The function of recommender systems, after all, is to help people make better choices. So you might expect work in this area to be based on a clear understanding of how people make choices and how these processes can be supported by recommender systems. But in fact we see only occasional attention to the psychology of choice and decision making in this area. One reason is that the most relevant knowledge is scattered around a number of areas of psychological research, including judgment and decision making, behavioral economics, social influence, habitual behavior, and learning. This talk will give a sample of key concepts and results from these areas, showing how they suggest new research issues and design ideas for those who work on recommender systems.