Galia Avidan

Experience is known to be a key element involved in the modulation of face-processing abilities as manifested by the inversion effect, other-race, and other-age effects. Yet, it is unclear how exposure refines internal perceptual representations of faces to give rise to such behavioral effects. To address this issue, we investigated short- and long-term experienced stimulus history on face processing. Participants performed same–different judgments in a serial discrimination task where two consecutive faces were drawn from a distribution of morphed faces. The use of stimulus statistics was measured by testing the gravitation of representations toward the experienced mean (regression-to-the-mean), and the dynamic of the biases was tested by investigating trial-by-trial performance. Own-race and own-age faces were tested alongside other-race and other-age faces employing a within-subject design. Results demonstrated greater regression biases in other-race and other-age faces than in own-race and own-age faces. Perceptual narrowing, measured by the ability to form and use the representation of the overall mean of the nonnative faces, varied with proficiency levels, with only those with low proficiency in face recognition showing the use of overall stimulus history for other-race faces. In contrast, the use of stimulus history for other-age faces was similarly affected by statistics in the low- and high-proficiency groups. The results demonstrate that narrowing is associated with specialization levels occurring more robustly for other-race faces, for which exposure is limited during sensitive periods in development.