Race categorization and face recognition stages in the processing of laterally displayed unknown faces

Bruyer and Dussart (1985) have recently shown that the "race effect", i.e. the difficulty in recognizing faces issuing from an ethnic group different from that of the subject, is limited to the right visual field. They suspected familiarization to be responsible for this asymmetry. In Exp. I, we tested this hypothesis by repeating the experiment of Bruyer and Dussart with a greater number of trials. A sample of 16 subjects were given the task of recognizing black and white faces laterally displayed for 180 msec. No laterality effect appeared, and the race effect was observed to an equal degree in each hemifield at all stages of the experimental session. It could thus be that various kinds of familiarization must be distinguished. In Exp. II, with 16 new subjects, the black and white faces were mixed so that the subjects had first to perform racial categorization, then a recognition. This time, an advantage of the left field appeared, the race effect was larger in the right than in the left field, and the race effect decreased with familiarization in the left field only. Two complementary experiments with 24 and 16 subjects showed that this phenomenon was not explainable by laterality effects in the early racial decision operation, but well by a lateralized effect of tasks requirements.