Human choices are remarkably susceptible to the manner in which options are presented. This socalled "framing effect" represents a striking violation of standard economic accounts of human rationality, although its underlying neurobiology is not understood. We found that the framing effect was specifically associated with amygdala activity, suggesting a key role for an emotional system in mediating decision biases. Moreover, across individuals, orbital and medial prefrontal cortex activity predicted a reduced susceptibility to the framing effect. This finding highlights the importance of incorporating emotional processes within models of human choice and suggests how the brain may modulate the effect of these biasing influences to approximate rationality.A central tenet of rational decision-making is logical consistency across decisions, regardless of the manner in which available choices are presented. This assumption, known as "extensionality" (1) or "invariance" (2), is a fundamental axiom of game theory (3). However, the proposition that human decisions are "description-invariant" is challenged by a wealth of empirical data (4, 5). Kahneman and Tversky originally described this deviation from rational decision-making, which they termed the "framing effect," as a key aspect of prospect theory (6, 7).Theories of decision-making have tended to emphasize the operation of analytic processes in guiding choice behavior. However, more intuitive or emotional responses can play a key role in human decision-making (8-10). Thus, when taking decisions under conditions when available information is incomplete or overly complex, subjects rely on a number of simplifying heuristics, or efficient rules of thumb, rather than extensive algorithmic processing (11). One suggestion is that the framing effect results from systematic biases in choice behavior arising from an affect heuristic underwritten by an emotional system (12, 13). However, despite the substantial role of the framing effect in influencing human decision-making, the underlying neurobiological basis is not understood.We investigated the neurobiological basis of the framing effect by means of functional magnetic resonance imaging (fMRI) and a novel financial decision-making task. Participants (20 university students or graduates) received a message indicating the amount of money that they would initially receive in that trial (e.g., "You receive £50"). Subjects then had to choose between a "sure" option and a "gamble" option presented in the context of two different frames. The "sure" option was formulated as either the amount of money retained from the initial starting amount (e.g., keep £20 of the £50; "Gain" frame) or as the amount of money lost from the initial amount (e.g., lose £30 of the £50; "Loss" frame). The "gamble" option was identical in both frames and was represented as a pie chart depicting the probability of winning or losing ( Fig. 1) (14).The behavioral results indicated that subjects' decisions were significantly affected by our framing...

SummaryDecisions are never perfect with confidence in one’s choices fluctuating over time. How subjective confidence and valuation of choice options interact at the level of brain and behavior is unknown. Using a dynamic model of the decision process we show that confidence reflects the evolution of a decision variable over time, explaining the observed relation between confidence, value, accuracy and reaction time. As predicted by our dynamic model, we show that an fMRI signal in human ventromedial prefrontal cortex (vmPFC) reflects both value comparison and confidence in the value comparison process. Crucially, individuals varied in how they related confidence to accuracy, allowing us to show that this introspective ability is predicted by a measure of functional connectivity between vmPFC and rostrolateral prefrontal cortex (rlPFC). Our findings provide a mechanistic link between noise in value comparison and metacognitive awareness of choice, enabling us both to want and to express knowledge of what we want.