Your, mine, OUR face: A meta-analysis of the enfacement illusion

Facial self-representation plays a crucial role in the development of self-consciousness and social cognition. The enfacement illusion, resulting from interpersonal synchronous multisensory stimulation, causes individuals to update their facial self-representation by incorporating another person's facial features. The discovery of this illusion is not far behind us, but plenty of studies have been conducted since then. Taking into account the numerous variations in the experimental implementation and measures, the overall picture of findings on enfacement seems intricate at first sight. In order to provide a systematic summary of the overall effect of the enfacement illusion, there is time for a meta-analysis. We identified 44 publications that described experiments consisting of at least one synchronous and one asynchronous multisensory facial stimulation condition. Our aim was to (a) determine the overall effect size of the enfacement illusion, (b) evaluate the moderating effects of methodological variability, and (c) assess the presence of publication bias. The results demonstrated a robust overall medium effect size, regardless of the experimental procedures and measures employed. Despite the risk of potential undocumented methodological variation and slight publication bias, the result of this meta-analysis provides evidence that the enfacement illusion is a replicable phenomenon and that human facial self-representations are indeed malleable.