crowd size. Although this pop-out effect suggests that the valence of a face is available preattentively, it is possible that it is only the detection of sign features (e.g. angle of brow) which triggers an internal code for valence. In experiments testing the merits of valence and feature explanations, subjects searched displays of schematic faces having sad, happy, and vacant mouth expressions for a face having a discrepant sad or happy expression. Because inversion destroys holistic face processing and the implicit representation of valence, a critical test was whether pop-out occurred for inverted faces. Flat search functions (pop-out) for upright and inverted faces provided equivocal support for both explanations. But intercept effects found only with normal faces indicated valences had been analysed at an early stage of stimulus encoding.