基于期望值最大化的理论何时失效：风险决策中为自己-为所有人决策差异的眼动研究

主流的风险决策理论专家发展了一系列基于期望值最大化(expectation-maximization)的理论, 以期捕获所有人的风险决策行为。然而大量证据表明, 这些基于期望值最大化的理论并不能如同描述性理论那样理想地描述单一个体的决策行为。本研究采用眼动追踪技术, 系统考察了个体在为所有人决策与为自己决策时的风险决策行为及信息加工过程的差异。本研究发现, 基于期望值最大化的理论可捕获为所有人决策或为自己多次决策时的情况, 却不能很好捕获个体为自己进行单次决策时的情况。本研究结果有助于理解基于期望值最大化的理论与启发式/非基于期望值最大化的理论的边界, 为风险决策理论的划分和发展提供实证参考。     

Ignore risk; Maximize expected moral value

Many philosophers assume that, when making moral decisions under uncertainty, we should choose the option that has the greatest expected moral value, regardless of how risky it is. But their arguments for maximizing expected moral value do not support it over rival, risk-averse approaches. In this paper, I present a novel argument for maximizing expected value: when we think about larger series of decisions that each decision is a part of, all but the most risk-averse agents would prefer that we consistently choose the option with the highest expected value. To the extent that what we choose on a given occasion should be guided by the entire series of choices we prefer, then on each occasion, we should choose the option with the highest expected moral value.     

自我框架、风险认知和风险选择

对行为决策中“框架效应”(Framing Effect)的研究进行了拓展：探讨了自我框架对风险决策的影响及其机制。面对运用图示方法表示的管理,健康,及投资方面的风险决策问题,参与者自主地选择对方案的描述（自我框架）。研究有四个主要发现：1）自我框架对风险选择的效应部分显著,而且对风险选择的影响方向因情境的不同而不同;2）机会威胁认知是自我框架效应的一个中介变量;3）自我框架在情绪语气上的差异对风险决策有显著影响：决策者对一个备选方案（确定性或风险性方案）相对于另一个备选方案的自我描述的情绪语气越积极正面,这个方案被选择的可能性越大;4）决策者的机会-威胁认知是这一自我框架效应的部分中介变量。也就是说,对备选方案的自我描述语气作为一种对决策信息的编码影响了风险（机会和威胁）认知,进而影响决策者的风险偏好和选择     

Mood effects on dominated choices: Positive mood induces departures from logical rules

In two studies, we investigated the role of mood states in dominated behavioral choices. Past research has shown that mood effects on judgment and decision‐making can be pervasive. Yet, the role of mood in dominated choices has so far been neglected. The present research represents a first empirical examination of mood effects on dominated choices. We measured (Study 1) or manipulated (Study 2) mood states in participants who made a series of choices in a gambling game. In this choice task without trade‐offs, participants were provided with information about the outcomes and probabilities associated with each choice option. The strategy to maximize the expected mean outcome implied the application of a straightforward and logical rule: Always choose the dominant option with the highest expected value. It has been argued in the literature that mood should have little or no impact when preferences are clear or strong. Still, we expected that mood states would affect even these dominated choices, building on previous work that showed that positive mood states enhance flexibility, creativity, and explorative behavior. The results showed that decisions made in a happier mood were less often in accordance with the logical rule than decisions made in a sadder mood. To conclude, happier mood states are associated to a lesser extent with decisions in accordance with a rule‐based strategy that maximizes expected mean outcomes in dominated choices. Copyright © 2010 John Wiley & Sons, Ltd.     

Preference for oddity: uniqueness heuristic or hierarchical choice process?

Traditional economic theories assume decision makers in multialternative choice tasks "assign" a value to each option and then express rational preferences. Here, I report an apparent violation of such rationality in gray jays (Perisoreus canadensis). I tested the jays' preference in a quaternary choice task where three options were the same color and the fourth option was a different color. All options offered an identical food reward and so the strictly rational expectation was that subjects would choose the odd-colored option in 25% of choices. In clear disagreement, every subject chose the odd option more frequently than expected. I speculate as to how this surprising preference for oddity might have been ecologically rational: by using a unique-choice heuristic, the jays might have been able to bypass a deliberative phase of the decision process and devote more attention to scanning for predators. Alternatively, it is conceivable that the jays did not prefer oddity per se. Instead, they might have used a hierarchical process, assigning options to color categories and then choosing between categories. If so, their behavior matches expectation after all (on average, subjects chose the odd option 50% of the time). It should be straightforward to test these competing hypotheses. The current results can be viewed as a new example of how simple mechanisms sometimes produce economically puzzling yet ecologically rational decision making.     

Task formats and ambiguity aversion

This paper proposes that task format (choosing or rejecting) moderates the effect of ambiguity aversion. Specifically, an ambiguous option is more attractive in a choosing task than in a rejecting task compared with a risky option. The author performed three experiments to test the propositions. In the first experiment, participants showed less ambiguity aversion when they had to choose a preferred option (risky or ambiguous) compared with when they had to reject an option they preferred less. In the second experiment with a monetary incentive, participants had to form a cash‐equivalent estimate for both a risky gamble and an ambiguous gamble in a traditional Ellsberg scenario. The ambiguous option emerged as more attractive than the risky option in the choosing task compared with the rejecting task. The third experiment showed that the participants' decision rationale mediated the effect of the task format on choice. These three experiments support the proposition that task formats moderate the effect of ambiguity aversion. On the basis of the findings, the author provides suggestions for practice and further research. Copyright © 2010 John Wiley & Sons, Ltd.     

迫选规则体验法: 检验规范性和描述性风险决策理论的新尝试

为寻求检验规范性和描述性风险决策理论的通用标准, 本研究以期望价值理论和齐当别抉择模型为例, 探讨了“迫选规则体验法”的适用性。被试为120名大学生, 实验任务为要求被试分别完成自主决策(采用未知规则: 真规则)和规则迫选决策(遵循给定规则: 假规则)任务, 并对决策后的情感和认可程度进行评定。研究发现: (1) 被试在自主决策条件下比在规则迫选条件下体验到的正性情感程度更强, 负性情感的程度更弱; (2) 被试在自主决策与规则迫选决策两种条件下做出的相同决策越多, 该被试对迫选规则更加认可并体验到的正性情感程度越强, 负性情感的程度越弱; (3) 与期望价值理论相比, 齐当别抉择模型可能符合更多决策者的实际决策规则。这些结果表明, 作为检验规范性和描述性风险决策理论的新尝试, 迫选规则体验法可能更有助于回答“决策者实际采用的决策规则是什么”的问题。     

Risking Everything in Obsessive–Compulsive Disorder: An Analogue Decision-Making Study

An experiment examined decision-making processes among nonclinical participants with low or high levels of OCD symptomatology (N?=?303). To better simulate the decision environments that are most likely to be problematic for clients with OCD, we employed decision tasks that incorporated “black swan” options that have a very low probability but involve substantial loss. When faced with a choice between a safer option that involved no risk of loss or a riskier alternative with a very low probability of substantial loss, most participants chose the safer option regardless of OCD symptom level. However, when faced with choices between options that had similar expected values to the previous choices, but where each option had some low risk of a substantial loss, there was a significant shift towards riskier decisions. These effects were stronger when the task involved a contamination based, health-relevant decision task as compared to one with financial outcomes. The results suggest that both low and high symptom OC participants approach decisions involving risk-free options and decisions involving risky alternatives in qualitatively different ways. There was some evidence that measures of impulsivity were better predictors of the shift to risky decision making than OCD symptomatology.

     

Choice,Rating, and Ranking: Framing Effects with Different Response Modes

In a typical risky choice framing task, people have to choose among two options, which are either positively or negatively framed. Choices in the two framing conditions are then compared. However, different preferences between the conditions can be due to changes in the evaluation of the single constituent options or due to specific processes triggered by the choice task. In order to clarify the source of the framing effect, we investigate the effect with different response modes: choice, rating, and ranking. The rating and ranking findings indicate that what is commonly called a risky choice framing effect is actually a framing effect that changes the evaluation of only the riskless option, although there is little or no effect on the risky option. According to these findings, risky choice framing might be construed as a process of attribute framing, which is independent of risk preference in choice contexts. Copyright © 2011 John Wiley & Sons, Ltd.     

With age comes wisdom: decision making in younger and older adults

In two experiments, younger and older adults performed decision-making tasks in which reward values available were either independent of or dependent on the previous sequence of choices made. The choice-independent task involved learning and exploiting the options that gave the highest rewards on each trial. In this task, the stability of the expected reward for each option was not influenced by the previous choices participants made. The choice-dependent task involved learning how each choice influenced future rewards for two options and making the best decisions based on that knowledge. Younger adults performed better when rewards were independent of choice, whereas older adults performed better when rewards were dependent on choice. These findings suggest a fundamental difference in the way in which younger adults and older adults approach decision-making situations. We discuss the results in the context of prominent decision-making theories and offer possible explanations based on neurobiological and behavioral changes associated with aging.     

The Impact of Depression on Self–Other Discrepancies in Decision Making

Although there is a small but growing body of literature on how people make risky decisions for others and predict others' decisions, results seem to be contradictory. The authors contribute to the understanding of these mixed results by investigating how depression affects self–other discrepancies in decision making and the psychological processes that underlie these discrepancies. In an experiment, depressed and nondepressed individuals read a series of scenarios involving decisions about health, money, and interpersonal relationships. They then indicated which of two options they would choose for themselves or for another person, or predicted which option this person would choose for himself or herself. Finally, participants reported benefits and drawbacks of the decisions (i.e., cognitions) and feelings about risk. Depressed individuals were less prone to bias when they predicted others' decisions than nondepressed individuals. Feelings about risk played a key role in determining the direction and the magnitude of this bias. In contrast, both depressed and nondepressed individuals showed bias when they made decisions for others. This bias affected their decisions in opposing ways and was determined by cognitions. This bias is consistent with literature showing that depression is associated with an increased sensitivity to social risks. The authors provide a theoretical explanation of self–other discrepancies in decision making in depressed and nondepressed individuals and conclude that the results support the assumption that depression is associated with psychological processes whose role is to increase sensitivity to social threats rather than with a more general negative bias in cognitive functioning. Copyright © 2014 John Wiley & Sons, Ltd.     

How Well Do We Know Our Inner Daredevil? Probing the Relationship Between Self‐Report and Behavioral Measures of Risk Taking

To measure a person's risk‐taking tendency, research has relied interchangeably on self‐report scales (e.g., “Indicate your likelihood of engaging in the risky behavior”) and more direct measures, such as behavioral tasks (e.g., “Do you accept or reject the risky option?”). It is currently unclear, however, how the two approaches map upon each other. We examined the relationship between self‐report likelihood ratings for risky choice in a monetary gamble task and actual choice, and tested how the relationship is affected by task ambiguity (i.e., when part of the information about risks and benefits is missing) and age. Five hundred participants (aged 19–85 years) were presented with 27 gambles, either in an unambiguous or an ambiguous condition. In a likelihood rating task, participants rated for each gamble the likelihood that they would accept it. In a separate choice task, they were asked to either accept or reject each gamble. Analyses using a signal‐detection approach showed that people's likelihood ratings discriminated between accept and reject cases in their choices rather well. However, task ambiguity weakened the association between likelihood ratings and choice. Further, older adults' likelihood ratings anticipated their choices more poorly than younger adults'. We discuss implications of these findings for existing approaches to the study of risk‐taking propensity, which have often relied on self‐reported risk tendency for ambiguous activities. Copyright © 2016 John Wiley & Sons, Ltd.     

艾勒悖论(Allais Paradox)另释

艾勒悖论违背了期望效用(Expected Utility)理论的独立性(independence)原则,成为欲推翻期望效用理论的杠杆。“齐当别”抉择模型不将风险决策行为看成是追求某种“最大期望值”的抉择反应,而将其看成是“最好可能结果之间的取舍”或者“最坏可能结果之间的取舍”。此项研究设计了一“判断”技术,并用此对艾勒设计的选择问题加以检验。实验表明,判断结果所示的“齐当别”策略能满意地对艾勒选择题作出解释。     

Effects of context expectation on prospective memory performance among older and younger adults

This experiment examined the impact of context expectation on prospective memory (PM) performance among older and younger adults. Participants responded to PM target words embedded in an ongoing lexical decision task (LDT). Older and younger adults performed similarly on the PM task. Regardless of age, PM was significantly better for participants in the correct context expectation condition and significantly worse in the incorrect context expectation condition relative to participants who held no expectations about the context in which targets would appear. Participants’ LDT response latencies were used to assess cost of the PM task to the ongoing task. Latencies were discernibly longer in the LDT block where the PM targets were expected compared to the block where they were not expected. The findings provide new information about how context can be used to support PM aging and suggest that contextual information can be equally beneficial for older and younger adults.     

概率贴现和时间贴现在人脑中的分离

本研究运用ERP技术来检验概率贴现和时间贴现是否反映了相同的神经机制过程。在本研究中,我们在一个刺激中同时操纵概率贴现（风险vs.安全）和时间贴现（1个月后vs.今天）水平。通过对两个过程上的ERN以及全时间段的ERP分析来确定它们是否反映了相同的认知过程。结果发现,这两者在ERN上存在差异,同时这两个效应在ERP的时程和出现的电极点上都存在差异。这些差异表明这两者可能包含着不同的神经机制过程。     

Rapid decisions from experience

In many everyday decisions, people quickly integrate noisy samples of information to form a preference among alternatives that offer uncertain rewards. Here, we investigated this decision process using the Flash Gambling Task (FGT), in which participants made a series of choices between a certain payoff and an uncertain alternative that produced a normal distribution of payoffs. For each choice, participants experienced the distribution of payoffs via rapid samples updated every 50 ms. We show that people can make these rapid decisions from experience and that the decision process is consistent with a sequential sampling process. Results also reveal a dissociation between these preferential decisions and equivalent perceptual decisions where participants had to determine which alternatives contained more dots on average. To account for this dissociation, we developed a sequential sampling rank-dependent utility model, which showed that participants in the FGT attended more to larger potential payoffs than participants in the perceptual task despite being given equivalent information. We discuss the implications of these findings in terms of computational models of preferential choice and a more complete understanding of experience-based decision making.     

风险决策过程验证：补偿/非补偿模型之争的新认识与新证据

风险决策是人类赖以生存和发展的重大决策。如何进行风险决策是人类不断认识和改造世界过程中遇到的未解之谜。主流风险理论认为, 风险决策是一个补偿性的、期望值最大化的过程; 而非主流的风险理论则认为, 风险决策是非补偿性的, 并不遵循期望法则所假设的加权求和等过程。这一谜团为何一直没有得以破解, 或许是因为我们未找到揭示其心理过程的令人信服的证据。近10年来, 我们针对风险决策过程, 借助行为实验、眼动记录法、事件相关电位、功能磁共振成像等技术, 系统探索风险决策的心理和神经机制, 为回答“风险决策是否遵循补偿性规则”这一问题提供了汇聚性证据。本文依据期望法则所假设的概率函数推导、加权过程、加权求和过程、总分最大化等步骤, 对这些研究进行梳理与回顾, 以期加深人们对风险决策机制的理解, 并为建立、健全与风险决策相关的政策、法律法规提供理论依据。     

Culture of honour theory and social anxiety: Cross-regional and sex differences in relationships among honour-concerns,social anxiety and reactive aggression

According to the Appraisal-Tendency Framework (Han, Lerner, & Keltner, 2007), certainty-associated emotions increase risk taking compared with uncertainty-associated emotions. To date, this general effect has only been shown in static judgement and decision-making paradigms; therefore, the present study tested the effect of certainty on risk taking in a sequential decision-making task. We hypothesised that the effect would be reversed due to the kind of processing involved, as certainty is considered to encourage heuristic processing that takes into account the emotional cues arising from previous decisions, whereas uncertainty leads to more systematic processing. One hundred and one female participants were induced to feel one of three emotions (film clips) before performing a decision-making task involving risk (Game of Dice Task; Brand et al., 2005). As expected, the angry and happy participants (certainty-associated emotions) were more likely than the fearful participants (uncertainty-associated emotion) to make safe decisions (vs. risky decisions).