This study provides a framework to guide educators and researchers within departments of mathematics at institutions of higher education involved in reform efforts for undergraduate mainstream calculus. It does so by using motivational constructs from Self-Determination Theory to define and measure student-centeredness within both traditional and reformed calculus learning environments within a large-scale, quasi-experimental study. Motivational inventories assessing students' perceived satisfaction of basic psychological needs and self-determined motivation were analyzed together with demographic variables, course outcomes, and prior math knowledge within traditional and reformed conditions in both Calculus I and Calculus II courses. Results include 1) positive correlates among students' perceptions of satisfaction of basic psychological needs, intrinsic motivation, and achievement; 2) overall increased student perception of BPN-satisfaction in the reformed condition; and 3) directional variation in achievement and perception of BPN-satisfaction between conditions across subpopulations. The results demonstrate how student-centered calculus learning environments operate through motivational processes to improve academic outcomes and how learning environments may differentially affect demographic categories at institutions of higher education. Specifically, learning environments are not culturally or socially neutral and may, despite good intentions, be centered about privileged populations to the detriment of historically disenfranchised groups. [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.]