Toddlers get the nod

This thesis presents three studies exploring how children and mothers use conventional head nodding and head shaking gestures in the child's first two and a half years of life. Study 1 examines children's comprehension of head gestures that convey agreement and disagreement, in an experimental context. Study 2 presents an analysis of mothers' head gesture production in interactions with their children in semi-structured play sessions. Study 3 examines children's head gesture production in these same interactions, and asks whether early head gesture use is associated with later language outcomes. Study 1 revealed that 24-month-olds, but not 18-month-olds, can use a bystander's head gestures to disambiguate an informant's correct and incorrect claims about object features, including their names and hiding locations. Developmental change in representational skills during this period appears to facilitate the child's comprehension of head gestures in this setting. In Study 2, mothers used head gestures for a wide range of communicative functions, often reflecting apparent socialization goals and the encouragement of language use. They more often used head nods than head shakes. Mothers' head gestures often accompanied their own yes/no questions, which may provide children with practice in a question-answer format of discourse.

Study 3 indicated that children produce head gestures with increasing frequency between 14 and 32 months, for a rather consistent set of functions. Increases in the rate of gesturing and of combining gestures with speech were detected earlier for head shakes than for nods. Though gesture use was relatively uncommon at 14 months, variation in the number of functions served by infants' head gestures significantly predicted vocabulary production at 32 months, above and beyond the effects of early verbal language production and demographic control variables. Although head gestures have been relatively neglected in developmental research, this thesis brings these deceivingly simple gestures to the forefront. These gestures provide infants with a mode for expressing meaning, and researchers and clinicians with a window into their communication skills. Further theoretical and clinical analyses of communication development must continue to consider the contribution of these gestures to children's language development.