Inclusion in a superordinate category, in-group prototypicality, and attitudes towards out-groups Sven Waldzus * and Am elie Mummendey University of Jena, Lisbon, Portugal Received 27 February 2002; revised 14 July 2003 Available online 21 November 2003 Abstract We hypothesized that group membersÕ attitudes towards an out-group are negatively related to the in-groupÕs perceived relative prototypicality for a superordinate category, but only if both the in-group and out-group are included in this superordinate cat- egory. In Experiment 1 (N ¼ 40), GermansÕ attitudes towards Poles were negatively correlated with the relative prototypicality of Germans when ‘‘Europe’’ (including Poles), but not when ‘‘West-Europe’’ (excluding Poles), was the superordinate category. In Experiment 2 (N ¼ 63), female single parentsÕ attitudes about the competence of single parents to raise children depended on the in- groupÕs relative prototypicality for ‘‘single parents’’ (including fathers), but not on their relative similarity to ‘‘mothers’’ (excluding fathers). Both experiments showed that inclusion in a superordinate category had a more negative influence on attitudes towards the out-group when relative in-group prototypicality is high rather than low. Ó 2003 Elsevier Inc. All rights reserved. Introduction Intergroup research has shown that out-groups are often evaluated less positively and treated less favorably than in-groups. Since Sumner (1906) coined the terms in-group, out-group, and ethnocentrism, intergroup re- search has assumed that the evaluation of an out-group depends on comparisons with the in-group (for reviews, see Brewer & Brown, 1998; Messick & Mackie, 1989; Tajfel, 1982). Comparison between the in-group and out-group serves to explain both in-group favoritism and out-group discrimination, which are viewed as two sides of the same coin. Nevertheless, the nature of this link between the (often positive) evaluation of the in- group and the (often negative) evaluation of the out- group has remained unclear. We still do not know when such comparisons are relevant for the evaluation of an out-group, and when a positive in-group evaluation implies a negative evaluation of the out-group. The question is, whether distinguishing the out-group from the in-group actually means ‘‘being worse,’’ or just ‘‘being different,’’ or even ‘‘being better’’ (see Boldry & Kashy, 1999; Jost, 2001; Jost & Burgess, 2000). Inclusion, relative prototypicality, and evaluation of the out-group To understand the process of out-group evaluation, we need to realize that mental concepts, such as social categories, are always evaluated with respect to partic- ular criteria or standards (Medin, Goldstone, & Gent- ner, 1993; Tversky, 1977). Thus, the evaluative implications of dissimilarity between an in-group and an out-group depend on the comparison background. On what basis are the two groups comparable, and thus similar or different? For intergroup comparisons, self-categorization the- ory (SCT, Turner, Hogg, Oakes, Reicher, & Wetherell, 1987) specifies this background. In SCT, it is assumed that the in-group and out-group are compared with respect to a superordinate category that includes both in- group and out-group members. This superordinate cat- egory provides dimensions, norms, and standards for group comparisons. For example, if Catholics are the in- group and Protestants are the out-group, then they are * Corresponding author. Present address: Departamento de Psico- logia Social e das Organizac ß~ oes, ISCTE, Av. Forc ßas Armadas, 1649- 026 Lisbon, Portugal. E-mail address: sven.waldzus@iscte.pt (S. Waldzus). 0022-1031/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.jesp.2003.09.003 Journal of Experimental Social Psychology 40 (2004) 466–477 Journal of Experimental Social Psychology www.elsevier.com/locate/jesp