Perceptual Context Boundaries Create Separate Events in Visual Working Memory

In daily life, individuals perceive a continuous stream of external information yet spontaneously segment the ongoing sensorimotor flow into describable, memorable, and discrete units. These event boundaries, occurring during context shifts (e.g., environmental changes), extensively influence subsequent cognitive activities. However, little is known about how events are formed and stored in VWM. This study investigates event-level organization in Visual Working Memory (VWM). Experiment 1 explores whether perceptual context shifts create independent events in VWM. To mimic that our vision captures the transient inputs from the ever-changing world, we asked participants to memorize two sets of items (colors and shapes) separated by a context shift (i.e., the change of both presentation mode and stimuli category), with fixed memory load for one event (e.g., 3 colors) and manipulated load for the other (e.g., 1/2/3 shapes). Results indicate independent storage of two events, that is, the memory load of one event did not affect the memory performance of the other event. Experiment 2, without event boundaries (i.e., color and shape appeared in a chaotic order), refutes independent color and shape storage. Experiment 3, which employs solely the background color change as the event boundary, confirms independent storage between shape events. Experiment 4 assesses the effect of perceptual context boundaries on temporal order memory. The temporal order memory test incorporated two shapes selected from either the same event or two adjacent events for recency discrimination. The results showed that participants had worse temporal memory for information spanning event boundaries than information from the same event, providing additional evidence for event structure presence. These findings align with the notion that across-event elements have weaker associations than within-event ones. In conclusion, context shifts during encoding shape subsequent VWM organization, with temporally close but perceptually divided events stored separately.