At Least Bias Is Bipartisan: A Meta-Analytic Comparison of Partisan Bias in Liberals and Conservatives

51 Pages Posted: 15 Apr 2017

See all articles by Peter H. Ditto

Peter H. Ditto

University of California, Irvine - School of Social Ecology

Brittany Liu

Kalamazoo College

Cory Clark

Florida State University; University of Pennsylvania

Sean P. Wojcik

University of California, Irvine

Eric Chen

University of California, Irvine - Department of Psychology and Social Behavior

Rebecca Grady

University of California, Irvine - Department of Psychology and Social Behavior

Joanne Zinger

University of California, Irvine - Department of Psychology and Social Behavior

Date Written: April 13, 2017

Abstract

One form of partisan bias is the tendency to more readily accept the validity of information that affirms one’s political beliefs than information that challenges those beliefs. Both liberals and conservatives accuse their political opponents of partisan bias, but is there empirical evidence that one side of the political aisle is indeed more biased than the other? To address this question, we meta-analyzed the results of 41 experimental studies of partisan bias involving over 12,000 participants who identified their political ideology. Based on previous literature, two hypotheses were tested: an asymmetry hypothesis (predicting greater partisan bias in conservatives than liberals) and a symmetry hypothesis (predicting equal levels of partisan bias in liberals and conservatives). Overall partisan bias was robust (r = .254) and there was strong support for the symmetry hypothesis: liberals (r = .248) and conservatives (r = .247) showed nearly identical levels of bias across studies. Several methodological features moderated the degree of overall bias, and the relative magnitude of bias in liberals and conservatives differed across political topics. Implications of the current findings for the ongoing ideological symmetry debate, and partisan bias’ role in scientific discourse and political conflict are discussed.

Keywords: Bias, Motivated Reasoning, Ideology, Politics, Meta-Analysis

Suggested Citation

Ditto, Peter H. and Liu, Brittany and Clark, Cory and Wojcik, Sean P. and Chen, Eric and Grady, Rebecca and Zinger, Joanne, At Least Bias Is Bipartisan: A Meta-Analytic Comparison of Partisan Bias in Liberals and Conservatives (April 13, 2017). Available at SSRN: https://ssrn.com/abstract=2952510 or http://dx.doi.org/10.2139/ssrn.2952510

Peter H. Ditto

University of California, Irvine - School of Social Ecology ( email )

4312 Social and Behavioral Sciences Gateway
Irvine, CA 92697
United States

Brittany Liu (Contact Author)

Kalamazoo College

1200 Academy Street
Kalamazoo, MI 49006
United States

Cory Clark

Florida State University ( email )

Tallahasse, FL 32306
United States

University of Pennsylvania ( email )

Philadelphia, PA 19104
United States

Sean P. Wojcik

University of California, Irvine ( email )

Campus Drive
Irvine, CA California 62697-3125
United States

Eric Chen

University of California, Irvine - Department of Psychology and Social Behavior ( email )

4201 Social & Behavioral Sciences Gateway
University of California, Irvine
Irvine, CA 92697-7085
United States

Rebecca Grady

University of California, Irvine - Department of Psychology and Social Behavior ( email )

4201 Social & Behavioral Sciences Gateway
University of California, Irvine
Irvine, CA 92697-7085
United States

Joanne Zinger

University of California, Irvine - Department of Psychology and Social Behavior ( email )

4201 Social & Behavioral Sciences Gateway
University of California, Irvine
Irvine, CA 92697-7085
United States

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