| BackgroundsThe process of decision-making under the uncertain situations is a complex problem because of the psychological factors. Therefore, it is one of the most popular researches in Psychology, Microeconomics, Management Science and other interdisciplinary studies. October 8, 2002 Royal Swedish Academy of Sciences, Professor Kahneman of Princeton University and Professor Smith of George Mason University were announced that they were awarded the Economic Nobel Prize because of their contributions in recognition of the economic psychology and experimental economics. Especialy, Kahneman's contribution is that "he carried out the researches of how people make judgment and decision in the uncertain state."Nowadays more studies of the behaviors in risk-decision were focus in the cognition and selection in decision-making situation. Both the classic theory-"expected utility theory"and the popular theory-"prospect theory"were also studied the human selective tendency of venture decision under the uncertain conditions and effective factors include in human cognition, emotion, motivation, personality traits and social situations and other related factors. With the improvement of research technologies and research tools in recent years, the researchers began to use more objective neuropsychological methods to explore human non-fully rational decision-making mechanism. For example, when the decision-makers were dealed with feeling, perception and emotional informations in different levels, the cortex, limbic system and a wide range of nerve-conditioning systems play a regulating role of intermediary. There are basic physiological mechanisms of risk decisions behaviors and so on. All the findings revealed the neuro bases of psychological factors and neuropsychological process.In the present research, we used the psychometric scales, Magnetic Resonance Imaging (MRI), Event-related Brain Potentials (ERP) and Multi-Modal Neuroimaging systems such as Curry5.0 instrument to explore the behavioral characteristics of human decision and the brain areas involving in these kinds of processes.AimsTo research cognitive neuromechanisms of decision-making in the gains and losses situations, Kahneman's prospect theory as a starting point, through the cognitive analysis and understanding of neuroscience, neuroimaging research methods and experimental psychology. Attempt to explore the normal adult Chinese behavioral characteristics of risk decision and cognitive process in the gain and losse situations. When the decision-makers choose risk aversion or risk seeking, whether it is exist the brain regions coincide and separation and which brain functional areas involved in the cognitive processing of risk informations. The present research results also provide a favorable perspective to explain the activated degree of brain functional areas and how to adjust the transmission mechanism in order to control the tendency of risk decision. The most important purpose is to provide the objective and scientistic initial experimental evidences in order to establish and use the predictive model of individual risk decision-making. The practical research has more theoretical guidance and practical significance in the fields of information publicity, making management policies and designs the marketing strategy.MethodsThe Kahneman's"prospect theory"as the theoretical basis, we use the questionnaires, interviews and laboratory experiments and other methods, and the computer simulation of the risk situations, combined with the technology of event-related potentials and neuroimaging methods to explore the decision-makers'cognitive processes and the brain functional areas in the gain and loss situations.Experiment I. We have researched the decision-makers'behaviors features in the income and losses situationas through the questionnaires and in-depth interviews. Further explore and explain the psychological and behavioral mechanism of the behaviors of risk aversion and risk seeking in the two kind of different contexts.Experiment II and experiment III. We used the laboratory experiments include the analysis techniques of Event-related potentials (ERP) and neuroimaging methods. First of all, through the DC / AC high-speed acquisition amplificatory system, using the EEG amplifier to finish the acquisition of synchronized high-speed signal. Then through the DC coupling to measure the low-potential, we apploy the software control system to calibrate and impedance measurements in order to speed up the trial process. To realize simultaneous acquisition of EEG mediated signals as many as 128 through a systematic expansion of connector modules. Secondly, through the EEG / EP workstation (i.e. evoked potentials workstation), we have got the better the results of ERP components through the systematic data collection and analysis methods to speed up the processing speed. Then we used the advanced signal processing methods and algorithms to analysis and interprate the related ERP components. Finally, we completed the rapid image processing, automatic analysis, accurate source localization of real cranial model and showing the results of three-dimensional visualization through the 3D positioning tools and Curry5.0 system softwares to make the multi-mode imaging and multi-modal neuroimaging. Therefore, we got the more reliable and precise experimental results through the comparison of a variety of positioning modes.ResultsI. In the middle-probability cases (50%), decision-makers were more inclined to choose risk-seeking in the loss situation, and decision-makers were preferred to choose risk-aversion in income situations. Losses loom larger than equivalent gains; motivational models are based on the claim that the emotions evoked by the losses generally are greater than those evoked by gains. In the gain situation, the subjects'reaction time of the choice of risk-seeking was significantly higher than the response time of the choice of risk-aversion. The reaction time of risk-aversion and risk-seeking in the income situation were higher than the reaction time of two kinds of risk decisions in the loss situation. The results suggest that compared the two risk decision (i.e. risk-aversion and risk-seeking) in the gain situation, when the subjects make the risk-seeking decision, they should pay more cognitive effort, and the cognitive processes between the two choices are different. Howere, there is no significant differences in reaction time and cognitive procedures between risk-aversion decision and risk-seeking decision in the loss situation.II. In the gain situation, the amplitude of N2 of risk-aversion decision is higher than N2 amplitude of risk-seeking decision, but P3 amplitude of risk-aversion decision is lower than P3 amplitude of risk-seeking decision. The amplitude of N2 of risk-seeking decision in loss situation is higher than N2 amlitude of risk-seeking decision in gain situation, but P3 amplitude of risk-seeking decision in loss context is lower than P3 amplitude of risk-seeking decision in gain context. Further illustrate that the subjects tend to risk aversion at the receipts situation, and tend to risk seeking in the loss of situation. Regardless of benefit or loss situations, people have significant sensitivity of"loss aversion". In different contexts, there are significant differences between the risk-aversion decision and risk-seeking decision in the physical characteristics such as the automatic processes of stimulus, identification process of simulus, the cognitive evaluation of stimulus information, decision-making and memory processing and so on.III. In the gains and losses contexts, when the subjects choose risk-aversion or risk-seeking, there are some brain functional regions involved in the procedure of risk decision include the frontal lobe, the central area and parietal lobe. To participate in risk-aversion and risk-seeking decisions in gain situation, the brain regions were activated which are frontal cortex include superior frontal gyrus, middle frontal gyrus and inferior frontal gyrus, orbitofrontal cortex, ventral medial prefrontal cortex, dorsolateral prefrontal cortex, parietal leaf cortex, ventral striatum, cingulate gyrus, amygdala and insula. Moreover, it exist the phenomenon of brain regions coincidence between the risk-aversion decision and risk-seeking choice in gain context, and the activated degree of those brain areas was different. In the loss situations, there are some brains functional areas participate in risk-aversion and risk-seeking decision, which include in the frontal cortex, parietal cortex, cingulate gyrus, amygdala and dorsal striatum. Howere, more brain region were overlap when the subjects choose risk aversion and risk seeking in loss context, and the variation of activation degree was not obvious.ConclusionI. In the middle-probability cases (50%), decision makers were more inclined to choose risk-seeking in the loss situation, and decision-makers were preferred to choose risk-aversion in income situations. Losses loom larger than equivalent gains; motivational models are based on the claim that the emotions evoked by the losses generally are greater than those evoked by gains. Compared the two risk decision (i.e. risk-aversion and risk-seeking) in the gain situation, when the decision makers make the risk-seeking decision, they should pay more cognitive effort, and the cognitive processes between the two choices are different. Howere, there is no significant differences in reaction time and cognitive procedures between risk-aversion decision and risk-seeking decision in the loss situation. The factor of situation is affected in the risk dicisions of decision makers.II. Regardless of gain or loss of situations, people have significant sensitivity for "loss aversion". In different contexts, there are significant differences between the risk-aversion decision and risk-seeking decision in the neurophysical characteristics such as the automatic processes of stimulus, identification process of simulus, the cognitive evaluation of stimulus information, decision-making and memory processing and so on.III. It exist the phenomenon of brain regions coincidence between the risk-aversion choice and risk-seeking choice in the gain or loss contexts, and also the activated degree of those brain functional regions were different. The brain functional regions of venture decision in two situations include in the frontal brain regions, the central area, parietal, orbito-frontal cortex, striatum, cingulate gyrus, and amygdala.
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