This chapter applies the concept of ecological rationality to the context of groups and teams. A summary of agent-based computer simulations is provided in which groups integrated member opinions on the basis of a majority rule. The simulations demonstrate that the performance of a group may be strongly affected by the decision strategies used by its individual members, and specify how this effect is moderated by environmental features. Group performance strongly depended on the distribution of cue validities. When validities were linearly distributed, groups using a compensatory strategy achieved the highest accuracy. Conversely, when cue validities followed a J-shaped distribution, groups using a simple noncompensatory heuristic performed best. While these effects were robust across different quantities of shared information, the validity of shared information exerted stronger effects on group performance. Consequences for prescriptive theories of group decision making are discussed.