Avoiding costly mistakes in groups: The evolution of error management in collective decision making

Individuals continuously have to balance the error costs of alternative decisions. A wealth of research has studied how single individuals navigate this, showing that individuals develop response biases to avoid the more costly error. We, however, know little about the dynamics in groups facing asymmetrical error costs and when social influence amplifies either safe or risky behavior. Here, we investigate this by modeling the decision process and information flow with a drift–diffusion model extended to the social domain. In the model individuals first gather independent personal information; they then enter a social phase in which they can either decide early based on personal information, or wait for additional social information. We combined the model with an evolutionary algorithm to derive adaptive behavior. We find that under asymmetric costs, individuals in large cooperative groups do not develop response biases because such biases amplify at the collective level, triggering false information cascades. Selfish individuals, however, undermine the group’s performance for their own benefit by developing higher response biases and waiting for more information. Our results have implications for our understanding of the social dynamics in groups facing asymmetrical errors costs, such as animal groups evading predation or police officers holding a suspect at gunpoint.Author summary: Decision makers must continuously balance the error costs of alternative decisions, especially in critical situations where the choices are associated with highly asymmetric error costs—such as pedestrian groups crossing the street, or animal groups evading predation. Acting independently, individuals can develop response biases to avoid more costly errors (e.g., when in doubt, escape from a potential predator). In groups, early decisions can spread via social influence and promote safe or risky behavior. Yet, little is known about how individuals in groups avoid the more costly error. We investigate this by modeling the decision process of individuals in groups using an evidence accumulation model. We derive the optimal strategies under different error costs, group sizes and pay off functions. We find that cooperative individuals in large groups do not evolve response biases because such biases rapidly amplify in groups. However, selfish individuals evolve high response biases and wait longer for the information of others, thereby undermining the group’s performance for own benefits. Our results shed light on the decision problems individuals in groups face in the presence of asymmetric error costs and how they could resolve them.