锚定效应的产生前提及作用机制

The Precondition and Mechanism of Anchoring Effect

为了探讨锚定效应的产生前提及基础锚定效应的理论解释,实验一选取高、低、无三种锚值,设置了15ms、45ms、75ms、1000ms四种呈现时间,结果发现只有15ms条件下未出现锚定效应,呈现时间越长,锚定效应越大。实验二设置了语意相同但表述形式不同的两种锚值,结果发现,大数字锚值使估计值偏高,小数字锚值使估计值偏低。该发现说明锚定效应的产生前提是注意,数字启动假说可以更好地解释基础锚定效应。

Anchoring effect–the disproportionate infl uence on decision makers to make judgments that are biased toward an initially presented value –is typically described as robust and prevalence, which affects human＇s decisions under uncertainty. Basic anchoring effect is caused by a single number. The researches of anchoring effect will help us understand the impact of this judgmental heuristic in decision making and explore effective ways to reduce the bias. There have been numerous researches on anchoring effect, however, the precondition of anchoring effect, whether basic anchoring effect exist and the mechanism of it are not clear to this day and there has been considerable controversy. In order to investigate these problems, we conducted two experiments. In the first experiment, we exploited a mixed design to explore whether attention to the anchor was the precondition of anchoring effect, with anchor levels（high, low, non） as within-subject variable and presentation time（15ms, 45 ms, 75 ms, 1000ms） as between-subject variable. We recruited 120 college students to participate in our experiment. The results showed that in 15 ms condition, there was no anchoring effect, whereas in 75 ms and 1000 ms conditions, both observed anchoring effect, suggesting that attention to the anchor not comparison was very important to anchoring effect. In addition, in 45 ms condition, participants were aware of low anchors but not high anchors, and we observed anchoring effect only in the low anchor condition. In sum, whether the anchor was high or low, anchoring effect emerged only when participants were aware of the anchor. Therefore, attention to the anchor is the precondition of anchoring effect. With increased time to pay attention to anchors, the anchoring effect grew larger, which provided initial evidence supported Numeric Priming Account. The second study started from the confl ict of the Selective Accessibility Account and the Numeric Priming Account, we set pairs of anchors which had identical semantic meaning but different presentations, such as 5 kilograms and 5000 grams. Results of 20 students showed that the two type of anchors lead to different anchoring effect, which supported the Numeric Priming Account.