Abstract: | The purpose of this study was to examine 32 mothers' sensitivity to social contingency during face‐to‐face interaction with their two‐ to four‐month‐old infants in a closed circuit TV set‐up. Prosodic qualities and vocal sounds in mother's infant‐directed (ID) speech during sequences of live interaction were compared to sequences where expressive behaviours were decoupled by presenting either the mothers (Replay 2) or the infants (Replay 1) with a replay record of the partners' former behaviour in a Live 1–Replay 1–Live 2–Replay 2–Live 3 design. Overall, the mothers produced significantly higher amount of ID speech during the live sequences. Compared to the Live 1 sequence, there was a significant reduction in mothers' ID speech during both replay sequences. However, the mothers only recovered ID speech after the Replay 2 sequence, not after the Replay 1. These findings suggest that the emotions signalled by the mothers' ID speech is affected by the contingency of the infant responses. |