Eye movements reflect capacity-dependent organization of working memory.

Abstract

Human cognition is capacity-limited, requiring strategies to actively structure information. Eye movements offer a natural mechanism for sequential sampling, but whether such sequences reflect memory organization is unknown. We developed a working-memory task where color-frequency pairings created a latent ordinal structure to optimally reduce memory load. Across two experiments, gaze patterns spontaneously aligned with this structure. Participants sampled items following this sequence during encoding and revisited them during maintenance. Critically, the expression of this structure depended on cognitive demand. In a 3-item task, high performers showed robust sequential sampling during encoding, whereas lower performers compensated with replay-like revisitation during maintenance. Under higher demand (4 items), encoding-based organization was disrupted, and structured revisitation emerged primarily during maintenance. These findings suggest that eye movements provide an overt expression of an internally generated organizational process that flexibly adapts to cognitive demands, revealing a behavioral analogue to neural replay when encoding resources are strained.