Infants initially use words and symbolic gestures in markedly similar ways,
to name and refer to objects. The goal of these studies is to examine how
parental verbal and gestural input shapes infants' expectations about the c
ommunicative functions of words and gestures. The studies reported here sug
gest that infants may initially accept both words and gestures as symbols b
ecause parents often produce both verbal labels and gestural routines withi
n the same joint-attention contexts. In two studies, we examined the produc
tion of verbal and gestural labels in parental input during joint-attention
episodes. In Study 1, parent-infant dyads engaged in a picture-book readin
g task in which parents introduced their infants to drawings of unfamiliar
objects (e.g., accordion). Parents' verbal labeling far outstripped their g
estural communication, but the number of gestures produced was non-trivial
and was highly predictive of infant gestural production. In Study 2, parent
-infant dyads engaged in a free-play session with familiar objects. In this
context, parents produced both verbal and gestural symbolic acts frequentl
y with reference to objects. Overall, these studies support an input-driven
explanation for why infants acquire both words and gestures as object name
s, early in development.