The proposed research has two basic objectives: (1) to learn more about how people make complex decisions, and (2) to develop and test computer-based decision support systems that are intended to improve the quality of such decisions. The research considers two factors that make decisions difficult. The first is uncertainty about what the consequences of each decision alternative will be, especially in cases where there is the risk of a substantial loss. The second is the presence of multiple objectives that conflict with one another, thus forcing decision makers to make tradeoffs among objectives. Two types of research activities are proposed. It involves laboratory and field studies designed to learn more about intuitive decision making strategies and the potential biases and other shortcomings of these strategies. Such research is important because it allows the anticipation potential biases or errors that may result from intuitive decision making processes. Second, computer software will be designed to improve the quality of decisions involving risk and conflicting objectives. Such computer-based decision support systems are important because they may significantly improve decision making processes in business, government, medicine, and engineering. They may even be helpful to consumers making complex decisions involving substantial financial or health outcomes.