AVVERSIONE ALL'AMBIGUITA' COME DETERMINANTE DELLE SOGLIE DI MAGGIORANZA IN LOTTERIE ELETTORALI DI DIVERSA DIMENSIONE

We present a theoretical model of majority threshold determination as a function of voter’s ambiguity aversion. Our model is a Second-Order Expected Utility model. We use the axiomatisation of Grant, Polak and Strzalecki (2009). A key feature of the model is that it separates ambiguity attitude, identified as a characteristic of the voter’s tastes, from ambiguity, a characteristic of the voter’s awareness of information. Ambiguity is reflected by the fact that, in the voter’s mind, the objective probabilities of the voting outcomes are unknown. We show that a confidence unbiased voter prefers a majority threshold higher than the simple majority if she is averse to ambiguity. The greater the degree of ambiguity aversion, the greater the majority threshold she prefers. Furthermore, when voter is ambiguity averse, we derive a positive correlation between the size of the electorate and the preferred majority threshold.