The neurocomputational mechanisms underlying the impact of social comparison on effort investment

Previous studies have documented stronger neural responses when participants receive better monetary outcome than others, but how performance-based comparisons shape self-efficacy and subsequent effort behavior remains unclear. We conducted behavioral (Experiment 1, N  = 32) and electrophysiological (Experiment 2, N  = 34) experiments where participants performed an effortful task and received downward/upward feedback relative to a purported competitor. Computational modeling and mediation analysis revealed dynamic self-efficacy updates, with downward feedback enhancing subsequent effort via full mediation by self-efficacy. Electrophysiological results revealed stronger neural activities in response to downward compared to upward feedback for the current round, and enhanced contingent negative variation (CNV) and cue-beta power, reflecting better task preparation, for the upcoming round. Notably, CNV amplitudes were modulated by efficacy, with higher efficacy predicting more negative-going CNV. These findings demonstrate that performance-based comparison dynamically regulates self-efficacy, thereby shaping both neural preparatory processes and subsequent effort allocation in goal-directed behavior.