Horizontal but not vertical saccades enhance memory retrieval: A meta-analysis and systematic review.

Saccade-induced retrieval enhancement (SIRE) refers to the phenomenon that actively engaging in horizontal eye movements before recall enhances subsequent memory performance. This effect is thought to be the result of interhemispheric interactions stimulated by saccades. An alternative explanation is that saccades promote memory retrieval by improving top-down attention control. Thus, the mechanisms of SIRE are unclear, and the present meta-analysis quantitatively analysed the effect of saccades on memory performance and examined the mechanisms of SIRE. We searched "Web of Science," "PubMed," and "Springer" for peer-reviewed papers using the keywords "eye movements + memory" and "saccades + memory." Twenty-two papers were included in the final analysis. There was a significant facilitation of horizontal saccades on overall memory performance, with a pooled effect size (Cohen's d) of 0.45 (p < .001). However, the overall effect of vertical saccades was not significant (d = 0.1, p = .14). Moderation analysis showed that the handedness of participants was a significant moderator of SIRE, with strongly right-handed individuals benefitting more from horizontal saccades than non-strongly right-handed individuals (p < .01). Horizontal saccades improved memory performance, particularly for strongly right-handed individuals. These results support the interhemispheric interaction hypothesis.