We develop and test a theoretical framework for understanding how cognitive and affective processes (cognitive and affective integration) influence the way in which disagreements (task and process) among group members affect their performance (individual and group level performance). We use this framework to explain how and why diversity may be either beneficial or detrimental to group process and outcomes. Specifically, we examine how group faultlines may hinder members' ability to create a shared understanding of the problem (cognitive integration) and a shared motivation to synthesize their knowledge (affective integration). If this happens, then groups will fail to share and process information, which will hinder group performance and satisfaction. We test this theory on 321MBA students in 88 five to six person teams from a prestigious East Coast university.