Feature Overlap & Oculomotor Disengagement - Experiment: Task script and stimuli

Visual search theories distinguish between attentional capture and disengagement, yet how multiple feature dimensions combine to delay disengagement remains unclear. This study investigated whether shared features (color, shape, object category) produce additive or super-additive costs in oculomotor disengagement. Forty-three participants performed a delayed-disengagement task where a central fixated stimulus shared zero to three features with a peripheral target. Saccadic latency (SL) served as the index of disengagement cost. Results showed that SL increased non-linearly with the number of shared features, following a quadratic trend. A component decomposition revealed that this acceleration was driven by hierarchical gating: Color overlap produced large main effects, whereas shape and object-category overlap produced costs primarily when combined with color. Our findings suggest that disengagement is not a simple summation of feature similarities. Instead, color acts as a high-priority gate; a match triggers a capacity-limited verification process where additional feature overlap disproportionately prolongs inspection. We propose a hierarchical gating model where high-salience features determine entry into verification, governing the temporal dynamics of visual selection. Migrated from OSF (https://osf.io/jntf3/). This record contains the Psychtoolbox/EyeLink task program and the full stimulus set; data are in the companion dataset record (see Related identifiers).