The enactment effect refers to a phenomenon in which the memory performance for action phrases is enhanced by performing the described action (e.g., sharpen a pencil) compared with simply reading the action phrase. This produced effect can result in improved motor processing. This study investigated the contribution of semantic integration to the enactment effect by contrasting well-integrated phrases, such as "blow up the balloon," with poorly integrated phrases, such as "sew the toothpick," and analysing the N400 component of event-related potentials (ERPs). The subjects encoded action phrases with different degrees of semantic integration by either pretending to perform or reading action phrases. They then completed a phrase recognition test, while electroencephalographic signals were simultaneously recorded. The behavioural results showed that semantic integration improved memory performance under the motor encoding condition but not under the verbal encoding condition. The ERP results revealed that, regardless of whether it was an old (memorised) or new (distractor) phrase, a larger N400 component was elicited under the motor encoding condition than under the verbal encoding condition. In the motor encoding condition, poorly integrated phrases elicited a larger N400 component than well-integrated phrases; in the verbal encoding condition, this effect was not observed. The N400 effect associated with semantic processing was enhanced by semantic integration under the motor encoding condition rather than the verbal encoding condition. These results supported a deep semantic processing mechanism under the motor encoding condition, and a semantic feedback processing mechanism for the enactment effect was partially supported.
Keywords: Enactment effect; N400; semantic feedback processing mechanism; semantic integration.