行为决策中模糊规避研究的回顾与展望

模糊规避是指在相同奖赏的情况下,决策者会偏好有精确概率的事件而不是从主观上判断具有相同模糊概率的事件。自从Ellsberg提出模糊规避的概念以来,模糊规避已在行为决策研究的多个领域得到广泛验证。本文梳理了近五十年来关于模糊规避的研究文献,系统分析了模糊规避的研究范式、心理机制和影响因素,同时提出了未来的研究展望。     

Attributions for ambiguity in a treatment-decision context can create ambiguity aversion or seeking

The phenomenon of ambiguity aversion suggests that people prefer options that offer precisely rather than imprecisely known chances of success. However, past work on people's responses to ambiguity in health treatment contexts found ambiguity seeking rather than aversion. The present work addressed whether such findings reflected a broad tendency for ambiguity seeking in health treatment contexts or whether specific attributions for ambiguity play a substantial role. In three studies, people choose between two treatment options that involved similar underlying probabilities, except that the probabilities for one option involved ambiguity. The attributions offered for the ambiguity played an important role in the results. For example, when the range of probabilities associated with an ambiguous treatment was attributed to the fact that different studies yield different results, participants tended to show ambiguity aversion or indifference. However, when the range was attributed to something that participants could control (e.g., regular application of a cream) or something about which they were overoptimistic (e.g., their immune system function), participants tended to show ambiguity seeking. Health professionals should be mindful of how people will interpret and use information about ambiguity when choosing among treatments.     

模糊规避的形成机制：基于可评价性假设的视角

模糊规避是指在相同奖赏的情况下,决策者会力图规避从主观上判断具有模糊概率的事件而偏好具有相同精确概率的事件。本研究使用同时评价、单独评价的研究范式从随机事件和自然事件两个领域来探讨模糊规避的形成机制。研究结果表明,当风险事件和模糊事件同时评价时,个体倾向于模糊规避;当风险事件和模糊事件单独评价时,模糊规避会消失。     

Impact of regulatory focus on ambiguity aversion

Although prior research has shown that some people prefer a risky to an ambiguous option, this study further proposes that people's regulatory focus (promotion vs. prevention) might influence their ambiguity aversion. Three experiments have tested whether people with promotion focus showed less ambiguity aversion than those with prevention focus: The first experiment revealed that, compared with chronically promotion‐focused individuals, prevention‐focused subjects preferred a risky to an ambiguous option. In the second experiment, priming of the subjects' goal orientations led to similar results. Experiment 3 demonstrated that participants showed less ambiguity aversion for the expected performance of an investment product representative of promotion (e.g., a stock fund) rather than one representative of prevention (e.g., a bond fund). In other words, people showed less preference for a bond fund when the probability distribution of its expected performance was unknown than when it was known, whereas they showed less preference difference between known and unknown probability distributions for the expected performance of a stock fund. This study has integrated research pertaining to regulatory focus and ambiguity aversion, and the results have confirmed that the impact of regulatory focus on ambiguity aversion is robust across different methods and decision tasks. Copyright © 2010 John Wiley & Sons, Ltd.     

Ambiguity Attitudes over Time

Previous research demonstrates that individuals exhibit a stronger level of ambiguity aversion for high probabilities than for low probabilities. Given that risky and ambiguous prospects are often unresolved until a future date (e.g., investment decisions, new product launches, and medical interventions), this study examines the impact of time on ambiguity preferences at different probability levels. Our experimental results indicate that although ambiguity preferences for low‐probability events remain constant, a robust effect of time occurs for high‐probability events. More specifically, temporal distance mitigates ambiguity aversion. This effect is consistent for different elicitation methods (preference rating and probability–ambiguity trade‐off tasks). We propose a dual‐process model (affective versus cognitive processing styles) to explain our results. Affective processing for high‐probability lotteries resolved in the current period increases ambiguity aversion, while cognitive processing leads to less ambiguity‐averse choices for future lotteries. Copyright © 2015 John Wiley & Sons, Ltd.     

概率大小、损益结果和认知闭合需要对模糊规避的影响

模糊规避是指在相同奖赏的情况下,决策者会力图规避从主观上判断具有模糊概率的事件而偏好具有相同精确概率的事件。本研究探讨了概率大小、损益结果和认知闭合需要对模糊规避的影响。研究发现,在小概率受益的情况下,个体倾向于模糊寻求;在中概率受益的情况下,个体倾向于模糊规避;在高概率受益的情况下,个体倾向于模糊规避;在小概率损失的情况下,个体倾向于模糊规避;在中概率损失的情况下,个体倾向于模糊规避;在高概率损失的情况下,个体倾向于模糊寻求。但是,研究并未发现认知闭合需要对模糊规避有预测作用。     

不确定性容忍度对模糊决策中决策偏好的影响及其情景依赖性*

研究以Ellsberg选瓶任务为决策材料,探讨了不同任务特征下个体不确定性容忍度对模糊决策中决策偏好的影响。结果发现,获益情景下:高概率时高、低容忍度个体对模糊选项的选择无显著差异,均偏好模糊规避;中概率时低容忍度个体比高容忍度个体表现出更低程度的模糊规避,前者倾向于模糊中立,后者倾向于模糊规避;低概率时两者对模糊选项的选择无显著差异,均倾向于模糊中立。损失情景下:高概率时两者对模糊选项的选择无显著差异,均倾向于模糊寻求;中概率时低容忍度比高容忍度个体更偏好模糊寻求,前者倾向于模糊寻求,后者倾向于模糊中立;低概率时两者对模糊选项的选择无显著差异,均倾向于模糊规避。这表明,不确定性容忍度对模糊决策偏好产生作用,但这种作用会受到损益概率和损益结果的影响,具有情景依赖性。     

The discounting of ambiguous information in economic decision making

In three experimental studies we investigated how decision makers respond to ambiguous information about costs and benefits. In Experiment 1, we studied the effect of ambiguity about prior costs. Experiments 2 and 3 focused on the effect of ambiguity about future outcomes. The collective results of the three studies suggest that decision makers discount ambiguous information. The findings are related to insights on the disjunction effect, the sunk cost effect, transaction decoupling, and ambiguity aversion. Copyright © 2003 John Wiley & Sons, Ltd.     

Resolving syntactic category ambiguity: An eye-movement analysis

In two experiments, participants' eye movements were monitored as they read sentences containing biased syntactic category ambiguous words with either distinct (e.g., duck) or related (e.g., burn) meanings or unambiguous control words. In Experiment 1, prior context was consistent with either the dominant or subordinate interpretation of the ambiguous word. The subordinate bias effect was absent for the ambiguous words in gaze duration measures. However, effects of ambiguity did emerge in other measures for the ambiguous words preceded by context supporting the subordinate interpretation. In Experiment 2, context preceding the target words was neutral. Ambiguity effects only arose when posttarget context was consistent with the subordinate interpretation of the ambiguous words, indicating that readers initially selected the dominant interpretation. Results support immediate theories of syntactic category ambiguity resolution, but also suggest that recovery from misanalysis of syntactic category ambiguity is more difficult than for lexical-semantic ambiguity in which alternate interpretations do not cross syntactic category.     

模糊决策的情境依赖性

实验1采用艾尔斯伯格悖论的研究范式,探究被试对模糊的厌恶倾向以及在决策过程中所采用的决策策略。结果发现：被试对确定选项和模糊选项的选择存在差异;在肯定形式下倾向于确定选项,而在否定形式下则倾向于模糊选项,采用了利益最大化策略。实验2采用艾尔斯伯格悖论的变式,通过操纵概率和任务类型,发现：模糊决策具有情境依赖性,并非任何情况下个体都厌恶模糊。当风险选项不能满足自己的需要,即获胜机率比较小时,人们会偏向模糊选项。     

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.     

Modelling the effects of semantic ambiguity in word recognition

Most words in English are ambiguous between different interpretations; words can mean different things in different contexts. We investigate the implications of different types of semantic ambiguity for connectionist models of word recognition. We present a model in which there is competition to activate distributed semantic representations. The model performs well on the task of retrieving the different meanings of ambiguous words, and is able to simulate data reported by Rodd, Gaskell, and Marslen-Wilson [J. Mem. Lang. 46 (2002) 245] on how semantic ambiguity affects lexical decision performance. In particular, the network shows a disadvantage for words with multiple unrelated meanings (e.g., bark) that coexists with a benefit for words with multiple related word senses (e.g., twist). The ambiguity disadvantage arises because of interference between the different meanings, while the sense benefit arises because of differences in the structure of the attractor basins formed during learning. Words with few senses develop deep, narrow attractor basins, while words with many senses develop shallow, broad basins. We conclude that the mental representations of word meanings can be modelled as stable states within a high-dimensional semantic space, and that variations in the meanings of words shape the landscape of this space.     

The role of competition and knowledge in the Ellsberg task

Ambiguity avoidance denotes people's preference for gambling situations with known over unknown, or ambiguous, probability distributions. In four experiments we provide evidence for the interaction between competitiveness and knowledge in Ellsberg's task, in which people have a choice between a risky box (distribution of balls known) and an ambiguous box (distribution of balls not known). If the situation is perceived as competitive (the experimenter or an opponent is responsible for composing the boxes) people avoid ambiguity by betting on the box with the known probability distribution. If the task is perceived as cooperative (a partner or friend is composing the boxes) people are indifferent toward ambiguity or even ambiguity seeking. In addition, we find that people expect their winning odds to be less than even in the ambiguous box. Copyright © 2003 John Wiley & Sons, Ltd.     

Ambiguous games: Evidence for strategic ambiguity aversion

The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game. Half the players knew that the ambiguous co-player types were equally likely, and half did not. Half expected the outcomes to be known immediately, and half expected a week's delay. Known-risk games were generally preferred, confirming a significant strategic ambiguity aversion effect. In the delay conditions, players who knew that the ambiguous co-player types were equally likely were significantly less ambiguity averse than those who did not. Decision confidence was significantly higher in 2 × 2 than in larger games.     

Ambiguous games: evidence for strategic ambiguity aversion

The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game. Half the players knew that the ambiguous co-player types were equally likely, and half did not. Half expected the outcomes to be known immediately, and half expected a week's delay. Known-risk games were generally preferred, confirming a significant strategic ambiguity aversion effect. In the delay conditions, players who knew that the ambiguous co-player types were equally likely were significantly less ambiguity averse than those who did not. Decision confidence was significantly higher in 2 × 2 than in larger games.     

Children’s Gender–Emotion Stereotypes in the Relationship of Anger to Sadness and Fear

Children’s perceptions of the emotional reactions of same- and different-sex characters in stories containing ambiguous and unambiguous emotional contexts were examined. According to the Parallel-Constraint-Satisfaction Theory (Kunda and Thagard. Psychological Review, 103, 284–308, 1996), stereotypes are more likely to be utilized in ambiguous contexts, defined here as those likely to elicit multiple emotional responses. Seventy suburban U.S. preschoolers were read vignettes describing boys or girls in ambiguous or unambiguous emotion-inducing events and reported how the vignette characters were feeling. Results suggest that the perceptions of participants were more likely to reflect gender–emotion stereotypes (e.g. perceiving males as angry and females as sad) in ambiguous contexts than in unambiguous contexts. Results are discussed in terms of children’s emerging understanding of gender–emotion stereotypes.     

Age-related changes in processing speed modulate context use during idiomatic ambiguity resolution

ABSTRACT

The goal of the current study was to investigate whether age-related changes in processing speed, as indexed by verbal fluency, modulate context use in the resolution of ambiguous idioms (e.g., tie the knot). Younger and older adults completed a cross-modal priming experiment where they decided whether visual word targets were related in meaning to idiomatically or literally biased auditory sentence primes. Older adults with high verbal fluency, similar to younger adults, showed context-dependent facilitation in both biasing sentence contexts. In contrast, older adults with low verbal fluency did not show facilitation of literal meanings in literally biased sentence contexts, likely because they had difficultly inhibiting the dominant figurative meaning. These findings argue that age-related changes in context use during ambiguity resolution are restricted to older adults with reduced processing speed. The results also suggest that verbal fluency may reflect the speed in recruiting frontally-mediated selection mechanisms during ambiguity resolution.     

Fragile promise: The role of justification in promise-breaking

People who consider themselves moral sometimes use self-serving justifications to rationalize their selfish behaviours. Previous studies have tested the role of ambiguity in justifying wrongdoings, but it remains unclear whether ambiguity also plays a role in justifying promise-breaking behaviour and whether heterogeneity exists. To investigate justification in promise-breaking, we introduced a new experimental paradigm called the card-guessing task and used hierarchical cluster analysis to classify participants based on their promise-breaking decisions in unambiguous and ambiguous conditions. Experiment 1 revealed three clusters of solutions: Cluster 1 always kept their promises (i.e., keepers); Cluster 2 only exploited the vague promises and broke their promises in the ambiguous condition (i.e., intermediates); Cluster 3 tended to take advantage of vague promises and broke their promises irrespective of ambiguity (i.e., breakers). Experiment 2 confirmed that participants in the three clusters differed in their norm-abiding preferences and social value orientations. Keepers were more altruistic and had a stronger sense of norm compliance than intermediates and breakers. In conclusion, our study demonstrates that self-serving justifications were more likely to be employed by people who are moderately sensitive to deviation from social norms, which has implications for strategic interventions and policy formulation concerning unethical behaviour.     

Is luck on my side? Optimism,pessimism, and ambiguity aversion

The influences of optimism and pessimism on ambiguity aversion were investigated in two tasks that manipulated the presence or absence of a potentially competitive experimenter. A total of 112 participants chose which option—ambiguous or known-risk—they preferred in the two slightly differing Ellsberg urns tasks. Optimism was measured using the Extended Life Orientation Test (ELOT). Highly optimistic people showed significantly less ambiguity aversion than less optimistic people when information was given that the number of balls was randomly determined. This pattern was present but less pronounced in the condition when the composition of the ambiguous urn could be interpreted as being influenced (rigged) by the experimenter. Pessimism was uninfluential. Perceptions of the situation, especially the degree of trust in the experimenter, were significantly influenced by the participants' optimism. People who do not have highly optimistic personalities tend to shy away from choosing ambiguous options. When ambiguity is clear, and trust issues are removed, people's optimistic outlook influences their degree of ambiguity aversion and thus their decisions.