Nested Contextual change and the temporal compression of episodic memory

Abstract

How does the structure of events influence the when and the where of life experiences in comparison to the what? We developed a novel virtual reality (VR) environment to understand how the quantity of information within nested structures influence participants memory for events. Participants moved through a series of virtual rooms (events) where images (items) appeared in randomised locations on a 3 by 3 grid located on a wall. Participants were asked to remember the what (old/new), when (timeline location), and where (grid location), of the images they experienced. Two types of nested events were tested (6 rooms, each containing 4 images; 3 rooms, each containing 8 images), all lasting an equivalent number of seconds. We found a strong temporal compression effect at nested levels in which participants remembered early items and events happening later, and later items and events happening earlier, than the original experience. Crucially, presenting four-item events resulted in a greater compression rate than eight-item events. We also found greater temporal distances between pairs of items occurring within eight-item events than pairs of items which occurred on either side of a boundary. Memory for when depends on the nested compression of information within events.