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.