The relationship between end-state comfort effects and memory performance in serial and free recall

In two experiments we examined the relationship between end-state comfort effects and memory performance in serial and free recall. In Experiment 1, 24 university students completed a bimanual end-state comfort task and a memory task. Participants viewed a series of 11 letters, then performed the bimanual overturned glass task in which they simultaneously moved two glasses from an upper shelf to a lower shelf, and then recalled the letters in either serial or free recall conditions. Memory recall was evaluated based on the presence or absence of primacy and recency effects. The end-state comfort effect was assessed by the percentage of initial hand positions that allowed the hands to end up in a comfortable thumbs-up posture. The end-state comfort effect was present in both memory conditions. The results revealed the disappearance of the recency effect in serial and free recall, although the effect was much stronger during serial recall. In Experiment 2, we asked whether simpler motor tasks might bring back the recency effect. Forty-eight participants completed either a bimanual or unimanual task that involved moving non-descript plastic cylinder(s) from an upper shelf to a lower shelf. An unexpected finding was that even after performance of the simpler motor tasks, the recency effect was still absent. The disappearance of the recency effect, regardless of the complexity of the motor task, suggests a reciprocal influence of physical action and cognitive processes, which we interpret as a basic concurrence cost.