Common ground on object use associates with caregivers' gesturese.

Caregivers modify their communication when interacting with infants, and these modifications have been related to children's language development. However, the factors influencing caregivers' modification of gestures are understudied. This study examined whether infants' object knowledge, considered as common ground shared with the caregiver, relates to caregivers' gesturese. Six caregiver-infant dyads were videotaped every two months for 15 min in their homes, from child age 8-to-16 months, while they played with two separate objects (i.e. toys). Results indicated that the changes in infants' object knowledge were paralleled by associated changes in caregivers' gestures: parents increased both the amount and the complexity of their gestures.