Though verbal rehearsal is a frequently endorsed strategy for remembering short lists among adults, there is ambiguity around when children deploy it, and what circumstantial factors encourage them to rehearse. We recoded data from a recent multilab replication of a serial picture memory task in which children were observed for evidence of task-related speech or lip movements to extract finer-grained detail about how children spoke during the task. With these data, we aimed to better understand the manner in which children rehearse and the task scenarios which elicit overt rehearsal. Children in several countries from 5 to 10 years old were tasked with remembering 2–5 nameable pictures in serial order across a 15-second delay. Coders categorized children’s speech or lip movements as reflecting fixed rehearsal of the last-presented item only, cumulative rehearsal of all the items presented so far, or some attempt at cumulative rehearsal. We found that most children, regardless of age, did not overtly rehearse at all during presentation of the objects or during the delay period. However, children who sometimes overtly rehearsed recalled longer lists of items than children who did not. Though rare, cumulative rehearsal was most frequently observed for list lengths close to the participant’s demonstrated maximum recall length. Critically, on the trials where overt rehearsal was observed, recall improved. This evidence supports previous suggestions that rehearsal strategy, and possibly also its effectiveness, changes with task difficulty, and raises further questions about how verbal rehearsal affects serial recall.
