In decision making under risk, probability of each outcome is known by all decision-makers. This is the case for instance, when one wants to choose between equestrian bets. There is a gain associated with each horses and an odds. This odds represents the horse’s probability of winning. Historically, theoretical models assumed that decision makers were rational and therefore sought to maximize gain over the different bets. However, experiences have shown that human decision-maker deviates from rational choices. Different explanations have been proposed. First, a utility function was introduced which led to the so called ”expected utility theory.” A utility is assigned to each outcome depending on the subject.