Research article. Group entitativity and similarity: Their differing patterns in perceptions of groups

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1 European Journal of Social Psychology Eur. J. Soc. Psychol. 40, (2010) Published online 8 December 2009 in Wiley Online Library (wileyonlinelibrary.com).716 Research article Group entitativity and similarity: Their differing patterns in perceptions of groups SARA A. CRUMP 1 *, DAVID L. HAMILTON 2, STEVEN J. SHERMAN 3, BRIAN LICKEL 4 AND VINITA THAKKAR 2 1 Department of Psychology, Baker University, Baldwin City, KS, USA 2 Department of Psychology, University of California, Santa Barbara, CA, USA 3 Department of Psychology, Indiana University, Bloomington, IN, USA 4 Department of Psychology, University of Massachusetts, Amherst, MA, USA Abstract Three studies were conducted to investigate the relation between perceptions of group entitativity and group similarity. The first two studies tested whether entitativity and similarity would be perceived differently in participants ingroups and outgroups. Across several different group types, we found that, in comparison to outgroups, ingroups were perceived to be relatively more entitative than outgroups, whereas outgroup members were perceived to be highly similar in comparison to ingroup members. The results of Study 3 showed that manipulation of group entitativity influenced perceptions of group entitativity but not of group similarity, whereas manipulation of similarity influenced perceptions of group similarity but not of group entitativity. The results of these studies provide support for the contention that entitativity and similarity are distinct (though related) concepts that function differently in group perception. Copyright # 2009 John Wiley & Sons, Ltd. Recent research on entitativity has examined the fundamental process of how and when perceivers come to see a collection of individuals as a meaningful group. Although the seeds for this work were planted long ago (Campbell, 1958), it is only in recent years that research on this basic facet of group perception has blossomed. Campbell observed, and recent research (Lickel, Hamilton, Wieczorkowska, Lewis, Sherman, & Uhles, 2000) has demonstrated, that groups vary along an entitativity continuum such that some groups are perceived to be higher in entitativity than others (Hamilton & Sherman, 1996; Hamilton, Sherman, & Lickel, 1998). Moreover, Lickel et al. (2000; see also Sherman, Castelli, & Hamilton, 2002) demonstrated that people reliably distinguish among certain group types that vary in perceived entitativity: intimacy groups (e.g., family, friends) are the most entitative, followed by task groups (e.g., committees), social categories (e.g., gender, race), and loose association groups (e.g., people who like classical music). In addition, the impressions that perceivers form and the way information is processed about highly entitative groups differs from that of low entitativity groups (Castano, Sacchi, & Gries, 2003; Castano, Yzerbyt, & Bourguignon, 2003; Crawford, Sherman, & Hamilton, 2002; Hamilton, Sherman, & Maddox, 1999; Johnson & Queller, 2003; Pickett, 2001; Pickett & Perrott, 2004; Rydell & *Correspondence to: Sara A. Crump, Ph.D, Department of Psychology, Baker University, P.O. Box 65, Baldwin City, KS 66006, USA. sara.crump@bakeru.edu Copyright # 2009 John Wiley & Sons, Ltd. Received 4 August 2008 Accepted 9 September 2009

2 Perceptions of groups 1213 McConnell, 2005; Yzerbyt, Rogier, & Fiske, 1998). Sherman, Hamilton, and Lewis (1999) proposed that perceivers should make more polarized judgments of highly entitative groups. Moreover, perceivers recall more information about highly entitative targets (McConnell, Sherman, & Hamilton, 1997). Although this research has contributed to our understanding of what constitutes a meaningful group for perceivers, the fundamental distinction between perceived entitativity and certain other concepts remains murky and in need of clarification. This is particularly true for perceived similarity (which in this paper is used interchangeably with perceived homogeneity). In the extensive literature on perceived group variability and the outgroup homogeneity effect (Boldry, Gaertner, & Quinn, 2007; Mullen & Hu, 1989; Ostrom & Sedikides, 1992; Park & Judd, 1990; Quattrone & Jones, 1980), some have considered entitativity to be similar in meaning to homogeneity. A group whose members look the same, think the same, or act the same is likely to be seen as a highly entitative unit. Conversely, members of a highly entitative group might be assumed to share a number of meaningful similarities. Indeed, Campbell (1958) cited perceived similarity as one of the factors that could contribute to perceptions of entitativity, and Lickel et al. (2000) empirically documented that relationship. Given the apparent parallel between these two variables, it is not surprising that entitativity and similarity have been thought of and used interchangeably. Is it the case that entitativity and similarity actually represent the same construct in group perception? Hamilton (2007) recently raised questions about possible redundancies among the concepts that have been used to study the perception of groups, including entitativity and similarity. Research on the outgroup homogeneity effect has a long history in the study of groups. In contrast, research related to perceived entitativity has only recently been developed. Researchers who have focused on the study of group homogeneity may have been drawing on different literatures and may have been guided by a different perspective than those researchers who study entitativity. Empirical research examining whether there is in fact a meaningful distinction between these two concepts is thus essential. If the two constructs are, in fact, the same, then it could be fruitful to combine the findings in both areas to extend our understanding of group perception. If, as we believe, the constructs of entitativity and similarity are indeed distinct, it will be very important for an understanding of group perception to ascertain both the antecedents and the consequences of perceived entitativity and similarity. The assumption that group membership is often based upon similarities shared by the members has led some researchers to manipulate and measure entitativity in terms of similarity (Abelson, Dasgupta, Park, & Banaji, 1998; Brewer, Weber, & Carini, 1995; Dasgupta, Banaji, & Abelson, 1999; Welbourne, 1999; Yzerbyt et al., 1998). For example, Dasgupta et al. (1999) varied entitativity by showing participants pictures of fictitious creatures that were either all the same color (high entitativity) or different colors (low entitativity). In addition, measures of ingroup and outgroup homogeneity as well as perceived consistency (McGarty, Haslam, Hutchinson, & Grace, 1995) have been used to assess perceived entitativity (Yzerbyt, Castano, Leyens, & Paladino, 2000). However, the results of several studies indicate a need for caution in equating entitativity and certain types of similarity. Brewer et al. (1995) had participants watch a video in which two groups of people, differentiated by shirt color, had a discussion. In one condition, shirt color was said to represent personality factors (overestimators or underestimators); in the second condition, no explanation was given for why the two groups were wearing different colors. The participants task was to watch the discussion and then to recall which person made each statement. The results differed for the two conditions. When shirt color represented a meaningful (and presumably more entitative) group distinction, participants were better at remembering which group generated the statement. When the difference between the two groups was based on physical similarity (shirt color) alone, participants were likely to confuse both the individual who made the statement and the group membership of the individual. These results indicate that physical similarity by itself is not sufficient to generate perceived entitativity. A similar point was made by Welbourne (1999), who found that manipulating entitativity in terms of similarity did not influence participants impressions of the group, but describing the group members as having unified goals and intentions did influence participants impressions. Finally, Pickett and Perrott (2004) found that perceivers were better able to make intragroup comparisons when members were part of a high versus low entitativity group. Participants also rated the groups on entitativity and similarity, and these ratings were used to predict the latencies for these comparative judgments. Although both perceived entitativity and similarity predicted how quickly participants made their judgments, only entitativity remained a significant predictor when controlling for similarity ratings (and not vice versa). The results of these studies argue that similarity by itself is not sufficient to generate perceived entitativity. These studies indicate that entitativity may not be effectively manipulated solely by describing or portraying group members as similar; other factors may be necessary for the perceiver to assume that a collection of people constitutes an

3 1214 Sara A. Crump et al. entitative group. Perceived entitativity is based on more than similarity alone. In fact, as originally suggested by Campbell, Lickel et al. (2000) found that, in addition to similarity, several other variables, such as how often group members interact, how important the group is to its members, and whether the members share common goals and outcomes, were all positively correlated with perceptions of entitativity. Castano, Yzerbyt et al. (2003) verified that these factors all led to increased identification with the ingroup. Thus, similarity by itself is not a necessary condition for perceiving entitativity. In addition, authors have proposed other bases of perceived entitativity. Hamilton et al. (1998) proposed that a group s degree of organization would be among the most important determinants of perceived entitativity, more so in many cases than similarity among group members. More recently, several authors have introduced conceptual frameworks that incorporate these and other constructs (see Hamilton (2007) for a discussion of these models). For example, Brewer, Hong, and Li (2004) proposed that people hold two theories of entitativity that are based on different properties. One type of entitativity reflects similarity among group members and the factors that distinguish the group from other groups. The second type of entitativity is based on the group s goals and plans, its development over time, and the interrelations among group members (see also Rothbart & Park, 2004). Recent research has provided some empirical support for these ideas (Bastian & Haslam, 2006; Denson, Lickel, Curtis, Stenstrom, & Ames, 2006; Ip, Chiu, & Wan, 2006; Magee & Tiedens, 2006; Rutchick, Hamilton, & Sack, 2008; Spencer-Rodgers, Hamilton, & Sherman, 2007). For example, Ip et al. (2006) found empirical support for two distinct pathways that separately lead to the perception that a group is entitative. The first path is taken when group members are thought to share similar physical traits, which then leads to the assumption that members share other common, essential characteristics and are therefore presumed to be members of an entitative group. The second path is taken when group members are perceived to act collectively, leading to the assumption that the members share common goals and are therefore entitative. Extending this work, Rutchick et al. (2008) indirectly induced people to think of groups either as dynamic, interacting units or as categories whose members share similar characteristics. Participants later learned about three groups and rated the entitativity of each one. For those induced to think of groups dynamically, entitativity ratings were more strongly predicted by information about how often those group members interacted. In contrast, when induced to think of groups as categories, entitativity ratings were more strongly predicted by information about similarity among group members. The findings by Ip et al. (2006) and Rutchick et al. support Brewer et al. s (2004) distinction between different routes to entitativity. The differentiation between perceived entitativity and perceived similarity is further suggested by consideration of their role in perceptions of ingroups and outgroups. There is robust evidence for the outgroup homogeneity effect (Boldry et al., 2007; Mullen & Hu, 1989; Ostrom & Sedikides, 1992; Yzerbyt, Judd, & Corneille, 2004), whereby outgroup members are perceived as more similar to each other than ingroup members. On the other hand, with regard to entitativity, some authors have theorized that our own ingroups should be perceived as highly entitative (e.g., Sherman et al., 1999). Research by Yzerbyt et al. (2000) has demonstrated that entitativity is a desired feature of the ingroup and that highly identified group members will exclude those from the group who deviate from group norms, thereby maintaining perceived entitativity. Indeed, given the importance of the groups to which we belong for social identity and ingroup identification, it seems implausible that we would see outgroups as more entitative (Hamilton & Sherman, 1996, p. 349). The goal of the present research was to empirically differentiate perceptions of entitativity and similarity. One way to tease apart these two concepts would be to measure perceptions of both entitativity and homogeneity in people s ingroups and outgroups. If the above reasoning is correct, then we would expect the ingroup to be perceived as more entitative than the outgroup, while outgroup members should be perceived as more similar to each other than ingroup members. Such findings would provide support for the idea that entitativity and similarity are distinct concepts. We conducted a series of experiments to further explore the relations and interplay between entitativity and similarity. The first two studies were designed to investigate whether people perceive that their ingroups are higher in entitativity than their outgroups and their outgroups are higher in similarity than their ingroups. This comparison was done for social categories (Study 1) and for intimacy and task groups (Study 2). In Study 3, we moved from measuring the perceived entitativity and similarity of various membership groups to manipulating the entitativity or similarity of a fictitious group. Participants read a description of a group that was either high or low in entitativity or in similarity, and then rated the group on measures of both entitativity and similarity. We predicted that the two manipulations should have differing effects on the two measures. Together the three studies used different methods and strategies to study the relationship between entitativity and similarity and to test the hypothesis that they are distinct concepts that influence perceptions of groups in reliably different ways.

4 Perceptions of groups 1215 STUDY 1 Study 1 assessed perceptions of entitativity and similarity for different ingroup and outgroup social categories (based on political, gender, religious, and ethnic groups). We hypothesized that, across different social categories, people would perceive their ingroups to be more entitative than outgroups but that members of the outgroup would be seen as more similar than members of the ingroup. For each domain of social categories, we used a 2 (ingroup/outgroup) 2 (ratings of entitativity/similarity) within-subjects design. Our hypothesis was tested by a predicted interaction. If the ingroup and outgroup are rated differently on entitativity and homogeneity measures, then those scales cannot be measuring the same construct. The differing slopes indicated by a significant interaction would provide evidence that entitativity and similarity function differently in the perception of ingroups and outgroups. Another way of studying the relationship between these two constructs is to examine the correlations between participants entitativity and similarity ratings of their ingroups and their entitativity and similarity ratings of their outgroups. There is undeniably a relationship between entitativity and similarity such that groups whose members share similarities will be perceived as more entitative and vice versa. If the concepts of entitativity and similarity reflect the same underlying construct, then we would expect to find very high correlations between the constructs, approaching reliability coefficients. In contrast, if the two concepts are distinct but related concepts, we would expect to find, at most, only moderate correlations between entitativity and similarity. Method Participants One hundred twenty nine UCSB undergraduates took part in exchange for partial credit for a course requirement. Based on responses to a questionnaire assessing demographic information, the sample of participants had the following characteristics. The sample included 100 female and 29 male participants with a mean age of 18 years. Among these participants were one American Indian, 17 Asian or Pacific Islander, 19 Hispanic, 81 White, and 11 participants categorized as Other. In addition, 36 of the participants were Catholic, 11 Jewish, 18 Protestant, and 34 were Atheists. Finally, 78 participants identified themselves as Democrats, 23 as Republicans, 10 as Other, and 17 as None of the above. Procedure The experimenter informed the participants that the goal of the study was to learn more about how people perceive groups to which they do and do not belong. Participants were led into individual cubicles and were told that they would make ratings of several groups on a series of rating scales. Stimulus groups and rating scales would be presented on the computer. Next, each participant answered both entitativity and similarity questions about 11 different groups representing political preference (Democratic and Republican), gender (male and female), religion (Catholic, Jewish, and Protestant), and ethnicity (Asian American, African American, Latino/a, and White). To control for order effects, the order of presentation of each group domain (e.g., politics, gender, religion, and race) was reversed, as was the order of the groups within each domain (e.g., Democrat, Republican; female, male, etc.). Finally, the order of the entitativity and similarity questions was randomized for each group. Dependent Measures Participants were asked a number of questions about each group in order to assess perceptions of entitativity and similarity. The questions were answered on 9-point Likert scales with the endpoints labeled appropriately for the question being asked. Participants rated the extent to which (for example) Catholics were perceived to be a meaningful group, the amount

5 1216 Sara A. Crump et al. of perceived interaction among members, the importance of the group to its members, whether the members have common goals and common outcomes, and whether or not the members have strong interpersonal bonds. Other questions asked how permeable the group boundaries are, whether the members have different roles, status, or power, the extent to which the group has formal or informal rules that guide behavior, and whether or not they share a lot of information with the other members. In addition, participants answered questions about how similar the group members are in general, and how similar they are in three specific respects: their appearance, their behavior, and their personalities and abilities. These items were then factor analyzed to determine the best items for assessing perceptions of entitativity and similarity (see below). After completing these questions, participants were given a demographic questionnaire on which they indicated their political party preference, gender, religion, and race. Their answers allowed us to determine each participant s ingroups and outgroups for each domain. To analyze the data for each group domain, we selected only those participants who belonged to one of the target groups they rated and groups for which there were adequate samples (at least 10 or more participants per group). In other words, when analyzing the data for the religious groups, we included data from participants who indicated that they were Catholic, Jewish, or Protestant. For the ethnic groups, we used data only from participants who indicated that they were Asian, Latino, or White (ratings of African Americans were disregarded due to lack of African American participants), and so on. Results Entitativity and Similarity Indices We performed a factor analysis on the 14 items listed above to identify those items that were separately assessing entitativity and similarity. For each domain of social categories (political, gender, religious, ethnic) we first averaged the ratings of the groups in that domain and correlated the measures with each other. We then conducted a principal components analysis with Varimax rotation for each domain. Each of these analyses revealed two primary factors; across analyses, Factor 1 accounted for between and 26.32% of the variance, and Factor 2 accounted for between and 24.32%. Although two primary factors emerged in each domain, there is no guarantee that they are the same factors. To determine the comparability of the two factors across domains, we correlated the factor loadings (converted to Fisher s Z scores) for the two factors across the four domains of social categories. This 8 8 correlation matrix revealed considerable consistency in the nature of the factors across domains. Correlations across domains for Factor 1 ranged from.26 to.56 (M ¼.42) and those for Factor 2 ranged from.25 to.64 (M ¼.52). Also, correlations between factors (within and across domains) were consistently low, ranging from.18 to.17 (M ¼.001). (Although low between-factor correlations within the same domain are virtually assured by the orthogonal rotation, such consistency is not a necessary outcome for crossdomain correlations.) These results provide useful evidence substantiating that the same two factors emerged in each of the four factor analyses. Our next concern was the content represented by each of these factors. For each factor, we identified the items loading most strongly on that factor. Criteria for item selection were (a) a loading of at least.45 on one factor, (b) a loading of no more than.40 on the other factor, and (c) to be included for later use, the item had to meet the first two criteria in all four factor analyses. Given these criteria, the results produced multi-item measures of each of the factors. The first factor, entitativity, consisted of the following items: The extent to which a collection of people is perceived to be a group, the amount of interaction among group members, how important the group is to its members, the strength of the interpersonal bonds between members, and the amount of information shared among members. Participants average ratings on these items comprised the entitativity index. The second factor, similarity, was comprised of the following items: Whether the group members share the same outcomes, whether the group members have similar roles, status, and power, and whether they have similar personalities and abilities. Participants average ratings on these items comprised the similarity index. The final measures, then, consisted of five entitativity items and three similarity items. 1 1 Campbell (1958) proposed that the perception that a group shares common outcomes is a component of entitativity. The results of the present factor analysis showed that the shared outcomes item was more closely correlated with the other similarity items. This finding is not entirely surprising, given the somewhat ambiguous nature of what it means to share outcomes. On the one hand, a perceiver may consider a group whose members share outcomes as having things in common and therefore being similar. On the other hand, a perceiver may interpret a group whose members share outcomes as working toward the same objectives, and therefore comprising a unified, entitative group. In the present study, the perceivers were more likely to interpret this item as an indicator of group similarity.

6 Perceptions of groups 1217 Overview of the Analyses Because we were most interested in the pattern of entitativity and similarity ratings between ingroups and outgroups, the primary focus of the analyses was on participants ratings of the ingroup and outgroup collapsed across groups in each social category. Thus, for each social category we collapsed across the groups and compared participants average ratings of their ingroups and outgroups. For example, to examine perceptions of the religious groups, we determined the average of the Catholic, Jewish, and Protestant participants ingroup ratings (e.g., Catholic participants ratings of Catholic targets; Jewish participants ratings of Jewish targets; and Protestant participants ratings of Protestant targets), and compared those to participants average outgroup ratings (e.g., Catholic participants average rating of Jews and Protestants; Jewish participants average rating of Catholics and Protestants; and Protestant participants average rating of Catholics and Jews). This strategy resulted in a 2 (Measure: entitativity or similarity) 2 (Group: ingroup or outgroup) repeated measures design for each social category. Our prediction was tested by the significance of the interaction term. Political Groups The 2 2 repeated measures ANOVA for political groups revealed a Measure main effect. Across groups, participants made higher entitativity ratings (M ¼ 6.09) than similarity ratings (M ¼ 4.45), F(1, 100) ¼ 90.05, p <.001, h 2 p ¼.474. As predicted, the Measure Group interaction was significant, F(1, 100) ¼ 21.13, p <.001, h2 p ¼.174. Paired-samples t-tests revealed that participants rated their political ingroup higher in entitativity (M ¼ 6.21, SD ¼ 1.26) than the outgroup (M ¼ 5.96, SD ¼ 1.28), t(100) ¼ 2.37, p <.05, whereas they rated members of the political outgroup as more similar (M ¼ 4.66, SD ¼ 1.71) than political ingroup members (M ¼ 4.24, SD ¼ 1.76), t(100) ¼ 2.66, p <.01. Finally, the entitativity and similarity indices were correlated for the political ingroups, r(101) ¼.277, p <.01, and the outgroups at r(101) ¼.222, p <.05. The correlations revealed a significant, although modest, relationship between entitativity and similarity that was comparable for ingroups and outgroups. Gender Groups Results of the 2 2 repeated measures ANOVA revealed a main effect for Group, such that (across indices) ingroups were given higher ratings (M ¼ 5.18) than outgroups (M ¼ 4.91), F(1, 128) ¼ 5.48, p <.05, h 2 p ¼.041. In addition, the main effect of Measure was again significant, revealing that (across groups) participants made higher entitativity ratings (M ¼ 6.45) than similarity ratings (M ¼ 3.64), F(1, 128) ¼ , p <.001, h 2 p ¼.746. Most importantly, these main effects were qualified by the predicted Measure Group interaction, F(1, 128) ¼ 28.58, p <.001, h 2 p ¼.183. Two paired-samples t-tests were conducted to further examine the significant interaction. As predicted, people perceived their own gender (the ingroup) (M ¼ 6.80, SD ¼ 1.34) to be significantly more entitative than the other gender (the outgroup) (M ¼ 6.09, SD ¼ 1.40), t(128) ¼ 4.71, p <.001. In contrast, there was a trend for members of the outgroup to be perceived as more similar (M ¼ 3.74, SD ¼ 1.63) than ingroup members (M ¼ 3.55, SD ¼ 1.50), although this difference was not significant, t(128) ¼ 1.45, n.s. Finally, the average correlation between the entitativity and similarity items for the gender ingroups was r(129) ¼.229, p <.01, and the correlation between measures for the gender outgroups was r(129) ¼.115, n.s. The gender ingroup correlation revealed a significant, although modest, relationship between entitativity and similarity whereas the correlation between entitativity and similarity for gender outgroups was not significant. Religious Groups The 2 2 repeated measures ANOVA for religious groups revealed a main effect of Measure, F(1, 64) ¼ , p <.001, h 2 p ¼.811 as well as the predicted significant Measure Group interaction, F(1, 64) ¼ 11.12, p ¼.001, h 2 p ¼.148. The pattern of means again conformed to predictions. We found a marginally significant difference between ratings of ingroup and outgroup entitativity t(64) ¼ 1.75, p <.09. Specifically, participants rated their religious ingroups (M ¼ 7.06, SD ¼ 1.39) as more entitative than their outgroups (M ¼ 6.73, SD ¼ 0.96). In addition, members of religious outgroups were seen as significantly more similar (M ¼ 4.66, SD ¼ 1.37) than members of religious ingroups (M ¼ 4.16, SD ¼ 1.60), t(64) ¼ 2.04, p <.05. Finally, the correlation between entitativity and similarity for religious ingroups was again significant, r(65) ¼.245, p <.05, as was the correlation for the outgroups, r(65) ¼.486, p <.001. These correlations suggest that entitativity and similarity are related, but again, the magnitude of the correlation is only of moderate size. Ethnic Groups Results of the 2 2 repeated measures ANOVA for ethnic groups revealed main effects for both Group and Measure. Participants made significantly higher ratings (across indices) of the outgroup (M ¼ 5.13) than of the ingroup (M ¼ 4.34), F(1, 116) ¼ 43.00, p <.001, h 2 p ¼.270 and (across groups) higher entitativity (M ¼ 6.01) than

7 1218 Sara A. Crump et al. similarity (M ¼ 3.45) ratings, F(1, 116) ¼ , p <.001, h 2 p ¼.731. Unlike the other groups, though, the interaction between Measure and Group was not significant, F(1, 116) ¼.152, n.s., h 2 p ¼.002. Contrary to the pattern for the other social categories, participants rated ethnic outgroups (M ¼ 6.39, SD ¼ 1.15) as significantly more entitative than their ethnic ingroups (M ¼ 5.64, SD ¼ 1.65), t(116) ¼ 5.19, p <.001. As expected, they saw outgroup members (M ¼ 3.86, SD ¼ 1.50) as more similar than ingroup members (M ¼ 3.04, SD ¼ 1.64), t(116) ¼ 6.05, p <.001. These results again provide support for the outgroup homogeneity effect but, unlike the other three domains, these data did not support the ingroup entitativity hypothesis. Finally, we again found moderate correlations between entitativity and similarity ratings for the ethnic ingroups, r(117) ¼.392, p <.001, and for the entitativity and similarity ratings of ethnic outgroups, r(117) ¼.226, p <.02. Discussion The results of Study 1 support the hypothesis that entitativity and similarity function differently in perceptions of ingroups and outgroups. If measures of entitativity and similarity were essentially tapping the same construct (or highly related constructs), then we would expect no interactions but rather would see parallel patterns of means between ratings of ingroups and outgroups on the two indices. Instead, the Group Measure interaction was significant in three of the four analyses. This nearly consistent outcome by itself reveals that the two measures did not function in parallel, documenting their distinct contributions in group judgments. In addition, for three of the four cases the pattern of means conformed to our specific predictions. We found strong support for the outgroup homogeneity effect in every group domain except gender, and even here the pattern of means was in the predicted direction. In addition, evidence of an ingroup entitativity effect was obtained for three out of the four social categories. These results provide some of the first evidence of perceived ingroup entitativity. We recognize that, in the real world, some groups are more entitative than others. In fact, our data revealed main effects due to certain groups (e.g., Jews were viewed as more entitative than Catholics or Protestants by participants of all faiths; women were seen as more entitative than men by both genders). These main effects may be the result of the tendency for minority groups to be perceived as higher in entitativity than majority groups (Brewer & Harasty, 1996; Brewer et al., 1995). In addition, White participants, who made up the majority of the participants, did not perceive their ingroup as being particularly entitative. This finding may be a function of the fact that White individuals, in general, do not think of their ethnicity as an important part of who they are (Perry, 2001). Instead, they rated outgroup members as significantly more entitative. These results may provide an explanation for the outgroup entitativity effect we found among the ethnic groups. However, our prediction is one of relative perceived entitativity. Regardless of these main effects, ingroup members still saw relatively more entitativity for their own group. For example, although both men and women rated women higher in entitativity, this difference between genders was smaller for male than for female participants. Parallel comments apply to perceptions of similarity. Thus, the predicted interactions document that ingroups are perceived as having relatively more entitativity and outgroups as having relatively more homogeneity. Across the four social categories, participants consistently made higher overall group entitativity ratings than group similarity ratings. Entitativity and similarity were measured on different scales that might have different properties. Therefore the present data do not allow us to determine the basis for this main effect or its generalizability. The correlations between ratings of entitativity and similarity were generally statistically significant and were of moderate magnitude. This is not surprising in that Campbell (1958) had identified similarity as one of the important components of entitativity, and research has shown significant empirical relations between the two concepts (Castano, Yzerbyt et al., 2003; Lickel et al., 2000). The purpose of the present research was not to argue, or try to demonstrate, that the concepts of entitativity and similarity are unrelated, uncorrelated constructs, but rather to show that they are differentiable, that they do not bear the same relations to other factors, and that they have different functional relations regarding important aspects of group perception. Our results provide additional evidence that the perceptions of group entitativity and similarity may have distinct foundations (Brewer et al., 2004; Ip et al., 2006; Rutchick et al., 2008). It should be noted that the statistically significant correlations all reflect relations between similarity and entitativity within a particular group. That is, the correlations indicate that the two concepts co-vary for the perception of some specific ingroup or outgroup (e.g., a religious or gender group). On the other hand, the primary goal of the first study was to show that, when considering perceptions of similarity and entitativity as we look between groups of different types (e.g.,

8 Perceptions of groups 1219 ingroups versus outgroups), the perceptions in fact move in opposite directions. The finding of an interaction between judgments of similarity versus entitativity for ingroups versus outgroups is the important result, rather than the simple correlation between similarity and entitativity within any single group. In Study 1, the focus was on perceptions of various social categories to which one may belong. Social categories are one of several group types evident in Lickel et al. s (2000) findings. In fact, despite their prominence in the social psychological literature, some recent evidence suggests that one s social category memberships may be less salient and influential than that literature might imply. Indeed, Lickel et al. found that social categories are perceived to be only moderately entitative, whereas intimacy and task groups (which are typically smaller and involve greater interaction among the members) are perceived to be much more entitative. Moreover, perceivers intuitive theories about social categories their characteristics, the norms and rules by which they function, the psychological needs they serve for group members are less well delineated than are the comparable features and functions of intimacy and task groups (Johnson et al., 2006; Lickel et al., 2000; Lickel, Hamilton, & Sherman, 2001; Lickel, Rutchick, Hamilton, & Sherman, 2006). Therefore in Study 2 we tested the same hypotheses for intimacy and task groups. STUDY 2 In order to examine participants perceptions of entitativity and homogeneity of intimacy and task groups, we had participants think about either an intimacy group or a task group to which they had or had not belonged in high school. They rated an ingroup and an outgroup on the same measures used in Study 1. We predicted that the results of Study 1 would generalize to these new group types. Thus we hypothesized that members of these two groups would rate their ingroups as higher in entitativity than their outgroups whereas outgroup members would be perceived as more homogeneous than ingroup members. Again, the critical statistical test of the hypothesis is the interaction between ingroup/outgroup target and entitativity/similarity indices. Method Participants Participants were 121 undergraduates (83 females, 38 males) from an introductory psychology course at UCSB who received credit toward a course requirement. Of these participants, 60 were randomly assigned to the intimacy group condition and 61 were randomly assigned to the task group condition. Participants were run individually or in groups of up to six. Procedure Participants were seated at individual cubicles and told that the purpose of the study was to learn more about the perception of the groups of which they were or were not members in high school. They were instructed to think about a group to which they belonged in high school. Those in the intimacy group condition were told to think about a group of close friends, while those in the task group condition were told to think about a group to which they belonged whose purpose was to achieve a goal (e.g., sports team, student newspaper). After bringing the group to mind, participants were asked to briefly describe the group on a piece of paper left next to their keyboard. Next, participants rated the group they had just described on a series of scales. These entitativity and similarity questions were the same as those used in Study 1. After completing these questions, participants were asked to think about a group from their high school to which they did not belong. Those in the intimacy group condition were asked to think about a group of friends that was similar in size to their own, but with whom they did not spend much time. Participants in the task group condition were asked to think about another group whose purpose was also to achieve some goal but was a group to which they did not belong. Again, participants were asked to write a description of this group. Finally, participants made entitativity and similarity ratings of the group. When they had completed these tasks, they completed a demographic questionnaire, were debriefed, and thanked for their participation.

9 1220 Sara A. Crump et al. Results To test our predictions, repeated-measures ANOVAs were conducted separately for the intimacy and task group conditions. 2 Intimacy Groups Results of a 2 2 repeated-measures ANOVA revealed a significant Measure main effect. Specifically, participants overall gave higher entitativity (M ¼ 6.95) than similarity ratings (M ¼ 5.37), F(1, 58) ¼ 76.47, p <.001, h 2 p ¼.569. More importantly, and as predicted, this main effect was qualified by a significant Measure Group interaction, F(1, 58) ¼ 26.52, p <.001, h 2 p ¼.314. To better understand this interaction, two paired-samples t-tests were conducted. As predicted, participants rated their intimacy ingroups (M ¼ 7.19, SD ¼ 0.96) as more entitative than their outgroups (M ¼ 6.72, SD ¼ 1.34), t(58) ¼ 2.39, p <.03. In contrast, members of the outgroup (M ¼ 5.82, SD ¼ 1.30) were perceived to be more similar than members of the ingroup (M ¼ 4.92, SD ¼ 1.42), t(58) ¼ 5.59, p <.001. Finally, ratings of entitativity and similarity were not significantly correlated for either ingroups, r(59) ¼.013, n.s., or for outgroups, r(59) ¼.140, n.s. Task Groups Results of the 2 2 ANOVA again revealed a main effect of Measure such that participants gave significantly higher entitativity (M ¼ 6.70) than similarity (M ¼ 5.63) ratings, F(1, 59) ¼ 90.03, p <.001, h 2 p ¼.604. Contrary to predictions, the Group Measure interaction for the task groups was not significant, F(1, 59) ¼ 1.67, n.s., h 2 p ¼.028. Although ratings of ingroup entitativity (M ¼ 6.79, SD ¼ 1.33) were higher than ratings of outgroup entitativity (M ¼ 6.61, SD ¼ 1.32), these means were not significantly different, t(59) ¼.779, n.s. In addition, there was a tendency for members of the outgroup to be seen as more similar (M ¼ 5.52, SD ¼ 1.48) than members of one s ingroup (M ¼ 5.34, SD ¼ 1.37), although this difference was again not significant, t(59) ¼.761, n.s. Finally, for task groups, ratings of entitativity and similarity were significantly correlated, both for judgments of ingroups, r(60) ¼.472, p <.001, and for judgments of outgroups, r(60) ¼.368, p <.01. Discussion The results of Study 2 provide further support for the hypothesis that entitativity and similarity play different roles in perceptions of ingroups and outgroups. Ratings of intimacy groups strongly conformed to our predictions. Participants rated their intimacy ingroups as higher in entitativity than comparable outgroups, and they rated their intimacy outgroups as more similar. These results replicate the pattern obtained in Study 1. For task groups, the differences between ingroup and outgroup ratings of entitativity and similarity were in the predicted direction but were not significant. Why was there a lack of significant results in ratings of task groups? In the present study, participants were asked to recall and rate groups to which they belonged in high school. It may be the case that (like the social categories rated in Study1) participants are still members of these intimacy groups, whereas it seems less likely that they are still members of their high school task group. If so, then it follows that they are less identified with this particular ingroup and it is less 2 After reading through the intimacy and task group descriptions provided by the participants, we were concerned that some of the intimacy group descriptions sounded more like task groups, that some of the task group descriptions were more characteristic of intimacy groups, and that some of the groups sounded equally like an intimacy and a task group. To address this concern, two independent coders, blind to condition, read each description and rated whether the group was an intimacy group, task group, or a combination of the two. The reliability between the two coders was 95%. Participants were dropped if both coders thought the groups were a combination of intimacy and task group. This resulted in 65 participants in the intimacy condition and 25 in the task group condition, with the remainder of participants being dropped. Similar repeated-measures ANOVAs were conducted on this revised data set, but the exact same pattern of means was found in both the intimacy and task group conditions. Therefore, we report the analyses based on the full sample.

10 Perceptions of groups 1221 important to them. Thus they may be less motivated to perceive a difference between ingroup and outgroup entitativity (Yzerbyt et al., 2000). Unlike the majority of research on the outgroup homogeneity effect, which usually examines perceptions of social categories, the results of Study 2 provide evidence that members of intimacy outgroups are also seen as more similar than ingroup members. Overall, these findings build on and extend the results of Study 1. STUDY 3 In Studies 1 and 2, participants made ratings of existing groups either social categories (Study 1) to which they do or do not belong or intimacy and task groups (Study 2) to which they were or were not members during their high school years. The significant interactions in judgments of entitativity and similarity for ingroups and outgroups obtained in those studies indicate that these concepts played different roles in group perceptions. These studies focused on differences in perception of the two constructs in judgments of real groups, groups that might vary in any number of properties (aside from their ingroup or outgroup status). Moreover, the specific groups that people envisioned as they completed these tasks may have varied considerably. The general consistency in outcomes across this diverse array of groups provides some reassuring evidence of the generality of the effect. Nevertheless, converging evidence of the differing functions of entitativity and similarity would be important in bolstering the argument. Thus, in Study 3 we took a different approach. We manipulated either entitativity or similarity (high or low) of a stimulus group and assessed perceptions of both entitativity and similarity. If the two constructs tap essentially the same thing in group perceptions, then manipulation of either construct should have parallel effects on judgments of both variables. If, however, entitativity and similarity are in fact meaningfully distinct constructs, then manipulation of each one should strongly influence perceptions of the group on the corresponding measure, but not show parallel effects on perceptions of the other variable. In Study 3, participants learned about a group and read a series of stimulus sentences describing behaviors performed by group members. Prior to reading the sentences, the group s specific form of bondedness was manipulated. Specifically, participants read a paragraph describing the group as high or low in entitativity, or a paragraph describing the group as high or low in similarity. In a third (baseline) condition participants received no orienting paragraph. Participants then rated the group on scales measuring both perceived entitativity and perceived similarity. Next, participants read a number of behavior-descriptive sentences and then rated their impressions of the group on a series of trait scales. Our primary prediction was that the specific form of bondedness (entitativity or similarity) manipulation would have an effect on its corresponding measure, but not on the theoretically less related measure. Thus, we predicted that the manipulation of entitativity would significantly influence perceptions of entitativity but would less strongly affect perceptions of similarity, whereas the manipulation of similarity would significantly influence perceptions of group similarity but would less strongly affect perceptions of the group s entitativity. The study also permitted a test of a secondary hypothesis regarding the consequences of perceiving group entitativity. Previous research has shown that higher levels of perceived entitativity induce more integrative, systematic processing of information as perceivers form impressions of target groups (for a review see Hamilton, Sherman, & Castelli, 2002). On the basis of this enhanced integrative processing, Sherman et al. (1999) proposed that perceptions of high group entitativity will lead to stronger evaluations, positive or negative, about a target group. In this view, entitativity induces a polarization effect in group judgments, such that positively-valued groups will be evaluated more favorably, and negatively-valued groups will be judged less favorably, than will positive and negative groups perceived as possessing lesser amounts of entitativity. The positive or negative value of the target group might be based on prior beliefs and expectations (as in Castano, Sacchi et al., 2003) or on the valence of the information acquired about the group and its members (as in the present study). This polarization effect was tested in Study 3 by manipulating the valence of the behavioral information describing high and low entitativity groups and by assessing participants impressions of the groups on a series of trait scales. Because similarity is not known to involve greater integrative processing, polarization effects for groups with high similarity might not be expected. In any case, if the effects of the entitativity and similarity manipulations on group impression judgments are different, this would constitute additional evidence supporting our main hypothesis, namely, that entitativity and similarity are different constructs.

11 1222 Sara A. Crump et al. Method Participants and Design Participants were 81 UCSB students who took part in exchange for partial course credit. They participated in the experiment in groups of 1 6. The study was a 3 (Bondedness: high, low, no information) 2 (Form of Bondedness: entitativity, similarity) 2 (Measure: entitativity, similarity) 2 (Information Valence: positive or negative) mixed-model design with Measure as the only within-subjects condition. In addition, there was a baseline condition in which no group entitativity or similarity bondedness information was provided. We ran extra participants in this baseline condition and then randomly assigned half to be in the no entitativity information condition and half to be in the no similarity information condition. This random assignment resulted in a balanced 3(Bondedness: high, low, no information) 2(Form of Bondedness: entitativity, similarity) design. Entitativity Manipulation The group entitativity manipulation was implemented through an introductory paragraph describing the group. The high entitativity group was described as follows: The members of this group pursue a common set of goals. Since the members of the group are concerned with achieving their common goals, they depend upon each other to a large extent. For the most part, this group is described as a tightly structured group. The low entitativity group was described as follows: The members of this group pursue a variety of goals that are relevant to completing their group s objectives. Since the members of the group are primarily concerned with completing their task assignments, they do not depend on each other a great deal. For the most part, this group is described as a loosely structured group. Similarity Manipulation The group similarity manipulation was implemented through an introductory paragraph describing the group. These items were adapted from McConnell et al. (1997). The high similarity group was described as follows: The members of this group are very similar to one another and do not differ in many ways from each other. Across a variety of situations, members of this group will act in a similar manner. The low similarity group was described as follows: The members of this group are very different from one another and the members do not have a lot in common. Across a variety of situations, members of this group will act in a different manner. In addition, a control group received no introductory paragraph conveying either the group s entitativity or similarity. Behavioral Information Two sets of behavior-descriptive statements were developed. Both sets contained six behavioral items relevant to each of three trait dimensions: adventurousness, friendliness, and intelligence. In one set, these 18 statements portrayed positively valenced behaviors; in the other set, the 18 statements described negatively valenced behaviors. Both sets also included six neutral behaviors, making a total of 24 stimulus sentences. The neutral behaviors were selected according to the criterion that they did not connote the positive or negative poles of any of the trait dimensions (based on pretest norms). The behavior-descriptive statements were presented in a random order.