We expand the rational choice theory of crime, as applied to cartels, with three psychological factors—personal norms, social norms and social ties—and knowledge of competition law. Through a survey of Dutch businesses, we find that adding psychological factors substantially increases the explanatory power of the model: All predict attitudes toward future cartel behavior, with personal norms as the strongest (negative) predictor. Better knowledge of competition law relates to stronger deterrence and norms against collusion. We conclude that psychological factors and knowledge of the law are likely necessary to understand and prevent potential cartel behavior
