Experience-dependent neural specialization during infancy.

The ability to recognize the difference among faces of another race or species declines from 6 to 9 months of age. During this time, perceptual biases are formed, leading to lasting deficits in recognizing individuals of other races and species. However, little is known about how early infant experience shapes the neural structures underlying face processing. Here we found neural specialization, in infants who received 3 months of training with six individually labeled monkey faces. However, neural specialization was not found after an equal amount of training with the same six faces labeled at the category-level (i.e., all faces labeled "monkey") or when infants were exposed to faces without labels. These results suggest that neural specialization for faces requires learning at the individual level during infancy.