【作者】 何飞；

【导师】 苗丹民；

【作者基本信息】 第四军医大学 ， 应用心理学， 2009， 博士

【摘要】 不确定情境下风险决策过程是一个复杂的过程,因为心理等因素作用的存在,所以一直是应用心理学、行为经济学、管理学等跨学科的研究热点之一。2002年10月8日瑞典皇家科学院宣布,将当年的诺贝尔经济学奖授予美国普林斯顿大学教授Daniel Kahneman和美国乔治梅森大学教授Vernon L. Smith,以表彰他们在经济心理学与实验经济学方面的贡献。颁奖词中提到Kahneman的突出贡献在于:“开展了在有关不确定状态下人们如何做出判断和决策方面的研究”。综合文献,大多数的相关研究都是从风险决策行为入手,从认知方面对风险决策的选择现象进行解释。经典的“预期效用理论”和“前景理论”,都是通过观察不确定条件下人们的风险决策行为倾向,据此推断情感、动机、人格特质、认知以及社会情境等相关因素的作用。目前,我们对于不确定条件下风险决策的认知神经机制还十分不清楚,随着学科的交叉,研究方法和研究工具的日益完善,研究者们也开始采用更加客观的认知神经心理学研究方法探索非完全理性的风险决策行为。相关研究结果显示:不确定条件下的风险偏好和不同脑区的激活密切相关;决策者风险决策行为中处理感觉、知觉和情感信息时,皮层、边缘系统和神经调节系统等都会起到调节作用;风险决策行为存在着与候选机制相关的基础神经生理机制等。这些结论都揭示了不确定条件下个体非完全理性行为心理因素的生理基础,进行认知神经机制的研究对于认识和利用决策者风险决策的神经—心理过程有着重要的意义。本课题基于上述认识,采用心理测评量表、核磁共振(Nuclear magnetic resonance imaging, MRI)成像、事件相关脑电位分析技术(Event-related brain potentials, ERP)和多模式神经影像(Multi-modal neuroimaging)系统等工具相结合的新方法,针对“前景理论”背景下的中国成年人风险决策行为学特点和脑区参与加工过程进行了研究。着重对“前景理论”中提出的“收益”和“损失”情境下两种风险决策的脑机制进行研究,初步阐明了不确定条件下个体有限理性决策行为的认知神经加工机制,为神经心理学、行为经济学、认知神经科学等交叉学科的研究提供新的思路和理论依据;运用多学科研究方法相互配合论证心理学问题,对风险决策的其它相关研究也具有方法学上的借鉴意义。目的本课题研究以Kahneman“前景理论”为基础,运用认知神经科学、神经影像学和实验心理学等研究方法,对Kahneman“前景理论”中提出的“收益”和“损失”情境下风险决策行为的认知神经机制进行初步研究,探究正常中国成年被试群体在“收益情境”和“损失情境”下做出“风险规避”和“风险寻求”决策时的行为学特征和认知神经加工过程,利用神经科学数据提供的有利视角,解释在“收益情境”和“损失情境”下,人们在进行“风险规避”和“风险寻求”决策时,是否存在着脑区的重合或分离,哪些脑功能区参与了对风险信息的认知加工过程,参与加工的脑区激活程度的差别以及神经传导机制是如何调节决策者的风险决策行为的。本课题从认知神经角度丰富了Kahneman“前景理论”;建立的计算机个体风险决策模拟系统为后续建立个体风险决策预测模型,判断信息宣传、营销策略设计的功效,改进改进与风险决策相关的心理测评量表等实际应用领域提供有效的实验研究平台,具有潜在的应用前景。另外,本实验研究方法可以作为辅诊工具对脑功能异常部位进行定位分析。方法本研究在Kahneman“前景理论”的背景下,采用问卷调查法和访谈法对“收益情境”和“损失情境”下决策者“风险规避”与“风险寻求”决策行为学特征进行研究。在行为学特征实验结果的基础上,通过计算机模拟现实的风险决策情境,结合事件相关脑电位分析和多模式神经影像学技术从心理和生理两个方面探究两种情境下“风险规避”与“风险寻求”决策时的认知加工机制和脑功能区溯源分析。实验一基于Kahneman“前景理论”,自编调查问卷和深入访谈。研究中国成年被试风险决策行为学特征,验证“前景理论”是否适用于中国正常成年人,并以实验结果为依据和研究基础,设计实验二和实验三的风险决策认知神经机制研究。实验二通过STIM2软件编制“收益情境”和“损失情境”游戏程序,模拟真实的风险决策情境,采用美国NeuroScan数据采集和分析系统(EEG/EP工作站Evoked potential workstation)对被试在上述情境模式下的“风险规避”和“风险寻求”决策行为的ERP进行采集、处理、分析和解释。实验三利用MRI和3D Space定位软件系统建立三维立体数字化真实头颅模型,采用多模式神经影像(Multi-modal neuroimaging)系统Curry5.0对实验二得到的ERP成分进行自动分析与影像处理,通过偶极子定位法、低分辨率电磁断层扫描术等技术,通过已建立的数字化真颅模型,进行精确源定位,并呈现三维可视化图像,以得到可靠和精确的脑功能区溯源分析结果。结果1.中国成年被试群体在收益情境中倾向于“风险规避”决策,在损失情境中更倾向于“风险寻求”决策。被试对于损失的敏感程度明显高于对于同等收益的敏感程度。收益情境下,被试进行风险寻求决策的反应时显著高于风险规避反应时,而损失情境下,风险寻求与风险规避决策的反应时没有显著性差异。收益情境下的风险规避和风险寻求的反应时都显著高于损失情境下风险规避和风险寻求反应时。该结果提示:被试在收益情境下做出风险寻求决策时所付出的认知努力程度高于做出风险规避决策,两种风险决策的认知加工过程存在差异;而损失情境下,被试做出风险规避决策和风险寻求决策时的认知努力程度和认知加工过程没有显著性差异。2.收益情境下风险规避决策时N2波幅高于风险寻求决策时N2波幅,但是风险规避时P3波幅低于风险寻求时P3波幅。收益情境下风险规避N2波幅高于损失情境下风险规避N2波幅。损失情境下风险寻求N2波幅高于收益情境下风险寻求N2波幅,但损失情境下风险寻求P3波幅低于收益情境下风险寻求P3波幅。该结果提示:被试在收益情境下倾向于风险规避,损失情境下倾向于风险寻求;无论收益还是损失情境下,人们都存在显著的“损失厌恶”效应。收益情境下两种决策对比分析表明:被试在风险规避决策时对刺激信息的物理特性、对刺激信息的辨别、对刺激信息的认知评价、加以决策以及记忆更新等认知加工过程与风险寻求决策时存在显著差异。收益情境与损失情境下两种决策行为波幅对比分析表明,情境因素也同样造成了上述差异。3.收益情境和损失情境下,被试做出风险规避与风险寻求决策时激活的脑功能区主要是额叶、中央区和顶叶,N2和P3成分的潜伏期表明额叶潜伏期最短,其次是中央区和顶叶。收益情境下参与风险规避和风险寻求决策时涉及的脑区包括:额叶皮质(额上回、额中回、额下回、眶额皮质、腹内侧前额皮质、背外侧前额皮质等),顶叶皮质(顶上小叶、顶下小叶),中央区(中央前回、中央后回),纹状体、扣带回、杏仁核。收益情境下被试选择风险规避决策或风险寻求决策时,各参与脑区的激活程度不同。损失情境下参与风险规避和风险寻求决策时的脑功能区与收益情境激活脑区较为重合,涉及脑区包括:额叶皮质、顶叶皮质、扣带回、杏仁核和纹状体。损失情境下被试选择风险规避与风险寻求决策时,各参与脑区的激活程度差异不明显。结论1.收益情境下,中国成年决策者倾向于风险规避决策;损失情境下,倾向于风险寻求决策;对于损失的敏感程度明显高于对同等收益的敏感程度。决策者在收益情境下做出风险寻求决策时所付出的认知努力较高,并且做出风险规避和风险寻求决策的认知加工过程存在差异。损失情境下,决策者做出风险规避决策和风险寻求决策的认知努力程度和认知加工过程没有明显差异。情境因素明显影响着决策者风险决策行为及风险偏好程度。2.收益情境和损失情境下,中国成年决策者显示出明显的“损失厌恶”。收益情境下的两种风险决策相比,收益和损失情境下风险规避决策相比,收益和损失情境下风险寻求决策相比,表明决策者在做出风险规避和风险寻求决策时,对刺激信息的物理特性、刺激信息的辨别、刺激信息的认知评价、记忆更新以及最终做出决策等认知加工过程存在明显差异。情境因素和风险偏好程度是造成这些差异的主要原因。3.收益情境下,决策者做出风险规避和风险寻求决策时,脑区激活程度不同,激活的脑区主要包括:额叶、中央区、顶叶、眶额皮质、纹状体、扣带回、杏仁核等。损失情境下,决策者做出风险规避和风险寻求决策时,脑区激活程度差异不明显,激活的脑区主要包括:额叶、中央区、顶叶、眶额皮质、纹状体、扣带回、杏仁核等。两种情境下做出风险决策时激活的脑区较为重合,但是激活程度不同。更多还原

【Abstract】 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.更多还原