Infants have rich visual categories in ventrotemporal cortex at 2 months of age

What are the foundations of visual categories in the human brain? Although infant looking behavior characterizes the development of overt categorization, it cannot measure neural representation or distinguish the underlying mechanism. For this, we need rich neuroimaging from young infants and the capacity to apply advanced computational models of vision. In this study, we conducted an awake functional magnetic resonance imaging (fMRI) study of more than 100 2-month-old infants, with follow-ups at 9 months, finding that categorical structure is present in high-level visual cortex from 2 months of age. This precedes its emergence in lateral visual cortex, suggesting non-hierarchical development of category representations. A deep neural network model aligned with infants' representational geometry, indicating that the features comprising infants' category template span a range of complexities and can be learned from the statistics of visual input. Our results reveal the existence of complex function in ventral visual cortex at 2 months of age and describe the early development of category perception.