The Prevalence and Effects of Scientific Agreement and Disagreement in Media by Sedona Chinn A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Communication) in The University of Michigan 2020 Doctoral Committee: Associate Professor P. Sol Hart, Chair Professor Stuart Soroka Professor Nicholas Valentino Professor Jan Van den Bulck Sedona Chinn [email protected] ORCID iD: 0000-0002-6135-6743 DEDICATION This dissertation is dedicated to the memory of my grandma, Pamela Boult. Thank you for your unending confidence in my every ambition and unconditional love. ii ACKNOWLEDGEMENTS I am grateful for the support of the Dow Sustainability Fellows Program, which provided much appreciated spaces for creative research and interdisciplinary connections. In particular, I would like to thank the 2017 cohort of doctoral fellows for their support, feedback, and friendship. I would also like to thank the Department of Communication and Media, the Center for Political Studies at the Institute for Social Research, and Rackham Graduate School for supporting this work. I truly appreciate the guidance and support of excellent advisors throughout this endeavor. Thanks to my advisors, Sol Hart and Stuart Soroka, for all of their long hours of teaching, critique, and encouragement. Know that your mentorship has shaped both how I think and has served as a model for how I Would like to act going forward in my professional life. Thanks to Nick Valentino and Jan Van den Bulck for your invaluable comments, insistence that I simplify experimental designs, and for your confidence in my Work. I truly appreciate all the ways in which your support and guidance have both improved the work presented here and my thinking as a researcher. I would also like to thank my collaborators, professors, and members of the Political Communication Working Group who have all provided feedback on the thinking that has informed the work presented here. Thank you for your time, energy, and expertise; this work is richer for it. Finally, I am anxious to thank all the friends and family who have encouraged and iii commiserated with me these past five years. Travis, I am so glad you followed me to Michigan. You bring so much care, joy, and love to my life. To my family, a heartfelt thank you for all your enthusiasm, support, and pictures of animals. I feel so lucky to have been part of the graduate student community while here at Michigan. In particular, thank you to my office mates Who have been there since day one, Dan Hiaeshutter-Rice and Dia Das, for your advice, support, and for moving your chairs every time I needed more tea. iv TABLE OF CONTENTS DEDICATION .................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................... iii LIST OF TABLES ............................................................................................................. vi LIST OF FIGURES ......................................................................................................... viii LIST OF APPENDICES .................................................................................................... ix ABSTRACT ........................................................................................................................ x CHAPTER I. Why Study Scientific Disagreement? .......................................................................... 1 II. Scientific Agreement, Disagreement, and Denial in Climate Change News, 1988- 2018 ................................................................................................................................... 17 III. Can’t You All Just Get Along? Effects of Scientific Disagreement and Incivility on Attention to and Trust in Science ............................................................................. 44 IV. Effects of Consensus Messages and Political Ideology on Climate Change Attitudes: Inconsistent Findings and the Effect of a Pretest ....................................... 81 V. Conclusions ............................................................................................................... 124 APPENDICES ................................................................................................................ 145 BILIOGRAPHY ............................................................................................................. 189 v LIST OF TABLES TABLE I.1: Summary of Dissertation Studies ............................................................................... 16 II.1: Data ........................................................................................................................... 27 III.1: Mean Differences in Outcomes by Experimental Condition ................................... 64 III.2: Mean Differences in Outcomes by Article Topic .................................................... 65 IV.1: Study Design and Findings of Prior Experimental Research Examining Moderating Influence on the Effects of Consensus Messages with U.S. Samples .............................. 89 IV.2: Outcomes by Experimental Condition ................................................................. 102 IV.3: Main and Interactive Effects of Experimental Condition and Political Ideology on Mediator, Outcomes (1/2) ............................................................................................... 106 IV.4: Main and Interactive Effects of Experimental Condition and Political Ideology on Mediator, Outcomes (2/2) ............................................................................................... 107 IV.5: Main and Interactive Effects of Agreement Estimate and Political Ideology on Outcomes (1/2) ................................................................................................................ 111 IV.6: Main and Interactive Effects of Agreement Estimate and Political Ideology on Outcomes (2/2) ................................................................................................................ 112 IV.7: Logistic Regressions Predicting Salience and Demand Characteristics ................ 117 A.1: Coding Reference Texts .......................................................................................... 149 A.2: Reference Texts by NeWspaper .............................................................................. 149 A.3: Percent of Climate Change Articles Containing Mentions, by Year ...................... 153 B.1: Main Effects of Deference to Scientific Authority and Conflict Aversion on Outcomes (1/3) ................................................................................................................ 171 vi B.2: Main Effects of Deference to Scientific Authority and Conflict Aversion on Outcomes (2/3) ................................................................................................................ 172 B.3: Main Effects of Deference to Scientific Authority and Conflict Aversion on Outcomes (3/3) ................................................................................................................ 173 B.4: Interactive Effects of Manipulation and Deference to Scientific Authority on Outcomes (1/3) ................................................................................................................ 174 B.5: Interactive Effects of Manipulation and Deference to Scientific Authority on Outcomes (2/3) ................................................................................................................ 175 B.6: Interactive Effects of Manipulation and Deference to Scientific Authority on Outcomes (3/3) ................................................................................................................ 176 B.7: Interactive Effects of Manipulation and Conflict Aversion on Outcomes (1/3) ..... 177 B.8: Interactive Effects of Manipulation and Conflict Aversion on Outcomes (2/3) ..... 178 B.9: Interactive Effects of Manipulation and Conflict Aversion on Outcomes (3/3) ..... 179 C.1: Dictionaries for Open-Text Responses ................................................................... 188 vii LIST OF FIGURES FIGURE II.1: Correlations betWeen Dictionary and Wordscores Results ....................................... 33 II.2: Substantive Levels of Agreement, Disagreement, and Denial in Climate Change Articles .............................................................................................................................. 36 IV.1: Study Procedure ....................................................................................................... 97 IV.2: Interactive Effects of Condition and Political Ideology on Agreement Estimates 109 IV.3: Interactive Effects of Agreement Estimate and Political Ideology on Worry and Concern about Climate Change ...................................................................................... 113 A.1: Paragraph-level Dictionary Results ........................................................................ 150 A.2: Paragraph-level Wordscores Results ...................................................................... 151 B.1: Interactive Effect of Condition and Topic on Trust in Commenting Scientist ....... 169 B.2: Visualization of Significant Interactive Effects of Deference to Scientific Authority and Experimental Condition ..........................................................................................