抄録
In this tutorial review, we discussed on the neural substrate of utility and the reason why decision-making often deviates from rationality, failing to serve people’s best long-term interests. It was pointed out that there are two valuation systems in the brain, one cognitive and the other affective. These two valuation systems perform automatic computations of values based on knowledge (cognitive valuation) and past history of learning (i.e., instrumental conditioning) and evolution (affective valuation). In the instrumental conditioning a signal such as money comes to be associated with primary reinforcer like food and thus acquires reinforcing power. Utility in economics can be equated with expectation of this secondary reinforcer, especially monetary reward. Final decision is made under the control of supervisory control system in the prefrontal cortex. The decision may wander from rationality when affective valuation system demands its request too pressingly to resist or the supervisor controller is not efficient enough to handle the situation due to temporally distracted by other tasks or for some other reasons like age (being too young or too old to be equipped with an efficient supervisory controller) and individual difference in impulsivity.
