Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections.

Although political action often requires activists to express who they are and what they stand for, little is known about the motivators of such identity expression. This research investigates how group identity content and identification with this content predict identity-expressive collective action in the U.S. 2016 presidential elections. We recruited a longitudinal community sample of U.S. party supporters (N = 426) mid-October (T1), beginning November (T2), and mid-November (T3). Participants listed words they associated with party campaigners, and self-reported their identification with this identity content and the politicized group. Supporting H1, politicized group identification longitudinally predicted increased frequency of collective action more strongly than did identification with specific identity content. Supporting H2, identification with specific identity content longitudinally predicted increased desires to express that content through collective action more strongly than politicized group identification. Implications for our understanding of identity expression and identity content in collective action are discussed.

Donald J. Trump’s 2016 election campaign has been credited with the process of changing ingroup definitions by changing social norms toward prejudice for U.S. citizens (Crandall et al., 2018). Indeed, once a (political) group clearly defines what it stands for (e.g., what it means to be a Democrat or Republican), group members can try to win support for this group’s vision from the general public. This may then redefine another group (e.g., the United States) in line with the own subgroup’s image (e.g., a Republican vision for the United States; Wenzel et al., 2008). Understanding such collective acts of identity expression (defined as displaying the symbolic meaning of your group to others; cf. Scheepers et al., 2003, 2006a, 2006b) is important because it is a key way group members can publicly communicate what their group stands for as they hope to gain public support for their cause (Simon & Klandermans, 2001). Yet despite this, little is known about what motivates people to engage in such identity expression.

This is precisely what we study in the current article. Our point of departure is that identity expression is one of a number of possible aims of collective action (Subašić et al., 2008; i.e., any action individuals undertake as group members to pursue group goals of social change; Wright et al., 1990). Usually, collective action research focuses predominantly on the strength of individuals’ identity (i.e., group identification; an individual’s relationship with their group; Postmes et al., 2013) to predict the frequency of collective action engagement. However, we argue that if we want to be able to predict what people want to express about their identity through collective action, we need to know about the meaning individuals associate with the group they identify with (i.e., group identity content; e.g., we are progressive). For example, an individual who strongly identifies as a Republican would be more likely to campaign on behalf of the party than a weak identifier. Yet crucially, this strong identifier would campaign differently if they supported Trump or Rubio (i.e., whose 2016 Republican presidential candidacy campaign presented an inclusive and modernized vision of being a Republican).

To this end, we conducted a longitudinal survey during the 2016 U.S. presidential elections to test whether and how an individual’s identification with both the group and its identity content predicted their willingness to engage in identity-expressive collective action and frequency of collective action engagement.[1] This context was ideal for testing identity expression in action, given its strong culture of campaigning/recruitment, and the identity politics this evokes (Grant et al., 2010). We expected that identification with specific identity contents would predict the desire to express this content through collective action (more strongly than generic group identification), whereas group identification would predict frequency of collective action engagement (more strongly than specific identity content). Although recent research has begun to demonstrate the importance of identity content for collective action (Becker & Wagner, 2009; Turner-Zwinkels, van Zomeren, & Postmes, 2015), this research moves beyond that work by investigating how specific group identity content predicts different identity-expressive collective action (above and beyond identity strength) within the U.S. political context.

Predicting Collective Action Through Group Identification and Group Identity Contents

Social identities (i.e., defined as the part of an individual’s self-concept which derives from the knowledge of one’s membership in a social group[s] together with the emotional significance attached to that membership; Tajfel, 1974) are central motivators of collective action (van Zomeren et al., 2008 see also Thomas et al., 2009]. This is because, first, social identities shift an individual’s experience of the self from “I” to “we,” promoting a group-based understanding of the world. As such, social identities are the psychological vehicles that allow people to care about their group and motivate them to protect their group’s interests or act on its behalf. In an election context in which one’s group faces a strong competition, one’s social identity directly predicts engagement in collective action. Second, social identities also indirectly motivate collective action via two other socio-psychological motivators of collective action: group injustice and group efficacy. Thus, social identities sit at the heart of collective action bridging psychological motivators, both directly and indirectly predicting frequency of collective action (van Zomeren et al., 2008).

So far, the role of social identity in collective action has been explored in two key ways. The most popular approach is to operationalize it as identity strength (i.e., group identification). This focuses on the quantitative strength of an identity, in how committed an individual is to their group (Postmes et al., 2013). Across different groups and contexts, this research has robustly demonstrated that the stronger an individual’s identification with their group (e.g., Republicans), the more likely they are to take part in collective action (e.g., voter drive) when exposed to a group disadvantage (e.g., closing coal mines; B. Klandermans, 2002; van Zomeren et al., 2008). Especially, identification with politicized groups (i.e., social movement organizations; e.g., election campaigners; Simon & Klandermans, 2001) predicts action to protect this group’s interests (e.g., getting the group’s candidate elected; P. G. Klandermans, 2014; Stürmer & Simon, 2004a, 2004b). This is because politicized groups have a strong action-oriented focus (e.g., their main goal is to win the election), which creates an inner obligation for group members to engage in collective action (Stürmer & Simon, 2004b). Together this research has emphasized that the strength of one’s identity, and especially their politicized identity, is a key ingredient predicting collective action engagement.

However, although this research demonstrates that politicized identities predict collective action generally (e.g., van Zomeren et al., 2008), it remains unclear what people want to express with their activism. For instance, a strong Republican identity may tell us something about the sort of identity an individual has, but it does not tell us what type of Republican a person is (e.g., if this person supports Trump or Rubio) and what specific meaning they may want to express through their activism (e.g., a traditional or progressive image of Republicans; Thomas et al., 2019). As such, politicized identification helps us understand the general direction of people’s motivation for collective action, but does not help us to understand this in terms of more specific content. To get deeper insight into this aspect of politicized identity, we need to explore the second (and less well researched) core element of social identity which plays a role in collective action, the qualitative part of an identity’s content (i.e., what the identity means to group members; Ashmore et al., 2004). Indeed, it has also been argued that identity content processes are central to political activism (e.g., Duncan, 2012; P. G. Klandermans, 2014).

Unfortunately, this idea has been often voiced without having been empirically tested.[2] For example, models and definitions of politicization are built around the idea that an individual needs to change not only who they are (e.g., I am an activist), but how they understand their social world (e.g., as structured by powerful groups) and their relation to it (e.g., as systemically disadvantaged; Cross, 1971; Downing & Roush, 1985; Simon & Klandermans, 2001; Subašić et al., 2008). Only more recently, this theory has been tested in empirical research, which has attempted to model qualitative identity content (changes) and statistically test its consequences (Becker & Wagner, 2009; Livingstone & Haslam, 2008; Thomas et al., 2009; Turner-Zwinkels et al., 2017; Turner-Zwinkels, van Zomeren, & Postmes, 2015). The findings of this research supported the idea that (changes in) identity content play a crucial role defining the meaning of groups and informing the likelihood that individuals will engage in different forms of collective action. However, research investigating the identity-expressive function of collective action is rather scarce, despite its important function of helping to achieve group goals (see Hornsey et al., 2006). As such, we do not know yet how the content of an individual’s group identity might motivate identity expression through (collective) action.

Conceptualizing Content Identification and Its Relation With Group Identification

We suggest that both increases in identity strength and (changes in) identity content should be important in motivating collective action: While identity content should inform the type of behavior an individual is likely to engage in (e.g., normative or radical action) and what they seek to express through this action, identity strength informs the likelihood that an individual acts on the basis of these understandings in the first place. However, theoretically, they should also have a joint influence on group activism. Even stronger than this, Turner (1999) argued that group identification and identity content are interdependent in that group identification develops to the extent that an individual finds meaning in an identity. So, without identity strength, the content of an identity has no impact on behavior—but without content, strength has no meaning.

How should this combined influence work in practice? One potential scenario is that identity content moderates the impact of group identification (e.g., Becker & Wagner, 2009). For example, Livingstone and Haslam (2008) demonstrated that the more an individual is committed to an identity which is seen as having content that is antagonistic with their outgroup (e.g., the ingroup values fairness, but the outgroup is seen to behave unfairly), the more likely they are to act with hostility toward that outgroup. Although this research presented strong evidence supporting the important moderating impact of identity content on group behavior, it tests a simple additive relation (i.e., a two-way interaction) between group identification and identity content. We suggest that it is not only how individuals define the group identity, but the extent that they identify with this specific content that is important for understanding identity-expressive collective action.

This introduces a two-part conceptualization of identification—(a) identification with the overarching group identity, and (b) identification with specific elements of content that make up the identity (see also Leach et al., 2008; McConnell, 2011).[3] First, broader group identification refers to an individual’s overall commitment to their group (Postmes et al., 2013). In contrast, identification with identity content is defined as an individual’s subjective commitment to their group’s identity content. Thus, content identification tells us something about the specific definitions individuals see as central to the group and their personal commitment to these identity understandings (e.g., this is not just a politicized identity, but a politicized identity about being a progressive Republican). Content identification therefore recognizes that identities are complex (Kervyn et al., 2010), and some group members may not perfectly agree about what the group means. Such deviations in identity content might be caused by a number of things, such as having different understandings of the group (potentially resulting in the emergence of different subgroups), in different contexts (e.g., times of peace vs. conflict), or being motivated by different psychological processes (e.g., self-projection vs. self-stereotyping; van Veelen et al., 2013). For example, even if a group of activists generally agree that being “pushy” is part of the activist identity, an introverted activist might identify less strongly as “pushy” and more strongly as “socially conscious.” So, although content identification should theoretically be constrained by social reality and the external social consensus about characteristics defining the group (i.e., the introverted activist may not identify strongly with content such as “quiet” that other group members believe is atypical of the group), it is primarily about the perceivers’ perceptions of their group and how it fits in the self.

Taken together, we expect that (a) politicized group identification is a strong predictor of an individual’s tendency to engage in collective action (van Zomeren et al., 2008), and (b) identification with specific identity content is a stronger predictor of what content they seek to express as characterizing their group. So someone who strongly identifies as a party-activist is more likely to participate in collective action more often than a weak identifier, but a highly identified introverted activist is more likely to behave in a way that shows their group as being socially conscious than pushy while participating (e.g., at a voter drive) than a highly identified extroverted activist.[4]

The Present Study

This research applies a longitudinal design in the context of the U.S. 2016 presidential elections to test the idea that group identification and content identification are two distinct forms of identification, with the latter being the strongest predictor of identity-expressive collective action and the former being the strongest predictor of frequency of collection action engagement. We test this in two main hypotheses. First, the collective action hypothesis (H1) states that politicized group identification and identification with identity content will predict frequency of engagement in political action over time, but the former will do so more strongly than the latter. Second, the identity-expressive action hypothesis (H2), predicts that content identification will predict the expression of identity content through action more strongly than politicized group identification (H2a). Furthermore, identification with identity content should only predict relevant forms of identity-expressive action. In other words, identification with one specific content unit should predict the expression of that specific content more strongly than identification with another content unit (H2b). In addition, group identification is partly composed of an individual’s understandings of the group (i.e., its identity content), but is also more than the sum of its parts: Thus politicized group identification will predict identity expression in action positively, so adding an identification with identity content will reduce the effect, but not remove it (H2c).

In order to empirically test identity content we use an identity content approach. This approach studies semantic identity content as group definitions, where group meanings are considered to be embodied in traits (e.g., kind, caring) individuals use to describe different groups (e.g., Leach et al., 2007). To access identity content, we ask participants to freely list the words they associate with ingroup (e.g., Democrat) party supporters who actively promote the party during the elections. This allows unique insight into an individual’s subjectively internalized identity content, which can vary freely between individuals and over time. By using an identity content approach this research will elaborate on the detailed process of linking specific units of identity content to identity expression, further developing our understanding of collective action and the role of identity content within it.

Method

Participants and Design

The design of the study was a three-wave, longitudinal survey. Data was collected on Amazon’s M-Turk at three time points: mid-October 2016 (T1), the start of November 2016 (T2; immediately before the elections), and mid-November 2016 (T3). A community sample of 494 participants was recruited, with 74.49% of participants returning at T2. We expected this sample size to yield sufficient power to detect small effects, with an expected attrition rate of 60%. Participants were paid 75 cents at T1, US$1.75 at T2. Main analyses focus on these first two time points. T3 was voluntary follow-up collected from 255 returning participants (a completion rate of 51.62%).

We selected a total sample of 426 participants (137 = male, 284 = female, 5 = na; Mage = 38.52, SD = 12.24) who reported a party preference at T1 (as this was required to complete the identification and identity content questions relevant to this analysis; 56.1% Democrat, 31.9% Republican, 7.0% Libertarian, 3.5% Green, 1.4% other), and who passed an attention check. Our sample for longitudinal analyses consisted of 299 participants (87 = male, 209 = female, 3 = na; Mage = 40.22, SD = 12.67) who in addition to this, also consistently supported the same party across T1 and T2 (55.5% Democrat, 36.5% Republican, 4.3% Libertarian, 3.0%, Green, 0.7% other). This was necessary, as it allows us to measure the consequences of their party supporter identity content across time. However this subsample did not differ from the total sample in terms of gender (χ2 = 5.80, p > .12), age, education, income, or religiosity, ts (337) = 0.34 – 1.77, ps = .72 – .08.

Measures

The questionnaire was programmed on Qualtrics and completed online. The questionnaire was entitled “You, the U.S. and the Presidential Elections” and was composed of four sections: about the individual, their party preference, party supporters, and action. All questions were scored on a seven-point Likert-type scale unless otherwise stated. Finally participants were thanked and paid.

Identity

Identity content was measured using the associative-recall task (ART). First, active party supporters were defined as

a group of people who aim to promote [party preference] in the 2016 Presidential elections. Importantly, active party supporters seek to influence the decisions of others and persuade them to vote for this party. The ultimate purpose of this is to . . . win votes for this party.

As such, this definition aligns with the definition of politicized identities as identification (Simon & Klandermans, 2001). Next, participants completed ART. This task asks individuals to freely list up to 20 words that they associate with active party supporters who support their party preference in the 2016 presidential elections. Participants were encouraged to think widely about “the traits, values, principles, attributes, roles, relations, goals, activities, lifestyle characteristics, and qualities that you consider to define an active party supporter or distinguishes them from other people,” and to answer relatively quickly as if for themselves (range 1–20, M = 11.77, SD = 6.48).

Politicized group identification was measured immediately after this task. Participants completed four items based on Doosje et al. (1995) tapping into identification as an active party supporter (e.g., I identify with other active party supporters; αT1 = .94, α T2 = .95, rT1–T2 = .76). Items were anchored at (1 = strongly disagree, 7 = strongly agree).

Identification with identity content-1 and content-2 was measured with the first two units of content written in position one and two of the ART list, respectively (e.g., loyal, honest, hardworking; see Table 1 for most frequently recalled identity content). This choice was made to test content that was likely to be reasonably important to participants due to its high salience. Furthermore, it ensured sufficient data—because we expected that randomly selecting two of the 20 options would select many entries left blank by the participant. First, participants were reminded that “Earlier, you wrote that [content-1] is something you associate with active party supporters for [party preference]. The following questions are about this.” Then participants were asked to complete three items per unit of content, with questions piping the relevant content into each question (“[content-1]” is an important part of my identity as an active party supporter for [party preference]; As an active party supporter for [party preference] I identify as “[content-1]”; I identify as being “[content-1]”: α = .93, α = .95, rT1–T2 = .68; content-2: α = .94, α = .96, rT1–T2 = .49). Items were anchored (1 = strongly disagree, 7 = strongly agree). Participants were also given the option to select “not applicable” in case the content written rendered the question difficult to interpret or otherwise irrelevant, but participants were usually able to provide an answer (7.95% selected inapplicable). Crucially, content identification for each participant was measured with the same content at T1 and T2 (i.e., the content participants listed at T1 was piped in at T2) to ensure longitudinal effects could be tested.

Table 1.

Most Frequently Occurring Identity Content Listed for Democrats, Republicans, and Others (Libertarian, Green, Other) at T1 and T2.

Rank	Democrats				Republicans				Other (Libertarian. Green. Other)
	T1 (n = 239)	% list	T2 (n = 177)	% list	T1 (n = 136)	% list	T2 (n = 122)	% list	T1 (n = 51)	% list	T2 (n = 34)	% list
1	Liberal	4.20	Liberal	6.78	Conservative	8.09	Conservative	9.88	Independent	4.95	Honest	4.76
2	Active	2.52	Loyal	4.80	Smart	2.94	Loyal	5.76	Caring	2.97	Independent	4.76
3	Committed	2.52	Passionate	3.67	Honest	2.94	Honest	2.88	Liberal	2.97	Intelligent	4.76
4	Passionate	2.31	Caring	3.11	Dedicated	2.57	Hardworking	2.88	Hippie	2.97	Eco friendly	4.76
5	Caring	1.89	Dedicated	3.11	Determined	2.57	Patriotic	2.47	Active	1.98	Activist	3.17
6	Loyal	1.89	Committed	2.54	Loyal	2.21	Intelligent	2.06	Free	1.98	Free	3.17
7	Smart	1.89	Honest	2.54	Persuasive	2.21	Determined	1.65	Intelligent	1.98	Loyal	3.17
8	Hardworking	1.89	Open minded	2.54	Patriotic	1.84	Pushy	1.65	Open minded	1.98	Environmentalists	3.17
9	Dedicated	1.47	Concerned	1.69	Committed	1.84	Outgoing	1.65	Political	1.98	A hippie	1.59
10	Determined	1.47	Outgoing	1.69	Strong	1.47	Traditional	1.65	Progressive	1.98	A little in the middle	1.59
11	Strong	1.47	Enthusiastic	1.69	Concerned	1.10	Ambitious	1.23	Realistic	1.98	Active	1.59
12	Engaged	1.26	Determined	1.41	Confident	1.10	Enthusiastic	1.23	Smart	1.98	Against war	1.59
13	Motivated	1.26	Fair	1.41	Political	1.10	Pro-life	1.23	Socially aware	1.98	Care about the environment	1.59
14	Persuasive	1.26	Kind	1.41	Pushy	1.10	Strong	1.23	Strong	1.98	Aggressive	1.59
15	Pushy	1.26	Progressive	1.41	Traditional	1.10	American	1.23	Understanding	1.98	Anti-racist	1.59
16	Enthusiastic	1.26	Active	1.13	Wealthy	1.10	Attentive	0.82	Activist	0.99	Anti-sexist	1.59
17	Honest	1.26	Compassionate	1.13	Active	0.74	Busy	0.82	Anti-big government	0.99	Community oriented	1.59
18	Assertive	1.05	Devoted	1.13	American	0.74	Caring	0.82	Anti-corporations	0.99	Compassionate	1.59
19	Fair	1.05	Driven	1.13	Annoying	0.74	Change	0.82	Aggressive	0.99	Conscientious	1.59
20	Outgoing	1.05	Engaged	1.13	Caring	0.74	Charismatic	0.82	Believes in liberty	0.99	Conscious	1.59
Total content		476		354		272		243		101		63
Total unique content		264		182		181		152		82		55

Action

Identity expression through action measured individuals’ desire to express specific identity content through action. First, participants were asked to tick boxes referencing 20 different actions they may have engaged in these actions in the last two weeks (e.g., posting on Facebook, talking to friends, wearing a political badge, attending a debate). Next, the key dependent variable presented two items which measured the extent participants aimed to express specific identity content units through this action (i.e., If applicable, when I take part in action ticked above, it is important to me to act in a way that is “[content-1],” I prefer to take part in action that is considered to be “[content-1]”). This was measured twice, once for content-1 (rT1 = .83, rT2 = .88, rT1-T2 = .71) and second for content-2 (rT1 = .85, rT2 = .83, rT1-T2 = .81). Items were anchored (1 = strongly disagree, 7 = strongly agree). As previously, the measure was directed at the same content in T2 as in T1 to allow longitudinal testing, and participants were given the opportunity to answer “not applicable.”

Frequency of collective action consisted of two items that measured how often on average, in the last two weeks of the 2016 presidential election campaign participants had, (a) shown support for, and (b) actively promoted the party they supported (rT1 = .74, rT2 = .63, rT1-T2 =.69). Items were scored on a seven-point scale anchored at “never” (=1) to multiple times per day (=7).

Demographic and control variables

Age and gender were recorded with open questions. Education was measured on a 7-point scale, 1 = Less than high school, 7 = Doctorate degree (e.g., PhD, EdD). Income was measured on a 12-point scale (1 = Less than US$10,000, 2 = US$10,000–US$19,999 . . . 11 = US$100,000–US$149,999, 12 = above US$150,000). Finally, religiosity was measured with one item asking how strong would you describe your faith (1 = very weak, 7 = very strong).

Results

Descriptives

Means, standard deviations, and correlations between key identity variables are presented in Table 2. First, means were inspected. It can be noted that the mean level of identity expression shows a high level of agreement with the aim to express identity content through collective action—therefore supporting the instrumental side of identity expression. Second, the relation between the different levels of identification was inspected. This shows that politicized group identification was moderately correlated with identification with specific identity content units. Indeed, a confirmatory factor analysis confirmed that politicized group identification and content identification were two related but separate factors (see Online Supplement 1). However, politicized group and content identification appeared similar in the stability of the scales from T1 and T2, where both were similarly strong, indeed, 95% bootstrapped confidence intervals overlapped substantially between politicized group identification (95% CI = [.68, .81]), content-2 identification (95% CI = [.69, .83]), and fairly strongly with content-1 identification (95% CI = [.56, .76]). Together, this suggests that although politicized group identification and content identification are distinct factors, they may share some similar properties. Furthermore, a visual inspection of the relation between identification and the action variables already hints at a pattern in line with our hypotheses: Politicized group identification was more strongly related to the frequency of action engagement, while identification with content was more strongly correlated with the expression of (the specific content of) identity through action (notably a factor analysis revealed that content identification and identity expression were correlated but separate factors; see Online Supplement 2).[5]

Table 2.

Means, Standard Deviations, and Bivariate Correlations Between Identity and Action Variables.

Variable	M	SD	2	3	4	5	6	7	8	9	10	11	12
Time 1: October
1. Politicized group identification	4.02	1.58	.52*	.47*	.60*	.49*	.49*	.74*	.43*	.44*	.56*	.37*	.39*
2. Content 1 identification	5.20	1.72		.60*	.32*	.78*	.54*	.42*	.66*	.51*	.30*	.63*	.48*
3. Content 2 identification	5.21	1.76			.26*	.53*	.82*	.36*	.47*	.75*	.23*	.43*	.73*
4. Action engagement	2.88	1.85				.25*	.23*	.55*	.29*	.25*	.71*	.23*	.20*
5. Action expresses content 1	5.53	1.83					.62*	.41*	.67*	.54*	.26*	.73*	.52*
6. Action expresses content 2	5.47	1.90						.37*	.50*	.76*	.22*	.47*	.82*
Time 2: Start of November
7. Politicized group identification	4.02	1.59							.42*	.43*	.61*	.33*	.37*
8. Content 1 identification	5.21	1.71								.67*	.31*	.73*	.52*
9. Content 2 identification	5.16	1.86									.29*	.51*	.82*
10. Action engagement	3.02	1.84										.24*	.25*
11. Action expresses content 1	5.42	1.80											.59*
12. Action expresses content 2	5.35	1.95

Note. *Correlation is significant at the .01 level.

Table 1 presents the most frequently listed content for Democratic, Republican, and a combined group of other party supporters across T1 and T2. Lists comprise 34.24%–50.79% of all content written on each respective set of lists—suggesting a reasonable consensus around group definition, but also substantial outstanding variation (e.g., Democrat party supporters associate 264 different units of content with their group). Lists highlight differences between groups: The content that uniquely distinguished Democrats from Republicans included open-minded, progressive and fair. The content that uniquely distinguished Republicans includes patriotic, American, pro-life. However there is also a lot of content shared across lists (e.g., loyal, passionate, motivated, honest). Thus, Table 1 emphasizes the diverse identity content that individuals associate with their groups, the expression of which will be modeled in subsequent analyses.

Hypothesis Testing

Analyses aimed to test if politicized group identification and content identification were differently related to expression of action. To do so, longitudinal, multiple regression models were run predicting frequency of action engagement (see Table 3) and desired expression of identity content through action (see Table 4) from politicized group identification and identity content-1 identification, and their interaction. Controls of age, gender, income, education, and religiosity were added, and removed if non-significant unrelated. Because our theory applies to all party supporters regardless of their specific party preference, the data for all parties was analyzed together. But, we also checked if party preference impacted results by adding party preference as a control and testing if party preference interacted with any parameters in the model (see Online Supplement 3). As expected, party preference did not change conclusions drawn. So, the original models with pooled samples are presented. As a robustness check, cross-sectional models were also run. Models were robust, with consistent parameters (also checked with residuals greater than 2 removed). Variance inflation factors revealed that predictors across all models were moderately correlated (range = 1.02–4.28), so multicollinearity was not a strong concern. Longitudinal models were run on a slightly reduced sample (n = 299) of individuals with a consistent party preference. However, results were identical across full and selected samples.

Table 3.

Identification With Politicized Group and Content Predicting Frequency of Collective Action Engagement Longitudinally and Cross-Sectionally.

Predictor	B	SE	β	t	95% CI
					Lower	Upper
Longitudinal: T2 frequency of collective action
Intercept	2.02	0.24		8.43***	1.55	2.50
T1 Action frequency	0.53	0.05	0.53	9.92***	0.42	0.63
T1 content-1 identification	0.06	0.06	0.05	0.94	−0.06	0.18
T1 politicized group identification	0.27	0.07	0.22	3.89***	0.13	0.40
T1 content-1 × group identification	0.05	0.03	0.08	1.71	−0.01	0.12
Income	−0.07	0.02	−0.11	−2.72**	−0.12	−0.02
Cross-sectional: T1 frequency of collective action
Intercept	2.78	0.08		34.58***	2.63	2.94
T1 content-1 identification	0.06	0.06	0.06	1.13	−0.05	0.17
T1 politicized group identification	0.73	0.05	0.61	13.53***	0.62	0.83
T1 content-1 × group identification	0.07	0.03	0.11	2.42*	0.01	0.12
Cross-sectional: T2 frequency of collective action
Intercept	3.31	0.19		17.31***	2.93	3.68
T2 content-1 identification	0.14	0.05	0.13	2.61*	0.03	0.25
T2 politicized group identification	0.65	0.06	0.55	11.57***	0.54	0.75
T2 content-1 × group identification	0.11	0.03	0.17	3.77***	0.05	0.16
Income	−0.06	0.03	−0.10	−2.21*	−0.11	−0.01

Note. CI = confidence interval.

p < .05. **p < .01. ***p < .001.

Table 4.

Identification With Politicized Group and Content Predicting Identity Expression of Action Engagement Longitudinally and Cross-Sectionally.

Predictor	B	SE	β	t	95% CI
					Lower	Upper
Longitudinal outcome: Action expression content-1 T2
Intercept	2.09	0.42		5.02***	1.27	2.91
T1 action expression content-1	0.52	0.07	0.53	7.90***	0.39	0.65
T1 content-1 identification	0.28	0.08	0.27	3.60***	0.13	0.44
T1 content-2 identification	0.03	0.06	0.03	0.56	−0.08	0.15
T1 politicized group identification	−0.03	0.06	−0.03	−0.54	−0.14	0.08
T1 content-1 × group identification	0.05	0.04	0.09	1.34	−0.02	0.13
T1 content-2 × group identification	0.00	0.03	0.01	0.13	−0.06	0.07
Education	0.12	0.06	0.09	2.11*	0.01	0.24
Longitudinal outcome: Action expression content-2 T2
Intercept	1.43	0.42		3.37**	0.59	2.26
T1 action expression content-2	0.65	0.07	0.63	9.48***	0.51	0.78
T1 content-1 identification	0.13	0.06	0.12	2.17*	0.01	0.25
T1 content-2 identification	0.15	0.08	0.14	1.95^	0.00	0.31
T1 politicized group identification	−0.02	0.05	−0.01	−0.33	−0.12	0.08
T1 content-1 × group identification	0.06	0.04	0.08	1.58	−0.01	0.13
T1 content-2 × group identification	−0.03	0.03	−0.05	−1.02	−0.10	0.03
Education	0.12	0.05	0.08	2.16*	0.01	0.22
Cross-sectional: T1, Outcome: Action expression content-1
Intercept	5.59	0.06		89.32***	5.47	5.72
T1 content-1 identification	0.64	0.05	0.60	12.76***	0.54	0.74
T1 content-2 identification	0.12	0.04	0.12	2.75**	0.03	0.21
T1 politicized group identification	0.12	0.04	0.11	2.92**	0.04	0.21
T1 content-1 × group identification	−0.10	0.03	−0.17	−3.70***	−0.16	−0.05
T1 content-2 × group identification	0.07	0.03	0.12	2.80**	0.02	0.12
Cross-sectional: T1, Outcome: Action expression content-2
Intercept	5.53	0.06		90.24***	5.41	5.65
T2 content-1 identification	0.04	0.05	0.04	0.92	−0.05	0.14
T2 content-2 identification	0.79	0.04	0.74	18.31***	0.70	0.87
T2 politicized group identification	0.10	0.04	0.08	2.44*	0.02	0.18
T2 content-1 × group identification	0.00	0.03	0.01	0.14	−0.05	0.06
T2 content-2 × group identification	−0.03	0.03	−0.05	−1.09	−0.08	0.02

Note. CI = confidence interval.

p < .055. *p < .05. **p < .01. ***p < .001.

First, we tested the collective action hypothesis (H1; see Table 3 and Figure 1). In line with expectations, in the longitudinal model predicting action frequency immediately before the elections (controlling for T1), the small positive effect of identity content identification at T1 is rendered very small, showing no significant relation with action frequency when politicized group identification is added. As expected, the strongest longitudinal predictor is politicized identification, which is both positive and significant. Interestingly, a smaller, but still significant, positive interaction between identity content and politicized group identification also remained, so when an individual was high on both politicized group- and content identification, they were more likely to increase the frequency with which they engage in action almost a month later. So the different aspects of identification add uniquely to the whole. This model presents strong support for the collective action hypothesis (H1), showing that individuals are most strongly motivated to engage in party activism by their commitment to their overarching politicized group identity: The more they care about this identity the more they reported acting in terms of it. Identification with identity content was a weaker, non-significant predictor.

Figure 1.

Dot and whisker plot of standardized beta coefficient estimates and corresponding 95% confidence intervals predicting desired expression of identity content-1 through collective action (Model 1) and frequency of action engagement (Model 2) in longitudinal regression models.

Note. Plot was generated in R (R core team, 2019) using package:dotwhisker (Solt & Hu, 2018), with beta coefficients standardized according to Gelman (2008).

Results generally replicated when tested in cross-sectional regressions (at T1 & T2). Models supported H1 that frequency of collective action engagement at T1 and T2 was predicted most strongly and positively by politicized group identification: The more an individual saw themselves as an active party supporter, the more frequently they reported engaging in collective action. Identity content identification was also positively related to the frequency of collective action engagement, but this effect was much smaller and its confidence interval overlapped with zero. Moreover, the interaction effect between politicized group and content identification was also positively and significantly related to frequency of collective action, suggesting a combined effect of identification with content and with the group, so that when both are high an individual is even more likely to engage in action.

Next, we tested the identity-expressive action hypothesis (H2), that identification with specific units of identity content would predict the extent individuals sought to express that content through their action more strongly than politicized group identification. In addition to the predictor variables mentioned above, identification with a second unit of content (i.e., content-2) was added to ensure that the expression of identity content was predicted most strongly by the relevant content (see Table 4). In line with predictions, identification with the relevant content was the strongest predictor of desire to express that content through action.

Two longitudinal models were run, one predicting the expression of content-1 at T2 (see Figure 1) and the second predicting the expression of content-2 at T2 (controlling for T1 identity expression). Results showed that politicized group identification was not a substantive predictor of identity expression through collective action at T2 in either model. This suggests that, in contrast to H2c, in the long term, identification with the group may have a smaller impact on action expression than expected. Instead, as predicted by H2a, identity content identification remained a strong, positive longitudinal predictor. Moreover, in support of H2b, when predicting expression of content-1, only identification with content-1 predicts the desire to express this content, and identification with content-2 was unrelated. When predicting expression of content-2, both identification with content-2 and identification with content-1 were positively predictive. This suggests that content-2 doesn’t imply content-1, but content-1 does imply content-2. Importantly, however, a comparison of standardized betas shows that, as expected, identification with content-2 was a stronger predictor of expression of content-2 than identification with content-1 was. No substantive interaction emerged.

Cross-sectional regressions largely converged with the longitudinal model. In support of H2b, expression of content-1 was associated most strongly and positively by identification with content-1. Similarly, when we predicted the expression of content-2, this was associated most strongly and positively by identification with content-2. Furthermore, although politicized group identification was positively and significantly associated with action expression in both cases (supporting H2c), this effect was significantly smaller than that of identification with the specific content units, as can be seen by the non-overlapping confidence intervals. Moreover, when the model is built stepwise entering identification with content more than halves the t-value of the politicized group identification estimate, supporting the idea that an individual’s understanding of the meaning of the group makes up part of their overall politicized group identification. Thus, findings strongly support H2a that both forms of content and politicized group identification predict the desire to express one’s identity through action, but identification with the specific element of content does so most strongly.[6]

Together results present strong support for the identity-expressive action hypothesis (H2). Although a relation between general politicized group identification and identity expression emerged (cross-sectionally only), there was substantial additional predictive power if there was a conceptual fit between the specific content identification and the resulting content expression. As such, identification with specific units of identity content (supporting H2a and H2b) is by far the strongest and most consistent predictor of identity expression.

Overall, results present strong support for both collective action and identity-expressive action hypotheses. (Notably a further explorative test of the hypothesis testing election reactions can be found in Online Supplement 4). Findings show that politicized group identification was the strongest longitudinal predictor of frequency of collective action engagement, but a weaker predictor of expression of that content through action. Mirroring this, identity content identification was the strongest longitudinal predictor of expression of that content through action, but a weaker predictor of frequency of collective action engagement (see Figure 1).

Sensitivity Power Analysis

A sensitivity power analysis in G*Power (Faul et al., 2009) determined that in our cross-sectional (longitudinal) sample of N = 426 (N = 299) a multiple regression model with 5 (7) predictors and 80% power could detect a small minimum effect size of f2 = 0.01 (f2 =0.02).

Discussion

Results present strong support for the idea that identity expression through collective action is most strongly predicted by identification with specific units of identity content. This was supported by longitudinal analyses and converging evidence was also presented in cross-sectional analyses. First, in strong support of the collective action hypothesis (H1), politicized group identification predicted increases in frequency of collective action engagement over time more strongly than did identification with identity content. Second, moving beyond this, and strongly supporting the identity-expressive action hypothesis (H2), longitudinal models showed that identification with identity content predicted increases in the desire to express one’s identity content through collective action over time more strongly that did identification with the politicized group (H2a). This supports the idea that politicized group identification determines the tendency to act, while content identification shapes what group members seek to express through their behavior. Results further suggested that identification with identity content most strongly predicted relevant forms of identity-expressive action, supporting H2b. This reinforces the conclusion that identity expression seeks to present a specific and meaningful aspect of the group’s identity to the public. Furthermore, although cross-sectional models presented some support for our H2c expectation that politicized group identification would also explain some unique variance of identity expression through action (but less than identity content identification), this relation did not persist in longitudinal models. This suggests that politicized group identification has a less to say about how an individual’s desire to express this content develops over time than we first expected. Thus, together findings strongly support the function of identification with specific components of identity content in motivating identity expression in collective action.

Theoretical Implications

First, this research indicates that identity expression is a crucial part of collective action. Although the spotlight in collective action research so far has generally been on predicting frequency of collective action engagement from politicized group identification (van Zomeren et al., 2008), this research suggests that by presenting one’s identity to the public, people with politicized identities can show who they are and what they stand for. With this information members of the public can decide whether to support the group or not. As such, identity expression represents a key mode through which activists could seek to influence their social world and political context. Indeed, our assumptions check (see Online Supplement 5) suggests that identity-expressive action is seen as an effective way of achieving social change (above and beyond simply acting more often). In other words, identity-expressive collective action is about undertaking the “right” form of collective action for one’s group (e.g., peaceful protests for mainstream movements, or more non-conventional or aggressive action for radical movements). This fits well with growing evidence that collective action participants may strategically deploy different modes of expression in the pursuit of third-party support (Klein et al., 2007; Kutlaca et al., 2016; Sasse et al., 2018).

This brings the issue of group definition (Subašić et al., 2008) and identity performativity (Klein et al., 2007) in collective action to the fore. Social movements should not only take a stance, but should present what it means to take that stance—what sort of people believe in this cause. In doing so they can (a) consolidate their own identity creating the basis for group consensus and coordinated action (Klein et al., 2007; Scheepers et al., 2003, 2006a, 2006b), and (b) mobilize others (e.g., undecided potential voters), by communicating what the group stands for and why others should stand with them (Simon & Klandermans, 2001). Thus, expressing one’s identity may not only be a goal in itself (i.e., to simply voice one’s values potentially to affirm one’s own beliefs; Hornsey et al., 2006), but it could be also help achieve the wider goal of making social change more possible (i.e., it also has an instrumental function).

Second, but equally important, this research illuminates a key motivator of identity expression in collective action: identification with specific identity content. This qualifies previous findings that an individual’s identity content was not very strongly related to action (Turner-Zwinkels et al., 2017), by demonstrating that content predicts a specific form of action strongly—its expression. Indeed, although politicized group identification was positively related to identity expression, this relation did not persist over time, once content identification was modeled. This has consequences for our understanding of the role of politicized group identification and identity content in collective action. It reinforces what we might already infer from the broad applicability of politicized group identification measure in the field—that it is a general predictor of tendencies to act on behalf of one’s group. As such, it taps into an individual’s commitment to the group, and most likely, their tendencies to stick with the group (and support its goals). Although politicized group identification depends in some part on its meaning, it does not tell us much about what the group identity means to the individual, nor what should follow from such identification (which depends on group norms). These content-based understandings are often inferred from context, but not from theory or empirical data. Instead, our results indicate that it is identification with the group’s identity content which offers insight into how an individual sees the group and what they want to express about their identity to others in public. As such, this serves as a way to empirically back up what is often assumed in the literature, that identity content is the “active ingredient” in group identity when it comes to collective action, motivating people not only to see themselves as politicized (Turner-Zwinkels, van Zomeren, & Postmes, 2015, p. 21) but to express and perform their politicized identity.

This joins with previous research which has highlighted how the transformation of identity content is central in politicization (Turner-Zwinkels, van Zomeren, & Postmes, 2015, p. 21). Our results suggest that the transformation of identity content in politicization might involve not only changing an individual’s understanding of their own identity but also gaining an understanding of how others might react to it. Indeed, we are not the first to argue that the position of a group identity in the wider social system might be of particular importance for political identities (van Breen et al., 2017). By extension, this also hints at a process through which the identity might develop functionally over time—a feedback cycle between identity content, its expression, and the reaction it gains from the public, among others. Based on the assumption that participants in collective action expresses elements of their identity content with the aim of gathering support, it is possible that the content which persists over time and becomes most central to the meaning of the group are those which are functional for the group’s survival (e.g., moral content; Turner-Zwinkels et al., 2017). In other words, the content which is most successful bolsters the support of the public. This could be seen as a sort of “natural selection” through expression, as part of a functionalist perspective of how politicized identities evolve over time.

More generally, results also further develop our understanding of the construct of identification. This research is novel in arguing that identification is a construct that not only applies to one’s general relationship with the group (as a whole), but can also be applied to assess an individual’s more specific understandings of what the group means to them. Findings presented evidence of the diverging roles of group and content identification motivating different forms of (frequency and expression of) collective action. We observed that politicized group identification captured the general tendency to act on behalf of one’s group, while specific content identification predicted the specific expression of content through collective action. This is reminiscent of the “correspondence principle” from the theory of planned behavior (e.g., Ajzen & Fishbein, 2005), which argues that specific behaviors are predicted more strongly from specific behavioral intentions and beliefs than general attitudes. Although in our case, we do not simply predict a more specific measure of collective action from more specific attitudes (Kelly & Breinlinger, 1995), we draw a distinction between the meaning people take from a group and their desire to express this meaning through their action. So, although group identification is partly composed of one’s identification with the meaning of the group, it captures unique variance separate from content identification, and therefore predicts substantively different outcomes. This lends support to the idea that these two constructs can be theoretically and empirically distinguished, adding to convergent and discriminant validity to this distinction. In this way, results converge with claims in Gestaltian psychology that the whole can be something other than the sum of its parts (Koffka, 1935). The group itself exists as an entity, with different psychological consequences than the specific elements (e.g., of content) that make it up. Thus, this research suggests that a more nuanced understanding of what group identification is can be gained from detailed and comparative tests of its boundaries.

Finally, results highlight the multidimensional nature of group identities. Our finding that identification with one unit of identity content might not be a particularly strong predictor of the desire to express another unit of identity content moves beyond preexisting conceptualizations of the multifaceted nature of group identities (e.g., Kervyn et al., 2010) in at least two key ways. First, it suggests that people can manage their image of the group through the content they identify with: A multifaceted group image allows people to identify with (somewhat) different images of the same group. As such, individuals might have more self-determination over depersonalization and self-stereotyping processes (Turner, 1985) than previously thought, with more potential to tailor even clearly defined identities to fit them better (cf. van Veelen et al., 2013). Second, and more speculatively, this multifaceted group image suggests that different units of content might fulfill different functions. For example, some content might play a self-evaluative role, ensuring a positive group image (e.g., sincere), while other content might play an instrumental role, ensuring efficacious action (e.g., pushy). This encourages a functionalist perspective of identities which might be conceptualized as complex systems. Ultimately, this moves the field away from more simplified representations of identities tested in experimental contexts, toward a truly multifaceted representation of identities which, we believe, has more to say about how people experience them in their everyday lives (Huddy, 2001).

Practical Implications

This research highlights the methodological value of measuring identity content using an associative-recall paradigm (see also Turner-Zwinkels, Postmes, & van Zomeren, 2015, p. 23). This circumvents at least two of weaknesses of methods which present individuals with specific content. First, our method minimizes the likelihood that participants’ self-reported behavior can be explained as an uncertainty reduction tool (Hogg, 2000) or via the priming of identity content by the researcher. According to uncertainty reduction research (e.g., Hogg, 2000), a key motivation for self-categorizing as a group member is to provide more certainty about one’s place in their social world. As such, a person should identify more strongly with content presented to them, and act in line with this content (especially if they are uncertain in the first place; Grieve & Hogg, 1999). Although this does not question the relation observed, it does question its strength. As such, the present results demonstrate that content identification remains a strong predictor of identity expression across diverse content listed and cannot be explained by uncertainty reduction alone. Second, measuring the content participants truly see as part of the identity increases ecological validity, and steps closer to a clearer understanding of how individuals apply their own personal understandings of their group memberships in the real world (Huddy, 2001).

This research also has practical implications for social movements, emphasizing the importance of forming a consensual image of what the group stands for. The benefits of this are twofold. First, it should bolster ingroup solidarity, as a consensual group image minimizes tensions within the group, reducing conflicts over competing ingroup meanings (Wenzel et al., 2008). Second, it should help third-party mobilization, as it ensures that a consistent (non-conflicting) message is expressed to the public. This suggests that clear leadership (Steffens et al., 2014) may be important for political movements. Group leaders can help sculpt a clear and meaningful social identity through phases of storming, forming, and norming (Tuckman, 1965), before performing it. Once the group has formed a stable identity, recruiting can then take place in earnest. A clear understanding of what the group’s identity content is—who we are and what we stand for—should provide a firmer starting point for successful action (van Zomeren, Kutlaca, & Turner-Zwinkels, 2018).

Limitations

First, the generalizability of the present results is limited given that we focused on one context: the U.S. presidential elections. We did so for two reasons: (a) to build on prior research (Turner-Zwinkels, van Zomeren, & Postmes, 2015, p. 24); (b) it allows a diverse community sample with different political (Liberal-Conservative) backgrounds to be tested in a comparable social context. Furthermore, we have reason to expect that findings should apply to other contexts too. Specifically, psychological processes present in election contexts may not be so different from those present in other protest contexts (van Zomeren, Saguy, et al., 2018). Despite this, it is imaginable that the applicability of such psychological processes could vary among different types of movements. For example, processes of identity expression might be more central to movements of affluence (Kerbo, 1982), who have the time and resources to be concerned with identity politics than movements of crisis, which are more strongly motivated by anger and immediate risk of harm to the ingroup.

Second, we did not test the specific aim of expressing the content through action. Given that the identity expression tested was measured as the expression through one’s collective action engagement, we think that the assumption that action was instrumental is fair (Simon & Klandermans, 2001). However, a more detailed investigation of the aims and consequences of identity expression would be valuable.

Notably, alternative models than that tested are both possible and plausible. From a social identity perspective, one may argue that identity content mediates the relation between group identification and collective action. This is because group identification implies self-stereotyping in terms of typical ingroup identity content, which in turn results in an inner obligation to engage in collective action (Stürmer & Simon, 2004b). Alternatively, ingroup projection might predict the reverse mediation. Given the observational nature of our current research we cannot firmly establish causation or causal ordering. Thus, future research would be valuable to dissect the different processes motivating action engagement and identity expression. Perhaps the most interesting context to study this in may be groups approaching a subgroup schism. Although we expect processes of differential content identification will be present in almost all groups (e.g., even groups with relatively clear identities show variation in identity content associated with their group; see Table 5 in Turner-Zwinkels, Postmes & van Zomeren, 2015), they may be most accessible in groups who are about to split.

Conclusion

This research presents new evidence supporting the instrumental nature of identity expression in collective action, and the crucial role of identification with identity content in motivating this. Results demonstrate that although politicized group identification is a key motivator of frequency of collective action engagement, identity content is the active ingredient motivating aims of identity expression through such action. Thus, the pivotal role of identity content in collective action is emphasized: Not only transforming identity content (Turner-Zwinkels, van Zomeren, & Postmes, 2015, p. 26) but also performing identity content is crucial in political activism.

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Supplemental material, Online_Supplement_1 for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin

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Supplemental material, Online_supplement_2 for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin

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Supplemental material, Online_supplement_3 for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin

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Supplemental material, Online_supplement_4 for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin

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Supplemental material, Online_Supplement_5 for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin

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Supplemental material, Turner-Zwinkels_Online_Appendix for Identity Expression Through Collective Action: How Identification With a Politicized Group and Its Identity Contents Differently Motivated Identity-Expressive Collective Action in the U.S. 2016 Presidential Elections by Felicity M. Turner-Zwinkels and Martijn van Zomeren in Personality and Social Psychology Bulletin