Applied a theory of information integration to decision making with probabilistic events. 10 undergraduates judged the subjective worth of duplex bets that included independent gain and lose components. The worth of each component was assumed to be the product of a subjective weight that reflected the probability of winning or losing, and the subjective worth of the money to be won or lost. The total worth of the bet was the sum of the worths of the 2 components. Thus, each (...) judgment required multiplying and adding operations. The multiplying model worked quite well in 4 experimental conditions. The adding model showed more serious discrepancies, though these were small in magnitude. The theory of functional measurement was applied to scale the subjective values of the probability and money stimuli. Subjective and objective values were nonlinearly related both for probability and for money. (shrink)