Context brings back all the memories: a review of the physical context reinstatement effect on episodic memory

Context reinstatement can be defined as an effect that enhances memory by reinstating contextual features from the encoding phase during retrieval. Early experimental studies revealed varying degrees of this effect in both recall and recognition memory tasks. These findings led to the development of different hypotheses regarding the factors influencing context reinstatement, often linking it to recollection-based memory processes. The main objective of the present review is to examine the methodological factors affecting context reinstatement with a primary focus on-but not limited to- two prevailing hypotheses: the outshining hypothesis and the item-context-ensemble hypothesis. In addition, the review critically considers the extent to which context reinstatement may be associated with recollection- and familiarity-based memory processes and the potential influence of response bias, an issue that has been largely overlooked in previous research. Reinstating the study context at test seems to aid memory in experimental designs where (i) the context was semantically rich, (ii) the stimulus was unfamiliar, (iii) the cue load was low, (iv) interactive encoding between the context and the stimulus was employed, and (v) the retention interval was relatively long. Methodological heterogeneity across studies and the tools used to assess memory accuracy may be key sources of conflicting findings. Building on the limitations of existing research, this review offers recommendations to support more systematic and insightful investigations of context effects on memory.