This study explored the predictability of motivation by analyzing effects of five elementary principal traits on teacher perceptions of competence, relatedness, and autonomy. My focus on this topic evolved from mounting teacher shortages across the United States. Through quantitative methods, I developed a factorial survey experiment. Using vignette methodology, I manipulated primary independent variables of principal gender, years of elementary teaching experience, and behaviors linked to basic psychological needs. I delivered traits hypothetically through two polar styles of leadership--transactional and collaborative. I examined motivation through Deci and Ryan's (1985) self-determination theory, Ryan and Deci's (2018) basic psychological needs theory, and Bandura's (1997) self-efficacy theory. The sample included 220 teachers from 26 schools across nine districts in rural Northeast Georgia. I used multiple linear regression to examine predictability of variables and one-way ANOVA to compare ratings among demographic groups. Results showed principal gender had no significant effect on teacher perceptions of competence and autonomy. Principal years of elementary teaching experience showed significant predictability of perceptions. Principal behaviors linked to competence, relatedness, and autonomy showed significant predictability of teacher perceptions. Autonomy-supportive traits filtered through collaborative leadership showed the largest effect size of all independent variables. There were no significant differences in teacher ratings based on respondent demographics. [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.]