The Ontogeny of the Motivation That Underlies In-Group Bias

Abstract

Humans demonstrate a clear bias toward members of their own group over members of other groups in a variety of ways. It has been argued that the motivation underlying this in-group bias in adults may be favoritism toward one’s own group (in-group love), derogation of the out-group (out-group hate), or both. Although some studies have demonstrated in-group bias among children and infants, nothing is known about the underlying motivations of this bias. Using a novel game, we found that in-group love is already present in children of preschool age and can motivate in-group-biased behavior across childhood. In contrast, out-group hate develops only after a child’s sixth birthday and is a sufficient motivation for in-group-biased behavior from school age onward. These results help to better identify the motivation that underlies in-group-biased behavior in children.

Keywords

in-group favoritism out-group derogation in-group bias ontogeny childhood development intergroup dynamics cognitive processes decision making social cognition

When humans are faced with the challenge of allocating resources among other persons, they often base their decisions on specific characteristics of the possible recipients. One of the most important of these characteristics is the recipients’ group memberships (Allport, 1954; Brewer & Caporael, 2006). People tend to prefer the members of their own groups (in-groups) and to discriminate against the members of other groups (out-groups) in social decision-making situations (Brewer, 1979; Hewstone, Rubin, & Willis, 2002; Tajfel & Turner, 1986). Given its severe negative consequences for human societies, understanding and minimizing intergroup discrimination is an important challenge not only for the social sciences but also for other fields. On one hand, favoring one’s in-group over out-groups increases the in-group’s absolute welfare. On the other hand, such favoritism decreases the welfare of the out-groups, both absolutely and relative to the in-group. The motivations that lead to these often interrelated consequences of in-group bias and intergroup discrimination have been labeled in-group love (or in-group favoritism) and out-group hate (or out-group derogation; Brewer, 1999).

Whether in-group love, out-group hate, or both are decisive for engagement in intergroup discrimination is an old debate. Some authors have argued that loyalty to and cohesion within the in-group and hatred of and contempt toward the out-group are inseparable motivations that emerge simultaneously (Sherif, 1966; Sumner, 1906). Other authors have argued that in-group bias and intergroup discrimination require positive attitudes toward the in-group, whereas attitudes toward the out-group may range from hatred to indifference and may even be positive (although at a lower level than toward the in-group; Allport, 1954). Supporting the latter view, recent research has shown that group members prefer a behavioral option that displays merely an altruistic desire to help the in-group rather than an option that (in addition) actively hurts the out-group (De Dreu et al., 2010; Halevy, Bornstein, & Sagiv, 2008; Halevy, Weisel, & Bornstein, 2012). However, given that all of these studies have focused on adolescents or adults, the stage at which in-group love and out-group hate develop in early childhood, as well as whether these developments occur jointly or independently of each other, remains an open question. Although behavioral research has shown strong in-group bias and discrimination effects among infants and children (Buttelmann, Zmyj, Daum, & Carpenter, 2013; Fehr, Bernhard, & Rockenbach, 2008; Kinzler, Dupoux, & Spelke, 2007; Moore, 2009), the designs and procedures used have not focused on revealing the specific motivations that underlie children’s behavior. Investigating the developmental origins of in-group love and out-group hate is important not only from a theoretical point of view but also from a practical perspective. For instance, to develop effective programs that may reduce prejudice and discrimination in childhood, it is important to know the underlying cognitions and motivations that lead to these phenomena in the first place.

Given that, particularly in early childhood, interactions with members of the in-group exceed interactions with members of the out-group in frequency and importance (Brewer & Caporael, 2006; Caporael, 1997), in-group love should not only dominate out-group hate in intensity but also precede it in the order of development. We tested this hypothesis in a behavioral experiment in which 6- and 8-year-olds participated in a computer-mediated experimental game. We chose these age groups because it has been shown that there are fundamental developmental changes with regard to distributional preferences in early school years (see, e.g., Fehr et al., 2008). Children in each experimental session were randomly assigned to one of two groups (green or yellow). The use of artificial groups excludes confounding variables, such as developmental differences in the conception of and reaction to real groups acquired through social learning (Hughes, Bigler, & Levy, 2007) and experience (McGlothlin & Killen, 2010) or the transmission of group-based attitudes from parents to children (Castelli, Zogmaister, & Tomelleri, 2009; Lam, Guerrero, Damree, & Enesco, 2011). Participants independently made third-party mini–dictator decisions when allocating 15 positive resources (e.g., a balloon, a cookie, a teddy bear) and 15 negative resources (e.g., pieces of broken glass, moldy toast, a spider) to a puppet that shared the features of an in-group member, a puppet that shared the features of an out-group member, or a neutral box (i.e., an egalitarian allocation).

To investigate the underlying group-based motivations, it was important not only to include allocations of negative resources but also to give participants the choice of a neutral option (i.e., the box). In previous research, in-group love, out-group hate, or both could motivate the dominant allocation of positive resources to an in-group member. In our research, in contrast, participants’ giving more negative items to an out-group member than to an in-group member and the neutral box solely indicates out-group hate. The fact that participants could not profit from the allocated resources either directly or indirectly (e.g., through reciprocal benefits; Trivers, 1971) was important because it excluded the children’s individual outcome-based preferences (e.g., self-interest) as a possible motivational confound (McClintock, 1974; Toda, Shinotsuka, McClintock, & Stech, 1978).

Materials and Method

Participants and design

The participants were 45 children aged 6 (mean age = 6 years 0 months; age range = 5 years 6 months to 6 years 9 months; 19 girls, 26 boys) and 36 children aged 8 (mean age = 7 years 11 months; age range = 7 years 2 months to 8 years 9 months; 19 girls, 17 boys). Three additional 6-year-olds were tested but were not included in the final sample because they did not understand the experimental game. Moreover, as a result of technical problems, 1 participant did not complete all the trials of the task and had to be excluded from some of the analyses. Children were recruited from a database of parents who had volunteered to participate in child-development studies in a medium-sized German city. There were 14 experimental sessions, each with 3 to 10 participants. The experiment used a 2 (age group: 6-year-olds vs. 8-year-olds; between subjects) × 2 (resources: positive vs. negative; within subjects) design.

Procedure

Group induction

After the children had been welcomed by a male experimenter (the instructor) outside the laboratory, they entered the laboratory and drew a lottery ticket that determined their group color (green or yellow) and a computer-cubicle number. Two hand puppets (each operated by a different female experimenter), one with a green and one with a yellow T-shirt, welcomed the children to their assigned groups in opposite corners of the laboratory. The puppets interacted with the children as real members of their groups. Besides their group membership, the puppets differed only in their hair color (black vs. blond, counterbalanced with respect to group color between experimental sessions; see Table S1 in the Supplemental Material available online). The puppets’ speech followed a strict protocol and was the same in both groups. To increase the children’s identification with their group, we provided them with a T-shirt in their group’s color and took pictures of each child wearing his or her T-shirt. Moreover, children of the same group were seated on the same side of the laboratory, opposite from the other group, and each side of the laboratory was decorated with murals in the respective group’s color.

Experimental game

Next, the instructor explained the computer-mediated game, which was programmed with z-Tree (Fischbacher, 2007). For this purpose, a computer screen was displayed schematically on a whiteboard to demonstrate the game’s characteristics and behavioral options. As displayed in Figure 1, the bottom of the screen contained pictures of each puppet—one puppet in the left corner and one puppet in the right corner—and a button in the respective group color underneath each picture (the left and right positions of the yellow and green puppets were counterbalanced between experimental sessions; see Table S1 in the Supplemental Material).

Fig. 1.

Example stimuli from the experimental game. The displays shown here are (a) the black-square presentation (displayed before and after each trial) and (b) a negative-resource presentation (of a spider).

A picture of a box, with a white button underneath it, was located between the pictures of the puppets. A black square was presented in a top-centered position (see Fig. 1). After a mouse click on this square, an item appeared at this location. This procedure was implemented to make participants move the mouse cursor back to a central position, roughly equidistant from all three buttons, after each allocation decision. The instructor explained and schematically showed on the whiteboard that a mouse click on the green (vs. the yellow) button would award the item to the puppet of the green (vs. the yellow) group and that clicking on the white button would put the item in the box, such that “no one would receive this item.” Thereafter, the black square reappeared and a mouse click again was required to start the next trial. The instructor presented two examples, one with a negative resource and one with a positive resource. Speaking through the puppets, the experimenters demonstrated that both puppets would like to receive positive resources (by having the puppet express a positive exclamation on receiving the example item and a negative exclamation on not receiving it) and that neither puppet would like to receive negative resources (by having the puppet express an exclamation of disgust on receiving the example item and an expression of schadenfreude on not receiving it). After the explanation of the experimental game, the children were allowed to ask clarifying questions.

Working independently in their assigned cubicles (without communicating with others), participants subsequently completed 30 experimental trials (15 involving positive items and 15 involving negative items). Item valence was pretested (for the pretest results and the full list of items, see Table S2 in the Supplemental Material). After all participants had finished the experiment, they returned their T-shirts, and the puppets “explained” to the children that group membership is really not important and that everybody is equal. The whole experiment took about 25 min to complete.

Approximately half of the younger children had participated in another experimental game directly before the experiment reported here (a short break was provided between the games). However, there were no behavioral differences between those participants and the children from their age group who had not participated in the preceding experiment.

Allocations in the experiment were fictitious and had no real consequences for the recipients (i.e., the puppets). The use of fictitious incentives, compared with real incentives, should produce different behavioral responses by the decision maker only if a behavioral norm of a specific outcome distribution is opposite to other (i.e., the decision maker’s personal) distributional preferences and if the decision maker is able to resist these other preferences. For instance, to increase their social image, decision makers might be more likely to act in line with a salient behavioral norm (e.g., fairness) and contrary to their personal distributional preference (e.g., egocentrism) if the consequences of doing so are fictitious rather than real. However, there is evidence that children younger than 9 years of age do not have sufficient self-control to suppress their personal preferences (Houser, Montinari, & Piovesan, 2012). In other words, 6-year-olds and 8-year-olds, as represented by our sample, are very likely not to discriminate between real and fictitious outcomes.

Coding and analyses

The dependent variable was participants’ allocations of resources in two types of third-party mini–dictator games: allocation of positive resources and allocation of negative resources. In the case of positive resources, participants could choose between a (+1, 0) allocation (giving the item to the in-group puppet), a (0, 0) allocation (putting the item in the box), or a (0, +1) allocation (giving the item to the out-group puppet). In the case of negative resources, participants could choose between a (−1, 0) allocation (giving the item to the in-group member), a (0, 0) allocation (putting the item in the box), or a (0, −1) allocation (giving the item to the out-group member). We aggregated allocation decisions of the 15 positive and 15 negative resources separately and transformed them into percentages.

For participants’ level of intergroup discrimination in positive- and negative-resource domains, we compared items given to the in-group member with those given to the out-group member. Although this difference reveals participants’ relative preference for the in-group over the out-group, it ignores egalitarian motives. For example, if a child allocated 20% of all positive items to the in-group member and 10% of all positive items to the out-group member, the resulting 2-to-1 ratio would suggest an in-group bias. However, this analysis ignores the fact that the child allocated 70% of all positive items to the neutral box, an egalitarian allocation (in which no one received the positive item), in the majority of trials. Therefore, to shed light on children’s dominant behavioral motivation, one also needs to consider their egalitarian motives.

Thus, for positive resources, we aggregated the allocations of items to the neutral box and to the out-group member and tested this sum against the allocations to the in-group member. As in previous research, this measure revealed children’s behavioral intergroup discrimination motivated by in-group love, out-group hate, or both. Likewise, for negative resources, we aggregated the allocations of items to the neutral box and to the in-group member and tested this sum against the allocations to the out-group member. If children care only about the absolute outcomes of their in-group (in-group love), they should not allocate negative resources to their in-group member and should not distinguish between allocations to the neutral box and the out-group member. However, if they predominantly care about derogating the out-group absolutely or relatively, they should allocate more negative resources to the out-group member relative to the box and the in-group member combined. This comparison in the domain of negative resources, in contrast to that in the domain of positive resources, provides an unambiguous index of children’s pure out-group hate. To estimate age and gender differences, we calculated algebraic difference scores from the allocations of positive (vs. negative) items to the in-group (vs. the out-group) member and the aggregated allocations to the box and the out-group (vs. the in-group) member and then compared these scores among groups of participants.

Results

For positive resources, the 6-year-olds (n = 45) allocated 75% of the items to the in-group member, 10% of the items to the out-group member, and 15% of the items to the box (see Fig. 2 for allocation percentages), which indicated a substantial in-group bias when we directly compared the percentages of resources given to the in-group member with those given to the out-group member, Wilcoxon test, T⁺ = 990.00, p < .001, r = .86. Furthermore, in-group love and out-group hate clearly dominated egalitarianism, as indicated by the contrast between positive resources allocated to the in-group member relative to the neutral box and the out-group member, Wilcoxon test, T⁺ = 907.50, p < .001, r = .66. The 8-year-olds (n = 36) also showed a clear in-group bias by allocating 90% of the items to the in-group member, 4% to the out-group member, and 6% to the box, with identical statistical results for both types of analyses, Wilcoxon test, T⁺ = 666.00, p < .001, r = .88. The difference between the age groups was significant—allocations to in-group versus out-group: Mann-Whitney U = 512.50, p = .004, r = .32; allocations to in-group versus neutral box and out-group: Mann-Whitney U = 528.00, p = .006, r = .30. Thus, if intergroup discrimination can be motivated by both in-group love and out-group hate, both age groups showed considerable in-group-biased allocations, with a stronger level of discrimination among the 8-year-olds than among the 6-year-olds.

Fig. 2.

Mean percentage of allocated resources as a function of age group, recipient (in-group member, out-group member, or neutral box), and resource domain (positive or negative). Error bars show 95% confidence intervals.

The more interesting scenario is one in which in-group love may not serve as a motivation for in-group-biased behavior: For negative resources, the 6-year-olds (n = 45) allocated 12% of the items to the in-group member, 51% of the items to the out-group member, and 37% of the items to the box (see Fig. 2), which again revealed a significant preference for the in-group relative to the out-group, Wilcoxon test, T⁺ = 832.00, p < .001, r = .78. However, when we investigated whether out-group hate was the underlying motive for this behavior by also considering egalitarian allocations (i.e., we aggregated resources allocated to the in-group member and to the neutral box and compared this sum with the allocations to the out-group member), mere out-group hate did not appear to be a significant behavioral motivation in this age group, Wilcoxon test, T⁺ = 477.50, p = .957, r = .01. The 8-year-olds (n = 35) allocated 4% of the items to the in-group member, 71% to the out-group member, and 25% to the box, which indicated a significant preference for the in-group relative to the out-group, Wilcoxon test, T⁺ = 630.00, p < .001, r = .87. In contrast to the results found for the younger children, the comparison of 8-year-olds’ allocations to the in-group and the neutral box with those to the out-group revealed a significant difference, Wilcoxon test, T⁺ = 555.50, p < .001, r = .67, which indicated that out-group hate was the dominant motivation for the 8-year-olds’ distributions of negative resources. Age differences were again significant—allocations to in-group versus out-group: Mann-Whitney U = 417.00, p < .001, r = .40; allocations to in-group and neutral box versus out-group: Mann-Whitney U = 484.00, p = .003, r = .33. Overall, the results indicated that in-group love is already present in children of preschool age and can motivate in-group-biased behavior, whereas out-group hate develops only after a child’s sixth birthday and is not sufficient to induce in-group-biased behavior before that age.

Another indicator of the importance of out-group hate for children’s level of intergroup discrimination is the correlation between intergroup discrimination in the domain of positive and negative resources. This correlation was stronger for the 8-year-olds, r_s = .61, p < .001, than for the 6-year-olds, r_s = .30, p = .048, which provided further evidence that the importance of out-group hate as an underlying behavioral motivation increases with a child’s age.

In addition to these main findings, our analyses yielded an interesting result: There were no gender effects in any of the analyses in the group of 6-year-olds (all ps ≥ .300). However, gender differences did appear among the 8-year-olds. For positive resources, 8-year-old boys (n = 17) and girls (n = 19) respectively allocated 94% and 86% of the items to the in-group member, 2% and 6% of the items to the out-group member, and 5% and 8% of the items to the box, which yielded a significant gender effect in in-group bias when we compared the difference scores for the allocations of positive items to the in-group member and the aggregated allocations to the neutral box and to the out-group member, Mann-Whitney U = 102.00, p = .046, r = .33. For negative resources, 8-year-old boys (n = 16) and girls (n = 19) respectively allocated approximately 3% and 5% of the items to the in-group member, 84% and 60% of the items to the out-group member, and 13% and 35% of the items to the box. These differences indicated an even larger gender gap in in-group bias when motivated by pure out-group hate, Mann-Whitney U = 58.00, p = .002, r = .53.

Discussion

Our aim in the current study was to investigate whether 6- and 8-year-olds show an in-group bias in their allocation of positive and negative resources. Specifically, we wanted to find out what motivations underlie in-group-biased behavior among children. We developed a new experimental game based on a behavioral measure that allowed us to discriminate between positive and negative group-based preferences, that is, in-group love and out-group hate. Both age groups showed a clear in-group bias in both domains of resources, positive and negative. With regard to the underlying motivations, however, our results showed a primacy of in-group love relative to out-group hate in human ontogeny. When both in-group love and out-group hate were able to serve as a behavioral motivation (i.e., in the allocation of positive resources), there was already substantial intergroup discrimination among the 6-year-olds, which became even stronger among the 8-year-olds. In contrast, when in-group love was excluded as a potential source of this effect (i.e., in the allocation of negative resources), we found out-group hate to be a behavioral motivation for intergroup discrimination among the 8-year-olds only. Whereas the younger children only prevented their in-group from receiving negative items, the older children intentionally harmed the out-group by giving the majority of negative items to the out-group rather than putting them in the neutral box (i.e., an egalitarian allocation). Thus, we conclude that in-group love develops before out-group hate in human ontogeny. Accordingly, the positive consequences for one’s own group constitute the foundation of in-group bias and discrimination, whereas the negative consequences for other groups become a behavioral motivation only at a later stage in human development.

It is interesting that among 8-year-olds, boys in particular showed out-group hate. From an evolutionary perspective, there are good reasons for why males are more prone than are females to engage in competitive intergroup conflict (e.g., the male-warrior hypothesis; Van Vugt, De Cremer, & Janssen, 2007), which is likely to be reinforced through cultural processes. This gender gap is also consistent with other research findings that have indicated that it is mainly boys who show parochial altruism (Fehr et al., 2008). Our study, however, provides the first evidence that differences in group-based preferences (i.e., out-group hate) between boys and girls may, at least partially, contribute to a gender gap in children’s competitive orientation (e.g., Gneezy & Rustichini, 2004; Moely, Skarin, & Weft, 1979).

The current study leaves some questions unanswered. Specifically, it is unclear whether we were able to exclude or control for all of the demand characteristics of our task. We tried to keep them as low as possible by making it clear that both puppets would like to receive positive resources and avoid negative resources and that the children’s allocations would not result in any personal gains or losses. Furthermore, in the current study, we used fictitious instead of real outcomes. Although we have argued that this should not be a problem for children at the ages of our participants, future research should include real outcomes. For instance, one could provide recipients with an endowment (of, e.g., candy) that may increase (positive domain) or decrease (negative domain) as a function of participants’ allocations. Finally, there might be different motivations that underlie the conception of out-group hate: to absolutely harm the out-group or to maximize the relative difference between the in-group and the out-group. Until now, these differences in motivation have not been distinguished empirically. Refining the distinction between competitiveness and pure harm on a behavioral level may be a direction for future research.

The implications of the obtained findings are far-reaching. The increase of cooperation and solidarity within groups clearly is of utmost importance for human societies. However, intragroup cooperation can sacrifice collective efficiency if the aim is to harm other groups to win an intergroup conflict (Böhm & Rockenbach, 2013). An in-group’s absolute welfare, in particular, can be severely damaged by engaging in long-lasting intergroup conflicts. Given that our results suggest not only that in-group love and out-group hate are independent of each other but also that in-group love emerges before out-group hate in human development, it is possible to affect both of these motivations separately by building on humans’ inherent prosocial nature. Children, and in particular boys, should be taught as early as preschool age that intragroup cooperation and loyalty are valuable and beneficial for humanity, and even for their own group in the long run, only if they do not imply out-group derogation at the same time.

Footnotes

Acknowledgements

The authors are grateful to their students M. Aßmann, I. Dübner, and K. Gerst, who provided excellent research assistance. We thank M. Pigors for valuable advice on technical implementation, the research group at the Center for Empirical Research in Economics and Behavioral Sciences for inspiring discussions, and K. Gellén for her helpful comments on an earlier draft of the manuscript. This research was carried out in accordance with the provisions of the World Medical Association Declaration of Helsinki.

Declaration of Conflicting Interests

The authors declared that they had no conflicts of interest with respect to their authorship or the publication of this article.

Supplemental Material

Additional supporting information may be found at

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