Spatial boundaries affect subjective time and order memory: the combined roles of contextual instability and unpredictability.

People form structured memories from continuous experiences through event segmentation, a process often triggered by contextual changes that demarcate the boundaries between events. Event boundaries have been linked with changes in subjective time perception and memory. To expand this finding to spatial navigation, we explored the effects of spatial boundaries on time perception and memory using a virtual "doorway effect". Participants were asked to find and pick up objects in three virtual environments: confined (only one room), duplicated (multiple identical rooms), and novel (multiple unique rooms). This design allowed us to test whether the mere instability of moving between rooms (i.e., duplicated) was enough to alter subjective time, or if unpredictable contextual changes (i.e., novel) were necessary. We found that subjective time intervals between items and across the entire route were perceived as shorter, and the temporal order between sequential items was remembered better in the absence of boundaries. Additionally, the findings suggest that unpredictability alone does not significantly affect memory, at least when contextual changes are incidental. Instead, contextual instability and unpredictability typically work together to account for the effects of spatial boundaries on memory. We consider how these results may be applied to time estimation during COVID-19 confinement.