Abstract
The generalization of adaptation effects across age-based categories of faces was examined using a gender classification task. On each trial, participants adapted to an adult male or female face for 5 s and then viewed a 300 ms presentation of a morphed face created from a different pair of male and female faces. The morphed faces were created from three different pairs of adult faces or from three different pairs of faces of 7 to 10 year old boys and girls. For each face, an ovular view of the internal regions of the face was presented so gender stereotypic cues, such as hairstyle, were not visible. Although gender markers are subtle in these faces, especially in the child faces, adults could accurately determine the gender of both the adult and child faces. Decisions about the intermediate morphed faces varied as a function of the adapting stimulus. After viewing an adult male, participants were more likely to perceive the intermediate morphed face as female. Conversely, after viewing an adult female, participants were more likely to perceive the intermediate morphed faces as male. This was true for both the adult and child faces. The present findings demonstrate that adaptation aftereffects generalize to new faces that are drawn from a different natural category than the set of adapting faces. These results suggest exposure to adult male and female faces may be important for defining the gender boundary in a different age-based category of faces.