Choice under risk and ambiguity
When choosing between different gains most people prefer smaller but more certain gains to larger but less certain ones. For example, a certain gain of $10 is usually preferred to a 50% chance of winning $25, even though the latter option offers more money on average ($12.5 vs. $10). This behavioral tendency is called “risk aversion”. Similarly, a 50% chance of winning $25 is often preferred to an unknown probability of winning much more than $25, a tendency which is termed “ambiguity aversion”. An opposite pattern of behavior is observed when losses are involved: most people prefer a 50% chance of losing $25 to a sure loss of $10, thus exhibiting “risk seeking”. A
lthough most people exhibit those traits, they differ significantly in their degree. An interesting question is whether differences in eating behavior might be explained, at least partially, by differences in attitudes towards risk and ambiguity. For example, overeating implies an immediate certain reward (food), accompanied by a future, uncertain punishment (gaining weight). Overweight individuals might therefore be more risk seeking in the realm of losses compared to lean individuals. We have previously identified brain areas whose activation tracks the “subjective value” of options that were presented to normal-weight young adults. Following these results we are now running similar experiments in lean and obese individuals, looking for weight-related differences both in behavior and in the neural activation.