The Effect Of Personality Traits On Intertemporal Decision-Making And Its Underlying Neural Basis

Intertemporal choices are decisions that involve tradeoffs among costs and benefits occurring at different times. In our real world, there are numerous examples about intertemporal choices. These choices, for example, range from the prosaic-which and how much food to eat at a meal-to life-changing vital decisions about public policy made by states and multinational organizations. In the one hand, the researches of intertemporal choice have important theoretical value. Firstly, it can exploit the mental origin and development process of animals and human. Secondly, it can help to find out the causes of a series of behavior disorder and psychological disease, such as tabacoo addiction, alcohol addiction, drug abuse, pathological gambling addiction, autism, attention deficit hyperactivity disorder (ADHD), and binge eating disorder. In the other hand, the researches of intertemporal choice also have important realistic applications. For example, it can make people more rational decision making in personal education, dietary habits, health, marriage, fertility and family retirement savings, investment and the country's economic macro regulation and the sustainable development of the world, or even the world's climate and environment decision problem.Based on previous studies, the thesis studied intertemporal choice from the perspective of personality trait. Combining the questionnaire survey, behavioral research, and fMRI researches, the thesis systematically invested the impact of self-control, future temporal perspective, and time perception on intertemporal choice and their neural basis using intertemporal choice tasks in six experiments.Study1preliminary probed into the relationship between delay discounting and self-control, impulsive and future temporal perspective by a questionnaire survey. The results showed that there are significantly positive relationships between individuals' indifferences and the self ratings of self-control and future temporal perspective, whereas there is a significantly negative relationship between individuals'indifferences and the self ratings of impulsive.In study2, experiment1and experiment2examined the choice difference of different groups which have different ability of self-control (high self-control group vs. low self-control group) and their neural response difference in intertemporal choice by fMRI. Behavioral results showed that, whether the choice task is difficult or easy, low self-control group chose more smaller-immediate rewards than high self-control group. fMRI results showed that high self-control group have higher activation than low self-control group in Right Inferior/middle Frontal Gyrus(BA45/46), Right Superior/middle Temporal Gyrus/Inferior Frontal Gyrus(BA38/47), Right Parahippocampal Gyrus/Fusiform Gyrus(BA37/20/36/35), Left Middle/Inferior Temporal Gyrus/Fusiform Gyrus(BA21/20), Left Fusiform/Lingual Gyrus(BA18), Parahippocampa Gyrus, Medial Frontal Gyrus(BA32), Right Lingual Gyrus(BA17), Right Inferior Temporal Gyrus/Middle Occipital Gyrus(BA21/22), Left Middle/Superior Temporal Gyrus(BA21/22), Right Superior Temporal Gyrus(BA42), Right Middle/Superior Temporal Gyrus(BA39/40), Left Postcentral Gyrus(BA5/7), Right Postcentral Gyrus (BA2/3), Left Middle Temporal/Superior Gyrus(BA39/19).In study3, experiment3and experiment4examined the choice difference of different groups which have different ability of future temporal perspective (high future temporal perspective group vs. low future temporal perspective group) and their neural response difference in intertemporal choice by fMRI. Behavioral results showed that whether the task is difficult or easy, low future temporal perspective group chose more smaller-immediate rewards than high future temporal perspective group. fMRI results showed that high future temporal perspective group have higher activation than low future temporal perspective group in Middle Frontal Gyrus(BA6), Fusiform Gyrus Middle/Inferior Occipital Gyrus(BA18/17), Fusiform Gyrus(BA37), Superior Temporal GyrusPara/hippocampa Gyrus(BA28/34), Middle Temporal Gyrus(BA39/19), Cingulate Gyrus(BA7/31), Parahippocampa Gyrus(BA28/36).In study4, experiment5and experiment6examined the choice difference of different groups which have different ability of time perception (high time perception group vs. low time perception group) and their neural response difference in intertemporal choice by fMRI. Behavioral results showed that whether the task is difficult or easy, low time perception group chose more larger-delayed rewards than high time perception group. fMRI results showed that low time perception group have higher activation than high time perception group in Left ParaHippocampal Gyrus(BA34), Right Superior/Middle Temporal Gyrus(BA38), Left Fusiform Gyru(BA37), Right Middle Occipital Gyrus(BA18), Left Middle/Inferior Frontal Gyrus(BA47), Left Middle Occipital Gyrus(BA19), Left Superior/Inferior Parietal Lobule/Precuneus/Parahippocampa Gyrus(BA19/7), Left Cuneus(BA17), Left Middle/Inferior Frontal Gyrus(BA6), Thalamus, Right Inferior Frontal Gyrus (BA9), Left Superior/Middle Frontal Gyrus(BA9/10), Left Superior Frontal Gyrus(BA6), Right Precuneus(BA7), Right Superior/Middle Frontal Gyrus/Cingulate Gyrus(BA6/32).To sum up, the present researches found that self-control, future temporal perspective, and time perception may play important roles in intertemporal choices. The differences of these ability factors may be the important reasons of the differences of individuals'choice and the differences of the neural activation. Future researches will further exams how these factors modulate individuals'choice response at neurological level in intertemporal choices.