The Combined Effect Of Time Discounting And Probability Discounting

Time discounting and probability discounting can respectively reflect the sizes ofthe discount rates deriving from the results of inter-temporal choices and riskdecisions. There-into, the former means that the subjective value of a desired resultreduces with the increase of the delay time, the latter is regarded as the subjectivevalue of a probable result reduces with the increase of the odds(the decrease of theprobability),and the two both follow the quasi-hyperbolic model. Most of past studysabout decisions thesis all focused on time discounting or probability discounting, andthe problems of their several effects and interaction, but rarely paid attention to theircombined effects, that is, the combined discounting including time-probabilitydiscounting and probability-time discounting.On the basis of the two different situations of gains and losses of threeamounts(10yuan,100yuan,100yuan), and seven different kinds of delay-time(1day,1week,1month, six months,1year, five years and ten years) andrisk-probability(97%,83%,54%,16%,9%,2%and1%), this study bands togetherinter-temporal choices and risk decisions, and uses separately methods offixed-sequence(experiment1) and bisection-titration (experiment2) to research thecombined effects of time discounting and probability discounting under the influenceof the delayed time and the probability.The results reveal that the combined effect also corresponds with thequasi-hyperbolic model under the influence of delay-time and risk-probability, as aretime discounting and probability discounting, and there is no significance differencebetween two combined discountings (time discounting and probability discounting).However, in the two combined discountings, the sign effect and magnitude effect bothhave not be explored, but time discounting and probability discounting. Moreover, forthe contributions to the discount rate of the combined effects, probability discountingis higher than time discounting.