The Impact of Prior Beliefs about Volatility on Adaptive Behavior.

Humans adapt to environmental changes by balancing empirical observations with prior beliefs and evaluating if unexpected events indicate a true change. The specific factors that govern updating behavior in dynamic environments remain to be elucidated. We here examined how prior beliefs about environmental volatility affect updating of cue-target contingencies, particularly when observations violate these beliefs. Thirty-two participants completed two versions of a probabilistic reversal-learning task, in which auditory cues signaled the location of a subsequent visual target stimulus. In a reactive task version, participants indicated the target location after its appearance; in a predictive task version, they predicted the target's location based on the cue information. Cue-target contingencies either remained stable or reversed once within a block, thereby creating a stable and a reversal environment. Before each block, participants received either true or false information about volatility, i.e., about whether the cue-target contingency would remain stable or change. We analyzed reaction times (reactive task) and choices (predictive task) with model-free measures and a Rescorla-Wagner learning model. Participants generally adapted to the contingency changes in both tasks. In the reactive task, prior beliefs had no significant effect. In the predictive task, believing that a reversal environment was stable reduced learning rates. In stable environments, falsely believing the environment contained a reversal increased decision noise, reduced accuracy and increased choice variability. These findings demonstrate that prior beliefs about volatility shape updating in response to task demands and environmental structure.