Olfactory‐to‐visual facilitation in the infant brain declines gradually from 4 to 12months

During infancy, intersensory facilitation declines gradually as unisensory perception develops. However, this trade‐off was mainly investigated using audiovisual stimulations. Here, fifty 4‐ to 12‐month‐old infants (26 females, predominately White) were tested in 2017–2020 to determine whether the facilitating effect of their mother's body odor on neural face categorization, as previously observed at 4 months, decreases with age. In a baseline odor context, the results revealed a face‐selective electroencephalographic response that increases and changes qualitatively between 4 and 12 months, marking improved face categorization. At the same time, the benefit of adding maternal odor fades with age (R2 = .31), indicating an inverse relation with the amplitude of the visual response, and generalizing to olfactory‐visual interactions previous evidence from the audiovisual domain.