A third kind of episodic memory: Context familiarity is a distinct process from item familiarity and recollection.

Memory for past events is widely believed to operate through two different processes: one called 'recollection' when retrieving confident, specific details of a memory, and another called 'familiarity' when only having an unsure but conscious awareness that an item was experienced before. When people successfully retrieve details such as the source or context of a prior event, it has been assumed to reflect recollection. We demonstrate that familiarity of context is functionally distinct from familiarity of items and recollection and offer a new trivariate model. The three memory response types were differentiated across multiple behavioral and physiological measures, and at the trial level and among individual variability between-subjects, too. That is, what has traditionally been thought to be two kinds of memory processes are actually three, which become evident when using sensitive enough multi-measures. Akin to missing obvious elements when using only a two-dimensional lens to see a three-dimensional picture, when we have the ability to look for the three processes of memory, we can see them clearly dissociate and as independently replicable across several different studies of diverse cohorts from different laboratories. Together, these data reveal that context familiarity is a third process of human episodic memory.