Abstract
Face adaptation can be used to explore the relationship between identity and expression representations. Robust facial expression aftereffects are obtained when face identity is held constant across adapting and test stimuli, but changes in identity diminish the strength of the effect (Fox & Barton, 2007). Similar effects are seen in children with 7-year-olds demonstrating adult-like aftereffects for happy-sad expressions (Vida & Mondloch, 2009). This suggests children use identity as a context for reading expressions. Individual differences in expression geometry point to the potential benefits of calibrating the perceptual system to read emotional expressions in individual faces. Although traditional models posit separate processing streams for emotion and identity, current models also include connections and/or coding redundancies (e.g., residual information for identity within the expression code.) If adaptation effects reflect moment-to-moment recalibrations in the perceptual system, (i.e., design features that help to optimize performance), identity-specific expression aftereffects (which reflect a recalibration for a specific identity) should grow stronger with age. We used a condensed (50 trial) version of Fox and Barton's task (2007) to explore changes in the relative strength of identity-specific expression aftereffects in school age children. Children (n = 47; ages= 5–12 years) were presented with adapting and test images that were different sizes to reduce the role that low-level features play in the strength of the same person adaptation effect. Neutral (no-adapt) trials were mixed within the block to assess response bias. A measure of “person-specific” adaptation was computed by comparing performance on same-person and different-person trials for happy and sad adaptors. Consistent with our hypothesis, the person specificity of the adaptation effect was significantly correlated with age (r = .396, p < .01, for sad adapt trials). This age-related increase in adaptation strength suggests that during middle childhood the perceptual system becomes increasingly fine tuned to how emotions are expressed in individual faces.