Post-Decision Gaze as a Behavioral Manifestation of Decision Confidence

Abstract

Decisions are naturally accompanied by a feeling of confidence in their correctness. Typically measured via self-reported judgments, decision confidence is also expressed implicitly through sensorimotor behavior. In one exploratory and two preregistered experiments (total N = 115), we combined VR-based probabilistic-learning and spatial-cueing paradigms with computational modeling to examine whether post-decision gaze can serve as an implicit behavioral measure of decision confidence. Gaze direction generally aligned with predictive decisions about a targets upcoming location, while the degree of alignment tracked the model-based probability underlying the decision. Gaze-decision alignment also exhibited previously established statistical hallmarks of confidence. Under increased uncertainty, gaze and decisions tended to diverge, reflecting strategic "hedging" behavior. Gaze-decision alignment and explicit confidence judgments were modestly correlated, and remained correlated after controlling for the decisions probability, suggesting that the two are partially overlapping manifestations of internal confidence. Notably, reported confidence showed higher metacognitive sensitivity and increased serial dependence across trials, while gaze-based confidence expressed a more trial-specific readout of internal confidence. These findings suggest that post-decision gaze in visual-spatial learning tasks is an implicit, embodied manifestation of confidence. The complementary functional characteristics of implicit and explicit expressions of confidence may support adaptive behavior during learning.