Focus groups are widely used to aggregate consumer preferences in many business and marketing arenas. Social psychological research suggests that this practice is questionable, because group members frequently fail to pool efficiently private information. Research in economics suggests that markets might be able to solve this problem by allowing traders to disseminate and aggregate private information. These two lines of research have been conducted separately according to strict disciplinary boundaries. Researchers in economics have been concerned with identifying the conditions of competitive market equilibrium, whereas social psychologists have been trying to uncover the rules and mechanisms underlying cooperative group decisions. The authors bridge these two disciplinary approaches with the aim of better understanding the similarities and differences of cooperative group and competitive market behaviour. The authors designed three experimental studies to answer the following questions: Can the inefficient pooling in groups be mitigated by the introduction of competitive market mechanisms? How many traders are needed to pool the information efficiently? How resistant are groups and markets to explicit manipulation attempts? The findings might have important implications for applied research, allowing companies to switch from focus groups to alternative information-pooling mechanisms that are less susceptible to biased responses.