Two fundamentally different explanations of gambling behavior have developed. The first is generally referred to as the psychological model. It stresses that gambling is an enjoyable activity for many people and is consumed like any other good or service. Participation in gambling provides one with social and personal gratification. Unfair bets, or those gambles with negative expected return, are taken because people misperceive probabilities in risk-taking situations. The best predictors of who will gamble according to the psychological model include race, sex, family and demographic characteristics, and one's cultural background. According to the Friedman-Savage model, a rational individual will gamble if he possesses a particular type of utility of wealth function [Friedman and Savage, 1948]. The motivation of the gambler according to this model is the high value he places on the chance of achieving a major increase in personal wealth and thus moving upward on the socioeconomic ladder: