This proposal offers new insights into the relationship between task characteristics and negotiation behavior. Negotiations frequently result in suboptimal, inefficient agreements; negotiators could have reach other settlements that all would have preferred. Unlike prior research, the focus in this proposal is on the impact of perceptual and judgmental factors on the process and outcome of negotiations. The research investigates how the structure of negotiation tasks is determined by negotiator's cognitive characteristics. Relatively slight differences in how negotiators evaluate the desirability of potential settlements may result in distinctly different feasible settlement spaces and efficient frontiers. Research will be conducted to asses the behavioral implications of these different task structures. The research will make use of both empirical and simulation studies, combining elements of psychological, decision theoretic, and game theoretic approaches to the study of negotiation. The objective of the proposal is to lead to greater understanding of the structure of negotiation tasks and their impacts on negotiation processes and outcomes. The results of this research will help guide the development of computer-based negotiation support systems.