The Domestic Chick as an Animal Model of Autism Spectrum Disorder (ASD); Developmental Homology Gives Validity

Equipped with an early social predisposition immediately post-birth, humans typically form associations with mothers and other family members through exposure learning, canalized by a spontaneous predisposition to biological motion, face configuration, and other cues of animacy. If impaired, reduced social preferences can lead to social interaction impairments such as autism spectrum disorder (ASD) via misguided canalization. Despite being taxonomically distant, domestic chicks also follow a homologous developmental trajectory toward adaptive socialization through imprinting, which is guided via predisposed preferences that are homologous to those of humans, thereby suggesting that chicks are valid animal models of ASD. In addition to the convergent similarities in predisposition with human newborns, accumulating evidence suggests the construct validity of the chick model. Considering the recent progress in the evolutionary neurobiology of vertebrates, we reviewed the advantages and limitations of the chick model of developmental mental diseases in humans.