Cognitive Process of Emotion Under Uncertainty

One of the missions of the cognitive process of animals, including humans, is to make reasonable judgments and decisions in the presence of uncertainty. The balance between exploration and exploitation investigated in the reinforcement-learning paradigm is one of the key factors in this process. Recently, following the pioneering work in behavioral economics, growing attention has been directed to human behaviors exhibiting deviations from simple maximization of re-ward. Here we study the nature of human decision making under the existence of reward uncertainty, employing a condition where the reward expectancy is constant (flat reward condition). The characteristic behavioral patterns exhibited by subjects reveal the underlying reward-related neural mechanism. The relevance of this result to the functions of dopamine neurons is discussed.