Objective: The goal of this study was to compare turn-transition duration, for gaps and overlaps, in free-play, with and without objects, in mother-infant interactions, at 7 and 12 months. Few studies have approached the developmental study of turn-transition durations in infancy, and most examine turn-taking only in the context of face-to-face or object-oriented playful interaction. But none has compared the effects of each mode of play in turn-transition duration. Method: We analyzed the vocalizations of 25 motherinfant dyads in a semistructured interaction with three tasks: (1) free-play with toys, (2) free-play without toys, and (3) challenging-object play. Gap and overlap frequency and duration were measured, and the effects of age point (7, 12 months), task (1, 2, 3), and direction of turn-transition (infant, mother) assessed using generalized linear mixed modeling for each dependent variable (DV: gaps, overlaps). Results: Gap durations were substantially shorter, and overlap durations had greater variability, in the free-play without objects condition. There were significant differences between face-to-face and object-oriented conditions for both DV's. Only for gaps, all fixed-effects (age, task, direction), and their two-way interactions, were significant. Posthoc pairwise comparisons found that, in object-oriented conditions, infants maintain similar durations between age points, unlike their mothers. In the face-to-face condition, infants and mothers had the same descending tendency between age points. Conclusions: Interactions without objects produce shorter gap durations and may reveal developmental changes in turn-taking. Research should account for the methodological and theoretical implications of this effect.
Public Significance StatementThis is the first study comparing two common social contexts in infancy-face-to-face and object-oriented interactions-and their effect on turn-transition duration. It provides evidence, that infants, at 7 months, can already produce gap durations closer to those found in adult-adult conversations, and that they get better at it, at 12 months. It shows that our understanding of the foundations and development of turn-taking should be further expanded.