Humans are cognitive misers because their basic tendency is to default to processing mechanisms of low computational expense. Although there are good evolutionary reasons why humans would be cognitive misers, the miserly tendency means that humans will display bounded rationality and not perfect rationality. Additionally, genetic goals can dissociate from the goal of personal utility maximization. These facts, along with some important concepts from dual-process cognitive theory, can help to resolve the Great Rationality Debate in cognitive science—the debate about how much rationality to ascribe to people.