This dissertation reports on research conducted to better understand how college student writers learned to work against their own biases as they researched and wrote arguments. I conducted a review of former studies to design a curriculum that would help students avoid bias and increase their ability to write arguments tailored to specific readers in ways that accomplish their goals. This review also informed the kinds of data to be collected and analyzed in order to accomplish the research goal, which was to understand whether and how each of seven students enrolled in a composition course reduced their biases. I collected written arguments, drawings, and classroom discussions of these students and administered surveys, and participants underwent interviews, to study the effect of the curriculum and instruction. This dissertation reports findings on how each student writer's bias shifted differently over the course of the semester, and the role identity played in bias shifting. Results include the observation that the curriculum was effective at reducing bias in student arguments, though to various degrees and for differing reasons, based on a variety of contextual factors. Unlike experimental studies of bias, this study provides rich details about seven individual students' experiences in a course designed to reduce bias. Implications include researched evidence upon which teachers, administrators, curriculum designers, and policymakers may base future decisions upon regarding the teaching of argumentation. [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.]