Gambling on an empty stomach: Hunger modulates preferences for learned but not described risks.

Introduction: We assess risks differently when they are explicitly described, compared to when we learn directly from experience, suggesting dissociable decision-making systems. Our needs, such as hunger, could globally affect our risk preferences, but do they affect described and learned risks equally? On one hand, decision-making from descriptions is often considered flexible and context sensitive, and might therefore be modulated by metabolic needs. On the other hand, preferences learned through reinforcement might be more strongly coupled to biological drives.

Method: Thirty-two healthy participants (females: 20, mean age: 25.6 ± 6.5 years) with a normal weight (Body Mass Index: 22.9 ± 3.2 kg/m ) were tested in a within-subjects counterbalanced, randomized crossover design for the effects of hunger on two separate risk-taking tasks. We asked participants to choose between two options with different risks to obtain monetary outcomes. In one task, the outcome probabilities were described numerically, whereas in a second task, they were learned.

Result: In agreement with previous studies, we found that rewarding contexts induced risk-aversion when risks were explicitly described (F  = 55.01, p < .0001, η  = .64), but risk-seeking when they were learned through experience (F  = 10.28, p < .003, η  = .25). Crucially, hunger attenuated these contextual biases, but only for learned risks (F  = 8.38, p < .007, η  = .21).

Conclusion: The results suggest that our metabolic state determines risk-taking biases when we lack explicit descriptions.