基础比率和认知风格对贝叶斯推理影响的眼动研究

An Eye Movement Study about the Influence of Base-rate and Cognitive Styles on Bayesian Reasoning

本文通过操纵基础比率和认知风格水平,采用Eye Link II眼动仪,考察了64名大二学生在经典贝叶斯推理任务上的眼动情况,探讨了基础比率作用机制的争论。结果发现,在总注视时间和注视次数指标上,基础比率和认知风格大都没获得显著的主效应,但两者交互效应均显著。这表明,推理者并没有完全忽视基础比率,对于不同认知风格个体而言,基础比率所起的作用不同。这一结果的启示:未来研究似乎应该将基础比率的作用机制与某些个体因素综合加以讨论。

The debate about the function of base-rate in Bayesian reasoning has never been stopped. There were three main viewpoints： （1） people overestimated the base-rate; （2） people neglected the base-rate completely; （3） people took it into account, but did not understand its function. The majority of the existing studies have been using the posterior probability and reaction time to infer the reasoning process reversely and there is a lack of support of the real-time data. The study provided eye-movement evidence for the process of Bayesian reasoning by using Eye View Monitoring Systems for the first time. The research hypothesized that the eye-movement targets induced by different levels of base-rate and cognitive styles would be significantly different. Sixty-four college students were sampled. In order to examine the effects of two different levels of base-rate （e.g., high vs. low） and two kinds of cognitive styles （e.g., the field dependence cognitive style vs. the field independence cognitive style） on Bayesian reasoning, the study recorded the total fixation duration and the number of fixation by using Eye View Monitoring Systems. The inference materials were about illness which was divided into four areas of interests （AOI）. AOI1 was about the base-rate, AOI2 was about the hit-rate, AOI3 was about the false alarm rate, and AOI4 was the area where the question was located. The results were as follows： （1） For the total fixation duration, the main effect of base-rate and the main effect of cognitive style were not significant, but the interaction between them was significant. And the simple effect analysis showed that when the base-rate was low, the total fixation duration of the group with the field dependence cognitive style were more than those of the group with the field independence cognitive style. Also, the total fixation duration of the group with the field independence cognitive style in high base-rate level was more than those in low base-rate level. （2） For the number of fixation, the main effect of base-rate and cognitive style was not significant, but the interaction between them was significant. And the simple effect analysis showed that when the base-rate was low, the number of fixation of the group with the field dependence cognitive style was more than those of the group with the field independence cognitive style. Also, the number of fixation of the group with the field independence cognitive style in high base-rate level was more than those in low base-rate level. （3） For the total fixation duration and the number of fixation, the main effect of AOI was significant; the order of the extent of each AOI that was paid attention to was： AOI2, AOI3, AOI4, AOI 1. These results indicated that： （1） in the process of Bayesian reasoning, the probability information was differently followed with interest, the order was： hit-rate, false alarm rate, base-rate, and the base-rate was not neglected completely but was just underweighted. （2） People with different cognitive styles held different process approaches. Generally speaking, people with the field independence cognitive style intended to think rationally while those with the field dependence cognitive style were always influenced by the external information.