Marchiori David, Papies Esther K, Klein Olivier
Department of Clinical and Health Psychology, Utrecht University, Utrecht, The Netherlands.
Department of Social and Organizational Psychology, Utrecht University, Utrecht, The Netherlands.
Appetite. 2014 Oct;81:108-15. doi: 10.1016/j.appet.2014.06.018. Epub 2014 Jun 17.
People consistently over-eat when served a large compared with a small (appropriate) portion of food. However, the mechanism underlying this so-called portion size effect is not well understood. We argue that the process of anchoring and adjustment naturally describes this effect, such that the size of a presented portion works as an anchor that strongly influences consumption. The classical anchoring and adjustment paradigm was applied to six hypothetical eating situations. Participants were asked to imagine being served either a small or a large portion of food (i.e., low and high anchor) and to indicate whether they would consume more or less than this amount. Then, they indicated how much they would eat. These estimates were compared with a no-anchor condition where participants did not imagine a specific portion size but only indicated how much they would eat. In addition, half of participants in the anchoring conditions received a discounting instruction stating that the portion size they had been asked to imagine was randomly selected and thus not informative for their consumption estimate. As expected, participants who imagined to be served larger portions estimated to consume significantly more food than participants in the no-anchor condition, and participants who imagined to be served smaller portions estimated to consume significantly less food than participants in the no-anchor condition. The discounting manipulation did not reduce this effect of the anchors. We suggest that the process of anchoring and adjustment may provide a useful framework to understand the portion size effect and we discuss implications of this perspective.
与少量（合适）食物相比，当人们面对大量食物时总是会吃得过多。然而，这种所谓的分量效应背后的机制尚未得到很好的理解。我们认为，锚定与调整过程能够自然地解释这种效应，即所呈现食物的分量起到了一个锚的作用，对食量有很大影响。经典的锚定与调整范式被应用于六种假设的进食情境中。参与者被要求想象自己得到的是少量还是大量食物（即低锚和高锚），并指出他们会吃得比这个量多还是少。然后，他们要表明自己会吃多少。这些估计值与无锚定条件下的情况进行了比较，在无锚定条件下，参与者没有想象特定的食物分量，只是表明自己会吃多少。此外，在锚定条件下，一半的参与者收到了一条折扣说明，称他们被要求想象的食物分量是随机选择的，因此对他们的食量估计并无参考价值。正如预期的那样，想象得到较大分量食物的参与者估计的食量明显多于无锚定条件下的参与者，而想象得到较小分量食物的参与者估计的食量明显少于无锚定条件下的参与者。折扣操作并没有减少锚定的这种效应。我们认为，锚定与调整过程可能为理解分量效应提供一个有用的框架，并讨论了这一观点的意义。
