IMPLICIT THEORIES OF PERSONALITY AND ADOLESCENT AGGRESSION: A PROCESS MODEL AND AN INTERVENTION STRATEGY A DISSERTATION SUBMITTED TO THE SCHOOL OF EDUCATION AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY David Scott Yeager August, 2011 © 2011 by David Scott Yeager. All Rights Reserved. Re-distributed by Stanford University under license with the author. This work is licensed under a Creative Commons Attribution- Noncommercial 3.0 United States License. http://creativecommons.org/licenses/by-nc/3.0/us/ This dissertation is online at: http://purl.stanford.edu/hv373wm7082 ii I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Carol Dweck, Primary Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. William Damon, Co-Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Deborah Jane Stipek Approved for the Stanford University Committee on Graduate Studies. Patricia J. Gumport, Vice Provost Graduate Education This signature page was generated electronically upon submission of this dissertation in electronic format. An original signed hard copy of the signature page is on file in University Archives. iii iv ABSTRACT Why do some adolescents respond to peer conflict, exclusion or victimization vengefully, while others seek more positive solutions? Five studies in the dissertation investigated the role of implicit theories of personality in predicting 9th and 10th grade adolescents’ violent or vengeful responses to peer conflicts, and extended this theoretical framework to understand stress and academic engagement at the transition to high school. A greater belief that traits are fixed (an entity theory) predicted a stronger desire for revenge after a variety of recalled peer conflicts (Study 1) and after a hypothetical conflict that specifically involved bullying (Study 2). Study 3 experimentally induced a belief in the potential for change (an incremental theory), which resulted in a reduced desire to seek revenge. This effect was mediated by changes in “bad person” attributions about the perpetrators, feelings of shame and hatred, and the belief that vengeful ideation is an effective emotion-regulation strategy. Next, Study 4 examined whether an implicit theories intervention could change aggression. Adolescents are often resistant to interventions that reduce aggression in children. At the same time, they are developing stronger beliefs in the fixed nature of personal characteristics. Study 4’s intervention addressed these beliefs. A randomized field experiment with a diverse sample of high school students (N = 230) tested the impact of a 6-session intervention teaching an incremental theory (a belief in the potential for personal change). Compared to No-Treatment and Coping Skills control groups, the Incremental Theory group behaved significantly less aggressively and more prosocially one month post-intervention and exhibited fewer conduct problems three months post- intervention. Interestingly, the Incremental Theory and the Coping Skills interventions v also eliminated the association between peer victimization and depressive symptoms. Study 5 extended the theoretical model to include the effects of implicit theories on stress and academic achievement. The transition to high school is often accompanied by stress and declining grades. One explanation is that many students think that the social adversities they face—such as rejection, exclusion or victimization—are permanent. To test this hypothesis, Study 5 included a double-blind, randomized field experiment that taught students the idea that people have the capacity for change. This incremental theory intervention, which lasted two class periods at the beginning of the school year, reduced stress and improved Math and English grades over eight months, until the end of the school year. These findings highlight the importance of social processes in shaping academic performance during times of stress. Together, the findings from Studies 1-5 illuminate the social-cognitive processes underlying reactions to conflict and suggest potential avenues for reducing violent retaliation in adolescents. The dissertation concludes with an essay discussing how seemingly “small” psychological interventions with adolescents—that is, brief exercises that target students’ thoughts, feelings, and beliefs in and about school—can lead to large gains in student achievement and reduce aggression even months later. It emphasizes that such interventions have lasting effects because they target students’ subjective experiences in school, because they use persuasive yet stealthy methods for conveying psychological ideas, and because they tap into recursive processes present in educational environments. By understanding psychological interventions as powerful but context-dependent tools, researchers will be better equipped to take them to scale. vi ACKNOWLEDGEMENTS This research was supported in part by a Dissertation Support Grant from the Stanford University School of Education, a Research Training Grant from the Spencer Foundation, a Spencer Foundation Dissertation Fellowship, a grant from the Thrive Foundation for Youth, and grants from the American Psychological Association and the Society for Research on Child Development. Portions of the dissertation have appeared in Developmental Psychology and the Review of Educational Research. I am grateful to the following people for their assistance: Christel Anderson, Kate Belden, Yi-Wen Chua, Geoffrey Cohen, Yana Galperin, Hunter Gehlbach, Rebecca Johnson, Matthew Kloser, Joseph Lester, Allison Master, Jennifer McDonald, Adriana Miu, Kerry Morrissey, Alexandria Ordway, Patrinia Sandles, April Scott, Jason Singer, James Stigler, Brian Spitzer, Sander Thomaes, Uri Treisman, Hector Villalpando, Alan Weyland, Whitney Worthen, Matthew Williams, and Terry Yu. I would also like to thank Chris Bryan, William Damon, S. Shirley Feldman, Melanie Killen, Kristin Pauker, Ann Porteus, Deborah Stipek, and members of the Dweck-Walton lab for their helpful suggestions. I am grateful to Carol Dweck, Gregory Walton and Kali Trzesniewski, who provided comments on and made changes to previous drafts. Last, I would like to thank Maggie Morrissey Yeager, R.N. for her inspiration and support. vii TABLE OF CONTENTS Title Page i Copyright Notice Page ii Signature Page iii Abstract v Acknowledgements vi List of Tables ix List of Figures x Text Chapter 1: Introduction 1 Chapter 2: A Process Model 13 Study 1 14 Study 2 24 Study 3 27 Discussion of Studies 1-3 41 Chapter 3: An Intervention to Reduce Aggression 49 Study 4 52 Discussion of Study 4 75 Chapter 4: Extension to Stress and Academic Achievement 83 Study 5 84 Discussion of Study 5 87 Chapter 5: General Discussion of Studies 1-5 90 Chapter 6: Concluding Essay 97 viii References 115 Tables 137 Figures 147 ix LIST OF TABLES 1. Descriptive Statistics and Correlations for Study 1 Measures. 2. Descriptive Statistics and Correlations for Study 3 Measures. 3. Overview of Incremental Theory and Coping Skills Interventions in Study 4. 4. Aggressive and Prosocial Behavior in Study 4: Coefficients from Regressions Testing the Effects of the Incremental Theory Intervention on Behavioral Responses to a Peer Provocation One Month Post-Intervention. 5. Mean Levels of Behavioral Responses to a Peer Provocation in Study 4. 6. Reduction in Conduct Problems in Study 4: Coefficients from OLS Regressions Testing Effects of the Intervention and Victim Status on Number of Teacher Nominations Per Student Three Months Post-Intervention. 7. Mean Number of Teacher Nominations (from 0-2) Per Student for Reduced Conduct Problems by Victim Status and Experimental Condition in Study 4. 8. Depressive Symptoms in Study 4: Coefficients from OLS Regressions Testing Effects of Incremental and Coping Skills Interventions, and Victim Status, on Depressive Symptoms Two Weeks Post-Intervention. 9. Mean Number of Depressive Symptoms Reported (By Victimization Status and Experimental Condition) in Study 4. 10. Effectiveness of Random Assignment in Study 5: Non-Significant Preintervention Differences Between Conditions. x LIST OF FIGURES 1. Multiple partial mediation model in Study 1. 2. Preliminary multiple mediation model in Study 3. 3. Path model leading from an incremental theory to a reduced desire for vengeance in Study 3. 4. Design of Study 4. 5. Aggressive and prosocial behavior in Study 4. 6. Examples of (a) prosocial note and (b) non-prosocial note written by participants to accompany the hot sauce they allocated to a peer after their Cyberball exclusion in Study 4. 7. Reduction in conduct problems in Study 4. 8. Depressive symptoms in Study 4. 9. Effects of the Study 5 intervention on achievement and stress.