When infants vocalize, parents listen; in fact everybody listens. But what do we hear, and how do we react?

Research in the iVoc project focuses on the categories of sounds that babies
make: squeals, growls, raspberries, and little vowel- like sounds. But these infant sounds are different from cry and laughter because cry is always negative and laughter positive, whereas squeals and growls can show any emotion.

Parents notice not only the emotions but also the fact that these sounds come in repetitive chunks indicating the infant’s control over them. These sounds are early foundations for language that no other primate ever shows. And parents react by paying attention to baby sounds and using them as information about the baby’s well-being.

The iVoc project studies how baby sounds and parent reactions to them can help us predict a child’s development, and identify disorders such as hearing impairment and autism.