Decision amid uncertainty

摘要

Choosing whether to stick to a belief or to abandon it in the face of uncertainty is central to human behaviour. Modelling implicates brain chemicals called neuromodulators in adjudicating this essential decision. Why did you choose to read this article? Perhaps you are a neuroscientist eager to refine your knowledge. Or perhaps you are keen to broaden your horizons outside your current discipline. These motivations reflect a fundamental tradeoff in how we invest our time and effort: individuals must continually decide whether it would be better to pursue known sources of reward, or whether there is more to be gained by searching for new strategies or opportunities. In reinforcement learning, this dilemma is referred to as the trade-off between exploitation and exploration. There is growing evidence that the mechanisms used to resolve this trade-off are directly regulated by neuromodulators. Yu and Dayan, writing in Neuron, extend this work by using simple principles from Bayesian probability theory to derive a sophisticated model of how neuromodulatory systems are central to the trade-off decision.