Brief article The positive and negative of human expertise in gaze perception Paola Ricciardelli a, * , Gordon Baylis b , Jon Driver a a Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, UK b Department of Psychology, University of South Carolina, Columbia, SC, USA Received 1 April 2000; accepted 26 May 2000 Abstract Judging where others look is crucial for many social and cognitive functions. Past accounts of gaze perception emphasize geometrical cues from the seen eye. Human eyes have a unique morphology, with a large white surround (sclera) to the dark iris that may have evolved to enhance gaze processing. Here we show that the contrast polarity of seen eyes has a powerful in¯uence on gaze perception. Adult observers are highly inaccurate in judging gaze direction for images of human eyes with negative contrast polarity (regardless of whether the surround- ing face is positive or negative), even though negative images of eyes preserve the geometric properties of positives that are judged accurately. The detrimental effect of negative contrast polarity is much larger for gaze perception than for other directional judgements (e.g. judging which way a head is turned). These results suggest an `expert' system for gaze perception, which always treats the darker region of a seen eye as the part that does the looking. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Gaze; Gaze perception; Social attention 1. Introduction In everyday life, where people look can signal where they are currently attending. Accordingly, many social and cognitive functions depend on the ability to perceive where another person is looking (see Baron-Cohen, 1995). The gaze direction of others can signal sources of possible interest, or of imminent danger. Gaze direction P. Ricciardelli et al. / Cognition 77 (2000) B1±B14 B1 Cognition 77 (2000) B1±B14 www.elsevier.com/locate/cognit 0010-0277/00/$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S0010-0277(00)00092-5 COGNITION * Corresponding author. Tel.: 144-20-7679-1126; fax: 144-20-7916-8517. E-mail address: p.ricciardelli@ucl.ac.uk (P. Ricciardelli).