Discussion ERP Reward Research And Cognitive Mechanisms Of Self-control Decisions

Reward is the benefit of positive value acquired by individuals from subjectively or objectively, including physical goods as well as mental experience. It has a greater temptation and incentives to individuals. Reward decision-making is the action process of choosing between two or more rewards choices, due to the restrictions or requirements of objective and subjective factors of the individual. Among these kinds of decisions, the individual often faced to choose between two rewards with different allures and values:one reward has larger temptation in short term but with lower long-term value, while the other has less temptation but with greater long-term value. In order to make the optimal choice between them, individuals need to perform self-control to resist current temptation to maximize the long-term interests. Therefore, the self-control in reward decision-making refers to the behavior that, in order to have a greater interest gains, individuals consciously resist the temptation which meets the direct needs, or voluntarily give up the smaller interests in front of them, and choose the target with larger long-term interests in the decision-making process.Being good at self-control is the representation of psychological maturity of individual, it can predict various aspects of individuals’positive performance, such as higher academic achievement, better social interaction skills, higher self-esteem experience and better ability of coping with frustrations and stress, as well as fewer mental disease or overeating behavior. Thus this shows the importance of self-control on individual growth and social harmony. Therefore, numerous philosophers, psychology, education researchers have discussed and studied with the research of self-control, and proposed their respective viewpoints from different angles about psychological mechanisms and processing model to self-control, deepening the understanding of the phenomenon of self-control.In recent years, with the gradual application of functional magnetic resonance imaging (fMRI) technology in psychological research, domestic and foreign researchers carried out a large number of neuroimaging studies with high spatial resolution to the brain activity of self-control in reward decision-making, and get a lot of useful discoveries. However, the time course of brain activity in self-control is not very clear. In addition, most previous neuroimaging studies used the paradigm of "intertemporal decision making", in which, however, the immediate rewards may not necessarily have a significant temptation, thus it may be difficult to achieve the objective of forming self-control situations. For this reason. employing event-related potentials (ERP) technology with the characteristic of high time resolution, this study uses the reward of charming women pictures (including beautiful women pictures and sexy women pictures) and money reward as experimental materials, to set up the situation of reward decision-making, giving a discussion in depth to the physiological mechanisms of self-control in the meaning of resist temptation.The whole study included two pilot behavioral experiments and a formal ERP experiment. Two types of glamour female pictures were contained in the first pilot experiment to be rated by male subjects:beautiful female pictures and sexy female pictures, and there were two levels to be chosen from. The purpose of the assessment is to increase the homogeneity of the experimental material and reduce the error. When finishing the assessment, the experimenter ranked all pictures from high to low according to liking degree of subjects, and then picked out most of the pictures in the front sequence. These pictures were gone through fuzzy processing and used for the second pilot experiment and the formal experiment. The first step of the second pilot experiment was the stage of classification and gathering. By means of the selection and assessment process to the two types of glamour fuzzy female pictures respectively by subjects, each category of picture was divided into two sets:the higher and lower degree of the subjects want to see the female pictures in clear. In the second step of the matching cash equivalent, through a series of decisions between the fuzzy female picture in higher collection of attractive women and a certain amount of money, the results determined the cash equivalent matched with the degree of subjects wanting to see the clear version of beautiful and sexy women pictures respectively.Adopting the way of decision-making between fuzzy female pictures and money by subjects, the formal experiment investigated the changes of time course in brain of self-control in the sense of temptation resisting. It consists of two tasks:the first one is the decision-making between a sexy female picture and money (referred as task S for short), the second one is the decision-making between a beautiful women picture and money (referred as task L for short). And each task consists of two steps respectively:the cash equivalent matching stage and the decision-making stage. The cash equivalent matching stage was same to the second step of the second pilot experiment, just changing the higher set of sexy women pictures into the lesser one. so that it could be compared with the beautiful women pictures better; at the same time, adjusting the amount of money, so that be better linked with the second phase of the decision-making process. The second step is the decision-making stage, in which subjects made decisions between fuzzy female pictures and the fixed cash equivalent of each subject respectively, and the scalp electrical activities of them were recorded at the same time. At this point, if you were to choose to enjoy the female picture in clear can be seen as impulsive decisions, and to choose money can be seen as self-control decisions. After data collection and analysis, the final results are as follows:(1) Within the time window of290-340ms after the stimulus was presented, the task L evoked a more positive ERP components (P2) than the task S. During this period, subjects have not started to make decisions yet, but only to conduct selective attention or feature recognition to the presented picture. So we considered that the P2component may reflect the perception process in which one compared or matched the visual stimulation of external input with the internal presentation in brain in the early visual stimulus processing; in the meantime, it also indicated that the cognitive processing of the two tasks had been different in the early stage of the decision-making.(2) In the time window340-390ms after decision-making stimulus presented, the task S evoked a more negative ERP component (N2) than the task L. In this period of time window, subjects needed to choose between fuzzy women pictures and money. The cognitive conflict subjects faced in task S was greater in task L, and in order to make the decision-making of self-control, they needed to resist greater the temptation and required greater cognitive effort. Therefore, the larger N2component may represent a greater conflict monitoring and cognitive inhibition process.(3) Finally, in the time window of550-1000ms, the task S evoked a more positive ERP component (LPC) than task L. We think it may be due to the decision-making value of the beautiful women pictures was higher than sexy women pictures, reflecting different subjective value of different types of stimuli in the decision-making process. More importantly, selecting glamour female pictures induced a larger late positive component (LPC) than selecting money, in other words, the decision-making that could not resist the smaller temptation evoked a greater LPC than that could be able to resist the temptation and perform self-control. This may be because in the face of current obtained temptation (glamour female pictures) and long-term greater benefit (money) to make decisions, subjects need to resolve strong cognitive conflicts, so influenced the subjective evaluation process; or because decision-making value of choosing the charm female picture is higher than the decision-making value of money which were not chosen, or because the reward glamour female pictures is more direct and appeared more earlier in human evolution process than the monetary reward. Our results represent the first attempt of understanding the physiological mechanisms of self-controlled decision-making between the primary reward (glamour female pictures) and the secondary rewards (money).