The Determinants and Consequences of Accurate Beliefs About Childhood Vaccinations

• Published date: 01 May 2019
• DOI: 10.1177/1532673X17745342
• Date: 01 May 2019
• Subject Matter: Articles

745342APRXXX10.1177/1532673X17745342American Politics ResearchJoslyn and Sylvester
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American Politics Research
2019, Vol. 47(3) 628 –649
The Determinants
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Accurate Beliefs About
Childhood Vaccinations
Mark R. Joslyn1 and Steven M. Sylvester2
Abstract
In this article, we examine the individual predictors that are responsible
for accurate beliefs about the link between vaccinations and autism. We
then show how these beliefs affect policy preferences about vaccines.
We derive two hypotheses from motivated reasoning theory and test
these on national survey data from Gallup and CBS News. Republicans
were less likely to report accurate beliefs than Democrats. In addition,
educational attainment modified the impact of party identification. The
gap between Republicans and Democrats in likelihood of reporting
accurate beliefs was largest among the most educated portion of the
public. Finally, we show that accurate beliefs about vaccines, independent
of statistical controls, are important predictors of policy attitudes about
unvaccinated children attending public school and parental choice about
the decision to vaccinate. We discuss the theoretical and practical
significance of these findings.
Keywords
health policy, vaccines, public attitudes, motivated reasoning
1University of Kansas, Lawrence, KS, USA
2Utah Valley University, Orem, UT, USA
Corresponding Author:
Steven Sylvester, Utah Valley University, 800 West University Parkway, CB 203A, Orem,
UT 84057, USA.
Email: ssylvester@uvu.edu

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Joslyn and Sylvester
629
In 1998, Andrew Wakefield published research that reported a link between
the Measles–Mumps–Rubella (MMR) shot and autism. The study was subse-
quently retracted by the medical journal that published it, and Wakefield’s
medical license was revoked. Yet, a persistent misunderstanding about vac-
cines and autism remains.
Debate about vaccinations and their alleged side effects appears to inten-
sify during significant outbreaks. In 2014, the Centers for Disease Control
and Prevention (CDC) announced a measles outbreak connected to
Disneyland resorts in California. Many of the patients were unvaccinated
children. Similarly, in May of 2017, a notable outbreak emerged among
unvaccinated Somali Americans in Minnesota. Both cases raised legitimate
concerns about the causes of plummeting immunization rates and the appar-
ent absence of public knowledge about vaccines.
The infant and childhood immunizations program is one of the most effec-
tive health interventions of the 20th century, and is frequently cited as a sig-
nificant factor for the increase in life expectancy (Gellin, Maibach, &
Marcuse, 2000). While coverage of most childhood vaccines is extensive,
studies show increasing doubt about vaccines among parents. For example,
in a national study that examined anxiety about vaccines, 50% of parents
indicated they had “concerns about vaccines” compared with 19% only 9
years before (Gowda & Dempsey, 2013). Similarly, a notable proportion of
Americans remain skeptical about vaccines. Fully 12% of 2016 American
National Election respondents said that the risks of vaccinations outweigh the
benefits, and 17% believed the risks and benefits were equal (Joslyn, 2017).
Yet scientific evidence overwhelmingly shows the benefits of vaccines far
outweigh the risks (C. Edwards, 2001), and vaccines have no relationship to
autism (CDC, 2017).
In this article, we examine the individual-level measures that increase the
likelihood of accurate beliefs about vaccines and autism. We argue that
knowledge about vaccines, like for other contested issues in politics, is pri-
marily rooted in directionally motivated reasoning, which leads people to
seek information that reinforces their partisan beliefs and counterargue con-
tradictory information (Lodge & Taber, 2013). We identify evidence of moti-
vated reasoning from an interaction between party identification and
educational attainment. The interaction reveals a notable gap between edu-
cated Democrats and educated Republicans in their likelihood of reporting
accurate beliefs about vaccines and autism. Finally, we demonstrate that
accurate beliefs about vaccines are consequential for policy preferences.
Accurate beliefs significantly decrease support for allowing unvaccinated
children to attend public schools and support for parents deciding whether or
not to vaccinate their children.

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630
American Politics Research 47(3)
Motivated Reasoning
A useful theoretical framework to assess the public’s understanding of politi-
cal issues generally (Lodge & Taber, 2013), and vaccines specifically (Kraft,
Lodge, & Taber, 2015), is motivated reasoning. When people process infor-
mation, two distinct goals may be activated (Kunda, 1990). First, directional
goals, which motivate people to reach a specific conclusion. People may seek
out information that reinforces their political preferences—confirmation
bias, counterargue information that contradicts their dispositions—disconfir-
mation bias (Taber & Lodge, 2006), or rationalize to maintain consistency
with partisan beliefs (Lauderdale, 2016). Second, accuracy goals, which
motivate people to process and evaluate information objectively, carefully
considering relevant evidence so as to reach a correct or best judgment
(Baumeister & Newman, 1994). Both motives affect how people search for
and integrate information into their judgments. In the context of political
beliefs, directionally motivated cognition is the most common way that peo-
ple process political information (Redlawsk, 2002; Taber & Lodge, 2006).
Directional Goals
Established sources of directional motivated reasoning are partisanship and
prior issue opinions (Bolsen, Druckman, & Cook, 2014; Taber & Lodge,
2006). Years of political science research exposed the powerful role of party
identification on political judgments (Johnson, 2006).
Campbell, Converse, Miller, and Stokes (1960) conceived party identifi-
cation as a “perceptual screen through which the individual tends to see what
is favorable to his partisan orientation” (p. 133). Similarly, Zaller (1992)
summarized a key information processing consequence of party identity;
“people tend to accept what is congenial to their partisan values and to reject
what is not” (p. 241).
People are thus “often unable to escape the pull of their prior attitudes and
beliefs, which guide the processing of information in predictable and some-
times insidious ways” (Taber & Lodge, 2006, p. 767). Research on direc-
tional motivated reasoning identified several important information
processing biases to help explain belief construction (see Kunda, 1990;
Molden & Higgins, 2005, for reviews). First, people are found to process
information with a bias toward their predispositions, accepting information
consistent with their predispositions and disparaging contradictory informa-
tion (K. Edwards & Smith, 1996; Lord, Ross, & Lepper, 1979). Second, peo-
ple actively seek out information that supports and confirms their views and
avoid dissonance producing information (Stroud, 2008).

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Joslyn and Sylvester
631
For example, Gaines, Kuklinski, and Quirk (2007) found that Democrats and
Republicans construed the same factual information—U.S. troop causalities—
in a manner consistent with their support or opposition to the Iraq War. Democrats
consistently interpreted given levels of troop causalities as higher than
Republicans did. Similarly, Joslyn and Haider-Markel (2014) showed that
Democrats and Republicans differed sharply in their beliefs about a host con-
tested political facts concerning the Iraq War, evolution, and global warming.
Democrats and Republicans maintained beliefs that supported their partisan
attachments, regardless of expert consensus or scientific evidence.
Likewise, opinion polls consistently showed a large segment of the public
endorsing the myth that President Obama was not born in this country. In
addition, these beliefs were heavily concentrated among Republicans; 28%
believed Obama was not born in the United States, and 30% were not sure.
Democrats overwhelmingly rejected the claim (cited in Nyhan, 2010).
Krosnick, Malhotra, and Mittal (2014) also observed persistent partisan dif-
ference about President Obama’s birth place regardless of changes in ques-
tion wording.
In these instances, Democrats possessed accurate beliefs. Many
Republicans did not. However, polls showed Republicans were more likely
to hold correct beliefs about a Republican president. In a Scripps Howard/
Ohio University survey in July 2006, approximately 80% of Republicans
thought it very or somewhat unlikely that “people in the federal government
assisted the 9/11 attacks or took no action to stop the attacks because they
wanted the United States to go to war in the Middle East.” About half that
percentage of Democrats reported similarly (Nyhan, 2010).
Jacobson’s (2010) analyses of people’s memories of their own attitudes
before the Iraq War offered comparable conclusions. He discovered selective
memory in favor of remembering pre-War attitudes consistent with current
attitudes, and misremembering attitudes that were contradictory with present
feelings. For example, before the War, approximately 70% of Democrats
believed Iraq possessed Weapons of...