Given the role of scientific argumentation in science education (Osborne, 2010), argumentative discourse styles provide a means to understand the various dialogue types with distinct rhetorical features that individuals adopt during argumentative activities. Previous research indicates that different argumentative discourse styles lead to varied positive and negative learning outcomes but were limited to experimental conditions. The purpose of the study was to explore what psychological factors (i.e., ability mindsets and 3 by 2 achievement goal orientations) as antecedents may contribute to students' argumentative discourse styles in science learning. Undergraduate students in science courses (N = 374) were surveyed to investigate direct and indirect relationships among their ability mindsets, 3 by 2 achievement goal orientations, and argumentative discourse styles in the science context. Findings from path analysis supported my classification of adaptive and maladaptive motivational and behavioral patterns and their connections to students' scientific ability mindsets, supporting the social-cognitive approach to motivation and personality model in the context of scientific argumentation. The study also validated the Peer Argumentive Discourse Style (PADS) in an English context and provided validation evidence for the 3 by 2 achievement goal orientation model in science learning. Implications for theory, practice, limitations, and future research are discussed. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]