The spatial layout of doorways and environmental boundaries shape the content of event memories

Physical boundaries in our environment have been observed to define separate events in episodic memory. To date, however, there is little evidence that the spatial properties of boundaries exert any control over event memories. To examine this possibility, we conducted four experiments that took manipulations involving boundaries that have been demonstrated to influence spatial representations, and adapted them for use in an episodic object memory paradigm. Here, participants were given 15 min to freely explore an environment that contained 36 objects, equally dispersed among six discriminable buildings. In a subsequent test of object-location binding, participants were required to indicate where they remembered encountering the objects. In Experiment 1 the spatial properties of the building boundaries were identical; however, in Experiment 2 the boundaries were differentiated by their geometric shape and the location of the doorways in the buildings. In the test phases of these experiments, we observed a shift from a bias towards remembering the positions of objects within a building but not the building itself (Experiment 1), to a bias towards remembering which building an object was in but not the location within the building (Experiment 2). In Experiment 3, the buildings shared the same geometry but were differentiated by the locations of doorways, and we observed no significant differences between response types. Finally, in Experiment 4, the buildings were uniquely shaped but shared the same doorway location, and we observed a bias towards remembering the positions of objects within a building. In addition, exploratory analyses of non-spatial interference revealed more correct recall for objects housed in the first building a participant visited during exploration, compared to all other buildings. Together, our data indicates that the location of doorways in boundaries and, to a lesser extent, boundary geometries influence event models, and that a primacy effect can be observed in the recall of multiple object-location bindings.