|Alternative Title||Is making an ambiguous choice based on a weighing and adding process? Evidence from eye-tracking method|
|Place of Conferral||中国科学院心理研究所|
|Keyword||风险决策 模糊决策 眼动追踪|
生活中，我们的决策往往会涉及两类问题:风险((risk)和模糊(ambiguity)。 17世纪起，学界就己经开始对己知各种结果以及结果出现概率的风险决策进行了系统的研究，诞生了期望价值理论((Expected Value Theory)。即使饱受挑战，风险决策的主流理论，即补偿性的期望家族理论仍保留着期望价值理论所提出的“加权求和”的核心假设，不断地修正、发展。在现实生活中更为普遍的是概率未知或不确定的模糊决策。但是直至Ellsberg (1961)提出双色、三色问题对主观期望效用理论(Savage, 1954)造成了巨大挑战，模糊决策的理论模型才逐渐出现、发展，但其主要思路基本是对期望效用理论的修正。
Decision problems often come in two kinds in our daily life: risk and ambiguity. Since the birth of Expected Value Theory in the beginning of the 17th century, systematically study of risk decision-making that has known results with known probabilities has begun. Although it has been continuously challenged, the mainstream theory of risk decision-making, that is, the family of compensatory model, still retains the core assumption of the "weighting and adding" of the Expected Value Theory, and has constantly revised and developed. More common in real life are ambiguity decisions with unknown or uncertain probabilities. Until Ellsberg (1961) proposed two-color and three-color problem that posed a great challenge to the Subjective Expected Utility Theory (Savage, 1954), the theoretical model of ambiguity decision-making gradually emerged and developed, but its main idea is basically the revision of the Subjective Expected Utility Theory.
However, more and more studies have testified that people do not follow the rule of "weighting and adding" when making risky choice with known outcomes and probabilities, but adopt a simple heuristic strategy. In ambiguity decision-making with unknown or uncertain probabilities, the process of "weighting and adding" becomes more difficult, and the "non-mainstream" heuristic theory in risk decision-making may be able to describe and explain ambiguity decision-making better. However, the study of ambiguity decision-making started late and existing research is mainly based on traditional behavioral experiments, and it is also lacking evidence from process tracking. Therefore, on the basis of behavioral results, this study uses eye-movement technology to directly measure the cognitive process of decision-making, in order to answer: 1) Does individual make ambiguity decision based on a "weighting and adding" process? 2) Compare with risk decision-making, is ambiguity decision-making more likely to be a simple heuristic process?
Study 1 refers to the proportion task paradigm in the risk decision study of Su et al. (2013) and designs an ambiguity proportion task in which participants will consciously weight outcome by probability before making choices in their natural state. Thus, study 1 adopted ambiguity proportion task as baseline to test whether the ambiguity decision is consistent with the "weighting and adding" hypothesis. From the behavioral results, the difference of the proportion of choices predicted by EV family is marginally significant, and the difference in reaction time is significant between the two tasks. In addition, the eye movement process of the two tasks is significantly different. Compare to the ambiguity proportion task that require weighting and adding, the information processing complexity of ambiguity decision is lower, the option-based information search is less, and the scanpath of the two tasks is significantly different Results of study 1 revealed that the eye movement process of ambiguity decision-making is inconsistent with the assumption of "weighting and adding".
Study 2 pr0esents probability/probability interval in the form of pictures to minimize the impact caused by the differences of experimental materials. Through the direct comparison between ambiguity decision and risk decision, study 2 explored whether making ambiguous choices is more likely to be a simple heuristic process than risky choices. At the level of behavioral results, marginally significant difference was found in the proportion of choices predicted by EV family between the two tasks, but there was no significant difference in decision time. By further analyzing the eye movement process, we found that: From the information processing complexity index, there was no significant difference between the two decision-making tasks; analysis of information search direction suggested that when subjects were making ambiguity decisions saccades between outcome dimension and probability dimension were significantly less than that of risk decision-making task, indicating that ambiguity decision-making was inconsistent with the eye-movement pattern of "weighting and adding". Analysis of scanpath shown that the overall and dynamic eye-movement process was significantly different between the two tasks. Moreover, in the task of risk decision-making, compare with the high computing difficulty condition, when subjects were making risky choice under low computing difficulty condition, their reaction time was shorter, and they had more option-based processing. But in the ambiguity decision task, no effect on computing difficulty was found. Results of study 2 suggested that compare with risk decision-malting, individuals are more likely to adopt a simple heuristic strategy when making ambiguity decisions rather than to follow the rule of "weighting and adding".
This article made a series of comparisons at the level of behavioral results and eye movement process. The analysis of eye movement process is mainly based on the "compensatory/non-compensatory" and "dimension-based/option-based" decision features to test that the cognition process of different decision types is more in line with which theoretical decision model. Overall, the results of Study 1 and Study 2 suggested that ambiguity decision-making behavior is unlikely to consistent with the process of "weighting and adding", and compare with risk decision-malting, individuals are more likely to adopt simple heuristic strategy when making ambiguity decisions.
|邵洋. 模糊决策是否是“加权求和”的过程:基于眼动证据的研究[D]. 中国科学院心理研究所. 中国科学院大学,2018.|
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