小概率权重问题及其市场应用

探讨了决策制定中有关“小概率权重”的理论问题和市场应用问题。若干实验结果表明概率的权重大小不是绝对的,而是背景依赖的,在决策问题中价值对比降低或不存在时,小概率事件权重不太可能被高估。然而,对小概率的权重也会因决策人所处的目前状况有关,个体在财富状况等方面的差异会对小概率事件的赋权产生影响。实验结果还证明有关小概率权重问题的理论发现对彩票价格制定、保险费用确定以及选择有效的有奖促销策略具有重要的启示     

参照依赖和损失规避对个体收入分配公平判断的影响

收入分配公平判断是人们对自己收入所得公平与否的主观评价。通过对参照点和收入金额的控制,探讨参照依赖和损失规避对收入分配公平判断的共同影响。结果发现,(1)民众的收入公平判断受参照点的影响,在有参照点的情景下比无参照点情景下更感觉不公平;(2)不同工资水平下,民众的公平判断具有显著差异,而且民众对低于平均工资的“受损”比高于平均工资同等金额的“受益”赋予的公平感的权重更大,即存在得失感受的不对称;(3)不同的工资参照点、多得和少得的分配结果共同影响民众的公平判断,即损失规避在参照依赖对公平判断的影响中起调节作用。     

概率估计的趋势效应及其对决策的影响机制——基于心理动量的视角

概率是反映风险与不确定性的重要指标, 概率估计具有趋势效应, 会对决策产生影响。文章描述了概率估计趋势效应的两种表现形式, 概率估计变化的趋势性(即不同时间点概率估计变化产生的趋势作用)与单边概率估计的趋势性(即高于或低于某个概率区间范畴的上界或下界的估计表述所产生的趋势作用), 揭示了概率估计趋势效应对于个体判断、决策行为和非理性决策偏差的影响; 基于心理动量的理论视角提出了一个整合模型, 阐述了概率估计趋势效应催生心理动量体验继而引发后续决策行为的内在机理。未来的研究可进一步关注：多方信息来源主体下概率估计的趋势效应; 动态趋势效应与静态概率估计的交互作用; 风险沟通中的概率估计变化趋势。     

数字差异和概率差异对比率偏差的影响

比率偏差是一种常见的决策偏差,指的是当小概率事件以不同比率形式呈现时,人们倾向于认为以较小数字呈现的事件更不可能发生.本文采用问卷调查方式,在两个研究中分别探讨了数字差异和概率差异对比率偏差的影响,结果发现：（1）比率偏差的产生具有跨情境的一致性和稳健性;（2）等概率条件下比率偏差的发生率不随两个比率间的数字差异的增大而增大;（3）不等概率条件下比率偏差程度不随两个比率间概率差异的改变而改变.     

用文字概率衡量不确定性：特征和问题

文字概率是衡量不确定性的方式之一, 即人们使用诸如“也许”、“未必”的词汇来描述特定事件发生的可能性。文字概率不同于数字概率, 主要体现在文字概率的模糊性、非概率运算性和语义特性上。这使得相对于数字概率, 用文字概率衡量不确定性既有优势也有问题, 进而对人们的不确定信息沟通和风险决策造成影响。虽然文字概率与数字概率存在特征上的差异并且人们在日常交流中偏爱文字概率, 但是大部分风险领域的研究却仅局限于数字概率, 今后有必要研究使用文字概率测量的风险决策。在已有文字概率特征研究的基础上, 还可以进一步探究其不同于数字概率的其它特征(文字/数字概率与双系统模型的联系、文字概率的跨文化差异等)及其对风险决策的影响。     

如何用行为经济学应对不确定性：拓展有效助推的范围

本文提出了决策中不确定性的五种类型及其行为学和心理学的应对机制：用简捷启发式替代加权求和应对信息不确定性, 用直觉应对认知不确定性, 用价值观预测选择偏好应对行为不确定性, 用决策参照点的权重替代概率应对结果不确定性, 用时间换时间以降低延迟折扣应对未来不确定性。新行为经济学应当通过“为什么”的功能性分析, 找到行为助推的心理杠杆。化解不确定性本身就是一种有效的行为助推; 化繁为简是行为助推的关键所在。     

基于语料库统计的“音-形”激活概率及加工机制

为了了解心理词典中语音与汉字的联结情况以及从音到形的加工机制,研究首先计算出了基于语料库统计的“音-形”激活概率(某个音节激活其对应汉字的概率),并通过一个听写实验来验证这种激活概率是否反映实际加工中的激活情况。结果证明基于语料统计得到的“音-形”激活概率基本可以预测实际的“音-形”激活情况,表现为:“音-形”激活概率越高的汉字被激活的概率和强度越高,并且有明显的优势字效应; 该统计概率具有可独立于其他影响因素的预测功能。     

基于预期理论的参照依赖

参照依赖是指个体基于某一参照点对得失价值进行判断:参照点之上,个体感受为收益,反之即为损失.参照依赖现象广泛存在于生活中的各种领域.当前,对参照依赖心理机制的解释主要有预期理论、后悔理论和三阶段参照点理论.参照依赖的影响因素主要包括经验、情绪状态、文化、目标和认知对象的特点等.未来的研究应主要集中于参照依赖的产生根源,深入探讨参照依赖的神经机制,加强动态参照点、多重参照点以及群体中参照依赖现象的研究.     

否定情绪词的具身动态模拟过程

实验1和实验2分别以“（不）+积极/消极情绪词”和“（不）+愤怒/悲伤情绪词”形式的情绪词语或否定短语作为实验材料,分别采取词-图匹配范式和趋近-回避范式,以否定加工的早期（250ms）和中后期（1000ms）两种探测时间,探讨否定对情绪词效价与动机维度加工是否符合否定的两步模拟假设。结果发现,否定情绪效价部分符合否定的两步模拟假设,早期以被否定的情绪状态模拟为主,即不高兴会首先激活高兴;中后期,否定消极词和积极词都被理解为积极;否定情绪动机维度并不符合否定的两步模拟假设,否定对愤怒与悲伤的趋近－回避的影响出现在否定加工中后期,否定改变愤怒的动机方向,由趋近变为回避,却没有改变悲伤的动机方向,悲伤仍表现为回避。本研究证明否定对情绪词的效价和动机维度部分符合两步模拟假设,否定情绪词有其特定的加工过程,各维度加工有所不同。     

EMMN受偏差-标准刺激对类型和情绪类型影响:来自元分析的证据

自动探测面孔情绪的变化对个体生存是十分重要的。许多采用事件相关电位(ERP)技术的研究表明情绪失匹配负波(EMMN)可以作为检测面孔情绪自动加工的指标。前人的研究表明偏差-标准刺激对(不同/相同)和情绪类型(消极/积极)影响了EMMN效应,但是结论存在争议。本研究对35项以EMMN为指标的研究(共721名被试)进行元分析,结果表明:(1)在早期(0～200 ms)和晚期(200～400 ms)都发现了显著的EMMN效应,偶然呈现的情绪性面孔在两个时间窗内诱发更负的ERP,表明EMMN反映了面孔情绪相关的早期和晚期ERP成分的概率效应;(2)偏差-标准刺激对类型影响了早期而不是晚期EMMN效应:在早期区间内,不同的偏差-标准刺激对诱发了更大的EMMN;(3)在相同偏差-标准刺激对的研究中,等概率和非等概率的EMMN效应在两个时间窗内都没有显著差异;(4)早期和晚期EMMN都具有消极偏向,即,消极情绪诱发的EMMN显著大于积极情绪诱发的EMMN。这些结果表明, EMMN效应受到偏差-标准刺激对和情绪类型等实验变量的影响。     

A cognitive‐emotional account of the shape of the probability weighting function

Research has shown a tendency of decision makers to overweight small probabilities and to underweight moderate and large probabilities. In standard treatments this is graphically modeled by an inverse S‐shaped probability weighting function. We suggest that emotions play a significant role in the shaping of the probability weighting function. In particular, the weighting function is proposed to be some function of objective probability, expected elation, and expected disappointment. The overweighting of small probabilities results from the anticipated elation after having won, given that winning was very unlikely. The underweighting of large probabilities results from anticipated disappointment after having failed to win, given that winning was very likely. Hence, probability is assumed to influence utility. Three experiments investigate these hypotheses. Experiments 1 and 2 show that a convex function relates probability to surprise. Experiment 3 elicits choice data and further supports the proposed hypotheses. The model adds to the understanding of the cognitive and emotional processes underlying the shape of the probability weighting function. Copyright © 2002 John Wiley & Sons, Ltd.     

Framing experts' (dis)agreements about uncertain environmental events

Agreements and disagreements between expert statements influence lay people's beliefs. But few studies have examined what is perceived as a disagreement. We report six experiments where people rated agreement between pairs of probabilistic statements about environmental events, attributed to two different experts or to the same expert at two different points in time. The statements differed in frame, by focusing on complementary outcomes (45% probability that smog will have negative health effects vs. 55% probability that it will not have such effects), in probability level (45% vs. 55% probability of negative effects), or in both respects. Opposite frames strengthened disagreement when combined with different probability levels. Approximate probabilities can be “framed” in yet another way by indicating reference values they are “over” or “under”. Statements that use different directional verbal terms (over vs. under 50%) indicated greater disagreement than statements with the same directional term but different probability levels (over 50% vs. over 70%). Framing and directional terms similarly affected consistency judgments when both statements were issued by the same expert at different occasions. The effect of framing on perceived agreement was significant for medium (10 and 20 percentage points) differences between probabilities, whereas the effect of directional term was stable for numerical differences up to 40 percentage points. To emphasize agreement between different estimates, they should be framed in the same way. To accentuate disagreements or changes of opinion, opposite framings should be used.     

Communicative functions of directional verbal probabilities: Speaker’s choice,listener’s inference,and reference points

Verbal probabilities have directional communicative functions, and most can be categorized as positive (e.g., “it is likely”) or negative (e.g., “it is doubtful”). We examined the communicative functions of verbal probabilities based on the reference point hypothesis According to this hypothesis, listeners are sensitive to and can infer a speaker’s reference points based on the speaker’s selected directionality. In four experiments (two of which examined speakers’ choice of directionality and two of which examined listeners’ inferences about a speaker’s reference point), we found that listeners could make inferences about speakers’ reference points based on the stated directionality of verbal probability. Thus, the directionality of verbal probabilities serves the communicative function of conveying information about a speaker’s reference point.     

Thinking styles and risky decision‐making: Further exploration of the affect–probability weighting link

People usually overweight small probabilities and underweight large probabilities leading to the familiar inverse S‐shaped weighting function. This research explores the link between affect and the structure of probability weighting from the perspective of thinking dispositions, a concept central to dual system theories of reasoning. The effects of affective priming and cognitive load on both probability weighting and the value function are also examined. The evidence suggests that thinking styles do have predictive implications for risky decision‐making. Participants with a more affective thinking style tend to be more risk‐seeking in small probability gambles. However, increasing access to the affective system by affective priming or cognitive load manipulations tend to reduce risk‐seeking behavior in small probability gambles as well as reduce risk averse behavior in large probability gambles. Previous research, manipulating the affective nature of lottery outcomes, found evidence for an increase in curvature (more overweighting of small probabilities and more underweighting of large probabilities) of the weighting function for affect‐rich outcomes, lending support to a hope‐and‐fear deconstruction of probability weighting. The present research suggests that increased anticipatory emotions characterized by the elevation of the weighting function (more overweighting at all probabilities) is also important and could sometimes be more significant than hope‐and‐fear in decision‐making under risk. An integrated approach incorporating the impact of affect on all three, the elevation and curvature of probability weighting as well as the curvature of the value function explains the empirical findings. Copyright © 2010 John Wiley & Sons, Ltd.     

What if I am the one? Measuring individual differences in emotional sensitivity to probability and emotional reactivity to possibility

Current theories of risk perception point to the powerful role of emotion and the neglect of probabilistic information in the face of risk, but these tendencies differ across individuals. We propose a method for measuring individuals' emotional sensitivity to probability to assess how feelings about probabilities, rather than the probabilities themselves, influence decisions. Participants gave affective ratings (worry or excitement) to 14 risky events, each with a specified probability ranging from 1 in 10 to 1 in 10,000,000. For each participant, we regressed these emotional responses against item probabilities, estimating a slope (the degree to which emotional responses change with probability) and an intercept (the emotional reaction to an event with a fixed probability). These two parameters were treated as individual difference scores and included in models predicting reactions to several health risk scenarios. Both emotional sensitivity to probability (slope) and emotional reactivity to possibility (intercept) significantly predicted responses to these scenarios, above and beyond the predictive power of other well‐established individual difference measures.     

Does probability weighting matter in probability elicitation?

One of the most widely used methods for probability encoding in decision analysis uses binary comparisons (choices) between two lotteries: one that depends on the values of the random variable of interest and another that is contingent on an external reference chance device (typically a probability wheel). This note investigates the degree to which differences in probability weighting functions between the two types of events could affect the practice of subjective probability encoding. We develop a general methodology to investigate this question and illustrate it with two popular probability weighting functions over the range of parameters reported in the literature. We use this methodology to (a) alert decision analysts and researchers to the possibility of reversals, (b) identify the circumstances under which overt preferences for one lottery over the other are not affected by the weighting function, (c) document the magnitude of the differences between choices based on probabilities and their corresponding weighting functions, and (d) offer practical recommendations for probability elicitation.     

There is a 60% probability,but I am 70% certain: communicative consequences of external and internal expressions of uncertainty

Current theories of probability recognise a distinction between external (un)certainty (frequentistic probabilities) and internal (un)certainty (degrees of belief). The present studies investigated this distinction in lay people's judgements of probability statements formulated to suggest either an internal (“I am X% certain”) or an external (“It is X% certain” or “There is an X% probability”) interpretation. These subtle differences in wording influenced participants' perceptions and endorsements of such statements, and their impressions of the speaker. External expressions were seen to signal more reliable task duration estimates, and a lower degree of external than internal certainty was deemed necessary to advise a course of action. In conversations about football, internal expressions were perceived as signalling more personal interest, and were expected to be on the average 10% higher than corresponding external probabilities. Finally, people who reported their outcome expectations for two major sports events let their degree of interest in these events influence their internal but not their external certainty. These results have implications for the communication of uncertainty and probability.