Cross-race effect (own-race bias)

Biological Parallel

Perceptual narrowing is universal across vertebrates. Human infants discriminate all face types at birth but specialize by nine months. Japanese macaques lose cross-species face discrimination after one month of selective exposure. Chickens imprint on available faces within hours of hatching. Emperor penguins identify chicks by vocal frequency among thousands. Brown-headed cowbirds bypass the system with innate vocal passwords that trigger species recognition without early exposure. The unifying pattern: neural systems allocate bandwidth to frequent inputs and compress infrequent categories into coarser representations.