The Research On The Staged Construction Of Temporal Discounting

Temporal discounting is the psychological phenomenon that the value of events is discounted when the temporal distance between the consequence of the event and its occurrence increases. It is the important part of the behavioral choice theory. In recent years the psychological factor has been involved into consideration for researching economical behavior in Behavioral economics, such as cognitive character. It is demonstrated the decision-maker is actually bounded rational, and it's hard for human to get all indispensable information into concern to make rational and reasonable decision. Particularly when they have to make judgment and decision under uncertainty, usually the judgment and decision they made are irrational. In this situation taking advantage of experience is the effective solution for living life, which is operated with heuristic rules. In general, these heuristics are quite useful, but sometimes they lead to severe and systematic biases. The temporal discounting decision is made based on the evaluation of the event, and the temporal information has impact on evaluating event. Taking insight of the influence of the temporal distance between the occurrence of event and its consequence on the behavior decision is helpful to understand how bounded rational human makes rational and reasonable decision without possessing all the indispensable information.By reviewing the reference in temporal discounting researches, it is improper that using a single function as fitting curve to describe how the value of the event is changing as the time goes by in whole temporal range. The strategy which is used in evaluation of the event in remote and recent time point from present has been ignored in previous researches. The Range-synthetic model of temporal cognition demonstrates the temporal cognition of human being dependent on multiple factors, such as the temporal duration, interval, order, time point of the occurrence of the stimulate and personality and cognition. Different strategy is taken to make decision when the event would happen in remote and recent time point from present. In temporal discounting we indirectly get knowledge of temporal cognition by evaluating the event in remote and recent time point from present. Moreover, past and future are two directions on temporal dimension. The cognition of our life we might have in future is built on the knowledge and experience we got from past and present life; the quality of our present life has powerful influence on the evaluation of the event which happened in the past, because the cognition of our past life is built on present. Some assumptions were hypothesized:decision maker operates behavioral decision strategy to evaluate the event in remote and recent time point from present, and the staged construction of temporal discounting is represented on the differently psychological mechanism which guides the decision making to process the temporal discounting tasks in in differently temporal distance from present; the temporal direction of future and past have different influence on the evaluation of the event in differently temporal distance from present, and the staged construction of temporal discounting in future direction is not symmetrical to the one in past temporal direction.This research explored the staged construction of temporal discounting in past and future temporal directions using psychological behavior measure, questionnaire survey, content analysis and ERP analysis. First we investigated the staged construction of temporal discounting in past and future temporal directions with psychological behavior measure, questionnaire survey and content analysis in first research and second research. We took the unit area under the curve of instantaneous temporal discounting UAUr(t₁,t₂)as indicator to detect how the value of event is discounted in delay and interval experiment paradigms. And then we recorded and measured the neural activity with ERP analysis, which were produced when accomplishing temporal discounting tasks, in order to investigate the staged construction of temporal discounting in past and future temporal directions. There are three researches in all. Specially, in first research we investigated the staged construction of temporal discounting in future direction by running three experiments and a questionnaire survey. We asked participants to make choice between two rewards which would be paid in different distance from present in future, and also asked them to decide subjective indifference of value by choice and matching methods. And then we indicated the speed of discounted value by UAUr[t₁,t₂) in time range (t₁,t₂). In second research, we explored the staged construction of temporal discounting in past direction by asking participants to make a decision on which reward they received in differently distance from present in past they prefer to choose in fourth and fifth experiment. The choice was made in delayed and interval temporal discounting experiment paradigms, and choice method was taken to decide subjective indifference of value. After data collection we insisted to indicate the speed of discounted value by UAUr(t₁,t₂) in time range(t₁,t₂).The sixth experiment, the only one experiment in the third research, is detecting the staged construction of temporal discounting in past and future temporal directions. We recorded and measured the neural activity when participants were working on tasks of temporal discounting in past and future directions with ERP technique. The potential difference on staged construction of temporal discounting between past and future temporal discounting was our attention in third research.The result demonstrates:1 The immediate reward is deposited in different psychological accounts when the probability of risk and requirement are both involved into consideration in working out task of temporal discounting in future temporal direction. Behavioral decision strategy is varying between risk seeking and loss aversion, which leads temporal discounting task to be resolved in different mental states in three ranges in temporal discounting. It is staged construction of temporal discounting in future temporal direction.2 Decision is made basing on the knowledge about what kind of present life we have when solving the task of temporal discounting in past direction. How much benefit they could get from the event happened in the past is taken as the standard to pick up behavioral decision strategy in temporal discounting task. The reward which is paid one hour ago is deposited into different psychological accounts in order to make sure present life could get most benefit from past, which indicate the construction of temporal discounting is staged in past direction and the temporal discounting task is solved in different mental states.3 The result from ERP research is consistent to the results from first and second research, which demonstrates the staged construction of temporal discounting in future and past temporal discounting, and the different influence of the temporal distance between the occurrence of event and its consequence on neural activity responding to the evaluation of event was represented on interval and delayed paradigms in past and future direction respectively. The neural activity responding to the differently temporal distance has significant difference when the preference was made in delayed paradigm in past temporal direction. The neural activation decreased as the temporal distance increased from two weeks to six months, while it increased as the temporal distance increased from six months to five years and fifty years. There was no significant correlation between the neural activation responding to five years and fifty years. However, in future discounting, the neural activation responded differently to the temporal distance when the preference was made between two delayed rewards.4 Based on the result from this research and previous researches, we made assumption:the temporal-directional model of decision making which is defined as decision-making system possessing characteristic in temporal direction. It might be capable to explain the difference of staged construction between past and future temporal discounting. The double systems in decision-making, the intellectual one which is capable of anticipating and caring about the distant future, and the emotional one which is much more oriented toward the present, both participant into the process of evaluation of future event and decision making in future temporal direction. However, there might have single decision-making system which is capable of manipulating the past event in past temporal discounting task.There are some innovations. (1) We found the staged construction of temporal discounting which is the result from using various decision making strategy when evaluation of event was made in different range. (2) It was found the staged construction of temporal discounting was not symmetric between past and future temporal direction. It's probably aroused by the different decision-making system in brain which processes the evaluation of past event and future event respectively. It means there might have two decision-making systems working on the evaluation of past event and future event. (3) In methodology, a reasonable doubt was made about representing the temporal discounting in whole range by using single function in previous researches. Instead of using single function to fit temporal discounting, we used a new measure, the unit area under the curve of instantaneous temporal discounting UAUr(t₁,t₂), as indicator for how fast the value is discounted. (4) In theory we proposed the temporal-directional model of decision-making by questioning the effectiveness of applying the double decision-making subsystems which is built on the research in future discounting into the decision making which is discussed in past discounting.In prospective research we are going to improve the temporal-directional model of decision making by exploring on neural activation responding to evaluation of event in different distance from present in past and future temporal directions. We are planning to take cognitive factors and personality traits into consideration and take advantage of Range-synthetic model of temporal cognition in order to advance the temporal-directional model of decision making into the one with higher ecological validity.