The influence of social interaction on the development of deictic gestures in infancy

Abstract

Infant deictic gestures, particularly infant index-finger pointing, are early manifestations of referential communication and are predictive of language development. Despite the social nature of gestures, research investigating the influence of social interaction experiences on infants’ gesture development is limited and results are inconsistent. Two social learning mechanisms and their parental behavioral correlates are of particular interest. First, parents’ relevant referential uptake in response to infants’ interest and communication possibly facilitates infants’ communicative development (Cameron-Faulkner et al., 2015; Ger et al., 2018). Second, parents’ own referential gestures (i.e., pointing) are a pertinent behavior through which infants learn via imitation (Liszkowski et al., 2012; Rüther & Liszkowski, 2023). However, other studies did not confirm the relationship between parent and infant pointing (Ger et al., 2023; Matthews et al., 2012; Salo et al., 2019). For this dissertation, I examined the causal effects of parental responsiveness and pointing on infants’ gesture development. In Study 1, I present a novel remote paradigm to observe infant pointing, parental responsiveness, and pointing in a natural interactional setting. In Study 2, parents received specific instructions regarding their responsiveness and their pointing frequency to assess whether 12-month-old infants directly adapt their pointing frequency to parental behavior. In Study 3, I investigated the relationship between infants’ pointing frequency and parental behavior in the context of a longitudinal parent-based training. The one-month training targeted parental responsiveness and pointing in interaction with their 12-month-old infants. Study 4 examined the influence of parental responsiveness and pointing on the development of infants’ showing and pointing gestures from seven to ten months of age. The included training group was instructed to respond contingently to infants’ interest and communication. Results of Study 1 showed that infants’ pointing frequency, parental responsiveness and pointing in the remote paradigm were comparable to established laboratory-based methods. Infants in Study 2 increased their pointing frequency directly in reaction to increased parental responsiveness and independently of parents’ pointing frequency. Parental responsiveness emerged as a longitudinal predictor of infants’ pointing frequency and contributed to the promoting effect of training in Study 3. In Study 4, infants’ development of showing and pointing gestures was differentially predicted by parental behavior. Training exclusively promoted infants’ showing gestures. I conclude that infants’ deictic gesture development is influenced by social interactional experiences, such as parental responsiveness and parental pointing, in interaction with infants’ social cognitive development.