The Cognitive And Neural Mechanism Of The Prospective Emotion On Intertemporal Choice

Intertemporal choice is that decision makers frequently balance the costs and benefits of decision making processes which occur at different times (Loewenstein,1988; Frederick, Loewenstein,&O’Donoghue,2002). As Adam Smith first recognized, such decisions not only affected one’s quality of life, but might also determine the economic prosperity of nations. Thus, the study of the cognitive and neural mechanism of intertemporal choice both has great scientific values,but also to help individuals, businesses and even the government to make more scientific and rational decisions. In recently studies, Researchers found that episodic prospection reduced the rate of delay discounting (Peters,&Biichel,2010) the human faculty of episodic prospection effectively motivated decisions in the present which will only be advantageous in the future(Benoit, et al.2011). But the cognitive and neural mechanism of episodic prospection affecting delay discounting is still unclear. Therefore, we proposes the emotion-of-episodic-prospection hypothesis to explain the cognitive and neural mechanism of them (Liu&Feng,2013). Therefore, the present research adoptd behavioral experiment and rs-fMRI technique, and with the classic behavior model in intertemporal choice, this study mainly explores two questions:(1) the cognitive mechanism of the prospective emotion modulate intertemporal choice (study1);(2) the neural mechanism of the prospective emotion modulate intertemporal choice.Study1operate the valence of prospective emotion by three experiments (Experiment1:positive prospective emotion; Experiment2:negative prospective emotion; Experiment3:neutral prospective emotion), explored how episodic prospection modulated delay discounting. The discount rates were fitting to hyperbolic functions, the result showed that imaging positive future events that trigger positive emotions lead to the delay discount rates reduction (Experiment1), imaging negative future events that trigger negative emotions lead to the delay discount rates increase (Experiment2), imaging neural future events that trigger neural emotions didn’t affect the delay discount rates (Experiment3). These findings supported the emotion-of-episodic-prospection hypothesis, episodic prospection did not change delay discounting, it might modulate the direction of change of delay discounting by prospective emotion.Study2using fMRI measures, we use the intertemporal choice task with episodic prospection tag(Experiment1-positive prospective emotion; Experiment2-negative prospective emotion; Experiment3-neutral prospective emotion), explore the prospective emotion affect the evaluation stage or choice stage of intertemporal choice.The result showed that:(1) imagine positive future events, in the evaluation stage, contrast "Imagine " and "no imagination", medial prefrontal cortex (VMPFC), anterior cingulate (ACC), posterior cingulate (PCC), Insula activation was significantly enhanced,these brain regions relate to evaluation value,also activated prospective memory brain regions, for example the Hippocampus, Parahippocampal Gyrus. In the choice stage, contrast" free-choice" and " forced-choice ", dorsal cingulate gyrus (dACC), dorsolateral prefrontal cortex (DLPFC), inferior frontal gyrus (IFG) activated stronger. The activation of Parahippocampal gyrus can predicted the degree of change of the discount rate (Experiment1);(2) imagine negative future events, in the evaluation stage, contrast "Imagine " and "no imagination", medial prefrontal cortex (VMPFC), posterior cingulate (PCC), Insula activation was significantly enhanced, In the choice stage, contrast" free-choice " and " forced-choice ", dorsal cingulate gyrus (dACC), dorsolateral prefrontal cortex (DLPFC) activated stronger. The activation of PCC can predicted the degree of change of the discount rate (Experiment2);(3) imagine neural future events, in the evaluation stage, contrast"Imagine" and "no imagination", no brain region’s activation was significantly enhanced. In the choice stage, contrast" free-choice" and " forced-choice ", inferior frontal gyrus (IFG) activated stronger.Overall, the results showed that:(1) episodic prospection modulate the direction of change of delay discounting by prospective emotion: positive prospective emotion attenuates delayed discounting, negative prospective emotion strengthens delayed discounting, neural prospective emotion doesn’t affect delayed discounting.(2) episodic prospection influence the results of the assessment of future value, and then change the individual’s preference, individuals imagine positive future events will give greater value to future, imagine negative future events will give a smaller value to future, imagine neutral future events does not affect the evaluation. This study systematically proven the cognitive and neural mechanism of the prospective emotion regulation intertemporal choice. The research doesn’t only have important scientific value, but also have important practical significance on how to improve the various pathological intertemporal choice.