Pre-existing brain states predict risky choices.

Rational decision-making models assume that people resolve an economic problem based on its properties and the underlying utility. Here we challenge this view by examining whether pre-stimulus endogenous neuronal fluctuations can bias economic decisions. We recorded subjects' pre-stimulus neural activation patterns with fMRI before presentation and choice between pairs of certain outcomes and risky gambles. Our results indicate that activities in the left nucleus accumbens and medial frontal gyrus can bias subsequent risky decision making, showing that neuronal activities in regions associated with uncertainty and reward processing are involved in biasing subsequent choice selection. This finding challenges theories which propose that choices merely reveal stable underlying distributions of hedonic utility. Endogenous brain states of this sort might originate from a systematic cause or a stochastic type of neural noise, which can be construed as contextual factors that shape people's decision making.