Human eye movements track stimulus meaning

Working memory (WM) is a capacity- and duration-limited system that enables the representation and processing of fleeting sensory phenomena. Human fMRI studies indicate that brain areas associated with oculomotor control contribute to WM, while human eye tracking studies indicate that the physical characteristics of items held in WM can be decoded from eye movements. Whether eye movements also encode the semantic attributes of remembered stimuli is unknown. Across three experiments, we demonstrate that stimulus meaning – operationalized via category membership – can be decoded from human gaze behavior (total N = 79 adults). Category decoding was driven by a mixture of eye movement parameters, could not be explained by manual response planning, and disappeared when participants attentively processed but did not categorize stimuli. These findings provide important and novel evidence demonstrating that human oculomotor behavior varies with the semantic meaning of a stimulus.