Why are lotteries valued less? Multiple tests of a direct risk-aversion mechanism

Recent studies have identified the uncertainty effect (UE), whereby risky prospects (e.g., a binary lottery that offers either a $50 or $100 gift certificate) are valued less than their worst possible outcome (a $50 certificate). This effect has been proposed to result from ``direct risk-aversion'' which posits that the mere uncertainty of a lottery directly decreases its value. However, this effect may also be driven by the potential disappointment inherent in not receiving the better of the two outcomes (disappointment aversion), or the mere fact that the risky prospect is referred to as a ``lottery''. The results of two experiments do not support either of these two alternatives. Specifically, the results of Experiment 1 indicate that the UE is observed even when the values of the two lottery outcomes are similar, or even identical. Experiment 2 further replicates the UE in a context in which the word ``lottery'' is never used (a company promotional). These results are consistent with a direct risk-aversion mechanism (Gneezy et al., 2006; Simonsohn, 2009) and suggest that the UE obtains across a number of different contexts.