社会与工程心理学研究室知识库

风险决策指决策者不知道哪种自然状态将会发生，但知道这些自然状态发生概率及其对应结果的一类决策，例如选择50%的概率获得100元还是选择80%的概率获得60元。风险决策与科技政策、经济、金融、环保等关乎国计民生的重要领域息息相关，但目前风险决策的心理机制尚未明确。本博士论文构建三个研究，借助眼动追踪技术，系统地考察了风险决策的心理机制，以期明确风险决策的心理机制，并为相关政策的制定提供参考建议。
在风险决策研究领域，存在基于加权求和计算方式的期望理论与基于直觉的启发式理论之争。本论文认为，加权求和的期望理论在为所有人决策时确实是行得通的，但是为自己决策时是行不通的。当为所有人进行决策时，由于无法得知众人对不同维度的权重信息和风险偏好，因此决策者更易采用理性的加权求和策略进行决策。而当为自己决策时，个体会根据自身的需求偏好和个人特点进行策，更易采用违背传统期望理论的启发式策略来决策。目前来看，在风险决策领域鲜有研究探索这种为所有人决策与为自己决策的差异。眼动追踪技术作为一种过程检验方法，具有无干扰性、适用范围广、采集信息多样等独特的优势，可为理解决策的心理机制提供新的研究视角，并丰富学界对经济行为心理机制的认识。
鉴于此，本博士论文的研究一利用眼动追踪技术，考察个体在为所有人进行风险决策时，是否采用与为自己决策时不同的策略，以期解开理论家坚持基于加权求和的期望理论之谜，为解决人们在风险决策中是否基于加权求和的计算过程这一争论提供更直接、更客观的证据。研究一发现:个体在为所有人做决策时更可能选择EV较大选项，其反应时更长、信息加工深度更深、复杂度更高、更可能采用基于选项的信息搜索模式，这意味着其更可能采用基于加权求和的期望策略，;个体在为自己做决策时更可能不根据EV策略进行决策，其反应时更短、信息加工深度更浅、复杂度更低、更可能采用基于维度的信息搜索模式，这意味着其更可能采用直觉的启发式策略。这一结果暗示，能够描述所有人决策行为的期望理论并不能描述单一个体的风险决策行为，风险决策理论家为所有人发展的期望理论并不适用于单一个体的决策，这或许是期望理论失效的原因之一。
在研究一的基础上，研究二进一步考察人们在风险决策时的眼动轨迹能否预决测其决策行为。一旦明确了人们在风险决策时的决策策略，就可以据此构建相关眼动指标，来预测其决策行为。研究二通过构建回归模型发现，注视信息比例、平均注视时长、SM值等一系列眼动指标都能够显著预测个体的风险决策行为和选择反转，最优预测模型的预测力高达81.4%。这意味着在被试观看选项之后，无须做出选择，研究者即可根据其搜索信息时的眼动轨迹来对其选择进行预测，使得心理学中所谓的“读心术”成为可能。
在研究二的基础上，研究三进一步操纵眼动注视来影响那些可预测风险决策的眼动指标，以影响个体的风险决策行为。研究三采用内生和外生两种操纵注视时间的实验范式，来操纵个体对特定维度的注视时长，结果发现两种操纵方式都能显著影响个体的风险决策行为。值得一提的是，研究三可以在被试无察觉的条件下操纵其对选项信息的注视时长，从而影响其决策行为，这一操纵方式或对现实生活中的风险决策干预具有一定启示。
本博士论文通过以上三个研究考察了风险决策的心理机制，以期达到通过追踪个体的眼动轨迹来描述、解释、预测、控制个体的风险决策行为这一目的。

Risky decision making refers to a condition in which a decision maker does not know which states of nature will occur but does know their probabilities of occurring. For example, the decision maker selects between "50% probability to obtain 100 RMB"and "80% probability to obtain 100 RMB". Risky decision making is associated with important areas such as policies in science and technology, economy, and finance.However, the underlying mechanism of risky decision making remains unclear. The current dissertation conducted three eye-tracking studies to explore the mental mechanism of risky decision making.
In risky decision making, a long-drawn debate exists on whether making a risky choice is based on an expectation (weighting and adding) strategy or on a heuristic strategy. Mainstream theorists on risky decision-making have developed various expectation theories with the goal of capturing everyone's choices. In my opinion, the expectation theories are effective when decision makers decide for everyone, but these theories are ineffective for decisions for one's self. When making decisions for everyone, decision makers do not know each individual's personal preferences, and therefore adopt the rational weighting and adding strategy. By contrast, when making decision for themselves, decision makers decide on the basis of their own preferences,and therefore are more likely to adopt the intuitive heuristic strategy. To the best of my knowledge, few studies have attempted to explore the discrepancies between making decisions for everyone and for one's self. As a process-tracing methodology, eye-tracking technique has advantages such as non-interfering, wide scope of application and variety of collecting information. Therefore, this technology allows decision makers to investigate information freely while providing a way for researchers to measure the information uptake process and has also been shown to be a powerful tool for capturing the cognitive process involved in decision-making.
In Study 1，eye-tracking technique was used to examine whether the decision strategy that individuals adopt when making decisions for everyone is the same as the strategy they use when making decisions for themselves. The results suggest that individuals are more likely to adopt the expectation-based strategy when decisions for everyone. When making decisions for everyone, individuals have making a deeper level of information acquisition and increased complexity of information processing;the direction of information search is more alternative-based than when making decisions for themselves. By contrast, individuals are more likely to adopt a heuristic strategy they use when making decisions for themselves. The results suggest that individuals are more likely to adopt the expectation-based strategy when making decisions for everyone. When making decisions for everyone, individuals have a deeper level of information acquisition and increased complexity of information processing; the direction of information search is more alternative-based than when making decisions for themselves. By contrast, individuals are more likely to adopt a heuristic strategy when deciding for themselves; the depth of information acquisition and level of complexity of information processing are lower and the direction of information search is more dimension-based. These results suggest that expectation theories may capture risky choices when individuals make decisions for everyone, but whether these theories could capture risky choices when they make decisions for themselves cannot be taken for granted.
In Study 2, I explored whether the individuals' eye movement during risky decision making could predict their final choices. If we know which strategy is adopted,we may be able to conduct corresponding eye-tracking measures to predict the risky choices. The results of Study 2 revealed that the eye-tracking measures, such as the proportion of information searched and mean fixation duration, could predict individuals' risky choice and choice reversal behavior. The prediction rate of the optimal regression model reached 81.4%. These results suggest that we could predict individuals' risky choice only based on their eye movement and without asking for any information. This task seems possible for mind reading in psychology.
In Study 3, I manipulated the eye-tracking measures that could predict risky choices to influence individuals' risky choices. Study 3 used both endogenous and exogenous paradigms to manipulate individuals' gaze while they decided between two risky alternatives and examined whether risky decisions could be biased toward a randomly determined target. I found that endogenous gaze-contingent manipulation was effective in biasing the participants' risky decisions toward randomly set targets. I also observed that the exogenous manipulation of gaze time on the predetermined target dimension affected the individuals' choice only when they performed the manipulation task first. The findings demonstrate that manipulating individuals' gaze while they make a decision can affect their risky decisions. Risky decisions are constrained and coupled with the immediate environment through the interplay between individuals,their sensorimotor systems, and the environment.
The current dissertation explored the underlying mechanism of risky decision making in three studies to describe, explain, predict, and control individuals' risky choices by monitoring their eye movement during risky decision making.