Many organizations today rely heavily on their knowledge assets and engage in collaboration to leverage those assets.Managers and decision makers increasingly are forced to forge strategy, negotiate, and make decisions based on a vast amount of complex and dynamic information and expertise. Furthermore, the implementation of planned courses of action increasingly requires consensus and commitment among diverse stakeholders. In sum, all facets of the problem solving process including problem identification, idea generation, convergence, and implementation, as well as harmonization among stakeholders, increases the demand for smart and effective group support. To design such support we believe the research on Group Decision and Negotiation would benefit from an increased understanding of the cognitive load and the cognitive processes that go on in the minds of decision makers and negotiators. Historically, the cognitive activities included in collaboration research have tended to be embedded and theorized about in the context of larger input-process-output (IPO)models. Such models often focus more on the interactions between individual team members than the cognitive mechanisms of the individuals themselves. Some of the more seminal IPO research models stress the social or organizational context of the work including individual and task characteristics (e.g., Nunamaker et al. 1991; Rao and Jarvenpaa 1991; Zigurs and Buckland 1998) or facilitation techniques and approaches (e.g., Miranda and Bostrom 1999; Wheeler and Valacich 1996). Grand models, however useful, tend to offer limited insight into the cognitive mechanisms involved in collaboration because they are simultaneously tackling somany dimensions of collaboration such as group characteristics, technological features, task-related characteristics, and the organizational environment (e.g., DeSanctis and Poole 1994; Gopal et al. 1993; Markus and Robey 1988). More recent research has focused on patterns of collaboration (Vreede et al. 2009) and design patterns for effective collaboration such as thinkLets (Vreede et al. 2006). These patterns are based on best practices and offer insight in the mechanisms that make collaborative activities more or less effective. However, they are based on practical know how, not on a more detailed theoretical understanding of why these techniques and methods work. To understand this, we need to understand the conditions for synergy; effective aggregation of individual contributions into a group result. Part of this puzzle, we believe lies in understanding the cognitive perspective on group decision and negotiation activities. In this special issue, we seek to advance the same goals of making organizations and teams more efficient and more productive but do so by focusing first and foremost on the individual cognitive activities involved in collaboration activity. Understanding cognitive load and cognitive activities involved in collaboration offers various design principles to efficiently and effectively use cognitive capacity. Cognitive research has mainly focused on individual tasks. In order to design interventions that improve cognitive efficiency in collaborative tasks we seek to understand individual cognition in the context of collaborative tasks. This special issue therefore intends to spark a rather newperspective, or at least an increased emphasis, in research on groupwork and collaboration; the cognitive perspective.We will present you five interesting papers that each discusses one or more cognitive aspects of group decision and negotiation. The papers show that the cognitive perspective can help us to identify new and promising design directions for collaboration, decision, and negotiation support. Further, the papers demonstrate that this perspective presents methodological challenges that will need to be addressed as researchers pursue new and innovative research approaches. In this introduction we will first summarize the papers in the special issue. Next we will discuss the key research challenges and potential of the cognitive perspective. Based on this we will sketch a research agenda to further explore this line of thinking and inquiry.