Since the publication of The Authoritarian Personality, political psychologists have debated how ideology and cognitive style are associated and how this association influences political tolerance and open-mindedness. One approach – the rigidity of the right – contends that there are consistent differences in cognitive style between people on the left and people on the right, and that intolerance, close-mindedness, and rigidity are more prominent on the political right (see e.g., Altemeyer, 1996; Jost, Glaser, Kruglanski, & Sulloway, 2003; Stone, 1980). An alternative perspective – ideological extremity – contends that the cognitive style of political moderates differs from those who are more politically extreme, regardless of ideology (see e.g., Conway, Gornick, Houck, Anderson, Stockert, Sessoms, & McCue, 2016; Greenberg & Jonas, 2003; Tetlock, Armor, & Peterson, 1994).

This blog post summarizes recently published research by Jan-Willem van Prooijen and Andre P.M. Krouwel. Across three studies, van Prooijen and Krouwel found evidence that dogmatic intolerance was predicted by extreme political beliefs, on the left and the right. Importantly, they also found evidence that dogmatic intolerance may result in an increased willingness to protest, an increased willingness to curtail the free speech of political opponents, and increased support for antisocial behavior (e.g., violence) directed towards political opponents.

Study 1

Study 1 tested the hypothesis that the political extremes exhibit dogmatic intolerance of political rivals.

Participants. The study used two online samples, one from the Netherlands and one from Germany. The combined sample was made up of 409 participants (262 from the Netherlands, 147 from Germany), M_age = 51.63 years, SD_age = 16.05 years. Of the 409 participants, 299 were men, 105 were women, and 5 did not report a gender.

Measures. Political ideology was measured with a single item that asked participants to place themselves on single dimension ranging from 0 (very left-wing) to 10 (very right-wing). Dogmatic intolerance was measured with 6 items on a 5-point likert scale (1 = strongly disagree, 5 = strongly agree):

1. I believe that everyone should think like me.
2. If everyone would think about it, they would hold the same opinions that I do.
3. How I feel about issues is the truth.
4. People who think differently than me are of lesser value than I am.
5. It scares me if other people think differently than I do.
6. I never really encounter people who think differently than I do.

Results. A hierarchical regression analysis was used to analyze the results. Prior to analysis, ideology was mean centered and a quadratic term was computed based on the centered ideology variable. Age, gender, and sample (Dutch vs. German) were entered at Step 1. Older age predicted reduced dogmatic intolerance. Additionally, dogmatic intolerance was higher in Germany. Political ideology was then entered at Step 2 and emerged as a significant predictor of dogmatic intolerance, in addition to age and sample. Consistent with the rigidity of the right perspective, dogmatic intolerance was stronger on the political right.

The quadratic term for political ideology was then entered at Step 3 and emerged as a significant predictor of dogmatic intolerance, in addition to age and sample. However, with the inclusion of the quadratic term, political ideology no longer emerged as a significant predictor. Simple slope analyses indicated that participants located closer to either extreme demonstrated increased levels of dogmatic intolerance.

Study 2

Study 2 was designed as an extension of Study 1. In addition to dogmatic uncertainty two closely related constructs–political intolerance (defined as a desire to formally prohibit unlikeable activist groups), and close-mindedness (defined as an unwillingness to have one’s knowledge confronted by alternative opinions or inconsistent evidence)–were also assessed.

Participants. 500 participants were ordered from Crowdflower. The final sample consisted of 497 participants from the United States (M_age = 33.74 years, SD_age = 12.02 years). If these 497 participants, 204 were men, 291 were women, and 2 did not report a gender.

Measures. The dogmatic intolerance scale used in Study 1 was revised so that the items focused more narrowly on politics (e.g., “I believe that everyone should think like me about political issues”). Political intolerance was measured by presenting participants with a list of 14 activist groups (7 left-wing and 7 right-wing) and asking them to rate the group they disliked the most on 5 items (e.g., “I think that this group should not be allowed to organize in order to influence policy”; see Crawford, 2014). Close-mindedness was measured with the close-mindedness subscale of the Need for Cognitive Closure Scale (Webster & Kruglanski, 1994). Finally, political ideology was assessed by asking participants to place themselves on a left-right scale (1 = very left-wing, 11 = very right-wing) and a liberal-conservative scale (1 = very liberal, 11 = very conservative).

Results. A factor analysis suggested that dogmatic intolerance, political intolerance, and close-mindedness were related but distinct constructs. As with Study 1, hierarchical regression analyses were used to analyze the results. For each variable of interest (dogmatic intolerance, political intolerance, and close-mindedness) age and gender were entered at Step 1, political ideology was entered at Step 2, and the quadratic term for political ideology was entered at Step 3.

For dogmatic intolerance, age and gender emerged as significant predictors at each step. Specifically, older age predicted lower levels of dogmatic intolerance and men were more dogmatically intolerant than women.

At Step 2, dogmatic intolerance was stronger on the political right than on the left. Finally, at Step 3 the quadratic term for political ideology was significant, while political ideology was no longer a significant predictor. Thus, consistent with Study 1, as one moved towards either the left or right extreme of the ideology measure, one was more likely to be dogmatically intolerant of different beliefs.

For political intolerance, none of the steps in the regression model were predictive. For close-mindedness only the quadratic term for political ideology entered at Step 3 emerged as a significant predictor. Political ideology predicted close-mindedness on the right but not on the left.

Study 3

Study 3 was designed to more directly test the idea that “the more strongly people endorse a certain political belief, the less willing they are to tolerate dissent regarding the topic in question” (van Prooijen & Krouwel, 2017, p. 246; see also Skitka 2010; Skitka, Bauman, & Sargis, 2005). To do so, participants were asked to describe a self-selected political belief that they endorse. Strength of belief was manipulated by asking participants to describe a strongly endorsed political belief or a weakly endorsed political belief. Willingness to protest, denial of free speech for those one disagrees with, and support for antisocial behavior (e.g., violence) were also assessed.

Participants. 200 participants were ordered from Crowdflower. The final sample consisted of 188 participants (89 men, 94 women, 5 did not report a gender) from the United States (M_age = 35.38 years, SD_age = 12.87 years).

Measures. In the strong political belief condition participants were asked to describe “a political opinion that you hold and feel very strongly about.” As a follow-up, they were then asked to “briefly describe why the above issue is really important to you.” In the weak political belief condition participants were asked to describe “a political opinion that you hold and do NOT feel very strongly about.” They were then asked to “briefly describe why the above issue is not really important to you.” The effectiveness of the manipulation was assessed with a 3-item manipulation check (e.g., “How strongly do you feel about the political issue you just described?” 1 = not very strongly, 7 = very strongly).

Participants then completed the following measures (1 = strongly disagree, 7 = strongly agree, unless otherwise noted):

• The dogmatic intolerance scale, tailored towards the issue they just described (e.g., “Everyone should think like me about the issue I described”).
• A 2-item measure of willingness to protest (‘‘I would be willing to publicly protest in support of the issue I described’’ and ‘‘I would be willing to sign a petition in support of the issue I described’’).
• A 3-item measure of denial of free speech (e.g., ‘‘People who think differently about the issue I described should be punished”).
• A 3-item measure of support for anti-social behavior (e.g., ‘‘I can imagine feeling sympathy for people who use violence in support of the issue I described’’).
• A left-right scale of political ideology (1 = very left wing, 7 = very right wing).

Results. The manipulation check indicated that strength of belief was effectively impacted (standard deviations in parentheses). Additionally, as predicted, participants in the strong political belief condition reported higher levels of dogmatic intolerance toward those who held a different viewpoint.

The remaining variables of interest were analyzed with a MANOVA and a significant multivariate effect was found. Additionally, the univariate effects for all three variables were also significant. In other words, stronger political beliefs, compared to weaker political beliefs, was linked to a greater willingness to protest, a stronger tendency to advocate denial of free speech, and greater support for anti-social behavior.

Bootstrapping step-wise regression analyses of 5,000 bias corrected samples suggested the strength of political belief predicted dogmatic intolerance which in turn predicted willingness to protest, denial of free speech, and support for anti-social behavior. Finally, political belief manipulation was effect coded (1 = strong belief, -1 = weak belief), political ideology was mean-centered, and interaction terms for all dependent variables were calculated. None of the interactions were significant, suggesting that the strength of political belief exerted its impact on dogmatic intolerance, willingness to protest, denial of free speech, and support for anti-social behavior independent of political ideology.

Conclusions

• Studies 1 and 2 found that when the relationship between political ideology and dogmatic intolerance is considered in a linear fashion, dogmatic intolerance is stronger on the political right.
• Yet, as one moves towards the left and right, extremes report greater dogmatic intolerance than do moderates on the left and right.
• Study 3 suggests that the strength of a political belief can influence dogmatic intolerance and that dogmatic intolerance then increases willingness to protest, denial of free speech, and support for anti-social behavior.
• When the results of all three studies are taken together they suggest that:
  • Dogmatic intolerance increases as one moves towards the extremes of the left-right political spectrum, although may be stronger on the extreme right.
  • People tend to be dogmatically intolerant towards those who disagree with their strongly held political beliefs.