This chapter demonstrates the mutual relevance of behavioural science and technology design. Ideally, this demonstration will encourage other social psychologists to consider how author's knowledge about information processing, interpersonal communication, and group dynamics might inform the design of information systems and how those basic psychological and social psychological processes might be affected by specific technological interventions. Unlike videoconferencing, which promises to transcend the physical barriers between people, group decision support systems promise to help people clarify their ideas and choose an optimal approach to solving a problem. Initiating a collaborative intellectual project usually requires that the project participants overcome a formidable set of intellectual, interpersonal and political problems. Behavioural research on individual and group decision making has demonstrated that both cognitive biases and social constraints can prevent people from behaving in ways that theories of rational choice would predict.