Decision theories like skew-symmetric additive models and similarity judgments assume that the similarity or contrast between specific pairs of payoffs shapes an agent's decision making process when faced with a choice between two lotteries. This rationale experienced a revival in economic theory with the recent introduction of salience theory, which - similarly to its skew-symmetric additive relatives - predicts the correlation between lotteries to affect agents' choices. This thesis investigates the role of similarity and contrast in decision making under risk and uncertainty based on implications derived from skew-symmetric additive models such as salience theory and from similarity judgments. Employing a laboratory experiment with decision problems presented in two different display formats, it is investigated whether the change of a common consequence shared by two perfectly correlated lotteries affects subjects' choices. Under both display formats and in contrast to the prediction of salience theory, subjects' choices shift systematically when altering the common consequence. A second experiment shows that recent evidence in support of salience-predicted correlation effects resulted from changes in the display format rather than the correlation between lotteries. In a third experiment involving a setup that allows studying correlation effects without confounding changes in the display format, no significant salience-predicted correlation effects can be found. Furthermore, in a horse-race between display format and potential salience effects, the former are quantitatively more important. Finally, by building on predictions derived from similarity judgments, the role of similarity and contrast is examined within a broader context, independently of the correlation between lotteries. However, altering the juxtaposition between payoffs in order to guarantee varying pair-wise payoff comparisons does not significantly affect subjects’ choices.    «

Decision theories like skew-symmetric additive models and similarity judgments assume that the similarity or contrast between specific pairs of payoffs shapes an agent's decision making process when faced with a choice between two lotteries. This rationale experienced a revival in economic theory with the recent introduction of salience theory, which - similarly to its skew-symmetric additive relatives - predicts the correlation between lotteries to affect agents' choices. This thesis investigat...    »