Izakson Liz, Yoo Minhee, Hakim Adam, Krajbich Ian, Webb Ryan, Levy Dino J
Sagol School of Neuroscience, Tel Aviv University, P.O. Box 39040, Tel Aviv 6997801, Israel.
Department of Psychology, The Ohio State University, 1835 Neil Avenue, Columbus, OH 43210, USA.
PNAS Nexus. 2024 Jun 24;3(7):pgae232. doi: 10.1093/pnasnexus/pgae232. eCollection 2024 Jul.
When people make choices, the items they consider are often embedded in a context (of other items). How this context affects the valuation of the specific item is an important question. High-value context might make items appear less attractive because of contrast-the tendency to normalize perception of an object relative to its background-or more attractive because of assimilation-the tendency to group objects together. Alternatively, a high-value context might increase prior expectations about the item's value. Here, we investigated these possibilities. We examined how unavailable context items affect choices between two target items, as well as the willingness-to-pay for single targets. Participants viewed sets of three items for several seconds before the target(s) were highlighted. In both tasks, we found a significant assimilation-like effect where participants were more likely to choose or place a higher value on a target when it was surrounded by higher-value context. However, these context effects were only significant for participants' fastest choices. Using variants of a drift-diffusion model, we established that the unavailable context shifted participants' prior expectations towards the average values of the sets but had an inconclusive effect on their evaluations of the targets during the decision (i.e. drift rates). In summary, we find that people use context to inform their initial valuations. This can improve efficiency by allowing people to get a head start on their decision. However, it also means that the valuation of an item can change depending on the context.
当人们做出选择时，他们所考虑的选项通常嵌入在（其他选项的）情境之中。这种情境如何影响特定选项的估值是一个重要问题。高价值情境可能会因对比（即相对于背景使物体感知趋于正常化的倾向）而使选项显得吸引力降低，或者因同化（即将物体归为一组的倾向）而使其更具吸引力。或者，高价值情境可能会提高对该选项价值的先前期望。在此，我们对这些可能性进行了研究。我们考察了不可用的情境选项如何影响两个目标选项之间的选择，以及对单个目标的支付意愿。在突出显示目标选项之前，参与者会先浏览一组三个选项几秒钟。在这两项任务中，我们都发现了一种显著的类似同化的效应，即当目标选项被更高价值的情境所包围时，参与者更有可能选择该目标或对其赋予更高价值。然而，这些情境效应仅在参与者最快做出的选择中显著。使用漂移扩散模型的变体，我们确定不可用的情境使参与者的先前期望向选项集的平均值偏移，但对他们在决策过程中对目标的评估（即漂移率）影响不明确。总之，我们发现人们利用情境来形成他们的初始估值。这可以通过让人们在决策时抢占先机来提高效率。然而，这也意味着一个选项的估值可能会因情境而异。
