a decision-making error in which information about the rate of occurrence of some trait in a population (the base-rate information) is ignored or not given appropriate weight. For example, given a choice of the two categories, people might categorize a man as an engineer, rather than a lawyer, if they heard that he enjoyed physics at school—even if they knew that he was drawn from a population consisting of 90% lawyers and 10% engineers. See representativeness heuristic.