| Despite our species' impressive cognitive sophistication in many domains, adult humans are nevertheless notoriously bad at making normatively rational economic decisions. Contrary to what would be expected if we were maximizing utility in an economically rational way, we make our economic decisions in ways that systematically violate most economists' notion of rationality. For example, we tend to care more about losses than equally-sized gains -- this leads decision-makers to take risks to avoid negative outcomes but avoid risk when seeking positive outcomes (termed the reflection effect). Similarly, because losses impact our well-being more than equally-sized gains, we tend not to exchange possessions for equivalent objects that we do not yet own (termed the endowment effect). In much the same way that we overweigh losses relative to gains, we also overweigh the end-points and peak-intensity (relative to other aspects of a memory) when assessing the utility of a past experience (termed the peak-end principle). Although much work has examined the nature of biased decisions in adult humans, research examining the origins of these biases is still in its infancy. This thesis examines existing work on origins of economic biases -- that is, whether these biases are shared with non-human primates. I first review data showing that capuchin monkeys attach extra value to goods in their possession and refuse to exchange owned goods for equally-valuable ones. I then show that capuchin monkeys' risk preferences are sensitive to framing. Finally, I demonstrate that capuchin monkeys make retrospective evaluations according to the peak-end principle. These data demonstrate that economic biases previously thought to be unique to humans are also found in ancestrally-related non-human primates. This similarity implies that these biases are evolutionarily old, and are therefore not the result of selective pressures or cultural experiences unique to humans. |
