Abstract

Adults have been shown to be highly inaccurate in judging gaze direction for eyes with negative contrast polarity (i.e. sclera darker than the iris). This contrast polarity effect has been proved to be robust and due to a simple rule based on the fact that irises are typically darker than their surrounding sclera (Ricciardelli, Baylis & Driver, 2000). However, in the previous studies only static-eye stimuli were used, although in real life we see moving eyes. 12 adult subjects (7M and 5F) participated in an experiment in which dynamic eye stimuli were employed to test whether motion could help judge gaze direction in negative polarity stimuli. An effect of the contrast polarity of the eye region was still found, making the direction of the negative polarity gaze extremely difficult to judge. Surprisingly, the difficulty with negative eyes remains even with dynamic eyes, although perceived motion in gaze stimuli improves somehow the perception of negative eyes. Therefore, the benefit from motion does not completely compensate for the detrimental contrast polarity effect.