跨期决策中的维度差异偏好:眼动证据

Preference of dimension-based difference in intertemporal choice:Eye-tracking evidence

在跨期决策研究领域,虽然基于维度的跨期模型得到了一些源自结果检验和过程检验的证据支持,但此类模型所假设的维度间差异比较的心理过程尚缺乏直接的过程证据。本研究通过两个眼动实验,系统考察了相关眼动指标对维度差异偏好的预测效应。结果发现,根据基于维度的权衡模型可有效拟合出个体在跨期决策中的维度差异偏好,并且反应时、眼跳注视熵和静态注视熵等指标均与维度差异偏好负相关,而基于维度的注意分配与维度差异判断正相关。这些研究发现支持了本研究所提出的跨期眼动模型的相关假设,证实了维度差异偏好与跨期决策的认知加工过程之间的联系,为基于维度的跨期模型提供了更直接的过程证据,并为今后跨期决策的眼动模型发展指明了新方向。

Intertemporal choice is an important and ubiquitous concept that refers to decisions involving tradeoffs among outcomes at different points of time.It is not only a unique feature of human behavior but also relevant to policymaking and national welfare.Dimension-based models,such as tradeoff model,equate-to-differentiate theory,and similarity model,assume that individuals tend to compare the difference between dimensions of delay and outcome before deciding on a single dimension when choosing between a smaller-sooner option and a larger-later one.Considerable empirical evidence from behavioral and process data supports the use of dimension-based models.The existing dimension-based models provide qualitative explanations for an individual’s intertemporal choice and focus on“which dimension is the greater difference dimension”,but ignore the preference of dimension-based difference(i.e.,“how much different of the difference between the two dimensions”).In the present study,we used eye-tracking technology to examine the relationship between the preference of dimension-based difference,which is estimated by the tradeoff model,and the information searching process,which is reflected by eye-tracking measures.Two experiments were conducted to test the hypotheses.A total of 75 college students(61 females;mean age=20.9±2.4 years)participated in Experiment 1.Participants were told to complete two tasks.In the intertemporal choice task,participants chose their preferred option between the two intertemporal options,and their eye movements were recorded in the task.In the analogue scale task,participants were asked to indicate their subjective dimension-based difference judgment by using numbers 1~7.In Experiment 2,we recruited 59 college students(33 females;mean age=21.9±2.1 years)to participate in the experiment.The tasks and procedures were similar to Experiment 1 except that the participants were asked to repeat the intertemporal choice task twice.The results indicated that preference of dimension-based difference(PDD),which is estimated by the tradeoff model,correlated with the subjective dimension-based difference judgment measured by the analogue scale task(Experiment 1)and could negatively predict the choice reversals(Experiment 2).These findings proved the validity of the estimation of PDD.The results in the two experiments consistently revealed that decision time,gaze transition entropy(a measure of visual scanning efficiency),and stationary gaze entropy(a measure of the level of even distribution across different areas of interest)could negatively predict the PDD,indicating that the information searching process during intertemporal choice could reflect the preference of dimension-based difference.We also found that the outcome gaze proportion(a measure of attention allocation)could predict the dimension-based difference judgment,which is consistent with previous research.Our findings proved the validity of the estimation method of PDD,which could quantitatively estimate the PDD when making an intertemporal choice based on their choices without extra inquiry.The current research highlighted the correlation between the preference of dimension-based difference and the information searching process,providing further process evidence for dimension-based intertemporal models.Future studies that focus on developing intertemporal models involving eye movements should consider replicating the pattern between PDD and eye-tracking measures as revealed in the present study when running data simulations.Our findings also suggest that compared to the determinant models,the probabilistic models can better describe an individual’s intertemporal choice,thereby highlighting the direction of the development of intertemporal models.