Joint attention (JA), the shared focus between a caregiver and their child on an object or event, has been shown to be crucial for language development and other early cognitive processes. However, JA research is often only measured in cross-sectional samples, which do not allow the differentiation between intra- and inter-individual differences. In addition, most studies focus on narrow participant groups, and sign language users represent one understudied group. However, signers offer a particularly valuable perspective for JA research, as the use of a visual-manual language may uniquely influence gaze and JA. This longitudinal study investigates the developmental trajectory of gaze and multimodal JA behaviours in seven native signing deaf-caregiver-hearing-child dyads between 12 and 24 months of child age during naturalistic interactions. Results show that while gaze and general JA properties remain stable across the second year of life, significant changes emerge in how children initiate JA. Over time, the native signing children in this study increasingly take on an active role in their interactions, being more frequently and more successfully initiators of JA and exploring different multimodal behaviours. These findings suggest that modality-specific experiences may shape developmental pathways and emphasise the importance of studying JA in diverse populations. Further longitudinal research is needed to disentangle the effect of language modality and individual differences in JA development.
Sander et al. (Sat,) studied this question.