Lewkowicz and Ghazanfar (2006) tested cross-species intersensory integration in infancy by testing infants’ ability to match monkey vocalizations and faces. They found that 4-6 month-old infants matched but that 8-10 month-old infants no longer did. More recently, Lewkowicz, Sowinski and Place (in press) found that this matching was mediated by temporal synchrony, that its developmental decline continues into the
second year of life, and that it’s not due to unisensory processing
deficits. Considered together with prior findings of narrowing in
responsiveness to nonnative stimulation in audition and vision, these findings suggest that perceptual narrowing in early development is a pan-sensory and fundamental feature of development. If so, intersensory perceptual narrowing also should occur in infants’ response to nonnative but intra-species (human) faces and vocalizations. To test this prediction, we investigated 6- and 11-month-old Spanish-learning infants’ integration of the audible and visible attributes of the nonnative contrast (/ba/-/va/). We first familiarized infants to an audible /ba/ or
/va/ and then tested their preferences for one of two faces producing these two phonemes. Results revealed that 6-month-olds looked longer at the matching face but that 11-month-olds did not providing the first evidence of perceptual narrowing of intersensory integration of speech in infancy.