Abstract
Behavioral data supports the commonsense view that babies elicit different responses than adults do. Behavioral research also has supported the babyface overgeneralization hypothesis that the adaptive value of responding appropriately to babies produces a tendency for these responses to be overgeneralized to adults whose facial structure resembles babies. Here we show a neural substrate for responses to babies and babyface overgeneralization in the amygdala and the fusiform face area (FFA). Both regions showed greater percentage BOLD signal change compared with fixation when viewing faces of babies or babyfaced men than maturefaced men. Viewing the first two categories also yielded greater effective connectivity between the two regions. Facial qualities previously shown to elicit strong neural activation could not account for the effects. Babyfaced men were distinguished only by their resemblance to babies. The preparedness to respond to infantile facial qualities generalizes to babyfaced men in perceivers' neural responses just as it does in their behavioral reactions.