The Cognitive And Neural Mechanism Of The Time Perspective Effect On Intertemporal Choice

Intertemporal choice refers to the individual weighing of benefits against costs in different time point, and the corresponding judgment and choices (Frederick, Loewenstein,&Donoghue,2002). Intertemporal choice can be found everywhere in modern lives from minor things like personal savings, health, and work, to major events like national policies of education invest and environmental protection. Therefore, studies of intertemporal choice is of significance to helping people better understand non-rational phenomena in daily life and to making decisions more rationally and scientifically.Recently, some researchers had made explanation on the phenomenon of time discounting in intertemporal choice from the perspective of perceived-time-based model (Kim&Zauberman,2009), and they considered that the delaying and discounting changes might be caused by the sensibility for time dimension and the integral time condensed levels. Then, here is the question:what would be the difference of their preference in intertemporal choice among individuals with different time perspective? Therefore, this study examined, from the sight of time perspectives, their behavioral preference in intertemporal choice among individuals with different time perspective, and discussed the effect of time perspective on intertemporal choice and the cognitive and neural mechanism. By adopting behavioral experiment and rs-fMRI technique, and with the classic behavior model in intertemporal choice, this study mainly explores two questions:(1) the characteristics of preference in intertemporal choice of individuals with different time perspective.(2) the cognitive and neural mechanism of the time perspective effect on intertemporal choice. Therefore, this study involved two experimental researches which results were as follows:Research I adopted behavior experiment in which two types of individuals with different time perspective (future-time-oriented group and present hedonistic-oriented group) were chosen to be assigned delayed discounting tasks, through which their behavioral preferences in intertemporal choice have been explored. It was found that there was marked distinction on the behavioral preference in intertemporal choice among individuals with different types of time perspective. Specifically,(1) compared to the group of future time oriented, the group of present hedonistic oriented performed higher rate of delayed discounting and hence showed preference for instant gratification;(2) the scores that the group of future time oriented have gained in "the dimension of future time perspective" were in negative correlation with the delayed discounting rate. The stronger their orientation on future time perspective, the lower the rate of delayed discounting. The result signified that there was marked distinction on the behavioral preference in intertemporal choice among individuals with different types of time perspective, and that time perspective, as a relatively stable individual personality, was able to predict individual behavioral preference in intertemporal choice. However, how does time perspective effect on intertemporal choice? And what is the cognitive and neural mechanism behind that? To answer these questions, this experiment adopted rs-fMRI technique to do research Ⅱ from the perspective of neural base and function nework.In research II, rs-fMRI was adopted to study the neural mechanism of time perspective effect on intertemporal choice. The key method was, from the perspective of cognitive neworks of time, evaluation and cognitive control, to explore time perspective’s regulating mechanism on intertemporal choice. Behavior results proved the conclusion from research I:AUC (the area under the curve of delay discounting) was in positive correlation with future time perspective, but in negative correlation with present hedonistic time perspective. Rs-fMRI data mainly found out that:(1) AUC were in negative correlation with the intensity of functional connectivity between ACC and d1PFC;(2) the varying amount of functional connectivity at ACC and d1PFC was in positive correlation with present hedonistic time perspective, contrarily negative with future time perspective;(3) Mediator analysis indicated that functional connectivity played a role of mediator in time perspective effect on intertemporal choice. These results indicated that the functional connectivity between ACC and d1PFC played key role in time perspective effect on intertemporal choice, and that the effect was probably caused by cognitive controlling abilities.Combining the results of research Ⅰ and research Ⅱ, it can be found out that:(1) there was marked distinction on the behavioral preference in intertemporal choice among individuals with different types of time perspective, and that present hedonistic oriented individuals performed inclination on instant gratification while future-time oriented individuals on delayed gratification;(2) the functional connectivity between ACC and d1PFC played mediate effect in time perspective effect on intertemporal choice. This study explored the cognitive and neural mechanism of time perspective effect on intertemporal choice from the perspective of individual personality, widening the study field of intertemporal choice and providing new perspective for its cognitive and neural mechanism, and thus is of important scientific values as well as practical significance.