The Influence of Varying Degrees of Enactability on the Enactment Effect in Action Memory During the Encoding and Retrieval Stages: A Study with Healthy Young Adults.

Whether the enactment effect benefits from motor information activation is a key concern in action memory; meanwhile, the degree of enactability may influence this activation. Accordingly, this study aims to examine the explanatory role of motor information reactivation in the enactment effect and to further clarify whether a certain degree of motor information activation is necessary for this effect to emerge. To this end, we manipulated the degree of enactability and separately investigated its impact on the enactment effect at the encoding stage (Experiment 1) and the retrieval stage (Experiment 2). Experiment 1 required participants to either silently read phrases or both silently read and physically enact the actions represented by the phrases during encoding. The research showed that an enactment effect was only observed for the high-enactability-phrases condition, but not for the low-enactability-phrases condition. Experiment 2 additionally required participants to either verbally recall (verbal retrieval) or verbally recall while simultaneously performing corresponding actions (enactment retrieval) during retrieval. The findings showed that under the verbal retrieval condition, the enactment effect was observed for the high-enactability-phrases condition but not for the low-enactability-phrases condition; under the enactment retrieval condition, the enactment effect was observed both for the high-enactability phrases and low-enactability-phrases conditions. Thus, motor information activation during encoding and retrieval is crucial for the enactment effect, which emerges only when motor information activation reaches a threshold, supporting and expanding motor information reactivation theory.