We hypothesized that the activation of a counterfactual mind-set minimizes decision errors resulting from the failure of groups to seek disconfirming information to test an initial hypothesis. To test this hypothesis, we conducted two experiments examining the decision making processes of groups. The task for both experiments was modeled after the Space Shuttle Challenger disaster, and groups had to actively seek disconfirmatory information to make a correct decision. Prior to beginning the group decision making task, groups were exposed to one of two pre-task scenarios in which the salience of counterfactual thoughts was manipulated. In Experiment 1, groups in the counterfactual prime condition were significantly more likely to make the correct decision than groups in the non-counterfactual prime condition. In Experiment 2, we replicated the effect of counterfactual primes on decision accuracy and demonstrated that groups in the counterfactual prime condition were more likely to seek disconfirmatory information than groups in the non-counterfactual prime condition. We also conducted mediation analyses that clarify the decision making process. Implications for group decision making are discussed.