Increased attention to how individuals and groups collect and evaluate information in changing environmental and sociopolitical situations can greatly improve our understanding of the evolution of cultural rules. Ethnographic evidence suggests that when people first confront an unfamiliar environmental or sociopolitical problem, they conduct a variety of low-cost experiments designed to gather information about the probable consequences of alternative responses. After assessing many such experiments, humans develop cultural rules that guide decision making in similar situations. These folk rules of thumb concerning appropriate behavior in familiar, recurring situations commonly prescribe low-cost information collection as an integral part of the decision-making process.