The Enactment Effect: A Systematic Review and Meta-Analysis of Behavioral, Neuroimaging, and Patient Studies

Public Significance Statement The enactment effect is the finding that physically performing an action represented by a word or phrase leads to enhanced memory for that information relative to simply reading it. This review integrates evidence from behavioral, neuroimaging, and patient studies to highlight the utility of encoding multiple facets of an item or an event to enhance its retention. Enactment was found to be a reliable and effective mnemonic tool for both neurotypical and patient populations. The enactment effect is the phenomenon that physically performing an action represented by a word or phrase (e.g., clap, clap your hands) results in better memory than does simply reading it. We examined data from three different methodological approaches to provide a comprehensive review of the enactment effect across 145 behavioral, 7 neuroimaging, and 31 neurological patient studies. Boosts in memory performance following execution of a physical action were compared to those produced by reading words or phrases, by watching an experimenter perform actions, or by engaging in self-generated imagery. Across the behavioral studies, we employed random-effects meta-regression with robust variance estimation (RVE) to reveal an average enactment effect size of g = 1.23. Further meta-analyses revealed that variations in study design and comparison task reliably influence the size of the enactment effect, whereas four other experiment factors-test format, learning instruction type, retention interval, and the presence of objects during encoding-likely do not influence the effect. Neuroimaging studies demonstrated enactment-related activation to be prevalent in the motor cortex and inferior parietal lobule. Patient studies indicated that, regardless of whether impairments of memory (e.g., Alzheimer's) or of motor capability (e.g., Parkinson's) were present, patients were able to benefit from enactment. The findings of this systematic review and meta-analysis highlight two components accounting for the memory benefit from enactment: a primary mental contribution relating to planning the action and a secondary physical contribution of the action itself.