The role of speech-gesture congruency and delay in remembering action events.

When watching others describe events, does information from their speech and gestures affect our memory representations for the gist and surface form of the described events? Does our reliance on these memory representations change over time? Forty participants watched videos of stories narrated by an actor. Each story included three target events that differed in their speech-gesture congruency for particular actions (congruent speech/gesture, incongruent speech/gesture, or speech with no gesture). Participants had to reproduce target event sentences, prompted after delays of 2, 6, or 18 minutes. Seeing gestures, either congruent or incongruent, led to better gist recall (more mentions of the target action, more gestures for the target action, and more complete target events) compared to not seeing gestures. However, seeing incongruent gestures sometimes led to reproductions of the incongruent gestures, particularly after short delays, as well as inaccuracies in speech. Our results suggest that over time people increasingly rely on multimodal gist-based representations and rely less on representations that include surface and source information about speech and gesture