Congruence of Inherent and Acquired Values Facilitates Reward-Based Decision-Making

摘要

Most real-life cues exhibit certain inherent values that may interfere with or facilitate the acquisition of new expected values during associative learning. In particular, when inherent and acquired values are congruent, learning may progress more rapidly. Here we investigated such an influence through a 2 x 2 factorial design, using attractiveness (high/low) of the facial picture as a proxy for the inherent value of the cue and its reward probability (high/low) as a surrogate for the acquired value. Each picture was paired with a monetary win or loss either congruently or incongruently. Behavioral results from 32 human participants indicated both faster response time and faster learning rate for value-congruent cue-outcome pairings. Model-based fMRI analysis revealed a fractionation of reinforcement learning (RL) signals in the ventral striatum, including a strong and novel correlation between the cue-specific decaying learning rate and BOLD activity in the ventral caudate. Additionally, we detected a functional link between neural signals of both learning rate and reward prediction error in the ventral striatum, and the signal of expected value in the ventromedial prefrontal cortex, showing a novel confirmation of the mathematical RL model via functional connectivity.