Proceedings of the Annual Meeting of the Cognitive Science Society

A longstanding conjecture that has been difficult to test holds that social interactions amplify the effects of people’s biases.We tested this conjecture in a perceptual decision-making paradigm. First, we formalized the algorithmic structure of de-cision making in networked crowds when individuals’ perceptions are biased by their utilities. Our analysis predicts thateven weak cognitive biases can be amplified by social interaction. We tested this prediction in a large networked behav-ioral experiment. Using a monetary incentive structure to induce a bias known as motivated perception, we manipulatedthe presence of a weak cognitive bias in social and asocial populations. Social decision making increased participants’perceptual accuracy relative to an asocial baseline. However, social decision making also led to significantly amplifiedrates of motivated perception, confirming the prediction that shared cognitive biases can be amplified in social networks.