European Journal of Social Psychology, Vol. 20,351-356 (1990)

Perceptions of relative group size and group homogeneity: We are the majority

and they are all the same

BERND SIMON and AMELIE MUMMENDEY Westfalische Wilhelms-Universitat, Psychologisches lnstitut IV, Sozialpsychologie, Fliednerstr, 2 1, 0-4400 Munster, Federal Republic of Germany

Abstract

On the basis of prior research on the false consensus eflect and on the perception of group homogeneity in minority-majority contexts, it was hypothesized that ( I ) with no information regarding group size available, group members would see their own group in the majority position and perceive more outgroup than ingroup homogeneity and (2) this outgroup homogeneity eflect would not occur, when there is no doubt about the numerical equality of ingroup and outgroup. Both hypotheses were confirmed in a laboratory study (n = 88).

INTRODUCTION

Many researchers claim that the outgroup is generally seen as more homogeneous than the ingroup (the outgroup homogeneity hypothesis, e.g. Linville and Jones, 1980; Quattrone and Jones, 1980; Jones, Wood and Quattrone, 198 1; Linville, Salovey and Fischer, 1986; Linville, Fischer and Salovey, 1989; Wilder, 1984; for reviews see Messick and Mackie, 1989; Quattrone, 1986; Wilder, 1986). Various explanations has been proffered for this outgroup homogeneity effect: (1) The motivation to assert one’s own individuality and to free oneself from constraining expectations (Quattrone and Jones, 1980; Jones et al., 1981); (2) intergroup discrimination which the percep- tion of outgroup homogeneity might help to justify (Wilder, 1984, 1986); (3) greater familiarity with the ingroup than with the outgroup which should lead to greater differentiation among ingroup members than among outgroup members (Linville et al., 1986, 1989).

However, there is now growing evidence that the perception of relative outgroup homogeneity might also depend on still other factors, such as the specific characteris- tics or dimensions in question and the relative size of the ingroup. For it could be shown that the outgroup is by no means seen as more homogeneous than the

This research was made possible by a grant to the first author from the Friedrich-Ebert-Stiftung, Bonn.

0046-2772f9OlO403 5 1 -O6$05 .OO 0 1990 by John Wiley 8z Sons, Ltd.

Received I1 October 1989 Accepted 20 December 1989

352 B. Simon and A . Mummendey

ingroup on all available dimensions. Rather, on dimensions relevant to ingroup identity the ingroup is likely to be seen as more homogeneous (Kelly, 1989; Simon and Pettigrew, 1989). Also, research indicates that members of majority groups are particularly inclined to show the outgroup homogeneity effect, while members of minority groups often perceive more ingroup than outgroup homogeneity, i.e. they show the ingroup homogeneity effect (Brown and Smith, 1989; Mullen and Hu, 1989; Simon and Brown, 1987). The latter researchers could also provide evidence for their assumption that this reversal of perceived relative homogeneity is due to stronger social identification with a minority ingroup compared to a majority ingroup (see also Simon and Pettigrew, 1990; McGuire and McGuire, 1988).

The findings regarding the impact of the relative ingroup size on the perception of relative ingroupoutgroup homogeneity are the starting point for the present study. More specifically, we argue that implicit assumptions about the relative ingroup size can also influence the perceptions of relative ingroupoutgroup homogeneity. In line with research on ‘false consensus’ (Ross, Greene and House, 1977), we assume that group members tend to overestimate the size of their ingroup. Thus, in the absence of explicit information about the relative ingroup size group members might perceive the ingroup in a majority position vis-a-vis the outgroup (Goethals, Allison and Frost, 1979; Manstead, 1982; Wallen, 1943), and consequently ascribe more homogeneity to the ‘minority’ outgroup than to the ‘majority’ ingroup. This possibi- lity may apply also to experiments - and explain the outgroup homogeneity effects found in those experiments - in which equal numbers of ingroup and outgroup members were present (Judd and Park, 1988; Wilder, 1984), because subjects in those experiments may still have assumed that in the entire population the ingroup held a majority position.

An experiment was conducted in which about half the subjects were told that usually 50 per cent of all people would belong to the ingroup and 50 per cent to the outgroup. No information about group size was given to the other subjects. Our predictions were that subjects in the no information condition would perceive the ingroup in the majority position and they would show the outgroup homogeneity effect. Yet no differential perception of ingroup and outgroup homogeneity was expected in the parity condition.

METHOD

Subjects

Eighty-eight students - average age 22.3 - from a college for social work partici- pated in the experiment.

Procedure, independent and dependent variables

At the beginning subjects were categorized into two groups (group V and group W, randomized across subjects) allegedly on the basis of their answers to an inventory measuring their interest in various fields (e.g. music, art, sports). Yet subjects were given no explicit information concerning intragroup similarities or intergroup differ- ences. Rather, they were told that the exact meaning of the groups would be revealed

Group size andgroup homogeneity 353

after the experiment. Subsequently, subjects were either told that usually 50 per cent of all people would belong to the ingroup and 50 per cent to the outgroup (parity condition) or subjects were given no information at all about group size (no information condition).

Two measures of general homogeneity (Quattrone, 1986) were administered. Sub- jects directly rated the degree of intragroup similarities (‘many similar members’) and - on a separate unipolar scale - the degree of intragroup differences (‘many different members’) within the ingroup and within the outgroup. The order of the two scales (i.e. intragroup similarities = SIM, intragroup differences = DIF) was randomized across subjects. Ratings for the two stimulus groups (i.e. ingroup, out- group) were made on separate 100-mm scales. The respective order was also rando- mized across subjects.

After they had provided the homogeneity ratings, subjects in the no information condition (but not those in the parity condition) estimated what percentage of all students at their college would belong to their ingroup and what percentage to the outgroup.

The experiment was run in four sessions with 20 to 24 participants per session. The first two sessions were assigned to the no information condition, the other two sessions to the parity condition. After the experiment had been completed, partici- pants were fully debriefed.

RESULTS

Six subjects were excluded from the analysis, four in the parity condition and two in the no information condition, because they doubted the cover story or did not understand the instructions. The final sample size was 42 in the parity condition and 40 in the no information condition.

As predicted, subjects in the no information condition perceived the ingroup in the majority position vis-a-vis the outgroup: the ingroup was ascribed a greater percentage than the outgroup (M(in) = 54.1 per cent, M(out) = 45.6 per cent, t(39) = 1.85, p c 0.05; unless noted otherwise, all t-tests are one-tailed).

The homogeneity ratings were analysed in a 2 (numerical information: parity vs no information) x 2 (scale: SIM versus DIF) X 2 (stimulus group: ingroup versus outgroup) analysis of variance. ‘Numerical information’ was a between-subjects fac- tor, ‘scale’ and ‘stimulus group’ were treated as within-subjects factors. SIM- and DIF-ratings were coded in such a way that higher scores indicate greater perceived homogeneity. Table 1 presents the means and standards deviations of the homo- geneity ratings together with all significant ANOVA effects.

A significant main effect for stimulus group emerged which was however qualified by a significant interaction with the between-subjects factor. As predicted, the out- group was seen as more homogeneous than the ingroup in fact only in the no infor- mation condition. And this finding was obtained on both scales. Though higher homogeneity ratings for both outgroup and ingroup were found on the SIM- than on the DIF-scale, the scale-factor did by no means qualify our main finding. This factor was not involved in any significant interaction (all Fs c 1).

In addition, we analysed the homogeneity ratings from two subgroups of subjects in the no information condition, that is from the subgroup of subjects who had

354 B. Simon and A. Mummendey

Table 1. Homogeneity ratings for ingroup and outgroup

Parity No information Ingroup Outgroup Ingroup Outgroup

SIM M 50.5 51.4 46.2 * 55.6 S. D. 21.1 21.6 25.4 24.6

M 35.4 37.2 31.8 * 42.0 S. D. 27.5 27.7 22.3 27.6

DIF

n = 42 n = 4 0

SIM = intragroup similarities, DIF = intragroup differences M = mean, S. D. = standard deviation. *Means for ingroup and outgoup @er scale) differ at the 0.5 level of significance or better in planned comparisons (1-tests). Significant ANOVA effects: Stimulus group (SG): F(1,80) = 7.32, p < 0.01. Numerical information (NI) x SG: F(1,80) = 4 . 2 2 , ~ c 0.05. Scale (S): F(1,80) = 2 1 . 3 5 , ~ < 0.001. All othereffectswere nonsignifi- cant (Fs < 1). MSe (between subjects) = 1295.41. MSe (within subjects; SG) = 348.36. MSe (within subjects; S) = 788.84. MSe (within subjects; S X SG) = 37.35.

ascribed a smaller percentage to the ingroup than to the outgroup (minority: M(in) = 37.7 per cent, M(out) = 61.0 per cent, n = 15) and from the subgroup who had ascribed a greater percentage to the ingroup than to the outgroup (majority: M(in) = 66.6 per cent, M(out) = 33.7 per cent, n = 21)’. Again, only ‘majority’ sub- jects showed clear outgroup homogeneity effects, whereas the ‘minority’ subjects perceived no significant difference between ingroup and outgroup homogeneity (majority: M(in) = 50.9, M(out) = 64.6, t(20) = -2.33, M(in) = 29.0, M(out) = 45.2, t(20) = -2.52, bothps < 0.02; minority: M(in) = 42.0, M(out) = 47.9, t(14) = - 1.43, M(in) = 35.9, M(out) = 40.7, t( 14) = - 1.02, both ns.; for SIM and DIF respectively).

DISCUSSION

Our hypotheses were clearly confirmed. In the absence of explicit information about group size, group members overestimated the size of their ingroup to the extent of perceiving the ingroup in a majority position vis-a-vis the outgroup. At the same time, those members perceived the outgroup as more homogeneous than the ingroup. Yet given groups of clearly equal sizes no outgroup homogeneity effects were observed.

Interestingly, higher homogeneity ratings for both ingroup and outgroup were found on the scale referring to intragroup similarities than on the scale referring to intragroup differences. Though that result is not directly relevant to our hypotheses, it is a neat confirmation of the ‘focusing hypothesis that people attend more to the common features in judgments of similarity than in judgments of difference’ (Tversky and Gati, 1978, p. 84).

It will be recalled that 15 subjects in the no information condition perceived the ingroup in a minority position, but did not show an ingroup homogeneity effect. At first glance, this result appears to be inconsistent with Simon and Brown’s (1987)

’ The remaining four subjects in the no information condition had ascribed the same percentage (50 per cent) to ingroup and outgroup. Also, their ratings for ingroup and outgroup homogeneity were virtually identical (M(in) = 37.8, M(out) = 37.5; M(in) = 30.3, M(out) = 30.0; for SIM and DIF respec- tively).

Group size andgroup homogeneity 355

argument that minority membership poses a threat to one’s self-esteem which is then countered by the perceptual accentuation of relative ingroup homogeneity. How- ever, in the Simon and Brown experiment minority membership was assigned by an authority (i.e. the experimenter) rather than chosen by the subjects themselves, and the ingroup was said to be a very small minority (less than 10 per cent in contrast to 37.7 per cent in the present study; see also Brown and Smith, 1989; Mullen and Hu, 1989; Simon and Pettigrew, 1990). Thus, it stands to reason that being assigned to a very small minority constitutes quite a different psychological situation - with different implications for social behaviour or perception - compared to voluntarily adopting membership in a group consisting of more than a third of the population.

It should also be noted that the outgroup homogeneity effects shown by members who assumed to be in the majority group can hardly be explained by a simple tendency to perceive the smaller group per se as more homogeneous than the larger one. First, given such a relation subjects who had assumed to be in a minority group should have shown an ingroup homogeneity effect which was in fact not observed. And second, in the no information condition there were only very weak or non- significant correlations between the estimates of relative ingroup size (i.e. ingroup minus outgroup size) and those of relative ingroup homogeneity (i.e. ingroup minus outgroup homogeneity): r(S1M) = -0 .18 ,~ > 0.12, r(D1F) = -0.26, p = 0.052; one- tailed, n = 40.

In conclusion, our findings are clearly in line with previous research (Brown and Smith, 1989; Simon and Brown, 1987; Simon and Pettigrew, 1990) indicating that majority members are particularly inclined to emphasize the individuality possible within the ingroup while ascribing uniformity and predictability to the outgroup (see Quattrone and Jones, 1980). More specifically, the present study suggests that the outgroup homogeneity effect may often depend on the implicit - and often not warranted - assumption of being a member of a majority group. Yet it would certainly be premature to conclude - solely on the grounds of this single experiment - that the perception of relative outgroup homogeneity is actually caused by subjects’ assumption of being in a majority group. However, the results of another study at least rule out the alternative possibility that assumed majority membership is the consequence rather than the cause of perceived relative outgroup homogeneity. In that study (Simon, Mlicki, Johnston, Caetano, Warowicki, van Knippenberg and DeRidder, 1989) it was found that irrespective of whether the ingroup was described as more homogeneous than the outgroup or vice versa, it was always the ingroup that was ascribed a clear majority position. Thus, future research on the perception of ingroupoutgroup homogeneity must take into account not only the explicit minor- ity-majority context of many intergroup encounters, but should also further investi- gate the role of people’s implicit assumptions about the minority or majority status of their ingroup.

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