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Journal of Information Technology & Politics
ISSN: 1933-1681 (Print) 1933-169X (Online) Journal homepage: http://www.tandfonline.com/loi/witp20
Facebook Politics: Toward a Process Model for
Achieving Political Source Credibility Through
Social Media
Elizabeth E. Housholder & Heather L. LaMarre
To cite this article: Elizabeth E. Housholder & Heather L. LaMarre (2014) Facebook Politics:
Toward a Process Model for Achieving Political Source Credibility Through Social Media, Journal
of Information Technology & Politics, 11:4, 368-382, DOI: 10.1080/19331681.2014.951753
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Journal of Information Technology & Politics, 11:368–382, 2014
Copyright © Taylor & Francis Group, LLC
ISSN: 1933-1681 print/1933-169X online
DOI: 10.1080/19331681.2014.951753
Facebook Politics: Toward a Process Model for Achieving
Political Source Credibility Through Social Media
Elizabeth E. Housholder
Heather L. LaMarre
ABSTRACT. The last two election cycles have seen an exponential rise in the number of political
campaigns integrating some form of social media into their communication plans. As candidates
and campaigns increase their social media communications, political communication scholars have
become increasingly interested in the process through which voters assess political candidates’ credibility
through social networking sites. Using experimental data, this study examines the mediating role
of attitude homophily in establishing political candidates’ source credibility among Facebook users.
A multiple mediation model outlines a process wherein attitude homophily mediates the relationship
between political cues and evaluations of source credibility. Theoretical and practical implications of
the results for political social media campaigns are discussed.
KEYWORDS. Multiple mediation, political campaigns, social media, source credibility
The advent of social media has been touted
as a revolutionary way for politicians to connect
directly with voters (Grant, Moon, & Grant,
2010), for citizens to engage in online political
discussions (Ifukor, 2010), and for non-elites
(such as bloggers) to influence political discourse
(Sweetser, Porter, Chung, & Kim, 2008).
Social media encourage active participation
among media consumers (Burns; 2010; Jenkins,
2006; Solis, 2010), creating a rich environment
for online political participation. Recent
research examining the interplay between political
social media and democracy suggests that
social media function as alternative channels
of communication, allowing voters to connect
Elizabeth E. Housholder is a PhD candidate in the School of Journalism and Mass Communication at the
University of Minnesota. Her research interests center around the intersection of political communication,
new media, and strategic communication.
Heather L. LaMarre is an assistant professor in the School of Media and Communication at Temple
University. Her research interests include political communication, public opinion, and the psychology of
strategic policy narratives.
Address correspondence to: Elizabeth E. Housholder, 111 Murphy Hall, 206 Church St. SE, Minneapolis,
MN 55455 (E-mail: gesk0034@umn.edu).
with elites and facilitating intergroup communication
(Hamdy & Gomaa, 2012; Lim, 2012;
Murthy, 2010; Rane & Salem, 2012). Moreover,
there appears to be a link between social media
use and election outcomes (LaMarre & SuzukiLambrecht,
2013).
As political social media use continues to rise
among the electorate, so do questions regarding
which sources are reliable, trustworthy, and
credible (Brenner, 2013). The mere volume
of political information shared and discussed
online makes it increasingly difficult for voters
to discern which sources hold relatively more
value. Perceptions of source credibility offer
online political consumers a way to make such
368
Housholder and LaMarre 369
distinctions. Specifically, high source credibility
is known to increase message persuasiveness
(Homer & Kahle, 1990; Petty & Cacioppo,
1986), develop favorable attitudes (Till &
Busler, 1998) and influence vote intention
(Mondak, 1995). Yet, little is known about how
individuals evaluate and assign credibility to
socially mediated political sources and/or their
messages. Although source credibility is one of
the most widely tested variables in traditional
persuasion research (Petty, Brinol, & Priester,
2009; Petty & Cacioppo, 1986), political social
media research offers few empirical examinations
of the social-psychological process underlying
individuals’ evaluations and judgments of
candidates’ source credibility in online environments
(e.g., Facebook). To this end, the current
study uses experimental data to investigate this
process, focusing on attitude homophily as a
potential mediator between exposure to political
candidates’ Facebook pages and evaluations
of their source credibility. Additionally, this
work employs motivated reasoning theory to
discern the relationship between perceptions of
social media source credibility (e.g., the political
candidate on Facebook) and information
credibility (e.g., the online political information
provided by said candidate). In doing so, this
work builds on extant political social media and
credibility research by focusing on the source
(rather than the medium) and examining the role
of attitude homophily as a source credibility
antecedent.
ESTABLISHING CREDIBILITY IN
POLITICAL SOCIAL MEDIA
Using social media to follow campaigns
and candidates has been linked to a range of
positive attitudinal and behavioral voter outcomes,
including increased offline participation
(Bakker & de Vreese, 2011; see also
Baumgartner & Morris, 2010 for a counterpoint),
increased feelings of political efficacy
(Towner & Dulio, 2011), and increased candidate
support (Gilmore, 2011). Political social
media studies have largely focused on key
behavioral outcomes including political participation
and political engagement, paying little
attention to the underlying processes that lead
to such outcomes. However, there is a growing
interest in credibility evaluations of political
social media (Powell, Richmond, & Williams,
2011).
Social Media Credibility
Among the few studies that have explored
the role of credibility in social media contexts,
focus has remained on the credibility of the
medium, platforms, and channels (e.g., Internet
blogs, online news), or the institutions that
occupy them (e.g., MSNBC, The Huffington
Post). Johnson and Kaye (1998, 2000) found
that perceived credibility of a traditional media
source (i.e., MSNBC) positively predicted credibility
ratings of that same source in an online
context, suggesting that the well-established traditional
media sources carry their credibility
into new media environments. Recent research
on blog credibility has found that among the
politically interested, blogs are generally considered
to be more credible than mainstream media
sources (Johnson & Kaye, 2004; Johnson, Kaye,
Bichard, & Wong, 2007). Sweetser et al. (2008)
also found that high users of blogs were more
likely to perceive blogs as credible sources of
information. Lee and Ahn (2013) demonstrated
that people are more likely to engage with
Facebook causes and pages when they perceive
Facebook to have higher medium credibility.
In one of the only studies examining political
source (as opposed to medium or platform) credibility,
Powell et al. (2011) found that those who
connected with a candidate on social media also
reported higher credibility ratings for that candidate
(but only for Barack Obama). However, this
study stopped short of examining the process
through which perceptions of source credibility
were fostered within the social media environments.
With the notable exception of Powell
et al., little is known about how individuals
evaluate and form judgments about political candidates’
credibility in online environments or the
conditions under which their socially mediated
campaign messages are accepted as credible
information. Yet, traditional persuasion literature
has repeatedly demonstrated the role that
the message source plays in fostering message
370 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
agreement and influencing behavior (Petty &
Cacioppo, 1986; Pornpitakpan, 2004).
Source Credibility
Conceptually, source credibility includes two
main dimensions: character and competence
(McCroskey & Young, 1981) or variations
thereof (such as trustworthiness and expertise).
Sources are considered to be trustworthy
(or have high character) to the extent that
the audience perceives their assertions to be
valid (Hovland, Janis, & Kelley, 1953). Sources
are considered to be competent to the extent
that they possess knowledge or relevant expertise
of a particular subject (Page, 1978; Teven,
2008). More recently, Teven and McCroskey
(1997) identified goodwill as a third important
dimension of source credibility. Goodwill has
been conceptualized as the degree to which an
audience perceives that a source cares about
their well-being and has their best interests at
heart (Teven & McCroskey, 1997). In general,
source credibility is conceptualized (and operationalized)
as a set of positive characteristics
attributed to the message source, which potentially
increase message acceptance by receivers
(Ohanian, 1990).
Higher source credibility can lead to many
desirable attitudinal and behavioral outcomes.
Attitudinally, individuals are more resistant
to persuasion when source credibility is low
(Greenburg & Miller, 1966) and low credibility
sources typically produce no change in
attitude (Milburn, 1991). From a strategic communication
standpoint, higher source credibility
results in more positive brand attitudes
(Lafferty & Goldsmith, 1999; Till & Busler,
1998), more agreement with proposed recommendations
(Ohanian, 1990), more positive attitudes
toward the endorser (Braunsberger, 1996),
and more positive perceptions of information
credibility (Greer, 2003; Moore, Hausknecht,
& Thamodaran, 1986). Higher evaluations of
source expertise have also been associated
with increased purchase intention (Lafferty &
Goldsmith, 1999; Till & Busler, 1998).
Politically, higher source credibility predicts
more positive global candidate evaluations
(Funk, 1999; Markus, 1982; Miller,
Wattenburg, & Malanchuk, 1986), as well as
higher assessments of leadership ability (Page,
1978). Additionally, high source credibility has
been shown to reduce voters’ reactivity to negative
political advertising (Yoon, Pinkleton, &
Ko, 2005), and increase the likelihood of reelection
for incumbent politicians (McCurley &
Mondak, 1995; Mondak, 1995). Taken together,
these studies suggest a positive relationship
between one’s source credibility evaluations
and their propensity to hold favorable attitudes
toward the source or source’s message. In a
political setting, favorable attitudes should manifest
as candidate support. Thus, we expect that
participants will be more likely to participate
in political activities (as a show of support) for
sources that they find more credible.
H1: There will be a direct, positive relationship
between one’s evaluations of
a candidate’s source credibility and
their intention to politically participate
in support of the candidate.
Motivated Reasoning and Political Source
Credibility
Most studies that examine source credibility
manipulate the credibility of the source (see
Wilson & Sherrell, 1993) by providing participants
with objective information about a
source’s education, experience, and credentials.
Yet in a political context, this type of manipulation
makes less sense, as political campaigns
hardly represent an objective context. Far from
perceiving sources in a neutral, objective context,
political campaigns are heavily affect-laden
and voter attitudes toward candidates (even
unknown candidates) are often constructed as
a function of prior attitudes and salient political
cues (Kunda, 1990; Lau & Redlawsk, 2006;
Lodge & Taber, 2013). This motivated reasoning
in the political realm undercuts the traditional
strategic communication argument that source
credibility can be objectively manipulated. In a
political context, motivated reasoning occurs
more often than not (Lodge & Taber, 2013),
which results in faulty judgments including
overscrutinization of information from out-party
Housholder and LaMarre 371
sources (Taber & Lodge, 2006), underscrutinization
of information from in-party sources (Lord,
Ross, & Lepper, 1979), and source derogation
(Smalley & Stake, 1996). Contrary to traditional
source credibility research (which suggests that
source credibility is a function of information
credibility), motivated reasoning predicts that
in a political context, source credibility influences
voter perceptions of information credibility.
Iyengar and Han (2008) offered empirical
support for this prediction, demonstrating
that source cues influenced information search
and evaluation. Because political contexts elicit
relatively more motivated reasoning (Lodge &
Taber, 2013) and source credibility can bias
message processing (Petty & Cacioppo, 1986),
individual-level perceptions of source credibility
are likely to influence perceptions of information
credibility. More formally:
H2: There will be a direct, positive relationship
between one’s evaluations
of a candidate’s source credibility
and their evaluations of information
credibility.
Party ID and Source Credibility
In addition to predicting outcomes (e.g., participation,
candidate support), identifying the
determinants of political source credibility in
social media environments provides political
strategists and candidates insights for building
online source credibility. For instance, one
mechanism known to influence political source
credibility evaluations is the presence of a politically
similar or dissimilar cue for voters (Lodge
& Taber, 2013). Although voters are able to process
and use many types of cues, Party ID is a
highly salient cue that signals whether a candidate
is similar or dissimilar to the individual
(Lau & Redlawsk, 2006). Thus, it would be
expected that source credibility evaluations for
politicians are higher when individuals are cued
that the candidate shares similar political identity
(e.g., they belong to the same party). Stated
more formally:
H3: Similar political cues positively predict
evaluations of source credibility.
As previously mentioned, motivated reasoning
research has shown that individuals are more
likely to participate in support of candidates
from their own political party (Lodge & Taber,
2013), and are more likely to judge information
from in-party candidates as credible (Lord,
Ross, & Lepper, 1979). Thus, there should be
a direct effect for the political similarity cue
(i.e., Party ID) on perceptions of information
credibility and participation intention. The credibility
literature (detailed earlier) also suggests
source credibility should mediate this relationship,
such that similar political cues influence
source credibility evaluations, which in turn
influence behavioral and attitudinal outcomes.
H4: Similar political cues positively predict
participation intention.
H4a: This relationship will be mediated by
source credibility.
H5: Similar political cues positively predict
credibility evaluations of the
information presented.
H5a: This relationship will be mediated by
source credibility.
The Mediating Role of Attitude Homophily
The relational nature of Facebook (specifically)
and social media (generally), suggests
an additional step in the mediation model.
To the extent that social media communication
can foster a sense of interpersonal connection
with a candidate, social media can potentially
spur feelings of closeness, or homophily (Kent
& Taylor, 1998). Conceptually, homophily is
the extent to which similarities are perceived
between two individuals or groups of individuals.
Increased perceptions of similarities lead to
increased attraction to each other’s beliefs and
increased influence in decision-making (Powell,
Richmond, & Williams, 2011). Homophily has
been defined as having three main dimensions:
demographic, attitude, and background
homophily (McCroskey, Richmond, & Daly,
1975). Attitude homophily is conceptualized
as the extent to which two individuals think
and behave in similar ways, whereas background
homophily describes the extent to which
372 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
two individuals come from similar cultural or
social backgrounds. The third dimension, demographic
homophily, is the extent to which two
individuals share key demographic characteristics.
However, perceptions of demographic
homophily have not been stable (McCroskey
et al., 1975) and therefore remain outside
the scope of this investigation. Additionally,
it is not expected that background homophily
would significantly impact source credibility
perceptions, because participants are unlikely to
be able to make judgments about the perceived
background similarity of candidates. As such,
this study will focus exclusively on attitudinal
homophily.
Attitude homophily (in the context of politics)
is the extent to which voters feel
attitudinally and behaviorally similar to politicians.
Although one’s Party ID could cue attitude
homophily (e.g., “We are from the same
political party so we must share political attitudes”),
it is possible for persons from the same
political party to differ in their attitudes or for
persons from different parties to share attitudes.
As such, attitude homophily is considered a
distinct construct from Party ID. Homophily
has been shown to be moderately related to
and predictive of source credibility (Wright,
2000). Generally speaking, perceived attitude
similarity (or homophily) facilitates interpersonal
liking (Aronson, 1980; Byrne, 1961) and
attraction (Lazarsfeld & Merton, 1954) among
individuals. Specific to online contexts, Wang,
Walther, Pingree, and Hawkins (2008) found
that within online health support groups, one’s
increased level of perceived homophily with
the group was positively related to participants’
perceived credibility of group members,
which was also related to increased trustworthiness
of group members. Dahlberg (2001)
similarly found in-group homogeneity of values
and viewpoints among online political communities.
Davis (1999) also pointed to the
importance of attitude homophily among political
social media groups, noting that political
social media users have a tendency to attract
and reinforce preexisting majority opinions.
A qualitative case study of political Facebook
group discussions revealed similar results,
wherein distinct majority and minority groups
were formed around homogeneity of political
views (Gaines & Mondak, 2009; Kushin
& Kitchener, 2009). These studies demonstrate
that attitude homophily can influence one’s perception
of trustworthiness and, by extension
source credibility. Additionally, online political
groups exhibit relatively high levels of attitude
homophily, suggesting that these platforms are
uniquely suited for this purpose. As such, it is
reasonable to assume that increasing perceptions
of attitude homophily between political candidates
and online users would result in higher
perceptions of the candidates’ credibility (within
the online community).
Additionally, because the political similarity
cue (e.g., Party ID) can signal attitude
homophily, it is plausible that the observed
effect of the similarity cue on relevant outcomes
(e.g., credibility evaluations, participation intention)
works through attitude homophily. Put differently,
when individuals see that a political
candidate shares their political party identification,
feelings of homophily should increase.
This, coupled with additional information that
reinforces shared attitude homophily (e.g., similar
interests, shared favorite hobbies, books,
movies, etc.), should increase one’s credibility
evaluations of the candidate, along with their
credibility evaluations of information presented
by the candidate and their intention to support
the candidate. More formally:
H6: There will be a direct, positive
relationship between perceptions of
attitude homophily and one’s evaluations
of source credibility.
H6a. Attitude homophily mediates the
positive relationship between similar
political cues and source credibility
evaluations.
Attitude Homophily and Source
Credibility: A Multiple Mediation
Perspective
Here, the multiple mediation process begins
to unfold. Thus far, the hypotheses predict a
series of direct and indirect effects with attitude
homophily and source credibility serving
as mediators between political similarity cues
Housholder and LaMarre 373
and relevant political outcomes. Given the vast
literature on the role of Party ID, it should
be no surprise that shared Party ID cues more
positive evaluations of a political candidate’s
credibility, along with more favorable evaluations
of information presented by said candidate
or intentions to support the candidate. However,
by integrating attitude homophily, we begin to
see a more nuanced process unfold. Here, the
political cue is thought to work in combination
with other relational information presented in
social media (e.g., candidates’ likes, favorites,
hobbies, etc.), signaling attitude homophily.
Subsequently, increased attitude homophily is
expected to increase source credibility evaluations
of the candidate, which (under motivated
reasoning conditions often found in political
contexts) are known to increase information
credibility ratings and candidate support. Thus,
a multiple mediation process is proposed for the
two relevant outcomes (i.e., information credibility
and political participation intention). More
formally stated:
H6b. The relationship between similar
political cues and participation intention
will be mediated by attitude
homophily and source credibility,
acting in serial.
H6c. The relationship between similar
political cues and perceptions of
information credibility will be mediated
by attitude homophily and
source credibility, acting in serial.
METHOD
To test the previously stated hypotheses,
a two-condition experiment was performed.
One hundred and twenty-six college students
at a large, Midwestern university participated
in this study in exchange for course credit.
Some students were recruited through an online
research participation system that grants course
extra credit in exchange for research participation
while others were recruited directly from
university courses. The majority of students
were recruited from large, introductory mass
communication courses that generally contain
a wide variety of majors. The resulting sample
was 75.4% female, 80.2% white, and had
an average age of 21.5 with some college education
(74.6%1). The sample leaned slightly
democratic (μ = 4.55) and liberal (M = 4.60).
Procedure
The experiment was conducted in a lab. Upon
entering, students read and signed a consent
form and were then randomly assigned a condition
(i.e., Democrat or Republican candidate
Facebook page). Upon sitting down at the computer,
the Facebook page of the assigned candidate
was already loaded and all participants
started on the “About” section of the page.
Participants were told verbally to spend as much
time as they needed getting to know the candidate.
Following this, participants were directed
to the questionnaire (description below). After
completion, participants were debriefed and
thanked for their time.
Stimuli
Participants were shown a fictitious Facebook
page for either a Republican or Democratic
purported Senate candidate (stimuli available
upon request). The pages were designed to look
like real candidates’ pages, mirroring the setup,
organization, design, and content of real pages.
All personal information about the candidate
was held constant across both profiles (e.g.,
musical tastes, favorite books, profile picture,
etc.), aside from party identification. The candidates
were stated as running in the state in which
most participants reside and the only difference
in personal information for each candidate was
stated political party. On the news feed, fictitious
past posts were constructed for each candidate.
The posts were on the subject of jobs/job
creation and were also taken from real status
updates by real Congressional candidates. Each
Facebook page for the politicians contained the
same number of posts on the same topics. The
only variation was the partisan nature of the
comments to align with the positions taken on
this issue by each of the major political parties.
374 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
Measures
Credibility
Credibility was measured using Teven and
McCroskey’s (1997) scales for competence,
character, and goodwill, which consist of
six each 7-point semantic differential scales.
They include statements such as “the politician
whose Facebook profile I just viewed
is reliable/unreliable, expert/inexpert, and
honest/dishonest.”2 The alpha reliabilities for
each dimension of source credibility were
sufficiently high (competence = .89, M =
4.41, SD = 1.04; character = .89, M = 4.50,
SD = .96; goodwill = .82, M = 4.31, SD =
.96). However, these three dimensions were all
highly correlated with each other (all correlations
above .70) and, therefore, were treated
as one overall credibility measure (M = 4.40,
SD = .91). An exploratory, principal components
factor analysis confirmed that all source
credibility indicators loaded on to one factor
(Table 1).
TABLE 1. Factor Loadings of Source
Credibility Indicators
Factor 1
Competence
Intelligent .802
Trained .569
Expert .700
Informed .748
Competent .804
Bright .813
Character
Honest .686
Trustworthy .810
Honorable .778
Moral .684
Ethical .684
Genuine .766
Goodwill
Cares about me .664
Has my interests at heart .732
Not self-centered .589
Concerned with me .651
Sensitive .614
Understanding .741
Homophily
Attitudinal homophily was measured using
the scales developed by McCroskey et al.
(1975). The attitudinal homophily scale consists
of four 7-point semantic differentials
designed to indicate perceived similarity in
thought and action between the participant and
the politician and includes statements such as
“the politician whose profile I just viewed
. . . is like/unlike me, is different/not different
from me, thinks/does not think like me, and
behaves/does not behave like me” (α = .88,
M = 3.46, SD = 1.32).
Information credibility
Information credibility was measured using
five, 7-point semantic-differential scales, which
asked participants to rate the believability
and trustworthiness of the information presented
by the politicians. Participants were
asked to indicate whether “the information
you just read was . . . believable/unbelievable,
inaccurate/accurate, trustworthy/untrustworthy,
biased/unbiased, and complete/incomplete”
(α = .80, M = 4.01, SD =1.16).
Political participation
Political participation was measured using
three items, which asked participants to indicate
on a 7-point scale “how likely would you
be to . . . vote for Alex Johnson, donate money
to Alex Johnson, and volunteer/publicly support
Alex Johnson.” These three items were highly
correlated and were combined into one general
participation index (α = .87, M = 2.65, SD =
1.40).
Party identification
Participants were asked to indicate their party
identification on a 7-point scale ranging from
strong Republican (1) to strong Democrat (7)
(M = 4.55, SD = 1.74). Party identification
was used to assess political agreement between
participants and the fictitious candidates they
were exposed to (i.e., Democrats matched with
a Democratic politician were in a “matched
Housholder and LaMarre 375
political cue” condition). Independents (n =
17) were removed from subsequent analyses.
Political knowledge/interest
Political knowledge scores were calculated
by counting the number of correct answers to
five political questions as outlined by Delli
Carpini and Keeter (1997). These questions
included participants’ knowledge of Joe Biden’s
political office, who is responsible for determining
constitutionality of a law, the majority
required to overturn a presidential veto, the party
that currently controls the house, and whether
one party is more conservative than the other at
the national level. Overall, participants had relatively
high levels of political knowledge (M =
3.83, SD = 1.07). Political interest was a singleitem
measure asking participants to indicate how
interested they were in politics on a 5-point
scale, with 1 indicating not at all interested and
5 indicating very interested (M = 2.92, SD =
1.02).
Analysis
In order to test the previously stated hypotheses,
OLS regressions as well as mediation and
multiple mediation models were tested. The
first, second, and third hypotheses predict nonmediated
relationships and as such, were tested
using OLS regression. The fourth, fifth, and
sixth hypotheses (and respective subhypotheses)
predict mediated relationships and were
tested using the PROCESS macro developed by
Andrew Hayes (2013). Specifically, the bootstrapping
procedure, as outlined by Preacher
and Hayes (2004, 2008) was used. Traditional
mediation analyses as outlined by Baron and
Kenny (1986) have been criticized for a lack of
power and high Type II error rates (MacKinnon,
Lockwood, & Williams, 2004). Preacher and
Hayes (2004) and MacKinnon et al. (2004) recommend
bootstrapping as a method for obtaining
confidence intervals for indirect effects in
mediation models. Bootstrapping tests for the
indirect effects in a mediation model by repeatedly
drawing subsamples from within the original
sample (Hayes, 2009). Bootstrapping allows
for two key advantages over prior mediation
tests. First, bootstrapping increases power and
reduces Type II error rates (a frequent critique
of Baron and Kenny, 1986). Bootstrapping does
not require stringent assumptions of normality
about the sampling data (unlike the Sobel test;
Sobel, 1987). Additionally, bootstrapping does
not require a standard error estimate for the
indirect effects.
This study uses Hayes’ (2013) PROCESS
macro, which allows for bootstrapping within
complex mediation and moderation models.
Specifically, the PROCESS macro allows for
the testing of multiple mediation models, where
multiple mediators are specified between the
independent and dependent variables. Because
this study is testing a multiple mediation model,
PROCESS was the best available tool to examine
this model. PROCESS has been empirically
tested and validated across numerous contexts
and studies (Hayes, 2012). In the present study,
on the basis of 10,000 bootstrap samples, the
PROCESS macro produces 95% bias-corrected
confidence intervals to assess the significance of
the indirect effects in the proposed credibility
model.
RESULTS
Direct Effects
The first and second hypotheses predicted
a direct, positive relationship between source
credibility and participation/information credibility.
The results of the regression analysis
show that source credibility positively predicts
both intended participation (b = 1.05, SE = .10,
p < .001, R2 = .69)3 and perceptions of information
credibility (b= .92, SE = .08, p < .001,
R2 = .72) Thus, hypotheses 1 and 2 were supported.
The third hypothesis tests the positive
direct effect of political cues on evaluations of
source credibility, such that similar politicians
would be seen as more credible. The regression
results provide support for hypothesis 3 (b =
.67, SE = .17, p < .001, R2 = .37). The sixth
hypothesis predicted that positive evaluations of
attitude homophily would lead to more positive
evaluations of source credibility and support
(b = .35, SE = .05, p < .001, R2 = .51). Thus,
the direct effects of key variables in this study
are confirmed.
376 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
FIGURE 1. Model 1: Effects on participation intention.
FIGURE 2. Model 2: Effects on information credibility.
Simple Mediation Model
Turning now to the mediation analyses,
the first set of analyses show the mediating
role of source credibility on the relationship
between political cues and participation
intention/information credibility (hypotheses 4,
4a, 5, and 5b). The relationship between political
cues and participation intention is partially
mediated by source credibility. Perceiving that
a politician’s party identification matches your
own predicts more positive evaluations of source
credibility (b = .67, SE = .17, p < .001), which
in turn predicts greater participation intentions
(b = .85, SE = .10, p < .001, R2 = .68). That
said, receiving a politically similar cue remains
significant, even when source credibility is in the
model (b = 1.34, SE = .17, p < .001). The indirect
relationship between the similar political
cue and participation through source credibility
is significant (95% bias-corrected confidence
interval: .28; .914; indirect effect size = .56,
Bootstrapped SE= .16). However, the direct
effect of receiving a similar political cue and
participation intention also remains significant
(95% bias-corrected confidence interval: 1.00:
1.69; direct effect size = 1.34, SE = .17).
The meditational relationship was fully supported
for information credibility (see Figure 2).
Similar to the first model, perceiving a politically
relevant cue leads to more positive
perceptions of source credibility and source
credibility positively predicts perceptions of
credibility of the information presented (b =
.90, SE = .09, p < .001, R2 = .52). This
is a fully mediated relationship because being
presented with a relevant source cue does not
significantly predict perceptions of information
credibility when source credibility is in the
model (b = .14, SE = .17, p = .39). The
indirect path between similar political cues and
information credibility through source credibility
is significant (95% bias-corrected confidence
interval: .30, .96, indirect effect size = .60,
SE = .17).
Multiple Mediation Model
Given the results for the mediating influence
of source credibility, the full multiple
mediation models were tested, such
that attitude homophily and source credibility,
acting in serial, fully mediate the relationship
between political source cues and
Housholder and LaMarre 377
participation/information credibility (hypotheses
6a, 6b and 6c).
Partial support was found for the mediating
influence of attitude homophily and source credibility
on participation. As Figure 1 highlights,
receiving a similar political cue positively predicts
attitude homophily (b = 1.68, SE = .21, p
< .001), which in turn predicts source credibility
(b = .29, SE = .09, p < .01). Moreover, source
credibility positively predicts political participation
(b = .68, SE = .12, p < .001, 2 for the total
model = .74). However, being presented with a
similar political cue (b = .83, SE = .20, p <
.001) and attitude homophily (b = .37, SE = .09,
p < .001), both remain significant, positive predictors
of political participation. In this case, the
direct effect of political similar cue reception on
political participation is significant (95% biascorrected
confidence interval: .44, 1.23, direct
effect size = .83, SE = .20), as are the indirect
paths through attitude homophily only (95%
bias-corrected confidence interval: .33, 1.03,
indirect effect size = .62, SE = .18) and through
both attitude homophily and source credibility
(95% bias-corrected confidence interval: .13,
.64, indirect effect size = .33, SE = .13).
Turning to information credibility, the multiple
mediation model is fully supported.
Perceiving a politically relevant cue leads to
greater attitude homophily (b = 1.68, SE =
.21, p < .001), which in turn leads to increased
perceptions of source credibility (b = .29, SE =
.09, p < .01). Finally, source credibility positively
predicts perceptions of credibility of the
information presented (b = .85, SE = .11, p
< .001, 2 of the overall model = .53). Neither
being presented with a relevant political cue
(b = −.01, SE = .20, p = .94), nor attitude
homophily (b = .12, SE = .08, p =
.16) predict perceptions of information credibility
when source credibility is included in the
model. The indirect path between similar political
cues and information credibility through
attitude homophily and source credibility is significant
(95% bias-corrected confidence interval:
.18, .76, indirect effect size = .35, SE =
.11). Neither of the effect sizes of the other two
indirect paths was significant.
DISCUSSION
This study examined the role of political
source credibility on social media to better
understand the determinants of source credibility
for politicians in a socially mediated communication
situation. The results provide an
exploratory first look at the relationship between
source credibility, attitude homophily, motivated
reasoning, and key attitudinal and behavioral
outcomes in a political context. The tested models
support the idea that source credibility is an
important determinant of behavioral and information
outcomes in a political context as well
as the idea that attitude homophily may be a
key determinant of source credibility. Past studies
looking at source credibility have found
that factors such as knowledge, credentials, and
strength of argument all increase source credibility.
However, these factors make less of an
impact in a political campaign situation, where
evaluations of credibility are shaped by motivational
forces as well as cognitive forces (Lodge
& Taber, 2013). By extending what is already
known about key credibility factors to include
attitude homophily, this study provides evidence
that feelings of attitudinal similarity are important
to credibility evaluations in politics in a
way that is different from traditional strategic
communication situations.
Past research has demonstrated the homogeneity
of groups on Facebook. We tend to
befriend and follow those who are attitudinally
similar to ourselves. On politician pages, the
majority of fans/followers are likely to be individuals
who are already somewhat sympathetic
to the party the politician represents. Thus,
social networking sites offer a unique opportunity
to politicians to enhance their perceived
credibility through increasing their perceived
attitudinal homophily. Facebook, for example,
offers many opportunities for politicians to personalize
their fan pages, from their cover photo
to the information in the “About Me” section.
Barack Obama’s Facebook page is an excellent
example of this, where one can view photos of
the president eating ice cream on national Ice
Cream Day or candid photos of the president
378 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
with his team. Additionally, one can discover
his favorite music, books, and activities. These
types of information may serve to humanize
politicians, all of which contribute to building
attitude homophily. Future work should extend
this line of research and investigate strategies
that are more or less successful at increasing
attitudinal homophily.
Increasing attitudinal homophily is important
because of its ability to significantly
increase source credibility evaluations and subsequent
participation among online stakeholders.
Motivating and rallying the base can be the
difference between winning and losing an election.
Not only does attitude homophily increase
participation through source credibility, it also
uniquely increases the likelihood of participation,
both in terms of voting as well as donating
time/money. Although these effects are predicted
by party cues, the inclusion of these variables
improves the model fit overall, suggesting
that campaigns may be able to use these strategies
to encourage participation beyond what
they would get otherwise. All of these activities
represent value to a campaign.
Additionally, this study provides evidence for
the idea that attitude homophily works through
source credibility to increase information credibility.
Past studies have shown that when voters
believe more strongly in their information (i.e.,
view their information as more credible) they are
better able to launch cognitive defenses against
contradicting or conflicting information. This
resistance to persuasion could help ensure that a
campaign’s supporters are not discouraged from
voting.
Finally, this study begins to bring together
literatures that, for all their similarities, rarely
speak to each other. This is especially true of the
attitude homophily and source credibility literatures;
this study provides early evidence for the
idea that these concepts are importantly related
to each other.
Practically, this study offers some insights
for political campaigns. To the extent that attitude
homophily can influence key credibility
and participation variables, especially among
young voters, strategies that enhance this feeling
of personal closeness should be employed by
the campaign. This could include activities such
as posting about family activities, favored interests,
or local community events in which the
politician takes a part. For example, the Obama
campaign recently posted a picture of the president
playing catch with a Secret Service member
on the lawn of the White House, while the Chris
Christie campaign posted a video of Christie’s
dance segment with Jimmy Fallon and prior to
that, a video of the governor dropping in on Tball
practice. These types of interactions serve
to humanize politicians.
Additionally, social media are an important
place to highlight these types of activities.
Recent Pew data (Brenner, 2013) suggests that
34% of young adults aged 18–24 get their news
from social media. Therefore, community events
in which politicians participate that are usually
covered by local news may not be reaching
much of the young adult demographic. As such,
continuing to highlight these community outreach
efforts on social networking sites is crucial
for campaigns.
Finally, these findings offer insight into a
very unique role that social media may play in
the campaign communication mix. Prior to the
proliferation of owned assets, politicians were
largely forced to either rely on media coverage
of community events or spend their own
money to include this information in direct-mail
pieces. Social media offer politicians a lowcost
way to promote and tailor messages, yet
little work has looked at what types of messages
may be more or less suited to a social
media environment. Although social media have
largely been adopted by campaigns at all levels,
campaigns are only beginning to take advantage
of the opportunity to employ different types
of campaign messages for relatively low cost.
The results of this study suggest that campaigns
could and possibly should expand the
types of campaign messages they disseminate
via social networking sites to include more messages
aimed at personalization of the politician.
There are a few limitations to this study
that need to be discussed. First, the sample
size of this study is small. Although the results
presented are significant, we suggest replication
before generalizing to the public as a
whole. Second, although youth aged 18–24 still
make up the largest proportion of Facebook
Housholder and LaMarre 379
users, college students may be different, politically,
than the general population (Sears, 1986).
However, there are still valuable generalizations
to be made, as the popular press has highlighted
that social networking sites are a key way that
politicians are able to interact with youth and
potentially gain the youth vote (Qualman, 2011).
Additionally, regarding the results of the
mediation models, it is important to highlight
possible limitations on the causal inferences
associated with these types of models. Some
scholars have suggested caution when inferring
causality from mediation models and have suggested
strategies (such as manipulation of key
mediators) for reducing bias in the point estimates
of the coefficients (Bullock, Green, &
Ha, 2010). Though other scholars have offered
a counterpoint to Bullock et al.’s conclusions
(see for example, Kenny, 2008), we do not
wish to overstate the implications of our findings.
This study should be considered largely as
an exploratory look into the mechanisms fostering
source credibility in a political, social
media context and future work should continue
to manipulate and validate the variables outlined
here.
Overall, this study suggests many directions
for future research. Central to the question
of source credibility is attitude homophily.
However, it is not known what features of social
networking sites lead to the greatest attitude
homophily. There are many ways that politicians
can interact on a personal level with their
fans (e.g., postings, information about themselves,
shout-outs to friends/individual fans).
Future research should investigate these different
modalities for increasing personalization and
homophily. Additionally, future research should
expand to look at other social networking sites.
Recent research (Lee & Ahn, 2013) suggests
that different social networking sites result in
different attitudinal and behavioral outcomes.
As such, effective mechanisms for enhancing
attitude homophily may differ from one social
networking site to the next. Functionally, the
range of options available on Facebook differs
significantly from options available on Twitter,
which in turn differ significantly from YouTube.
This type of research would help campaigns
develop an easy set of best practices for using
social media more effectively to communicate
with voters.
In conclusion, there is more work needed
to understand how features of specific social
networking sites can be optimized for strategic
uses. This study is an important first step,
as it affirms the importance of source credibility
to the political process while also identifying
a key factor, attitude homophily, that may
be used to promote feelings of closeness to a
politician as well as enhance cognitive evaluations
of both politicians and the information
they present. Moreover, attitude homophily is
under the control of campaigns, which makes
it an essential part of strategically engaging in
online political messaging. Understanding the
underlying social-psychological processes that
influence perceptions of credibility can help
politicians and other political communicators to
more effectively tailor and target their messaging.
Future work in this area should begin to
investigate how attitude homophily and source
credibility can be manipulated by campaigns
to produce stronger attitudinal and behavioral
effects.
NOTES
1. Although the sample included all students, there
were some graduate students in the sample (16%) as well as
freshman who had not completed their first semester of college
and therefore answered this question with “high school
graduate” (8%). Dropping these students did not substantively
change any results reported hereafter. As such, they
were left in the final models.
2. Competence: intelligent/unintelligent, untrained/
trained, inexpert/expert, informed/uninformed, competent/
incompetent, stupid/bright
Goodwill: cares/does not care about me, has/does not
have my interests at heart, self-centered/not self-centered,
concerned/unconcerned with me, insensitive/sensitive,
understanding/not understanding
Character: honest/dishonest, untrustworthy/trustworthy,
honorable/dishonorable, moral/immoral, unethical/ethical,
phony/genuine
380 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
3. All OLS models were run with and without demographic
and political controls. Strictly speaking, random
assignment to condition should eliminate the need for
these controls. The results reported here do not change
with the inclusion of demographic and political controls
in the model. As such, the more parsimonious results were
reported here.
4. These numbers represent the upper and lower confidence
intervals.
REFERENCES
Aronson, E. (1980). The social animal. San Francisco: W.
H. Freeman.
Bakker, T. B., & de Vreese, C. H. (2011). Good news for
the future? Young people, Internet use and political participation.
Communication Research, 38(4), 451–470.
Baron, R. M., & Kenny, D. A. (1986). The moderatormediator
variable distinction in social psychological
research: Conceptual, strategic, and statistical considerations.
Journal of Personality and Social Psychology,
51(6), 1173–1182. doi:10.1037/0022-3514.51.6.1173.
Baumgartner, J. C. & Morris, J. S. (2010). MyFaceTube
politics. Social networking web sites and political
engagement of young adults. Social Science Computer
Review, 28(1), 24–44.
Braunsberger, K. (1996). The effects of source and product
characteristics on persuasion. Dissertation Abstracts
International: Humanities and Social Sciences, 57 (6A),
2575.
Brenner, J. (2013, February 14). Pew Internet: Social
Networking. PEW.
Bullock, J. G., Green, D. P., & Ha, S. E. (2010). Yes, but
what’s the mechanism? (don’t expect an easy answer).
Journal of Personality and Social Psychology, 98(4),
550–558. doi:10.1037/a0018933
Burns, A. (2010). Distributed creativity: Filesharing and
produsage. In S. Sonvilla-Weiss (Ed.), Mashup cultures
(pp. 24–37). Germany: Springer-Verlag/Wien.
Byrne, D. (1961). Interpersonal attraction and attitude similarity.
Journal of Abnormal and Social Psychology, 62,
73–77. doi:10.1037/h0044721
Dahlberg, L. (2001). Computer–mediated communication
and the public sphere: A critical analysis.
Journal of Computer-Mediated Communication, 7(1),
doi:10.1111/j.1083-6101.2001.tb00137.x
Davis, R. (1999). The Web of politics: The Internet’s
impact on the American political system. New York,
NY: Oxford University Press.
Delli Carpini, M. X., & Keeter, S. (1997). What Americans
know about politics and why it matters. New Haven,
CT: Yale University Press.
Funk, C. L. (1999). Bringing the candidate into models
of candidate evaluation. The Journal of Politics,
61(3), 700–720. Retrieve from http://dx.doi.org/10.
2307/2647824
Gaines, B. J., & Mondak, J. J. (2009). Typing together?
Clustering of ideological types in online social networks.
Journal of Information, Technology & Politics,
6(3-4), 216–231. doi:10.1080/19331680903031531
Gilmore, J. (2011). Ditching the pack: Digital media in the
2010 Brazilian congressional campaigns. New Media
and Society, 14(4), 617–633.
Grant, W. J., Moon, B., & Grant, J. B. (2010). Digital dialogue?
Australian politicians’ use of the social network
tool twitter. Australian Journal of Political Science,
45(4), 579–604. doi:10.1080/10361146.2010.517176
Greenburg, B. S., & Miller, M. (1966). The
effects of low-credible sources on message
acceptance. Speech Monographs, 33, 127–136.
doi:10.1080/03637756609375488
Greer, J. D. (2003). Evaluating the credibility of online
information: A test of source and advertising influence.
Mass Communication and Society, 6(1), 11–28.
doi:10.1207/S15327825MCS0601_3
Hamdy, N., & Gomaa, E. H. (2012). Framing the Egyptian
uprising in Arabic language newspapers and social
media. Journal of Communication, 62(2), 195–211.
doi:10.1111/j.1460-2466.2012.01637.x
Hayes, A. F. (2009). Beyond Baron and Kenny:
Statistical mediation analysis in the new millennium.
Communication Monographs, 76(4),
408–420.
Hayes, A. F. (2012). PROCESS: A versatile computational
tool for observed variable mediation, moderation and
conditional process modeling (White paper). Retrieved
from http://www.afhayes.com/public/process2012.pdf
Hayes, A. F. (2013). Introduction to mediation, moderation,
and conditional process analysis: A regressionbased
approach. New York, NY: Guilford Press.
Homer, P. M., & Kahle, L. R. (1990). Source expertise,
time of source identification, and involvement
in persuasion: An elaborative processing perspective.
Journal of Advertising, 19(1), 30–39.
doi:10.1080/00913367.1990.10673178
Hovland, C. I., Janis, I. L., & Kelley, H. H. (1953).
Communication and persuasion: Psychological studies
of opinion change. New Haven, CT: Yale University
Press.
Ifukor, P. (2010). “Elections” or “selections”? Blogging
and Twittering the Nigerian 2007 general elections.
Bulletin of Science, Technology & Society, 30(6),
398–414. doi:10.1177/0270467610380008
Iyengar, S., & Han, K. S. (2008). Red media, blue
media: Evidence of ideological selectivity in media use.
Journal of Communication, 59, 19–39.
Jenkins, H. (2006). Convergence culture: Where old
and new media collide. New York, NY: New York
University Press.
Johnson, T. J., & Kaye, B. K. (1998). Cruising is
believing?: Comparing Internet and traditional sources
on media credibility measures. Journalism & Mass
Communication Quarterly, 75(2), 325–340.
Housholder and LaMarre 381
Johnson, T. J., & Kaye, B. K. (2000). Using is believing:
The influence of reliance on the credibility of
online political information among politically interested
Internet users. Journalism & Mass Communication
Quarterly, 77(4), 865–879.
Johnson, T. J., & Kaye, B. K. (2004). Wag the blog: How
reliance on traditional media and the Internet influence
credibility perceptions of weblogs among blog users.
Journalism and Mass Communication Quarterly, 81(3),
622–642. doi:10.1177/107769900408100310
Johnson, T. J., Kaye, B. K., Bichard, S. L., & Wong,
W. J. (2007). Every blog has its day: Politically interested
Internet users’ perceptions of blog credibility.
Journal of Computer-Mediated Communication, 13(1),
100–122.
Kenny, D. A. (2008). Reflections on mediation.
Organizational Research Methods, 11(2), 353–358.
doi:10.1177/1094428107308978
Kent, M. L., & Taylor, M. (1998). Building dialogic
relationships through the World Wide Web. Public
Relations Review, 24(3), 321–334. Retrieved from
http://dx.doi.org/10.1016/S0363-8111(99)80143-X
Kunda, Z. (1990). The case for motivated reasoning.
Psychological Bulletin, 108(3), 480–498.
Kushin, M. J., & Kitchener, K. (2009). Getting political
on social network sites: Exploring online political
discourse on Facebook. First Monday, 14(11).
Retrieved from http://firstmonday.org/htbin/cgiwrap/
bin/ojs/index.php/fm/article/viewArticle/2645/2350
Lafferty, B. A. & Goldsmith, R. E. (1999).
Corporate credibility’s role in consumers’ attitudes
and purchase intentions when a high
versus a low credibility endorser is used in the
ad. Journal of Business Research, 44, 109–116.
doi:http://dx.doi.og/10.1016/S0148-2963(98)00002-2
LaMarre, H. L., & Suzuki-Lambrecht, Y. (2013). Tweeting
democracy? Examining Twitter as an online public
relations strategy for congressional campaigns. Public
Relations Review, 39(4), 360–368.
Lau, R. R., & Redlawsk, D. P. (2006). How voters
decide: Information processing in election campaigns.
Cambridge, UK: Cambridge University Press.
Lazarsfeld P. F., & Merton R. K. (1954). Friendship as a
social process: A substantive and methodological analysis.
In M. Berger (Ed.), Freedom and control in modern
society (pp. 18–66). New York, NY: Van Nostrand.
Lee, Y. J., & Ahn, H. Y. (2013). Interaction effects of
perceived sponsor motives and Facebook credibility on
willingness to visit social cause Facebook page. Journal
of Interactive Advertising, 13(1), 41–52.
Lim, M. (2012). Clicks, cabs, and coffee houses:
Social media and oppositional movements in Egypt,
2004–2011. Journal of Communication, 62(2),
231–241. doi:10.1111/j.1460-2466.2012.01628.x
Lodge, M., & Taber, C. S. (2013). The rationalizing voter.
Cambridge, UK: Cambridge University Press.
Lord, C. G., Ross, L., & Lepper, M. R. (1979). Biased
assimilation and attitude polarization: The effects of
prior theories on subsequently considered evidence.
Journal of Personality and Social Psychology, 37(11),
2098–2109.
MacKinnon, D. P., Lockwood, C. M., & Williams,
J. (2004). Confidence limits for the indirect effect:
Distribution of the product and resampling methods.
Multivariate Behavioral Research, 39(1), 99–128.
doi:10.1207/s15327906mbr3901_4
Markus, G. B. (1982). Political attitudes during an election
year: A report on the 1980 NES panel. American
Political Science Review, 76(3), 538–560. doi:http://
www.jstor.org/stable/1963730
McCroskey, J. C., Richmond, V. P., & Daly, J. A.
(1975). The development of a measure of perceived
homophily in interpersonal communication.
Human Communication Research, 4(1), 323–332.
doi:10.1111/j.1468-2958.1975.tb00281.x
McCroskey, J. C., & Young, T. J. (1981). Ethos and credibility:
The construct and its measurement after three
decades. Central States Speech Journal, 32(1), 24–34.
doi:10.1080/10510978109368075
McCurley, C., & Mondak, J. J. (1995). Inspected by
#1184063113: The influence of incumbents’ competence
and integrity in U.S. House elections. American
Journal of Political Science, 39(4), 864–885.
Milburn, M. A. (1991). Persuasion and politics: The
social psychology of public opinion. Pacific Grove, CA:
Brooks/Cole.
Miller, A. H., Wattenberg, M. P., & Malanchuk, O.
(1986). Schematic assessments of presidential candidates.
American Political Science Review, 80(2),
521–540. doi:http://www.jstor.org/stable/1958272
Mondak, J. J. (1995). Competence, integrity and the electoral
success of congressional incumbents. Journal
of Politics, 57(4), 1043–1069. doi:http://dx.doi.org/10.
2307/2960401
Moore, D. L., Hausknecht, D., & Thamodaran, K. (1986).
Time compression, response opportunity, and persuasion.
Journal of Consumer Research, 13, 85–99.
Murthy, C. N. (2010). Imperatives of citizen-centric Web
2.0 political networks for an effective democracy:
A case study of websites of southern Indian states.
Journal of International Communication, 16(2), 25–41.
doi:10.1080/13216597.2010.9674766
Ohanian, R. (1990) Construction and validation
of a scale to measure celebrity endorsers’
perceived expertise, trustworthiness, and attractiveness.
Journal of Advertising, 19(3), 39–52.
doi:10.1080/00913367.1990.10673191
Page, B. I. (1978). Choice and echoes in presidential elections:
Rational man and electoral democracy. Chicago,
IL: University of Chicago Press.
Petty, R. E., Brinol, P., & Priester, J. R. (2009). Mass
media attitude change: Implications of the elaboration
382 JOURNAL OF INFORMATION TECHNOLOGY & POLITICS
likelihood model of persuasion. In J. Bryant &
M. B. Oliver (Eds.), Media effects: Advances in theory
and research (pp. 125–164). New York, NY:
Routledge.
Petty, R. E., & Cacioppo, J. T. (1986). The elaboration
likelihood model of persuasion. In R. E. Petty & J. T.
Cacioppo (Eds.), Communication and Persuasion (pp.
1–24). New York, NY: Springer.
Pornpitakpan, C. (2004). The persuasiveness of source
credibility: A critical review of five decades’ evidence.
Journal of Applied Social Psychology, 34(2),
243–281.
Powell, L., Richmond, V. P., & Williams, G. C. (2011).
Social networking and political campaigns: Perceptions
of candidates as interpersonal constructs. North
American Journal of Psychology, 13(2), 331–342.
Preacher, K. J., & Hayes, A. F. (2004). SPSS and
SAS procedures for estimating indirect effects
in simple mediation models. Behavior Research
Methods, Instruments, & Computers, 36(4), 717–731.
doi:10.3758/BF03206553
Preacher, K. J., & Hayes, A. F. (2008). Asymptotic
and resampling strategies for assessing and comparing
indirect effects in multiple mediator models.
Behavior Research Methods, 40(3), 879–891.
doi:10.3758/BRM.40.3.879
Qualman, E. (2011). Socialnomics. Hoboken, NJ: John
Wiley & Sons, Inc.
Rane, H., & Salem, S. (2012). Social media, social movements
and the diffusion of ideas in the Arab uprisings.
Journal of International Communication, 18(1),
97–111. doi:10.1080/13216597.2012.662168
Sears, D. (1986). College sophomores in the laboratory:
Influences of a narrow data base on social
psychology’s view of human nature. Journal of
Personality and Social Psychology, 51(3), 515–530.
doi:10.1037/0022-3514.51.3.515
Smalley, R. L., & Stake, J. E. (1996). Evaluating sources
of ego-threatening feedback: Self-esteem and narcissism
effects. Journal of Research in Personality, 30(4),
483–495.
Sobel, M. E. (1987). Direct and indirect effects in linear
structural equation models. Sociological Methods &
Research, 16(1), 155–176.
Solis, B. (2010). Engage! The complete guide for brands
and businesses to build, cultivate, and measure success
in the new Web, revised and updated. Hoboken, NJ:
John Wiley & Sons.
Sweetser, K. D., Porter, L.V., Chung, D., Kim, E.
(2008). Credibility and the uses of blogs among
professionals in the information industry. Journalism
and Mass Communication Quarterly, 85, 169–185.
doi:10.1177/107769900808500111
Taber, C. S., & Lodge, M. (2006). Motivated skepticism in
the evaluation of political beliefs. American Journal of
Political Science, 50(3), 755–769.
Teven, J. J. (2008). An examination of perceived credibility
of the 2008 presidential candidates: Relationships
with believability, likability and deceptiveness. Human
Communication, 11(4), 383–499.
Teven, J. J., & McCroskey, J. C. (1997). The relationship
of perceived teacher caring with student learning and
teacher evaluation. Communication Education, 46(1),
1–9. doi:10.1080/03634529709379069
Till, B. D., & Busler, M. (1998). Matching products
with endorsers: Attractiveness versus expertise.
Journal of Consumer Research, 15(6), 576–586.
doi:10.1108/07363769810241445
Towner, T. L., & Dulio, D. A. (2011). An experiment of
campaign effects during the YouTube election. New
Media & Society, 13(4), 626–644.
Wang, Z., Walther, J. B., Pingree, S. C., & Hawkins, R.
P. (2008). Health information, credibility, homophily,
and influence via the Internet: Web sites versus discussion
groups. Health Communication, 23(4), 358–368.
doi:10.1080/10410230802229738
Wilson, E. J., & Sherrell, D. L. (1993). Source effects
in communication and persuasion research: A metaanalysis
of effect size. Journal of the Academy of
Marketing Science, 21(2), 101–112.
Wright, K. (2000). Perceptions of on-line support
providers: An examination of perceived
homophily, source credibility, communication
and social support within on-line support
groups. Communication Quarterly, 48(1), 44–59.
doi:10.1080/01463370009385579
Yoon, K., Pinkleton, B. E., & Ko, W. (2005). Effects of
negative political advertising on voting intention: An
exploration of the roles of involvement and source
credibility in the development of voter cynicism.
Journal of Marketing Communications, 11(2), 95–112.
doi:10.1080/1352726042000315423