Delay and probability discounting in risky decisions: A comparison between gamblers and non-gamblers.

This study jointly examined delay and probability discounting in risky decisions comparing gamblers and nongamblers participants. In order to do so, in a lottery task, the amount of winning, the probability to obtain it, and the delay for winning were systematically varied. The hypothesis according to which gamblers, compared to not gamblers, preferred hazardous options with immediate and high rewards, rather than more sure options with delayed and small rewards was tested. Furthermore, it was investigated whether the level of impulsiveness was related to the choices of participants. Eighty individuals (M=33.7; s.d.=6.9) participated in this study. The 3x3x3x2 experimental design involved three within-subjects variables and one betweensubjects variable. Within-subjects variables were: winning amount (low/ medium/ high); winning probability (low/ medium/ high); delay for winning (short/ medium/long). The betweensubject variable was the attitude toward gambling (gamblers – non-gamblers). Results showed that, compared to control group, gamblers were more sensitive to the amount of the reward and to delay discounting, but less sensitive to the probability discounting. Participants with high level of impulsiveness made less bets with long delay for winning. The theoretical implications of these findings are discussed.