Aftereffects in the Perception of Emotion Following Brief, Masked Adaptor Faces

Abstract

Adaptation aftereffects are the tendency to perceive an ambiguous target stimulus, which follows an adaptor stimulus, as different from the adaptor. A duration dependence of face adaptation aftereffects has been demonstrated for durations of at least 500ms, for identity related judgments. Here we describe the duration dependence of the adaptation af- tereffects of very brief (11.7ms-500ms) backwardly masked faces, on both expression and identity category judgments of ambiguous target faces. We find significant aftereffects at minimum duration 23.5ms for emotional expression, and 47ms for identity, but these are abolished by backward masking with an inverted face, although these same adaptors can be cor- rectly categorized above chance. The presence of a short duration adaptation effect in expression might be mediated by rapid transfer of low spatial fre- quency (LSF) information. We tested this possibility by comparing aftereffects in low pass and high pass filtered ambigu- ous targets, and found no evidence of independent adaptation of a LSF specific channel.