7 Bayesian approaches to modelling action selection

We live in an uncertain world, and each decision may have many possible outcomes; choosing the best decision is thus complicated. This chapter describes recent research in Bayesian decision theory, which formalises the problem of decision making in the pres-ence of uncertainty and often provides compact models that predict observed behaviour. With its elegant formalisation of the problems faced by the nervous system, it promises to become a major inspiration for studies in neuroscience. Choosing the right action relies on our having the right information. The more infor-mation we have, the more capable we become at making intelligent decisions. Ideally, we want to know what the current state of the world is, what possible actions can we take in response to it, and what the outcomes of these actions will be. When we choos