Images that Matter: Online Protests and the Mobilizing Role of Pictures

• Date: 01 June 2019
• DOI: 10.1177/1065912918786805
• Published date: 01 June 2019
• Author: Nora Webb Williams,Andreu Casas
• Subject Matter: Articles

https://doi.org/10.1177/1065912918786805

Political Research Quarterly

2019, Vol. 72(2) 360 –375

© 2018 University of Utah

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DOI: 10.1177/1065912918786805

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Article

Introduction

Do images affect online political mobilization? If so,

how? People today are bombarded with more images

than ever before in human history. However, despite

small-N studies and experimental research demonstrating

the effects of images on political information seeking

(Ryan 2012), issue-framing (Corrigall-Brown and Wilkes

2012; Rohlinger and Klein 2012), voting preferences

(Rosenberg et al. 1986; Todorov et al. 2005), political

attitudes (Dahmen 2012; Grabe and Bucy 2009; Wright

and Citrin 2011), and even compliance with authoritarian

regimes (Bush et al. 2016), there is still little work sys-

tematically addressing the role of images in mobilizing

participation in protests and social movements online,1

nor are there studies that have leveraged large, digitized

corpora of real-world protest images. Moreover, those

works that study the more general political effects of

images tend to rely on clear experimental treatments

(e.g., Ryan 2012), while real political images from every-

day individuals are messy and often vary on multiple

dimensions, making large-N observational studies a must.

In this paper, we attempt to fill these gaps in the litera-

ture by presenting and testing a set of hypotheses derived

from a specific mechanism pathway for why images

might affect social movement mobilizations. We first

confirm that, as expected from prior research, images

increase participation in the context of online mobiliza-

tion. Beyond this main effect, we suggest that images are

mobilizing because they generate stronger emotional

reactions than text. Emotions such as enthusiasm, anger,

and fear are known to positively affect participation in a

wide range of political contexts. We argue that images

evoking these three emotions are likely to be strongly

correlated with higher levels of protest participation. We

test the argument with a new, large-N dataset related to

the Black Lives Matter (BLM) movement. We track the

online spread of general support in Twitter for BLM and

a specific BLM protest, ShutdownA14, that occurred on

April 14, 2015.

The idea that images might matter to social move-

ments like BLM is not new. The Civil Rights movement

in the United States and recent contentious events such as

the Arab Spring became known for its powerful

mobilizing images (Howard and Hussain 2013; Raiford

786805PRQXXX10.1177/1065912918786805Political Research QuarterlyCasas and Webb Williams

research-article2018

1New York University, New York, USA

2University of Washington, Seattle, USA

Corresponding Author:

Andreu Casas, New York University, 60 5th Ave., Office 637, New

York, NY 10011, USA.

Email: andreucasas@nyu.edu

Images that Matter: Online Protests and

the Mobilizing Role of Pictures

Andreu Casas1 and Nora Webb Williams2

Abstract

Do images affect online political mobilization? If so, how? These questions are of fundamental importance to scholars of

social movements, contentious politics, and political behavior generally. However, little prior work has systematically

addressed the role of images in mobilizing online participation in social movements. We first confirm that images

have a positive mobilizing effect in the context of online protest activity. We then argue that images are mobilizing

because they trigger stronger emotional reactions than text. Building on existing political psychology models, we

theorize that images evoking enthusiasm, anger, and fear should be particularly mobilizing, while sadness should be

demobilizing. We test the argument through a study of Twitter activity related to a Black Lives Matter protest. We

find that both images in general and some of the proposed emotional attributes (enthusiasm and fear) contribute to

online participation. The results hold when controlling for alternative theoretical mechanisms for why images should

be mobilizing, and for the presence of frequent image features. Our paper provides evidence supporting the broad

argument that images increase the likelihood of a protest to spread online while teasing out the mechanisms at play

in a new media environment.

Keywords

images, social movement mobilization, Black Lives Matter, social media

Casas and Webb Williams 361

2007). The issue with studying these cases, however, is

the biasing selection effect of only looking at potentially

rare cases. Our challenge is to study images without

knowing in advance whether any of them will have an

effect on behavior. We chose a case prior to mobilization

to see which images, if any, explained subsequent varia-

tion in the spread of the given protest and support for its

associated social movement. Our paper also speaks to the

urgency of studying images now, in the current new

media environment. With the rise of mobile phones with

cameras, the ability of almost everyone to share images

from or related to a protest has become an important con-

sideration for scholars (cf. Howard and Hussain 2013;

Webb Williams 2015). Today, small or emerging social

movements such as BLM can rely on thousands of par-

ticipants to take pictures “from the trenches” (Payne

1998) and immediately share them.

We focus our efforts on the effect of online image

sharing on online social movement mobilization. We

acknowledge that mobilization in the online arena is

equally, if not more, important for social movements.

Organizations today use hybrid online and online tactics

to achieve their goals (Bimber, Flanagin, and Stohl 2012;

Chadwick 2011; Theocharis et al. 2015). And while some

scholars are skeptical of the role of online activism

(Morozov 2011), others find that online participation is

an increasingly important tool to recruit committed sup-

porters (Hsiao and Yang 2018), increase protest turnout

(De Choudhury et al. 2016), and to set the media and

political agendas (Casas, Davesa, and Congosto 2016;

Freelon, McIlwain, and Clark 2016b).

We operationalize online mobilization as retweets of

movement-related messages on Twitter. Although

retweeting, like most forms of online mobilization, is a

relatively low-cost form of participation, it still has value

to social movement organizers. A simple action such as a

retweet of a protest message can help drive public,

media, and political attention (Freelon, McIlwain, and

Clark 2016b). We refer to this form of mobilization as

generating movement “attention,” or an increase in the

amount of public discussion about the movement.

Retweeting can also help a movement see who its new

supporters are. If many new Twitter users are engaging

with a movement through its messages and hashtags, this

is a signal that movement themes are affecting, and being

affected by, a broader audience. We refer to this form of

mobilization as generating movement “diffusion,” or the

spread of online support to new members. We discuss the

nuances of treating retweeting as participation in more

detail below.

The contributions of this paper are fourfold. First, we

confirm an image effect in the case of a specific BLM

protest. Second, we derive specific theoretical mecha-

nisms that might make certain types of images more

effective at mobilizing participants. Third, we test these

hypotheses using a large-N observational dataset of

tweets containing protest keywords and hashtags from

April 13 to April 20, 2015, along with all of the images

included in those tweets. The dataset includes approxi-

mately 150,000 tweets and 9,500 manually labeled

images. Finally, we add to the available body of knowl-

edge regarding the BLM movement and the means by

which the movement has spread.

Theoretical Framework and

Expectations

Social Media Messaging as Mobilization

Treating retweets as participation in a social movement

links our research to a wider conversation about the

nature of mobilization in the digital age. Many scholars

have debated the value of social media for social move-

ments (Bennett and Segerberg 2013; Bimber, Flanagin,

and Stohl 2012; Castells 2012; Earl and Kimport 2011;

González-Bailón et al. 2011; Howard and Hussain 2013;

Kharroub and Bas 2015; Morozov 2011). Internet tech-

nologies have greatly lowered the costs of connecting

with potential supporters (Bimber, Flanagin, and Stohl

2012; Lupia and Sin 2003; Olson 1965), and although

some argue that networked technologies have given place

to cheap and meaningless forms of engagement,2 another

line of research shows that this is often not the case. This

literature argues that, today, simply sharing social media

messages should be seen as a form of participation that

helps social movements achieve their intermediate and

longer-term goals (Barberá et al. 2015; González-Bailón

et al. 2011; Theocharis et al. 2015).

Social movements are groups protesting against a sta-

tus quo and seeking some sort of social change (Tarrow

2011). To achieve their goal, they use a wide range of

tactics (McAdam 2000). Raising awareness about a

movement’s claims is often a necessary condition preced-

ing social change, and as a result, tactics pursuing agenda

setting objectives are seen as crucial by social movements

and organizations (Baumgartner, De Boef, and Boydstun

2008). In the current digital media environment, protest

movements use a repertoire of online but also online tac-

tics to influence the public, media, and political agenda

(Chadwick 2011).

In this context, a high volume of social media mes-

sages (original and shared) can raise awareness about a

protesting group in three ways. First, it helps set public

agendas by exposing the movement’s claims to new

audiences and by keeping engaged those who already

care about the issue. For example, González-Bailónet

et al. show how retweet chains allowed the variety of

claims of the Indignados movement to spread to a