Rolf Degen summarizing... Groups are as susceptible to "choice blindness" as individuals, failing to notice that they had been given false feedback about their previous choices, making the case for the planted ones

Pärnamets, Philip, Jorina von Zimmermann, Ramsey Raafat, Gabriel Vogel, Lars Hall, Nick Chater, and Petter Johansson. 2020. “Choice Blindness and Choice-induced Preference Change in Groups.” PsyArXiv. December 22. doi:10.31234/osf.io/zut93

Rolf Degen's take: https://twitter.com/DegenRolf/status/1341427051413327872

Abstract: Contrary to common belief, our preferences do not only shape our decisions but are also shaped by what decisions we make. This effect, known as choice-induced preference change, has been extensively studied in individuals. Here we document choice-induced preference change in groups. We do so by using the choice-blindness paradigm, a method by which participants are given false feedback about their past choices. Participants are given a second round of choices following the choice blindness manipulation´measuring preference change resulting from accepting the manipulation. In Experiment 1 (N=83), we introduce a roommate selection task used in this paper and use it to replicate choice-induced preference change using choice-blindness in individuals. In Experiment 2 (N=160), dyad members made mutual choices in the roommate selection task and then receive either veridical or false feedback about what choice they made. The majority of the false feedback trials were accepted by the dyads as their own choices, thereby demonstrating choice blindness in dyads for the first time. Dyads exhibited choice-induced preference change and were more likely to choose the originally rejected option on trials where they accepted the manipulation compared to control trials. In Experiment 3 (N=80), we show that the preference effect induced by the choice blindness manipulation at the group level does not generalize back to follow up choices made by individual participants when removed from the group. In all studies, response time analyses further support our conclusions. Choice-induced preference change exists for both individuals and groups, but the level at which the choice was made constrains the influence of that choice on later preferences.