Beneficial Roles of Emotion in Decision Making: Functional Association of Brain and Body

Though traditional microeconomics has supposed that human decisions are based on logical and exact computation of cost-benefit balances or efficacies, studies in behavioral economics have shown that humans sometimes make seemingly irrational decisions driven by emotions. In our everyday situations, factors related to decisions are complex and which alternative will be the most beneficial is uncertain. In such cases, emotions have been thought adaptive because they can quickly reduce negative alternatives and facilitate fast and effective decision making. Some theorists argued that one of important sources of such emotional drives affecting decision making is bodily responses that are represented in brain regions (Craig, 2009; Damasio, 1994). In this article, empirical evidence for the functional associations of the brain and body accompanying decision making will be shown as follows. (1) Heart rate responses and concentration of inflammatory cytokine (IL-6) can predict acceptance or rejection of an unfair offer in an economical negotiation game, the Ultimatum Game. Activation of the anterior insula mediates relationship between bodily states and decision making. (2) Sympathetic responses reflected by secretion of adrenaline are represented in brain regions such as the midbrain, anterior cingulate cortex, and anterior insula, and furthermore can determine exploration of decision making in a situation where an action-outcome contingency is stochastic and unstable. These findings suggest beneficial roles of emotion and bodily responses in decision making.