Widening polarization about political, religious, and scientific issues threatens open societies, leading to entrenchment of beliefs, reduced mutual understanding, and a pervasive negativity surrounding the very idea of consensus []. Such radicalization has been linked to systematic differences in the certainty with which people adhere to particular beliefs []. However, the drivers of unjustified certainty in radicals are rarely considered from the perspective of models of metacognition, and it remains unknown whether radicals show alterations in confidence bias (a tendency to publicly espouse higher confidence), metacognitive sensitivity (insight into the correctness of one’s beliefs), or both []. Within two independent general population samples (n = 381 and n = 417), here we show that individuals holding radical beliefs (as measured by questionnaires about political attitudes) display a specific impairment in metacognitive sensitivity about low-level perceptual discrimination judgments. Specifically, more radical participants displayed less insight into the correctness of their choices and reduced updating of their confidence when presented with post-decision evidence. Our use of a simple perceptual decision task enables us to rule out effects of previous knowledge, task performance, and motivational factors underpinning differences in metacognition. Instead, our findings highlight a generic resistance to recognizing and revising incorrect beliefs as a potential driver of radicalization.

The unthinking or confident extremist? Political extremists are more likely than moderates to reject experimenter-generated anchors.

Psychological motives and political orientation--the left, the right, and the rigid: comment on Jost et al. (2003).

Results and Discussion

3 Ortoleva P.

Snowberg E. Overconfidence in political behavior. 4 Toner K.

Leary M.R.

Asher M.W.

Jongman-Sereno K.P. Feeling superior is a bipartisan issue: extremity (not direction) of political views predicts perceived belief superiority. 5 Greenberg J.

Jonas E. Psychological motives and political orientation--the left, the right, and the rigid: comment on Jost et al. (2003). 6 Brandt M.J.

Evans A.M.

Crawford J.T. The unthinking or confident extremist? Political extremists are more likely than moderates to reject experimenter-generated anchors. 3 Ortoleva P.

Snowberg E. Overconfidence in political behavior. 4 Toner K.

Leary M.R.

Asher M.W.

Jongman-Sereno K.P. Feeling superior is a bipartisan issue: extremity (not direction) of political views predicts perceived belief superiority. 6 Brandt M.J.

Evans A.M.

Crawford J.T. The unthinking or confident extremist? Political extremists are more likely than moderates to reject experimenter-generated anchors. 8 Ais J.

Zylberberg A.

Barttfeld P.

Sigman M. Individual consistency in the accuracy and distribution of confidence judgments. 9 Rouault M.

Seow T.

Gillan C.M.

Fleming S.M. Psychiatric symptom dimensions are associated with dissociable shifts in metacognition but not task performance. 7 Fleming S.M.

Lau H.C. How to measure metacognition. An unjustified certainty in one’s beliefs is a characteristic common to those espousing radical beliefs [], and such overconfidence is observed for both political and non-political issues [], implying a general cognitive bias in radicals. However, the underpinnings of radicals’ distorted confidence estimates remain unknown. In particular, one-shot measures of the discrepancy between performance and confidence are unable to disentangle the contributions of confidence bias (changes in an overall belief about performance, which may be affected by optimism [] and mood []) from changes in metacognitive sensitivity (an ability to distinguish accurate from inaccurate performance; []).

10 van den Berg R.

Anandalingam K.

Zylberberg A.

Kiani R.

Shadlen M.N.

Wolpert D.M. A common mechanism underlies changes of mind about decisions and confidence. 11 Fleming S.M.

van der Putten E.J.

Daw N.D. Neural mediators of changes of mind about perceptual decisions. 12 Fleming S.M.

Dolan R.J. The neural basis of metacognitive ability. 13 Rabbitt P.M. Errors and error correction in choice-response tasks. 14 Yeung N.

Summerfield C. Metacognition in human decision-making: confidence and error monitoring. 15 Nyhan B.

Reifler J. When corrections fail: The persistence of political misperceptions. 16 Kaplan J.T.

Gimbel S.I.

Harris S. Neural correlates of maintaining one’s political beliefs in the face of counterevidence. 17 Taber C.S.

Cann D.

Kucsova S. The motivated processing of political arguments. 18 Redlawsk D.P. Hot cognition or cool consideration? Testing the effects of motivated reasoning on political decision making. This distinction may be particularly important as changes in metacognitive sensitivity may account for radicals’ reluctance to change their mind in the face of new evidence. Decision neuroscience has highlighted that metacognitive sensitivity depends on mechanisms that facilitate monitoring and revision of confidence in previous choices []. This ability relies on specific neural circuitry in the prefrontal cortex [] that promotes reflection on one’s performance and, even in the absence of explicit feedback, a realization that mistakes have been made []. It has generally been assumed that a resistance of radicals to change their beliefs is due to social and motivational factors, such as the desire to maintain a positive self-image [], whereas the role of metacognitive capacities has received less attention. However, changes of mind depend not only on a motivation to change but also on a (metacognitive) capacity to realize that one’s beliefs are wrong.

7 Fleming S.M.

Lau H.C. How to measure metacognition. By employing simple perceptual discrimination tasks, it is possible to precisely quantify metacognitive sensitivity—the extent to which people’s confidence judgments are sensitive to task performance—and to disentangle metacognitive sensitivity from overconfidence bias []. Such tasks provide an objectively correct answer (which is rarely the case for direct assays of political attitudes where the ground truth is often unknown or unavailable), thus enabling a precise, quantitative, and objective measure of metacognitive ability as well as a normative prediction for changes of confidence in light of new evidence. Moreover, the usage of a perceptual task makes it unlikely that participants have a priori vested interests in a particular decision outcome, thus diminishing any strong link to participants’ self-concept and providing an assay of the relationship between domain-general metacognitive abilities and radicalism. Here, we test a hypothesis that limitations in metacognitive sensitivity lead to a resistance to belief change, even when motivational factors are minimized, and that such metacognitive limitations are associated with the entrenched beliefs that are exemplified by radicals.

4 Toner K.

Leary M.R.

Asher M.W.

Jongman-Sereno K.P. Feeling superior is a bipartisan issue: extremity (not direction) of political views predicts perceived belief superiority. 19 Everett J.A. The 12 item social and economic conservatism scale (SECS). 20 Funke F. The dimensionality of right-wing authoritarianism: Lessons from the dilemma between theory and measurement. 21 Van Hiel A.

Duriez B.

Kossowska M. The presence of left-wing authoritarianism in Western Europe and its relationship with conservative ideology. 22 Altemeyer B. Dogmatic behavior among students: testing a new measure of dogmatism. 23 Rokeach M. The open and closed mind. 24 Van Hiel A. A psycho-political profile of party activists and left-wing and right-wing extremists. 25 Eysenck H.J. The psychology of politics. 22 Altemeyer B. Dogmatic behavior among students: testing a new measure of dogmatism. 26 Altemeyer B.

Hunsberger B. Authoritarianism, religious fundamentalism, quest, and prejudice. 27 Cross R.

Snow D.A. Radicalism within the context of social movements: Processes and types. To typify a spectrum of radical views, we first conducted a separate online survey of 344 US participants (study 1) who completed questionnaires about political issues []. We included standard questionnaires about political orientation, voting behavior, attitudes toward specific political issues, intolerance of opposing political attitudes, belief rigidity, and (left- and right-wing) authoritarianism. These questionnaires were selected based on prior models of political radicalism as stemming from a combination of intolerance to others’ viewpoints, dogmatic and rigid beliefs, and authoritarianism, which represents adherence to in-group authorities and conventions, and aggression in relation to deviance from these norms []. However, we stress that radicalism is likely to reflect a general cognitive style that transcends the political domain—as exemplified by links between religious fundamentalism and increased dogmatism and authoritarianism []—and instead refers to how one’s beliefs are held and acted upon [].

23 Rokeach M. The open and closed mind. 24 Van Hiel A. A psycho-political profile of party activists and left-wing and right-wing extremists. 25 Eysenck H.J. The psychology of politics. Figure 1 The Left and Right Extremes of the Political Spectrum Are Associated with Intolerant and Dogmatic World Views Show full caption Data presented from study 1 (n = 344). (A) Using factor analysis, we investigated the underlying factor structure of multiple questionnaires about political issues. Three latent factors were identified and labeled “political orientation,” “dogmatic intolerance,” and “authoritarianism” according to the pattern of individual item loadings. Item loadings for each question (questionnaires indicated by different colors) are presented. (B–D) To investigate the relation between these constructs, scores on the three factors were extracted for each individual. (B) We observed a quadratic relationship between political orientation and dogmatic intolerance, revealing that people on the extremes of the political spectrum are more rigid and dogmatic in their world views. (C) A linear relationship between political orientation and authoritarianism was observed, with people from the far right of the political spectrum showing more obedience to authorities and conventions. (D) Dogmatic intolerance and authoritarianism were positively correlated, indicating commonality between these two sub-components of radicalism. See also STAR Methods and Figure S1 A factor analysis of individual items identified three latent factors ( Figure 1 A; see STAR Methods for detailed information about the factor loadings and their interpretation), which we labeled “political orientation” (loading on leftward versus rightward political views), “dogmatic intolerance” (loading on questions related to intolerance to opposing political beliefs and rigidity of belief system), and “authoritarianism” (loading on questions related to obedience to authorities, adherence to group conventions, and aggression against deviating behavior). Together, these three factors explained 40% of the variance in questionnaire responses. In what follows, we focus on the dogmatic intolerance and authoritarianism factor scores as summary indices of radicalism [].

−11), indicating that both the far left and far right of the political spectrum hold similarly intolerant and rigid beliefs, replicating previous findings [ 28 Van Prooijen J.W.

Krouwel A.P. Extreme political beliefs predict dogmatic intolerance. −11), showing that those on the right of the political spectrum displayed higher levels of authoritarianism, also as reported previously [ 29 Altemeyer B. The authoritarian specter. Notably, a clear quadratic relationship was evident between political orientation and dogmatic intolerance (β = 0.37, p < 10), indicating that both the far left and far right of the political spectrum hold similarly intolerant and rigid beliefs, replicating previous findings []. On the other hand, a linear relationship of authoritarianism with political orientation was found (β = 0.38, p < 10), showing that those on the right of the political spectrum displayed higher levels of authoritarianism, also as reported previously []. Finally, dogmatic intolerance and authoritarianism were positively correlated (β = 0.21, p < 0.0001).

−16; study 3: β = 0.40, p < 10−15; linear relationship between authoritarianism and political orientation, study 2: β = 0.32, p < 10−8; study 3: β = 0.38, p < 10−12; positive association between authoritarianism and dogmatic intolerance, study 2: β = 0.22, p < 10−4; study 3: β = 0.29, p < 10−7). Figure 2 Behavioral Tasks Show full caption (A) Confidence task (task 1): Participants were asked to judge which of two patches contained a greater number of flickering dots before rating their confidence in each decision. Task difficulty was determined by a fixed difference in dot number between the patches and was individually adjusted in an initial calibration phase to target approximately 71% correct performance. (B) Post-decision evidence integration task (task 2): Participants performed the same perceptual decision as in part (A), but after each decision, they were presented again with a new sample of flickering dots before rating their confidence. In half of trials, participants received the same evidence strength post-decision as pre-decision, while in the other half of trials, they received stronger post-decision evidence (pre-adjusted to a strength that led to 80% performance). (C) Metacognitive sensitivity is defined as the correspondence between task performance and confidence ratings—the extent to which participants rate higher confidence when correct and lower confidence when incorrect. Each graph shows a hypothetical probability distribution over confidence ratings for correct and incorrect trials, with the overlap between distributions determining metacognitive sensitivity. A small separation between these distributions indicates low metacognitive sensitivity (upper), while a large separation indicates high metacognitive sensitivity (lower). See also STAR Methods We next investigated whether metacognitive aspects of decision-making predict facets of radicalism. Subjects were asked to carry out a series of perceptual discrimination tasks assaying decision-making and metacognition ( Figures 2 A and 2B ) before filling out the same questionnaires administered in study 1. A first experiment was conducted on a new sample of 381 US participants (study 2), and all key findings were replicated in an independent sample of 417 US participants (study 3). Importantly, we also replicated both the three-factor structure of questionnaire responses observed in study 1 and the pattern of interrelations between factors (quadratic relationship between dogmatic intolerance and political orientation, study 2: β = 0.42, p < 10; study 3: β = 0.40, p < 10; linear relationship between authoritarianism and political orientation, study 2: β = 0.32, p < 10; study 3: β = 0.38, p < 10; positive association between authoritarianism and dogmatic intolerance, study 2: β = 0.22, p < 10; study 3: β = 0.29, p < 10).

30 Maniscalco B.

Lau H. A signal detection theoretic approach for estimating metacognitive sensitivity from confidence ratings. 7 Fleming S.M.

Lau H.C. How to measure metacognition. In the confidence task (task 1), participants first completed a series of perceptual discrimination judgments as to which of two flickering patches contained a greater density of dots, followed by confidence ratings in their choices. Participants were rewarded according to the extent to which confidence ratings tracked their objective performance over 60 trials and were thus incentivized to report their confidence as accurately as possible. Our measure of interest was metacognitive sensitivity (meta-d′) [], which quantifies subjects’ ability to discriminate correct from incorrect decisions (see Figure 2 C for the intuition underpinning this measure). Metacognitive sensitivity is conceptually and empirically distinct from a bias toward reporting higher or lower confidence [].

2 = 0.01; see 2 = 0.014), again in the absence of any observed link with perceptual performance (β = 0.04, p = 0.60) or confidence bias (β = 0.07, p = 0.24). These results show that more dogmatic people manifest a lowered capacity to discriminate between their correct and incorrect decisions, after controlling for differences in both primary task performance and confidence bias. We obtained a qualitatively similar pattern for authoritarianism (see Figure 3 Impaired Metacognitive Sensitivity and Reduced Disconfirmatory Evidence Integration Predict Facets of Radicalism Show full caption (A–C) Multiple regression analyses predicting factor scores (dogmatic intolerance, authoritarianism, and political orientation) from metacognitive sensitivity and post-decision evidence integration, controlling for multiple demographic variables (gender, education, age) and other task-related variables (e.g., performance in the perceptual decision task). Perceptual performance was averaged across tasks 1 and 2. We present standardized beta coefficients ± SE of predictors for study 2 (left markers, n = 381) and study 3 (right markers, n = 417). (A) Dogmatic intolerance was associated with impaired metacognitive sensitivity and reduced disconfirmatory evidence integration, in the absence of differences in overconfidence or performance. (B) Authoritarianism showed qualitatively similar patterns of association as dogmatism. (C) Political orientation (higher values represent more conservative views) was consistently associated with a bias toward overconfidence but not changes in metacognitive sensitivity or post-decision evidence integration. Effects in study 3 were tested one-tailed based on the directional hypothesis derived from study 2. †p < 0.1, ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. Task 1, confidence task; task 2, post-decision evidence integration task. See also Figures S3 and S4 Figure 4 Individual Differences in Radicalism Are Captured by a Choice Bias Model Show full caption (A) A choice bias model fitted to the confidence data across both tasks best accounted for variations in a composite measure of radicalism (summed factor scores of dogmatic intolerance and authoritarianism). We compared among three computational models within multiple regressions that predicted radicalism from fitted model parameters. We present the BIC of each regression against the lowest BIC in the model set (the best model has a difference in BIC of zero). (B) Radicals reduce their confidence less when new evidence indicates they are wrong (reduced disconfirmatory evidence integration). To visualize this effect, we combined data from study 2 and study 3 and compared the 10% most radical participants (based on the composite measure) against the rest of the sample. Aggregate confidence ratings are separated according to whether the decision was correct (green) or incorrect (red). Markers (circles and squares) show raw data (group averages ±95% confidence interval) for each condition. Lines (solid line, moderates; dashed line, radicals) show posterior predictives from the choice bias model. Predictions were simulated from best-fitting parameters and represent group averages ±95% confidence interval. Task 1, confidence task; task 2, post-decision evidence integration task. See also STAR Methods and Figures S3 and S4 In line with our hypothesis, higher values of dogmatic intolerance were associated with reduced metacognitive sensitivity (study 2: β = −0.12, p = 0.032, R= 0.01; see Figure 3 A), in the absence of any effect on perceptual discrimination performance (study 2: β = 0.02, p = 0.77) and controlling for key demographic variables (i.e., age, gender, education). Importantly, there was also no relation between dogmatism and overconfidence (study 2: β = 0.07, p = 0.26), suggesting a specific reduction in the sensitivity with which confidence tracks performance, rather than a bias in confidence. We replicated this reduction of metacognitive sensitivity in dogmatic individuals in study 3 (β = −0.13, one-tailed p = 0.008, R= 0.014), again in the absence of any observed link with perceptual performance (β = 0.04, p = 0.60) or confidence bias (β = 0.07, p = 0.24). These results show that more dogmatic people manifest a lowered capacity to discriminate between their correct and incorrect decisions, after controlling for differences in both primary task performance and confidence bias. We obtained a qualitatively similar pattern for authoritarianism (see Figure 3 B), with trends of reduced metacognitive sensitivity (study 2: β = 0.11, p = 0.051; study 3: β = −0.08, one-tailed p = 0.08), but no relation with perceptual performance or confidence bias (all p values > 0.17). Across both facets of radicalism, this failure in metacognition was driven by radicals holding unreasonably high confidence in incorrect decisions compared to moderates ( Figures 4 B and S4 ).

5 Greenberg J.

Jonas E. Psychological motives and political orientation--the left, the right, and the rigid: comment on Jost et al. (2003). 31 Jost J.T.

Glaser J.

Kruglanski A.W.

Sulloway F.J. Political conservatism as motivated social cognition. 2 = 0.01; study 3: β = 0.12, one-tailed p = 0.033, R2 = 0.008; see 32 Moore D.A.

Healy P.J. The trouble with overconfidence. In light of long-standing debates about whether the cognitive profile of radicals is more similar to those on the left or right sides of the political spectrum [], we also tested the relation between political orientation (rightward versus leftward) and metacognition. Here, the pattern of results was qualitatively different, with no reduction of metacognitive sensitivity (study 2: β = −0.08, p = 0.18; study 3: β = −0.02, p = 0.73) in more conservative participants. In contrast, more conservative participants showed an increased bias toward overconfidence (study 2: β = 0.15, p = 0.035, R= 0.01; study 3: β = 0.12, one-tailed p = 0.033, R= 0.008; see Figure 3 C), as found previously [].

10 van den Berg R.

Anandalingam K.

Zylberberg A.

Kiani R.

Shadlen M.N.

Wolpert D.M. A common mechanism underlies changes of mind about decisions and confidence. 11 Fleming S.M.

van der Putten E.J.

Daw N.D. Neural mediators of changes of mind about perceptual decisions. 14 Yeung N.

Summerfield C. Metacognition in human decision-making: confidence and error monitoring. Metacognitive sensitivity is thought to be strongly linked to an integration of evidence following a decision, allowing latitude for the recognition and reversal of incorrect choices []. Having demonstrated a specific decrease in metacognitive sensitivity in more radical participants, we next considered the same participants’ sensitivity to new evidence. To specifically probe such post-decisional processing, in a second phase of the experiment, we inserted an additional sample of evidence (a new series of flickering dots) after subjects had committed to a choice but prior to providing a confidence rating (task 2). Following correct choices, additional evidence should normatively increase participants’ confidence (due to integration of confirmatory evidence; green markers in Figure 4 B), whereas for incorrect choices, additional evidence should lead to a decrease in confidence (due to integration of disconfirmatory evidence; red markers in Figure 4 B).

10 van den Berg R.

Anandalingam K.

Zylberberg A.

Kiani R.

Shadlen M.N.

Wolpert D.M. A common mechanism underlies changes of mind about decisions and confidence. 2 = 0.015; study 3: β = −0.1, one-tailed p = 0.034, R2 = 0.008; see 2 = 0.019) and the same trend in study 3 (β = −0.09, one-tailed p = 0.05, R2 = 0.01), despite no effect on confirmatory evidence integration (study 2: β = −0.04, p = 0.53; study 3: β = −0.09, p = 0.16). In contrast, while higher conservatism was related to reduced disconfirmatory evidence integration in study 2 (β = −0.17, p = 0.012), this effect was not replicated in study 3 (β = −0.02, one-tailed p = 0.33). In line with the proposal of a post-decisional process supporting metacognition [], metacognitive sensitivity measured in task 1 explained participants’ sensitivity to post-decision evidence in task 2 (study 2: β = 0.1, p = 0.034; study 3: β = 0.18, one-tailed p < 0.0001). Furthermore, and consistent with a tripartite relationship between radicalism, metacognitive sensitivity and post-decision evidence integration, dogmatic intolerance was associated with a specific reduction in disconfirmatory evidence integration (study 2: β = −0.15, p = 0.016, R= 0.015; study 3: β = −0.1, one-tailed p = 0.034, R= 0.008; see Figure 3 A), representing a smaller decrease in confidence on incorrect trials. Conversely, there was no association between confirmatory evidence integration on correct trials and dogmatism (study 2: β = 0.06, p = 0.37; study 3: β = −0.09, p = 0.13); i.e., more dogmatic people showed similar increases of confidence on correct trials as that seen in moderates. We again found a similar pattern of results in relation to authoritarianism (see Figure 3 B) with decreased disconfirmatory evidence integration in study 2 (β = −0.19, p = 0.005, R= 0.019) and the same trend in study 3 (β = −0.09, one-tailed p = 0.05, R= 0.01), despite no effect on confirmatory evidence integration (study 2: β = −0.04, p = 0.53; study 3: β = −0.09, p = 0.16). In contrast, while higher conservatism was related to reduced disconfirmatory evidence integration in study 2 (β = −0.17, p = 0.012), this effect was not replicated in study 3 (β = −0.02, one-tailed p = 0.33).

2 = 0.018; study 3: β = −0.13, one-tailed p = 0.006, R2 = 0.015) and reduced disconfirmatory evidence integration (study 2: β = −0.21, p = 0.001, R2 = 0.027; study 3: β = −0.12, one-tailed p = 0.015, R2 = 0.011). We next used this score to identify putative mechanisms underpinning reduced metacognitive sensitivity and disconfirmatory evidence integration in more radical participants. In light of associations among dogmatic intolerance, authoritarianism, and multiple behavioral measures of metacognitive sensitivity, we next asked whether we could identify a core computational driver of radicalism. We first combined the factor scores of dogmatic intolerance and authoritarianism to construct a composite measure of radicalism. As expected, this combined measure showed similar relationships with metacognition as the individual components (see Figure S3 ), with impaired metacognitive sensitivity (study 2: β = −0.13, p = 0.0098, R= 0.018; study 3: β = −0.13, one-tailed p = 0.006, R= 0.015) and reduced disconfirmatory evidence integration (study 2: β = −0.21, p = 0.001, R= 0.027; study 3: β = −0.12, one-tailed p = 0.015, R= 0.011). We next used this score to identify putative mechanisms underpinning reduced metacognitive sensitivity and disconfirmatory evidence integration in more radical participants.

11 Fleming S.M.

van der Putten E.J.

Daw N.D. Neural mediators of changes of mind about perceptual decisions. 33 Bronfman Z.Z.

Brezis N.

Moran R.

Tsetsos K.

Donner T.

Usher M. Decisions reduce sensitivity to subsequent information. low and μ high ) representing internal evidence strength for the weak and strong evidence conditions, respectively. The models differed in how they updated their confidence in light of new evidence. A “temporal weighting” model allows an asymmetry in the overall weighting of pre- and post-decision evidence; a “choice bias” model adds evidence for the chosen response, without altering post-decision evidence integration; and a “choice weighting” model incorporates asymmetric weighting of confirmatory and disconfirmatory evidence. We fit the model simultaneously to data from the confidence task (task 1, no post-decision evidence) and the post-decision evidence task (task 2) and compared models based on how well variability in fitted parameters captured individual differences in radicalism in a linear regression. To this end, we compared alternative computational models of how post-decision evidence affects confidence [] (see STAR Methods for detailed descriptions of the models). All models were grounded in signal detection theory, with two free parameters (μand μ) representing internal evidence strength for the weak and strong evidence conditions, respectively. The models differed in how they updated their confidence in light of new evidence. A “temporal weighting” model allows an asymmetry in the overall weighting of pre- and post-decision evidence; a “choice bias” model adds evidence for the chosen response, without altering post-decision evidence integration; and a “choice weighting” model incorporates asymmetric weighting of confirmatory and disconfirmatory evidence. We fit the model simultaneously to data from the confidence task (task 1, no post-decision evidence) and the post-decision evidence task (task 2) and compared models based on how well variability in fitted parameters captured individual differences in radicalism in a linear regression.

The “choice bias” model best explained variations in radicalism (difference in Bayesian information criterion [BIC] relative to next best model: study 2 = 3.5 and study 3 = 3.3; see Figure 4 A) via a positive association with choice-dependent biases in confidence (study 2: β = 0.14, p = 0.012; study 3: β = 0.18, one-tailed p = 0.0005). This model accounts for a reduction in post-decisional processing in more radical participants by boosting confidence in chosen options, thereby making changes of mind less likely ( Figure 4 B).

3 Ortoleva P.

Snowberg E. Overconfidence in political behavior. 4 Toner K.

Leary M.R.

Asher M.W.

Jongman-Sereno K.P. Feeling superior is a bipartisan issue: extremity (not direction) of political views predicts perceived belief superiority. 6 Brandt M.J.

Evans A.M.

Crawford J.T. The unthinking or confident extremist? Political extremists are more likely than moderates to reject experimenter-generated anchors. Taken together, our data show that key facets of radicalism are associated with specific alterations in metacognitive abilities. The finding that decision performance per se was not associated with radicalism reveals that a specific change in information processing is manifest at a metacognitive, rather than cognitive, level. Importantly, our results show that radicalism is associated with reductions in metacognitive sensitivity, i.e., the reliability with which subjects distinguish between their correct and incorrect beliefs. Thus, our findings complement and extend previous studies documenting alterations in confidence in political radicals [] but suggest that these alterations may stem from changes in metacognitive sensitivity. In contrast, for more right-wing subjects (as indexed by political orientation), a change in confidence bias was observed. Without the application of psychophysical measures of metacognition, it has not, up until now, been possible to disentangle these two factors.

15 Nyhan B.

Reifler J. When corrections fail: The persistence of political misperceptions. 16 Kaplan J.T.

Gimbel S.I.

Harris S. Neural correlates of maintaining one’s political beliefs in the face of counterevidence. 17 Taber C.S.

Cann D.

Kucsova S. The motivated processing of political arguments. 18 Redlawsk D.P. Hot cognition or cool consideration? Testing the effects of motivated reasoning on political decision making. What is striking is our demonstration that these impairments are evident during performance of a low-level perceptual discrimination task, where participants are unlikely to have strong a priori vested interest in the outcome of their decisions, ruling out multiple possible confounds (e.g., prior knowledge and motivational factors). This contrasts with previous studies that have investigated changes of mind about political attitudes themselves, a context where there exists a strong motivation for people to maintain their current beliefs in order to sustain a positive (and consistent) self-image []. Thus, our results suggest a potential explanation for why it is notoriously difficult to change extreme beliefs by what would appear to be the simple expediency of confronting people with evidence that contradicts these beliefs. Before such information can update attitudes, the manner in which a recipient processes this information may need to be altered. We stress, however, that our results are entirely compatible with a complementary role of motivational factors as contributing to the maintenance of radical beliefs, and it is possible that motivational factors may themselves interact with metacognitive abilities.

34 Brehm J.W. Postdecision changes in the desirability of alternatives. 11 Fleming S.M.

van der Putten E.J.

Daw N.D. Neural mediators of changes of mind about perceptual decisions. 33 Bronfman Z.Z.

Brezis N.

Moran R.

Tsetsos K.

Donner T.

Usher M. Decisions reduce sensitivity to subsequent information. Our modeling results suggest that a reduction in changes of mind in radicals is driven by a boosting effect of choice, leading participants to assign undue probability to the option they chose without affecting the integration of post-decision evidence. This computational mechanism shares notable similarities with classical findings in psychology in which the act of making a choice itself affects subsequent preferences []. In contrast, recent laboratory studies of post-decision evidence integration have found that subjects’ behavior was best described either by a near-optimal Bayesian model [] or by diminished sensitivity to post-decision evidence []. However, since both of these studies investigated small samples of participants, variability in radicalism of political and other beliefs was presumably limited, where, for example, a majority of “moderates” would obviate the need for a choice bias term. We stress that our modeling approach aimed to find a model that best accounts for individual differences in radicalism (while also fitting the overall behavioral pattern). How to reconcile such individual differences with a general model of post-decision evidence integration across different tasks remains a rich topic for future investigation.

35 Zmigrod L.

Rentfrow P.J.

Robbins T.W. Cognitive underpinnings of nationalistic ideology in the context of Brexit. 36 Meyniel F.

Schlunegger D.

Dehaene S. The sense of confidence during probabilistic learning: A normative account. In our study, we investigated independent judgments wherein participants integrate two consecutive samples of information. This is distinct from more elaborate beliefs formed over longer timescales, which require integration of multiple samples of information. A useful future extension of our work will be to extrapolate our findings to situations where learning is required over extended periods of time []. Our computational model fits indicate that more radical participants assign undue probability to chosen options when updating their confidence, which over repeated exposure to multiple samples of evidence may summate, such that even small asymmetries in information processing could lead to a highly skewed representation of reality. In the current task, such resistance to updating is detrimental, leading to a loss of earnings ( Figure S3 ). However, in other scenarios, such as if there were reason to distrust the fidelity of the new information, a reduction in belief flexibility may prove adaptive. Such considerations remain to be explored in future studies and point to the intriguing notion that metacognitive flexibility may itself be amenable to strategic or environmental influences.