Other-race faces are generally recognised more poorly than own-race faces. According to Levin's influential race-coding hypothesis, this other-race recognition deficit results from spontaneous coding of race-specifying information, at the expense of individuating information, in other-race faces. Therefore, requiring participants to code race-specifying information for all faces should eliminate the other-race effect by reducing recognition of own-race faces to the level of other-race faces. We tested this prediction in two experiments. Race coding was induced by requiring participants to rate study faces on race typicality (experiment 1) or to categorise them by race (experiment 2). Neither manipulation reduced the other-race effect, providing no support for the race-coding hypothesis. Instead, race-coding instructions marginally increased the other-race effect in experiment 1 and had no effect in experiment 2. These results do not support the race-coding hypothesis. Surprisingly, a control task of rating the attractiveness of study faces increased the other-race effect, indicating that deeper encoding of faces does not necessarily reduce the effect (experiment 1). Finally, the normally robust other-race effect was absent when participants were instructed to individuate other-race faces (experiment 2). We suggest that poorer recognition of other-race faces may reflect reduced perceptual expertise with such faces and perhaps reduced motivation to individuate them.

Perceptual adaptation not only produces striking perceptual aftereffects, but also enhances coding efficiency and discrimination by calibrating coding mechanisms to prevailing inputs. Attention to simple stimuli increases adaptation, potentially enhancing its functional benefits. Here we show that attention also increases adaptation to faces. In Experiment 1, face identity aftereffects increased when attention to adapting faces was increased using a change detection task. In Experiment 2, figural (distortion) face aftereffects increased when attention was increased using a snap game (detecting immediate repeats) during adaptation. Both were large effects. Contributions of low-level adaptation were reduced using free viewing (both experiments) and a size change between adapt and test faces (Experiment 2). We suggest that attention may enhance adaptation throughout the entire cortical visual pathway, with functional benefits well beyond the immediate advantages of selective processing of potentially important stimuli. These results highlight the potential to facilitate adaptive updating of face-coding mechanisms by strategic deployment of attentional resources

Our ability to recognize faces despite their similarity as visual patterns depends on high-level face-coding mechanisms that are strongly tuned to upright faces. If face aftereffects reflect adaptation of these mechanisms, as widely assumed, then they should be sensitive to face orientation. Previous studies have not supported this hypothesis, but have generally used a figural aftereffect paradigm, which may not optimally engage expert face-coding mechanisms. Here, we used an identity aftereffect paradigm, which requires identification of target faces, to provide a stronger test of the hypothesis. We measured identity aftereffects for upright and inverted faces, with and without eliminating low-level retinotopic adaptation. Baseline identification performance was substantially better for upright than inverted faces, confirming that our task tapped orientation-selective face expertise. With orientation varied between participants, aftereffects were almost twice as large for upright as inverted faces, on three different aftereffect measures (change in threshold, change in overall proportion correct, change in perceived identity of the average face). With orientation varied within participants, the results were less clear. We suggest that adaptation of expert face-coding mechanisms can contribute to face identity aftereffects, although the effect may not be very robust.

Face identity aftereffects suggest that an average face, which is continuously updated by experience, functions as a norm for coding identity. Sex-contingent figural face aftereffects indicate that different norms are maintained for male and female faces but do not directly implicate them in coding identity. Here, we investigated whether sex-specific norms are used to code the identities of male and female faces or whether a generic, androgynous norm is used for all faces. We measured identity aftereffects for adapt-test pairs that were opposite relative to a sex-specific average and pairs that were opposite relative to an androgynous average. Identity aftereffects are generally larger for adapt-test pairs that lie opposite an average face, which functions as a norm for coding identity, than those that do not. Therefore, we reasoned that whichever average gives the larger aftereffect would be closer to the true psychological norm. Aftereffects were substantially and significantly larger for pairs that lie opposite a sex-specific than an androgynous average. This difference remained significant after correcting for differences in test trajectory length. These results indicate that, despite the common structure shared by all faces, identity is coded using sex-specific norms. We suggest that the use of category-specific norms may increase coding efficiency and help us discriminate thousands of faces despite their similarity as patterns.

Discrimination and recognition are often poorer for other-race than own-race faces. These other-race effects (OREs) have traditionally been attributed to reduced perceptual expertise, resulting from more limited experience, with other-race faces. However, recent findings suggest that sociocognitive factors, such as reduced motivation to individuate other-race faces, may also contribute. If the sociocognitive hypothesis is correct, then it should be possible to alter discrimination and memory performance for identical faces by altering their perceived race. We made identical ambiguous-race morphed faces look either Asian or Caucasian by presenting them in Caucasian or Asian face contexts, respectively. However, this perceived-race manipulation had no effect on either discrimination (Experiment 1) or memory (Experiment 2) for the ambiguous-race faces, despite the presence of the usual OREs in discrimination and recognition of unambiguous Asian and Caucasian faces in our participant population. These results provide no support for the sociocognitive hypothesis. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

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