¹ Gibson, James L. and Gouws, Amanda, ‘Making Tolerance Judgments: The effects of Context, Local and National’, Journal of Politics, 63 (2001), 1067–1090CrossRefGoogle Scholar.

² Gibson, James L., ‘The Paradoxes of Political Tolerance in Processes of Democratization’, Politikon, 23 (1996), 5–21CrossRefGoogle Scholar; Gibson, James L., ‘A Sober Second Thought: An Experiment in Persuading Russians to Tolerate’, American Journal of Political Science 42 (1998), 819–850CrossRefGoogle Scholar; Gibson, James L. and Gouws, Amanda, Overcoming Intolerance in South Africa: Experiments in Democratic Persuasion (Cambridge: Cambridge University Press, 2003)Google Scholar; Sniderman, Paul M., Fletcher, Joseph F., Russell, Peter H. and Tetlock, Philip E., The Clash of Rights: Liberty, Equality and Legitimacy in Pluralist Democracy (New Haven, Conn.: Yale University Press, 1996)Google Scholar; Sullivan, John L., Piereson, James E., and Marcus, George E., Political Tolerance and American Democracy (Chicago: The University of Chicago Press, 1982)Google Scholar.

³ Gibson and Gouws, ‘Making Tolerance Judgements’.

⁴ Sullivan et al., Political Tolerance and American Democracy.

⁵ Gibson, James L., ‘Enigmas of Intolerance: Fifty Years after Stouffers’s Communism, Conformity, and Civil Liberties’, Perspectives on Politics, 4 (2006), 21–34CrossRefGoogle Scholar, p. 22.

⁶ Mondak, Jeffery L. and Sanders, Mitchell S., ‘Tolerance and Intolerance, 1976–1998’, American Journal of Political Science, 47 (2003), 492–502CrossRefGoogle Scholar; Gibson and Gouws, Overcoming Intolerance in South Africa; Gibson, ‘Enigmas of Intolerance’; Gibson, James L., ‘Political Intolerance in the Context of Democratic Theory’, in Russell J. Dalton and Hans-Dieter Klingemann, eds, The Oxford Handbook of Political Behavior (New York: Oxford University Press, 2007), pp. 323–341Google Scholar.

⁷ Mondak and Sanders, ‘Tolerance and Intolerance’; Sullivan et al., Political Tolerance and American Democracy.

⁸ Gibson, ‘A Sober Second Thought’; Gibson, ‘Enigmas of Tolerance’; Gibson, ‘Political Intolerance in the Context of Democratic Theory’; Gibson and Gouws, Overcoming Intolerance in South Africa.

⁹ Stouffer, Samuel A., Communism, Conformity & Civil Liberties (Garden City, N.Y.: Doubleday, 1955)Google Scholar; Sullivan et al., Political Tolerance and American Democracy.

¹⁰ Sullivan et al., Political Tolerance and American Democracy, p. 2; see also Gibson, ‘Enigmas of Tolerance’; Gibson, ‘Political Intolerance in the Context of Democratic Theory’.

¹¹ Sullivan et al., Political Tolerance and American Democracy.

¹² Mondak and Sanders, ‘Tolerance and Intolerance’; Gibson and Gouws, Overcoming Intolerance in South Africa; Gibson, ‘Enigmas of Tolerance’; Gibson, ‘Political Intolerance in the Context of Democratic Theory’.

¹³ Sniderman, Paul M., Tetlock, Philip E., Glaser, James M., Green, Donald P. and Hout, Michael, ‘Principled Tolerance and the American Mass Public’, British Journal of Political Science, 19 (1989), 25–45CrossRefGoogle Scholar, p. 42; see also Sniderman et al., The Clash of Rights, pp. 225, 232–4.

¹⁴ Gouldner, Alvin, ‘The Norm of Reciprocity: A Preliminary Statement’, American Sociological Review, 25 (1960), 161–178CrossRefGoogle Scholar; Fehr, Ernst and Gintis, Herbert, ‘Human Motivation and Social Cooperation: Experimental and Analytical Foundations’, Annual Review of Sociology, 33 (2007), 42–46CrossRefGoogle Scholar; Ostrom, Elinor and Walker, James, eds, Trust and Reciprocity. Interdisciplinary Lessons from Experimental Research (New York: Russell Sage Foundation, 2003)Google Scholar; Chong, Dennis, ‘How People Think, Reason, and Feel about Rights and Liberties’, American Journal of Political Science, 37 (1993), 867–899CrossRefGoogle Scholar; Kuklinski, James H., Riggle, Ellen, Ottati, Victor, Schwarz, Norbert and Wyer, Robert S. Jr, ‘The Cognitive and Affective Bases of Political Tolerance Judgments’, American Journal of Political Science, 35 (1991), 1–27CrossRefGoogle Scholar.

¹⁵ Rohrschneider, Robert, ‘Institutional Learning versus Value Diffusion: The Evolution of Democratic Values among Parliamentarians in Eastern and Western Germany’, Journal of Politics, 58 (1996), 442–466CrossRefGoogle Scholar; Sullivan et al., Political Tolerance and American Democracy; Gibson, ‘Enigmas of Tolerance’; Gibson, ‘Political Intolerance in the Context of Democratic Theory’; Kuklinski et al., ‘The Cognitive and Affective Bases of Political Tolerance Judgments’.

¹⁶ Gibson, ‘The Paradoxes of Political Tolerance in Processes of Democratization’; Gibson, ‘A Sober Second Thought’.

¹⁷ Gibson, ‘A Sober Second Thought’; Peffley, Mark, Knigge, Pia and Hurwitz, Jon, ‘A Multiple Values Model of Political Tolerance’, Political Research Quarterly, 2 (2001), 279–306Google Scholar; Gibson and Gouws, Overcoming Intolerance in South Africa.

¹⁸ See also Rohrschneider, ‘Institutional Learning versus Value Diffusion’.

¹⁹ E.g., Nelson, Thomas E. and Garst, Jennifer, ‘Values-based Political Messages and Persuasion: Relationships among Speaker, Recipient, and Evoked Values’, Political Psychology, 26 (2005), 489–515CrossRefGoogle Scholar; Peffley, Mark and Hurwitz, Jon, ‘Persuasion and Resistance: Race and the Death Penalty in America’, American Journal of Political Science, 51 (2007), 996–1012CrossRefGoogle Scholar.

²⁰ Details on the sample are available in the web appendix at http://www.journals.cambridge.org/jps.

²¹ Schuman, Howard and Presser, Stanley, Questions and Answers in Attitude Surveys (Thousand Oaks, Calif.: Sage, 1996)Google Scholar.

²² For a comparable approach, see Gibson and Gouws, Overcoming Intolerance in South Africa.

²³ Rohrschneider, ‘Institutional Learning versus Value Diffusion’; Kuklinski et al., ‘The Cognitive and Affective Bases of Political Tolerance Judgments’.

²⁴ The autonome is a loose grouping of anarchist youth grown out of the squatter movement of the 1970s and 1980s and has links to similar groups in other Western countries. Their demonstrations and activities are often associated with vandalism and violent clashes with the police.

²⁵ Full details on the sample etc. are available in the web appendix at http://www.journals.cambridge.org/jps.

²⁶ We return to the classification of the eight groups in the conclusion.

²⁷ Rohrschneider, ‘Institutional Learning versus Value Diffusion’; Kuklinski et al., ‘The Cognitive and Affective Bases of Political Tolerance Judgments’.

²⁸ The ordering of the groups is roughly identical on each of the four individual indicators. See the web appendix at http://www.journals.cambridge.org/jps for details.

²⁹ Since all respondents were randomly presented with both a political group and a social group it is not possible to conduct a combined test for the significance of the difference between extremist and non-extremist groups. When running the tests separately for political and social groups, however, we find that the difference between the percentages of tolerant responses is clearly significant (p < 0.001) for both sets of groups.

³⁰ Again, the difference between the percentages of tolerant answers is clearly significant (p < 0.001) among both social and political groups. In this context, it should also be emphasized that with the exception of ordinary Muslims, to whom we shall return, the results among all respondents are not driven by people who feel sympathetic towards the groups. Thus, the percentage scoring above the mid-point on the sympathy scale is small for all groups expect ordinary Muslims and the far left: Muslims: 35.6; the far right: 12.3; Christian fundamentalists: 8.2; the far left: 22.3; Neo-Nazis: 1.1; bikers: 4.6; Islamic fundamentalists: 1.5; the autonome: 5.3.

³¹ Our analyses below provide further evidence that the difference in tolerance towards extreme and non-extreme groups is not primarily driven by group sympathy. See also Hurwitz, Jon and Mondak, Jeffrey J., ‘Democratic Principles, Discrimination and Political Intolerance’, British Journal of Political Science, 32 (2002), 93–118CrossRefGoogle Scholar.

³² Sniderman, Paul M. and Hagendoorn, Louk, When Ways of Life Collide (Princeton, N.J.: Princeton University Press, 2007)Google Scholar.

³³ Sniderman and Hagendoorn, When Ways of Life Collide.

³⁴ Gibson, ‘Political Intolerance in the Context of Democratic Theory’.

³⁵ See, e.g., Rohrschneider, ‘Institutional Learning versus Value Diffusion’; Gibson, ‘A Sober Second Thought’; Gibson and Gouws, Overcoming Intolerance in South Africa.

³⁶ The findings in Table 1 are robust to the exclusion of respondents who are sympathetic towards the groups. Thus, when the relatively few respondents scoring above the mid-point on the sympathy scale (see fn. 30) are omitted from the analysis, we obtain substantially equivalent results: The group × sympathy interactions are significant for both political (F _{3, 1297} = 3.327, p = 0.019) and social (F _{3, 1272} = 7.275, p < 0.001) groups and the effect of sympathy on tolerance also varies in a similar way across the groups. Thus, for the political groups, we find fairly strong and significant effects of 0.302 (p = 0.005) and 0.346 (p < 0.001) for the two extreme groups (Neo-Nazis and the autonome, respectively), while the effects are much weaker for the two non-extreme groups: 0.134 (p = 0.041) for the far right and 0.052 (p = 0.505) for the far left. The pattern is replicated for the social groups, although again Muslims stand out: for the non-extreme groups we find effects of −0.096 (p = 0.184) for Christian Fundamentalists and 0.387 (p < 0.001) for Muslims. For the extreme groups, the effects are 0.353 (p < 0.001) for Islamic Fundamentalists and 0.117 (p = 0.097) for bikers (the latter coefficient is only 0.017 smaller than in the analysis reported in Table 1, but combined with the reduction in sample size it results in a marginal significance level). The online appendix contains the full table of coefficients from the analysis on the reduced dataset.

³⁷ When interpreting the figures, it should be kept in mind that the distributions on the sympathy variables vary across the groups (cf. fn. 30). This means that at the extreme positive values where e.g. Islamic fundamentalists, are predicted to enjoy greater tolerance than Christian fundamentalists, there are virtually no respondents. In this sense, the predictions at these levels for the extreme groups are of no substantial interest and border on meaninglessness.

³⁸ Cf. also Sniderman et al., ‘Principled Tolerance and the American Mass Public’.

³⁹ It is worth noting that our results speak strongly against an alternative interpretation claiming that people’s answers to our questions about the groups’ commitment to democracy and non-violence (cf. Figure 1) are driven by their dislike or threat-based intolerance – in essence that the answers reflect people’s justifications for their intolerance rather than their genuine perceptions of the groups. Table 1 clearly shows that the differences across the eight groups persist even when we take the respondents’ levels of perceived threat and sympathy towards the groups (as well as a range of other variables) into account. The inability of these factors to account for the different tolerance levels displayed towards the groups, as well as our finding that the mechanisms behind the formation of tolerance differ between extreme and non-extreme groups, consistently supports our reciprocity argument.

⁴⁰ Gibson, ‘A Sober Second Thought’; Gibson and Gouws, Overcoming Intolerance in South Africa.

⁴¹ Thus, we ignore those who initially responded ‘neither agree nor disagree’ or ‘don’t know’. When referring to the percentage who changed opinion, we are thus referring to the respondents who were initially (completely or somewhat) in agreement or disagreement, who allowed themselves to be persuaded to be (completely or somewhat) in disagreement or agreement, respectively.

⁴² Gibson, ’The Paradoxes of Political Tolerance’; Gibson, ‘A Sober Second Thought’; Gibson and Gouws, Overcoming Intolerance in South Africa; Sniderman et al., ‘Principled Tolerance and the American Mass Public’.

⁴³ In response to each of the four counterarguments, more respondents changed their opinion in the direction of the argument than in the opposite direction. We can, therefore, rule out the possibility that opinion changes were caused merely by the counterargument stimulating people to elaborate more on the question and in turn alter their opinion. In that case, a roughly equal number would have changed their opinion in either direction.

⁴⁴ We also found that the strength of initial opinion influenced the pliability of tolerance. Thus, while we could move 26 and 22 per cent, respectively, of those who initially agreed or disagreed completely, we could persuade 38 and 28 per cent of the respondents who initially agreed or disagreed somewhat. Moreover, susceptibility to persuasion was moderated by gender, education and authoritarian–libertarian values among the initially tolerant, but not among initially intolerant individuals in whom only general democratic rights played a role. Details are in the web appendix available at http://www.journals.cambridge.org/jps.

⁴⁵ Gibson, ‘Enigmas of Intolerance; McClosky, Herbert and Brill, Alida, Dimensions of Tolerance (New York: Russell Sage Foundation, 1983)Google Scholar.

⁴⁶ Sniderman et al., The Clash of Rights; Kuklinski et al., ‘The Cognitive and Affective Bases of Political Tolerance Judgments’; Chong, ‘How People Think, Reason, and Feel about Rights and Liberties’; Gouldner, ‘The Norm of Reciprocity’; Fehr and Gintis, ‘Human Motivation and Social Cooperation’; Ostrom and Walker, eds, Trust and Reciprocity.