Identification breeds equity: the regulation effect of group decision-making on beauty premium

Beauty premium permeates decision-making behaviours in various fields such as politics, economics, and management, and has a certain impact on social equity. Controlling the impact of this bias can improve the fairness and efficiency of decision-making. Studies have shown that group decision-making is more rational and objective than individual decision-making. This study attempts to explore ways and mechanisms of weakening the beauty premium effect from the perspective of fostering group decision-making environment and utilizing group normative influence. We modified the trust game by adding an evaluation stage at the end of each trial. The online and off-line experiments were implemented, with participants making decisions in individual or group decision-making environments. Results showed that group decision-making could significantly and broadly suppress beauty premium. For exploring the underlying mechanism, this study employed a genetic-algorithm-based modelling method to analyse participants’ trial-by-trial dynamic adjustment in group environment. Besides, the drift diffusion model was used to further decode the cognitive processing differences between two environments. Based on the findings, a regulation mechanism of group decision-making on beauty premium was proposed. A sense of social identification, the membership of a group, motivated individuals to conform to group norms, leading them to dynamically adjust their decisions trial by trial. Through this process, social normative influence crowded out their intrinsic preferences for facial attractiveness, resulting in a reduction of beauty premium. Together, these results underscore the intricate interplay between social norms and cognitive mechanisms in shaping group decision-making behaviours. The method of creating group decision-making environment to weaken the beauty premium is proposed in this study, which has certain enlightening significance for the research of beauty premium and management practice.