The description-experience gap in risky choice in nonhuman primates.

Risk attitudes in humans depend on the format used to present the gamble: we are more risk-averse for common gambles in the gains domain whose properties are described to us verbally than for those whose properties we learned about solely through experience. This difference, which constitutes part of the description-experience gap, is important, because it highlights the role of knowledge acquisition in decision-making. The reasons for the gap remain obscure, but could depend upon uniquely human cognitive abilities, such as those associated with language. Thus, the gap may or may not extend to nonhuman animals. For this study, rhesus monkeys performed a novel task in which the properties of some gambles were explicitly cued (described), whereas others were learned through previous choices (experienced). Our monkeys displayed a description-experience gap. Overall, monkeys were more risk-seeking for experienced than for described gambles. This difference was observed for a range of gamble probabilities (from 20% to 80% likelihood of payoff), indicating that it is not limited to low probability events. These results suggest that the description-experience gap does not depend on uniquely human cognitive abilities, such as those associated with language, and support the idea that epistemic influences on risk attitudes are evolutionarily ancient.