Is the public legitimacy of protests rooted in the political context? An experimental study comparing protests by environmentalists and farmers

Abstract

What are the characteristics of a political protest that enable it to win public support, and what is the role of the political environment? The literature has argued about the characteristics that induce the public to sympathize with protesters (such as the identity of the protesters, their demands, and their methods), but little research has focused on the role of the political context, which includes the presence of other protests making different (or even opposite) demands, the contrasting identity of the protesters, and protest methods. In the research reported in this study, we focused on two protests that unfolded during 2023–24 in Italy (protests by environmental activists and farmers/livestock raisers) to investigate the impact of protesters' identity on public perceptions of their action's legitimacy, when two protests with contrasting aims but similar methods occur at the same time. We used a pre-registered randomized experimental design that manipulated the sequence in which a sample of respondents was presented with descriptions of protests by both groups. Our findings suggest that the sequence in which protests are presented significantly affect respondents' perceptions. Once primed with the evaluation of the farmers' protests, in fact, they perceive climate activists' actions as more legitimate. Our results suggest that people tend to comparatively evaluate social movements and to adjust their opinions accordingly when exposed to cognitively dissonant information.

Introduction

Protests are vital for democracy. Not only do they serve as a fundamental expression of democratic citizenship, allowing individuals to voice grievances and press for change, they also act as catalysts of societal progress, fostering dialogue, raising awareness, and holding governments accountable to the will of the people. Moreover, protests serve as a crucial medium for social and political movements, enabling them to mobilize support and influence public opinion (Della Porta, 2020). However, the effectiveness of these protests often hinges on public opinion's perception of their legitimacy and appropriateness.

It is important to understand how and if the public perceives the legitimacy of protests, given that a sympathetic public opinion impacts the effectiveness of social movements in achieving their goals and, eventually, bringing about social and political change. The literature shows that public support influences the size and sustainability of a movement, because greater legitimacy often leads to increased participation and resource mobilization (Gamson, 1990; Benford and Snow, 2000). Although this topic is rarely systematically tested in the social movements' literature (Andrews et al., 2016), we know that perceived legitimacy can be significantly shaped by protesters' identity and demands (Wouters, 2019), as well as by the methods employed in the protests themselves (Simpson et al., 2018). Moreover, little research has focused on the comparative evaluation of different protests.

This paper stands in between the fields of social movements and public opinion by investigating the role that the political environment has in shaping public reactions to specific protests. While the political process theory underscores that context matters and that movement milieus interact with significant actors – including other movements – in influencing movement dynamics (Tilly and Tarrow, 2015), our focus is on how the general public, often not directly involved in these protests, perceives and evaluates different movements occurring within the same political landscape.

In particular, we posit that, as with every political object (such as parties, policies, ideologies, but also protests and social movements), the audience evaluates social movements comparatively (Druckman and Lupia, 2016). The process of preference formation in politics involves comparative assessment among an array of items. In this scenario, campaigners, lawmakers, policy advocates, and other citizens seeking influence must compete for the limited resources of the public (monetary resources, attention, support). Because public support, theoretically, is not a finite resource, this argument should not significantly concern social movements. However, it is plausible that individuals may also make comparative evaluations regarding political entities that are not necessarily competing in a situation of scarcity, or which are not interchangeable. People can thus adjust their levels of sympathy with a movement's identity, demands, and methods in relation to other protests. In this paper, we argue that in times of contentious politics (Tilly and Tarrow, 2015), when movements are usually followed by counter-mobilizations that directly or indirectly seek to maintain the status quo (Inata, 2021), understanding public opinion reactions to these conflicts becomes highly relevant, from both a normative and a scientific point of view. Overall, this paper addresses the overarching research question: How does the public perceive the protest legitimacy and methods of movements when similar tactics are employed by groups with differing degrees of social acceptance?

To answer this question with empirical evidence, we exploit the case of the environmental activists and farmers' protests which took place in Italy over the 2023–24 period. Beginning in 2023, Italian environmental groups (mainly Last Generation activists, see Stuppia, 2023) routinely employed roadblocks as a method to protest against climate change. These protests were generally very unpopular and were condemned by local and national authorities (see Cottone, 2023, Diamanti, 2024). Roadblocks were also used by an entirely different (and much more popular) movement in early 2024, when an international protest was mounted by farmers in several European countries, including Italy. Protesters used their tractors to block roads, protesting against European agricultural and environmental policies. The demands of these two protest movements stand in stark contrast: one aimed to protect the environment, potentially at the expense of immediate economic interests; the other aimed to defend those selfsame economic interests, possibly at the environment's expense. This juxtaposition provides a unique opportunity to investigate how public opinion reconciles its perceptions of the methods used by the two movements.

We know from the literature that when people evaluate protests, they consider two main features: who the protesters are and how they conduct their actions. The former, linked to socio-political identity, determines whether individuals perceive protesters favorably or unfavorably from an external perspective (Wouters, 2019). The latter feature, which pertains to protest methods, has less decisive weight because the use of violence is generally condemned (Huff and Kruszewska, 2016). However, in a contentious political environment (Tilly and Tarrow, 2015), individuals may encounter trade-off scenarios. For instance, people may be exposed to protests that are politically appealing but resort to violence or other unpopular methods (Simpson et al., 2018).

In this paper, we argue that dilemmas of this type may trigger cognitive dissonance phenomena and necessitate some form of re-adjustment: to avoid cognitive dissonance (Festinger, 1957; Taber and Lodge, 2006), people may more readily accept the methods used by a less socially accepted protest, as soon as they have been exposed to similar methods used by a more socially accepted group. The simultaneous presence of a socially accepted protest (i.e. the one by farmers) and a less approved protest (the one by environmental activists) using similar methods (roadblocks) allows us to test this hypothesis. Although cognitive dissonance has been widely studied in various political contexts, we maintain that the application of the concept to the evaluation of protests is still under-explored. By extending this theoretical framework to protest evaluations, our study aims to make a novel contribution to understanding how cognitive processes influence public perceptions of protest legitimacy in contentious political environments. Moreover, we hypothesize that public concern about climate change (Bouman et al., 2020) and political orientation (see Barker et al., 2021) can act as moderators of this change: both are expected to be connected to some sort of partisan issue ownership of the two protests – with the environmentalists' protest being perceived as more left-wing and appealing to people more concerned with climate change with respect to the farmers' protest. This provides further empirical evidence for the cognitive dissonance argument.

By employing a pre-registered experimental design, in the research reported in this paper we manipulated survey questions to make this dilemma as clear as possible by randomizing the sequence in which participants were presented with information about the protests of the two groups. This enabled us to isolate the effect of question order on the participants' perceptions of protest legitimacy and methods.

The results showed that, as predicted, the general public was much more sympathetic to the farmers' protests than it was with those by environmentalists. However, once the experimental group was primed with the evaluation of the farmers' protests, it perceived climate activists' actions as more legitimate. In other words, participants adjusted their opinions of environmentalists' methods once they had compared them with farmers' protests. This effect was stronger for people who were more concerned about climate change. In sum, priming a protest with another one that uses a similar method depolarizes the opinions that people have about it (see Chen et al., 2022), increasing the legitimization of the less legitimized protest.

Background

What determines public support for protests and the role of context

The social movement literature has paid relatively little attention to the effect of movements' protests on public opinion (Branton et al., 2015) and to the audience's reactions to protests (Andrews et al., 2016). It has focused more on the effects of protests on politics and policy. However, securing public support is crucial for social movements that want to be successful, particularly when they operate with limited resources (Wouters, 2019). Indeed, protests often influence politics indirectly; when protesters gain public support, this support can affect policies and, in turn, lead to social–political change (Agnone, 2007). Consequently, social movements organize public protest events not only to raise awareness about their cause and gain support for a specific framing of a social issue (Benford and Snow, 2000) but also to obtain public legitimization and thus be seen as a credible discussant by their political counterparts.

Given that the public is mostly uninvolved in protests, we can ask what characteristics of people affect their evaluations of protests. Scholars have mostly focused on socio-demographic and ideological properties (age, gender, political ideology, media exposure, education, religion, etc.), as well as on people's proximity to protest events (an aspect shown to foster more positive attitudes to a protest, see Andrews et al., 2016; Branton et al., 2015), to explain the positive/negative evaluations of a protest. However, one aspect that has received less attention in the literature is the effect that the characteristics of protests can have on citizens and their opinion formation: garnering public support hinges on the appeal of these characteristics; an appeal which operates through a mechanism of identification (Wouters, 2019). If the identity of protesters resounds with a (more or less large) part of the citizenry, showing an “attractive” collective socio-political identity, people are more likely to support their protest. In essence, to gain support, protest groups seek to convey an appealing public identity that fosters identification (Wouters, 2019). The literature has shown that this kind of similarity between protesters and their potential public resides mainly in the characteristics of protesters (who they are) and the behaviors adopted during protests (how protesters behave).

According to Tilly (2006), collective action is “attractive” when it displays characteristics such as worthiness, unity, numbers, and commitment.¹ The success of protest organizers in mobilizing large numbers of unified and committed individuals who care deeply about an issue increases the likelihood that a movement projects an appealing identity. In particular, the way in which protesters conduct their protest is significant in determining worthiness: peaceful behavior makes protesters more socially acceptable and, hence, easier to identify with. In Western democracies, moderate forms of protest have become increasingly legitimate in the eyes of the public, whereas the opposite holds for violent forms of protest (see Huff and Kruszewska, 2016): the use of violence, indeed, may induce the general public to view a protest group as less reasonable, reducing identification with the group and lowering public support. Even when violence targets a widely despised group, it still undermines support for the group perpetrating the violence (Simpson et al., 2018). The same applies to radical flanks within a movement (Dasch et al., 2024).

So far, we have considered movements individually. But what happens when two movements with different aims and claims, but similar methods, are simultaneously present in the foreground of public debate? How is public support influenced? Previous research on demonstrations and counter-demonstrations has examined how the general political context influences public support for protests (Andrews et al., 2016; Simpson et al., 2018). As noted by Meyer and Staggenborg (1996), movements and their opponents tend to strategically select tactics that resonate with the public. For example, counter-movements that successfully frame their opposition in terms of broader societal values and utilize tactics perceived as legitimate are more likely to garner public support. As stressed above, however, the use of violence, even by counter-demonstrators, can backfire and erode public sympathy (see Reynolds-Stenson and Earl, 2018; Vüllers and Hellmeier, 2022). In this study, our aim is not to test the effect of the dynamics between directly opposing movements, as done in previous literature; instead, we shall explore the effect on the public's mind of the presence, within the political context, of two movements with similar (unpopular) methods but vastly different claims and degrees of support in society. As stressed above, the case under study presents us with a puzzle stemming from the fortuitous circumstance of the simultaneous presence of two movements exhibiting a captivating interplay among protesters' identities, methods, and demands.

The case of environmental and farmers' protests in Italy

As anticipated, between the end of 2023 and the beginning of 2024, the protest by environmental activists and the one by farmers against the new European Union green regulations coincided in Italy, where they received large media coverage and public opinion attention (O'Brien, 2024; Vuong et al., 2024). The two protests had opposite objectives. Environmental activists protested in order to raise citizens' awareness about climate change and its effects, as well as the responsibility of fossil fuels for increased CO₂ emissions. Conversely, farmers protested against certain provisions in the Green New Deal aimed at greater agricultural sustainability, which they argued would hamper their work and significantly increase production costs.²

As a result of this divergence, the two protests had different time horizons (environmental activists had a longer-term perspective, while farmers' concerns were more short-term and tied to labor issues). They also differed in their primary addressees and in the scope of their demands. The farmers' protests were primarily aimed at political decision-makers, and their purpose was to change or halt specific policies that directly impacted farmers' economic interests and livelihoods. In contrast, environmental activists not only targeted political leaders but also addressed the general public. One of their key goals was, in addition to changes at the decision-making level, increased public awareness. This could influence public support, since climate change is perceived as a slow and distant crisis, with no simple answers, and long-term effects. Citizens' and governments' reactions are consequently less effective and swift (Van der Ven and Sun, 2021). Moreover, the protesters belonged to very distinct social groups and embraced profoundly different values (activists lean toward post-materialism, while farmers are more materialistic) and could trigger two very different stereotypical social identities (on the one hand, a young, possibly middle-class, and educated activist; on the other, a hard-working farmer who “gets their hands dirty”).

An additional feature is that, despite their profound divergence (in aims, claims, and participants' characteristics), both protests adopted similar tactics (i.e. roadblocks). We cannot say that these were inherently violent protests, but they certainly caused significant inconvenience for blameless citizens and were therefore considered widely inappropriate. Moreover, also those kinds of protests had unwanted consequences that caused serious damage (e.g. a roadblock that delayed an ambulance and thereby caused a person's death: see Ansa, 2024).

Moreover, we have evidence that the environmentalists' protest was much less legitimized than the one by farmers: a survey (conducted at the beginning of February 2024, see Diamanti, 2024) asked a representative sample of Italian citizens for their opinions on the farmers' and environmentalists' protests. Although the survey asked respondents to evaluate other tactics employed by environmentalists (more specifically, throwing washable paint on monuments to raise awareness about climate change: see also Vuong et al., 2024), the difference in public support for the two protests (and, indirectly, protesters) was striking. Almost 8 Italians out of 10 (77%) stated that they supported the farmers' roadblocks, as opposed to the slightly more than 2 respondents out of 10 (22%) who supported climate activists' protests. The scant sympathy for environmental protests was further certified by the (right-wing) political majority. In November 2023, before the start of the farmers' roadblocks, the Italian government passed a law intended to prevent environmentalists' roadblocks and impose more severe sanctions on those opting for this method of protest, who in some cases would be charged with criminal offenses rather than being subject to administrative sanctions (see also Yuen, 2023).

A final factor to be taken into account concerns the timing of the protests: roadblocks were a routine tactic for climate change activists, who employed them for at least 1 year. On the contrary, farmers' roadblocks were concentrated in around 4 weeks (from the last week of January to the last one of February).

Hypotheses

The aim of the paper is threefold. Our primary objective is to provide empirical evidence of public support for the protests: although we have indirect evidence of it (see Diamanti, 2024), we will systematically test whether the levels of support for environmentalists' roadblocks were actually less legitimized in the public domain with respect to farmers' roadblocks. Consistently with the above, the first hypothesis can be stated as follows:

H0³: Environmentalists’ protests are seen by the public as less acceptable than those by farmers.

As stressed above, our argument is that the general public actively compares different protests and dynamically adjusts its opinion according to the worthiness of specific protest techniques. So, what happens to people's beliefs when they are exposed to a juxtaposition between two protests employing similar (and unpopular) methods but which have different goals and legitimacy? In this case, we argue that the best means to explore this psychological reaction is represented by the cognitive dissonance framework.

According to cognitive dissonance, individuals experience psychological discomfort when they hold conflicting attitudes or beliefs (Festinger, 1957; Harmon-Jones and Mills, 2019). This discomfort induces them to perform a set of cognitive actions aimed at reducing the dissonance. The classical theory of cognitive dissonance lists four main actions (Festinger, 1957): the denial or avoidance of information that could foster dissonance (e.g. avoiding discussing or thinking about topics that could highlight inconsistencies in one's beliefs or behaviors); reduction of the salience or significance of the dissonant information (by downplaying the importance of dissonant pieces of information); the acquisition of new information that makes it possible to overcome the dissonance; re-adjustment of the information (which eventually leads to a belief change).

When suddenly exposed to a protest that is generally perceived as socially acceptable, such as that by farmers, individuals who harbor negative attitudes toward environmentalists' roadblocks may encounter cognitive dissonance, since one of the reasons why environmentalists are unpopular is the very fact that they use roadblocks. Our contention is that people will be more likely to partially re-adjust their attitudes: this may result in an upward adjustment of perceptions toward the less acceptable protest, that by climate change activists. By adjusting the negativity associated with the tactics of the less acceptable protest, individuals seek to restore consistency in their attitudes, with the ironic consequence that the public evaluation of the less acceptable protest (environmentalists' roadblocks) becomes more positive when juxtaposed with a more socially acceptable protest (farmers' roadblocks). Our second hypothesis runs as follows:

H1: Once exposed to the (more acceptable) farmer protest tactics, the public evaluation of environmental protests tactics will be more positive.

In order to give additional theoretical substance to our theoretical argument, we will examine two moderators that have particular theoretical significance and provide a theoretical rationale for their expected effects: political orientation and concern about climate change.

Political orientation can influence both the support for protests per se and the support for the specific content of protests: research suggests that support for protests tends to be weaker among those on the ideological right (McCright and Dunlap, 2008). Conservative ideology values social order, conformity, tradition, and respect for established authorities, while protests inherently challenge authority. However, the ideological bias in perceptions of protest legitimacy is also driven by the ideological leaning of the protest and its issue content (Barker et al., 2021). For example, when protesters represent historically privileged groups or advocate for conservative causes, antipathy may be replaced by support (e.g. in the case of the Tea Party in the USA, see Skocpol and Williamson 2012). Political ideology is a significant factor influencing attitudes toward climate change, and it often exerts a stronger impact than socio-demographic variables (Hornsey et al., 2016). Left-right ideology is closely associated with beliefs about climate change (McCright et al., 2016): individuals identifying with right-wing ideologies generally exhibit weaker belief in and concern about climate change compared to their left-wing counterparts.

Although we have evidence that also left-wing individuals generally disapprove of the disruptive methods used by climate activists (see above), we can hypothesize that these citizens, upon exposure to the information that farmers were using roadblocks to advance their own economic agendas, might reassess the legitimacy of the climate activists' methods. They may decide that if roadblocks are acceptable when used by farmers for material gains, then they could be even more justifiable when used by climate activists pursuing an idealistic and altruistic goal, one also seen as more politically congruent with their beliefs. This comparative evaluation may induce left-wing individuals to increase their acceptance of the climate activists' tactics once being primed with the farmers' protests. H2 thus can be stated as follows.⁴

H2: When exposed to the (more acceptable) farmer protest, the change in the evaluation of environmental protests by right-wing people will be weaker with respect to left-wing people.

Empirically, in the Italian case, we observe a general concern for climate change alongside a soft polarization on the issue (Bertolotti and Catellani, 2023). Therefore, it seems pertinent to test a hypothesis using a more precise measure of climate change concern. Our basic theoretical expectation is that the more individuals are concerned about climate change, the more likely they are to take and support climate action (Bouman et al., 2020). Similarly to the argument concerning ideological orientation, we might expect that individuals less open to environmentalism will have more crystallized or resilient opinions on climate activists. Consequently, the exposure to a new protest movement employing the same tactics could have a weaker impact on their perception of the legitimacy of environmental activists' actions. Conversely, as far as individuals more open to environmentalism are concerned, we might argue that this group is more sensitive to new information and, therefore, is more liable to alter its perceptions.

H3: When exposed to the (more acceptable) farmer protest, the change in the evaluation of environmental protests by people who are not concerned about climate change will be weaker with respect to that by more concerned people.

Experimental design, data, and methods⁵

To empirically test our hypotheses, as stressed above, we exploited the contrasting protests of environmental activists and farmers in Italy between late 2023 and early 2024. While both groups employed similar protest methods – specifically roadblocks – they differed significantly in their objectives, time horizons, social group characteristics, and levels of public support (see above). This juxtaposition provides an ideal context in which to examine how these factors shape public perceptions of protest legitimacy and methods.

Experimental design

As stressed above, the research reported in this study employed a pre-registered, between-group experimental design focusing specifically on environmental activists' and farmers' protests. Participants were randomly assigned to one of the two groups, with each group receiving information about the protests in a different sequence. Group A (selected as a randomized 50% of the sample) first read about the environmental activists' protests and then about the farmers' protests. Conversely, group B received the same information in the reverse order (see Table 1).

Table 1. Structure of the experimental design

More specifically, the question asked the respondents to evaluate, on a 0–10 scale, the methods of the two protests. The wording of the question was “How much do you approve the actions of [farmers/climate activists] who have blocked roads to protest against [political decisions/global warming]? Use a scale from 0 to 10, where ‘0’ means ‘Not at all’ and ‘10’ means ‘Completely’.”

This research design was aimed at experimentally inducing cognitive dissonance – the key psychological mechanism underpinning our research questions – among participants. By randomizing the order in which questions were presented – specifically, whether participants first evaluated the actions of climate activists or farmers – the design was intended to simulate the real-world process whereby individuals encounter information about one group's tactics before those of the other.

In the questionnaire context, participants who first assessed the protests of climate activists might form initial judgments based on their pre-existing attitudes toward environmental issues. Subsequently, confronting a question about farmers – who use similar tactics but for different ends – could trigger a reassessment of those judgments.

Thus, the randomized question order not only served to control for order effects but also allowed us to experimentally simulate the juxtaposition of similar protest actions by ideologically distinct groups, thus enabling a robust test of our hypotheses concerning cognitive dissonance and possible re-adjustments. This type of design has also the advantage of being able to test the actual difference in popularity of the two protests. If we take into account the first evaluation given by each randomized group (which was unprimed), we can easily analyze the differences between the climate change activists' and farmers' roadblocks.

Data and models

Data were collected by employing a survey based on a computer-assisted web interviewing method through an Italian online survey platform (Pollstar). The aim was to obtain a sample representative of the Italian population in terms of age, gender, and macro-region (n = 1136, see Supplementary material 2 for descriptive statistics). The survey incorporated socio-demographic questions, assessments of political orientation, and environmental attitudes. More specifically, these two latter variables (which represent the moderators of the experimental effects) were measured, respectively, with a standard 0–10 scale of left-right self-placement and a question asking, on a 1–10 scale, how much respondents were concerned about climate change (the wording of the question, borrowed from Eurobarometer, was “How serious do you think the issue of climate change is right now? Use a scale from 1 to 10, where ‘1’ means ‘not at all serious’ and ‘10’ means ‘extremely serious’”). The experimental manipulation of respondents' evaluation of protests was conducted at the end of the interview. Our data also included gender, age (continuous), and education level (recoded as 1 “Professional qualification completed”; 2 “High school completed”; 3 “Some university degree”).

To systematically test our hypotheses, we constructed a set of linear regression models. Each model's coefficient was estimated through ordinary least-squares regression, providing insights into the direct experimental effects and the moderating effects of concern and ideology.⁶

Results

Figure 1 illustrates the test results for H0, which posits that people, overall, legitimize farmers' roadblocks more than environmentalists' roadblocks. As can be seen from Figure 1, the difference between the evaluations of farmers' and climate activists' protests is quite large (a difference of almost 2.5 points on a 0–10 scale). This confirms what evidence from opinion polls suggested, namely that farmers' protests are dramatically more legitimized.

Figure 1. Linear prediction for evaluations of climate activists' actions and farmers' actions (both non-primed – P-value <0.000).

H1 argued that, once respondents are primed with the evaluation of the farmers' protests, the climate activists' actions (which included roughly equivalent types of mobilization, namely, roadblocks) will be perceived as more legitimate. Figure 2 shows substantial evidence for this hypothesis. The difference between primed and unprimed respondents is significant to the 5% threshold. The experimental effect has a quite substantial magnitude (about 0.4 points on a 0–10 scale), especially if we take into account that the experimental treatment is indeed quite weak. We can thus conclude that priming produced a substantial difference.

Figure 2. Evaluations of climate activists' actions (primed and non-primed – P-value = 0.029).

H2 and H3 deal with possible theoretically-relevant moderators of the experimental effects. Ideology does not induce any significant difference in the experimental effect (see Supplementary material 3 for the coefficients and Supplementary material 4 for the graphical representation). This contradicts our H2, which posits a stronger effect on more progressive respondents. In other words, ideology does not moderate the priming effect.

The empirical outcome is different in the case of H3. The interaction effect of climate concern is strong and significant, and increases, as expected, the magnitude of the experimental priming – see Figure 3.⁷ Respondents who believed that climate change is a very important issue tended to more strongly adjust their evaluation of the methods of climate change activists after they had been primed with the farmers' protests. We thus have evidence that respondents more concerned about climate change, once primed with the farmers' roadblocks, tended to be more indulgent toward climate activists' roadblocks. The same is not true of respondents relatively less preoccupied with climate change, who, as expected, did not adjust their opinions once primed with the farmers' protest.

Figure 3. Evaluations of climate activists' actions (by climate concern interaction P-value = 0.020).

Conclusion and discussion

Conclusion

How are public perceptions influenced when two contrasting protests, occurring at roughly the same time, employ similar methods? What happens to the perception of an unpopular movement when another, potentially more socially accepted one, uses the same disruptive methods? The role of the context – and in particular the presence of other protests in the political landscape potentially able to change people's views and influence public support – has rarely been taken into consideration by researchers.

To explore this matter, we analyzed the case of protests by environmental activists and farmers in Italy in 2023–24. These protests had opposing objectives, time horizons, reference groups, and values. While one protest sought to heighten awareness of climate change and environmental protection (if necessary, at the expense of economic interests), the other one sought to defend material economic interests (if necessary, at the environment's expense). However, both protests used the tactic of blocking roads and highways; a tactic generally deemed as not popular for the common citizen.

We know from the literature that tactics deemed inappropriate by the general public can hinder an organization's ability to attract support, which is crucial for a movement's success. However, this paper suggests that the matter is more complicated. In fact, our results show that, once respondents were primed with the evaluation of farmers' protests, the perceived legitimacy of climate activists' actions increased. Priming one protest method with another one similar in tactics but more accepted in principle seemed to depolarize opinions, increasing the legitimization of the less legitimized protest.

Interestingly, the simultaneous occurrence of protests by farmers and environmentalists ironically led to a slight increase in the perceived legitimacy of the environmentalists' actions. This finding highlights a nuanced relationship between the popularity of a specific tactic and the ideological packaging of protests, suggesting that even unpopular methods can acquire conditional legitimacy when the context allows for it, that is, when the unpopular method is used by a popular movement.

As far as psychological mechanisms are concerned, we hypothesized that individuals act in this way to avoid cognitive dissonance. In order to sustain our hypothesis, we looked at possible moderators of our effects. We thus hypothesized that political orientation and concern about climate change could moderate this relationship by increasing the priming effect exerted by farmers' protest for only those individuals more likely to be concerned about climate change, as well as more left-wing ones. In other words, this latter quota of the population, exogenously more likely to be more indulgent with climate change activists, is more likely to adjust its opinions. We have provided some evidence of this by showing that this effect works more strongly when climate change is perceived as a serious problem.

Notably, our findings suggest that the traditional left-right political spectrum does not significantly influence the comparative reassessment of protests. This outcome may stem from several factors, including measurement limitations or the overshadowing influence of other variables such as climate change concern, which show a robust effect. On the other hand, it appears that the salience of climate change in public discourse reshapes traditional political alignments, at least in the context of comparative protest evaluations.

Discussion and limitations

We think that our results highlight a broader dynamic of public opinion, and opinion changes, in the political landscape. As widely stressed in the political science debate, people constantly compare political entities – be they parties, policies, or leaders – and adjust their opinions on the basis of, among other variables, new information (Druckman and Lupia, 2016). This comparative evaluation is essential for understanding the volatility of public sentiment and the potential for opinion change in the face of new or competing narratives. One way to read our results is to conclude that people tend to comparatively evaluate also political objects that do not necessarily compete in a situation of scarcity (of attention, or support) or are substitutable. Rather, this form of competitive evaluation seems to be rooted in how people evaluate political objects in their everyday lives.

The results shed light on broader dynamics within social movements, particularly when viewed through the lens of the diffusion of protest tactics and their influence on public perception. As the literature documents (see, for instance, Soule, 1999), protest tactics often diffuse across movements when they are perceived as effective or resonate with broader societal concerns. This diffusion can impact not only the strategies adopted by different movements but also the manner in which the public and authorities perceive and respond to these tactics.

The phenomenon we observed – where similar tactics used by groups with differing social acceptance affect public legitimacy – may extend to other cases, such as those related to immigration, LGBT+ rights, or economic justice. For instance, tactics like sit-ins, marches, or even more confrontational actions like rioting or clashing with the police may elicit different public reactions depending on the groups employing them, the socio-political context, and the array of other movements employing similar tactics. However, our experimental setup was not able to fully disentangle these possibilities, and we acknowledge that further research is needed to explore these dynamics comprehensively. Future studies could build upon our work by examining a wider range of movements and protest tactics in order to understand the conditions under which public perceptions adjust in response to tactic diffusion.

Partially related to this first drawback, another limitation of the study concerns the external validity of our results. While the experimental design allowed us to isolate and observe the effects of juxtaposing two contrasting protests, it is still unclear whether these effects persist in natural settings where individuals are exposed to a multitude of influences. The controlled environment of our experiment simplified complex real-world interactions, potentially limiting the generalizability of our findings. Moreover, the duration of the observed effects is uncertain. Our study has not considered whether the changes in perceptions induced by the experimental conditions are transient or whether they have lasting impacts on public opinion. This temporal dimension is crucial for more broadly understanding the practical implications of our findings, especially in terms of the strategic timing of protests and public campaigns.

Despite these limitations, we believe that the study contributes to research by isolating specific experimental effects within a controlled environment. By doing so, it enhances understanding of how juxtaposition within protest, and more generally the political context, can shift public opinions, providing insight into the cognitive processes that may operate when individuals evaluate similar protest actions by different groups.