Skills associated with collaborative problem solving (CPS), especially in STEM-related disciplines, are increasingly regarded as essential for success in work and life. In the last decade, simulation-based games have emerged as rich environments for the situated learning of such skills, and are instrumental in the study of CPS because they provide rich data for detailed analysis of discourse and social interaction. One type of social interaction, "Academically Productive Talk" (APT), has been found to support collaborative activity, encourage knowledge integration, and promote academic gains for individuals. However, little is known about the relationship between APT and how groups develop complex STEM thinking. Additionally, despite evidence that students' attitudes affect social interaction during collaborative activity, little is known about how collaborative social interaction may affect students' attitudes. The primary goals of this study were to examine CPS discourse in order to: 1) investigate the relationship between the qualities and characteristics of how groups talk and what groups talk about; and 2) understand whether how groups talk effects a change in students' attitudes. To meet these aims, this study paired conversation analysis with an innovative analytical methodology, Epistemic Network Analysis (ENA), to study groups' endogenous use of APT and its relationship with substantive qualities of group discourse in the virtual simulation of professional practice in engineering, "Nephrotex." This study presents empirical evidence that, (1) specific APT-style contributions were effective for introducing critical, domain-specific evidence into student discourse, and (2) more use of APT in group discourse resulted in better knowledge integration of human-centered design constraints (i.e., their client's needs; their consultants' interests) and data analysis. These findings varied in terms of how, when, and what type of, integration occurred. No evidence was found to suggest that students' participation in groups that engage in more APT affects a positive change in their attitudes. A better understanding of the effects of APT in a simulation-based game environment can be used to inform the ongoing research and development of technologies capable of shaping and observing discourse as it occurs in virtual environments for learning, and that support students' development of CPS skills. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]