Alireza Soltani, Ph.D.
Psychological and Brain Sciences
“On the flexibility of basic risk attitudes in monkeys and humans”
We respond in reliable ways to risk; for example, generally we avoid risky options, but are our risk preferences stable traits or flexible characteristics? In this talk, I examine choice behavior of macaques and humans in experiments that involve selection between risky options. I show that monkeys exhibit several deviations from “classic” risk preferences: risk-seeking as opposed to risk-aversion, loss-seeking as opposed to loss-aversion, and linear and S-shaped probability distortion as opposed to inverse-S-shaped. When evaluating gambles with multiple possible outcomes, humans use different quantities for evaluating each gamble outcome and for weighting the values of possible outcomes to construct an overall reward value or to make decisions. I provide evidence that this allows subjects to make decisions more easily and quickly, and thus to become more flexible. At the end, I present some modeling results demonstrating how some of the observed flexibility can emerge as a result of interactions between attentional and reward valuation systems. These results challenge the idea that our risk attitudes are evolved traits that are shared with the last common ancestor of macaques and humans; suggesting, instead, that behavioral flexibility is the hallmark of risky choice in primates.