Procedure
Participants assigned to the individual condition were provided with asocial information only in the form of their payoff for each decision round. In the two group conditions, participants were provided with both asocial information (decision payoff) and implicit social information. They inferred the latter from whether their individual choice was a minority opinion or aligned with the majority in each round, based on whether it mismatched or matched the group’s choice, respectively.All participants performed the experiment individually on their own computer terminal. In the individual condition, participants read the following instructions:
You will play a game of 100 rounds. In each round, you will be asked to choose one of two money machines. When you click on the machine, you will win or lose points. Your payoff at each round will be determined based on your choice and the probability of winning, which may change during the game. At the end of each round, you will see your payoff and the forgone payoff had you chosen the other machine. If you have any questions, please ask the experimenter. Please press start when you are ready.In the two group conditions, we deviate from the design of Lejarraga et al. (The instructions of the low conformity (LoConf) group condition were as follows:
You are part of a group of three players. You will play a game of 100 rounds. In each round, you will be asked to choose one of two money machines. When you click on the machine, you will win or lose points. Your payoff at each round will be determined according to your choice and the other players’ choices and to the probability of winning, which may be changed during the game. At the end of each round, you will see your payoff and the forgone payoff had the group chosen the other machine. If you have any questions, please ask the experimenter. Please press start when you are ready.The LoConf game has multiple Nash equilibria.In the high-conformity (HiConf) group condition, the procedure and instructions are the same as for the low-conformity (LoConf) group condition, with one difference: the payoff for each player is also affected by whether their individual choice aligns with the majority choice. In the case of a minority opinion, two points are deducted from the dissenting participant’s payoff, whereas each majority participant receives an additional point.When players cannot know with certainty which button maximizes their payoff, behavior in the present game is likely to depend on the way the players have adapted to past experiences. As noted above, the common assumptions in cultural evolution predict that conformity facilitates efficiency in a stable environment but may impair maximization in a dynamic environment. The following experiment is designed to evaluate the robustness of these predictions.Beyond its direct effect on players’ potential payoff, this novel treatment of conformity is intended to draw their attention to social information—specifically, whether the player’s opinion aligns with or differs from the majority. We therefore test the efficacy of this treatment at both the group and individual levels. At the group level, we estimate the prevalence of minority opinions within group decisions across the two group conditions. At the individual level, we assess whether the treatment increases players’ propensity to change their choices after finding themselves in a minority opinion, controlling for the monetary payoff. These analyses are reported in the “Results.”Cultural-evolutionary theory identifies several important considerations in designing experimental studies of conformity. First, not all forms of social learning constitute conformity. Social learning is defined as the acquisition of behavior through observation or interaction with other individuals (Aplin et al., The design of this study addresses these considerations. First, given that conformity leads to the homogenization of group behavior, we evaluate the efficacy of our conformity treatment by comparing the proportion of minority decisions [i.e., 1 – The two group conditions provide the comparisons required to test our main hypotheses in both the stable and variable stages of the game. In order to address the alternative claim made by Lejarraga et al. (The instructions in all conditions informed the participants that a change in the probability of gaining the positive payoff is possible, without indicating how prevalent the change would be, nor when in the sequence of trials it would occur. Our goal was that participants would not assume a static environment. In all three conditions, payoffs in points were converted to monetary sums. In the group conditions, all three members received full compensation; thus group members had the same economic incentives as individual participants. The mean total individual compensation was equivalent to US $9.70.