Bidirectional Mechanisms rather than Alternatives: The Role of Sustained Attention in Interactive Contexts Can Only Be Understood through Joint Attention

Although associations between joint attention and infant development have been extensively investigated (e.g., Carpenter et al., 1998; Donnellan et al., 2020; Mundy & Newell, 2007), the question of how, exactly, interactive behaviours support infant learning remains widely debated (Abney et al., 2020; Tomasello et al., 2007). Hudspeth and Lewis (this issue, DOI 10.1159/000515681) suggest that measures of joint attention in early interaction with an adult partner might merely reflect the ability of the infant to sustain their attention. This theory places infant object engagement at the forefront of attention and learning in joint interaction, in contrast to more traditional views that emphasise infants’ engagement with the attentional behaviours of their adult partner (e.g., Carpenter et al., 1998). First, we discuss Hudspeth and Lewis’s comments on methodological issues to do with defining sustained attention. Next, we consider an important point that they do not mention – namely, the inconsistencies in defining joint attention in the literature. We end by exploring endogenous and exogenous influences on sustained and concurrent looking in early interaction, as well as their implications for understanding infant learning.