Research Article
Under Threat of Social Exclusion, Females Exclude More Than Males
Psychological Science 22(4) 538–544 © The Author(s) 2011 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0956797611402511 http://pss.sagepub.com
Joyce F. Benenson1,2, Henry Markovits3, Melissa Emery Thompson4, and Richard W. Wrangham2 1
Department of Psychology, Emmanuel College; 2Department of Human Evolutionary Biology, Harvard University; 3Department of Psychology, Université du Québec à Montréal; and 4Department of Anthropology, University of New Mexico
Abstract Theoretical analyses and studies with children suggest that females are more likely than males to respond to threats of social exclusion with exclusion. Here we present a series of studies using a modified version of a computerized competitive game that participants play against two fictitious opponents. In previous studies, females and males have typically made identical strategy choices when playing this game. We show that when players are told that the two fictitious opponents may form an exclusionary alliance against them, females modify their competitive strategies by forming more preventive exclusionary alliances than males do. These results support the idea that adult females are more likely than males to form preventive exclusionary alliances when faced with a social threat. The results further suggest that females and males compete in different ways. Keywords social exclusion, sex differences, competition Received 10/14/10; Revision accepted 11/7/10
Much research demonstrates that compared with males, females use less direct physical and verbal aggression (Archer, 2004; Archer & Coyne, 2005; Björkqvist, 1994; Crick & Grotpeter, 1995; Maccoby & Jacklin, 1974). Females bear greater responsibility for child care than males do, so engagement in direct aggression poses a higher risk to their reproductive success (e.g., by limiting their ability to care for their offspring, who are likely to be nearby; Campbell, 1999). Females thus tend to employ less direct forms of aggression, including reputation denigration, social manipulation, subtle demeaning facial and bodily gestures, and social exclusion (e.g., Archer, 2004; Björkqvist, 1994; Crick & Grotpeter, 1995; Underwood, 2003). Nondirect forms of aggression, typically termed indirect, relational, or social aggression, are also used by males, however. For example, one form of nondirect aggression, overt reputation denigration, is used more frequently by males than by females (Maccoby, 1990; Maltz & Borker, 1983). A key question therefore is whether, and under what circumstances, particular forms of nondirect aggression may be used more by females than by males. Studies examining sex differences in overall use of nondirect forms of aggression have shown that in childhood, females may use such forms of aggression slightly more than males do, but these sex differences are small (e.g., Archer, 2004, 2009; Archer & Coyne, 2005; Card,
Stucky, Sawalani, & Little, 2008). Previous studies have used combined measures that did not allow for the isolation of specific forms of nondirect aggression (Archer & Coyne, 2005), so it is difficult to infer sex differences in specific forms of nondirect aggression from existing data. From childhood through adulthood, females are more likely than males to form one-on-one peer relationships, whereas males are more likely to form interconnected group relationships (Benenson, 1990; Gabriel & Gardner, 1999; Markovits, Benenson, & Dolenszky, 2001). A one-on-one relationship is inherently more fragile than is a relationship situated within a larger group containing temporary substitute partners, allies, and mediators, all of whom exhibit loyalty and commitment to the maintenance of the larger group (Benenson & Christakos, 2003; Benenson, Nicholson, Waite, Roy, & Simpson, 2001). Given this difference in social ecology, females should be particularly alert to any alliance that could displace an existing relationship. In a same-sex friendship, a female whose friend forms another close same-sex relationship would have a higher risk of losing this friendship than would a male, who in the Corresponding Author: Joyce F. Benenson, Department of Psychology, Emmanuel College, 400 The Fenway, Boston, MA 02115 E-mail:
[email protected]
Social Exclusion same situation would stand a greater chance of adding another social partner to his group. Consistent with this hypothesis, research shows that females become more jealous than males do when their friends form a new friendship (Parker, Low, Walker, & Gamm, 2005). Thus, being the target of social exclusion in a competitive situation may result in a significant immediate disadvantage for a female, who has a higher probability than a male of losing an ally. From a theoretical perspective, key differences in human females’ and males’ social ecology suggest that social exclusion may be one form of nondirect aggression particularly salient to females. Only a few behavioral studies have isolated social exclusion from other forms of nondirect aggression, however. In Feshbach’s studies with children (Feshbach, 1969) and adolescents (Feshbach & Sones, 1971), female newcomers were less accepted and were rated more negatively by pairs of same-sex peers than were male newcomers. Similarly, in a yearlong observational study of friendships in middle childhood (Eder & Hallinan, 1978), female triads were more likely than male triads to divide into pairs by excluding one of the individuals. In contrast, male pairs were more likely than female pairs to expand into triads. A more recent study further suggests that under conditions of competitive threat, females are more likely than males to actively exclude a third party. Benenson, Antonellis, Cotton, Noddin, and Campbell (2008) presented same-sex triads of 4-year-old children with one, two, or three highly attractive puppets. No sex differences in use of exclusion were observed when the children had two or three puppets to play with. However, when only one puppet was available, females formed more exclusionary alliances (i.e., two girls combined to exclude a girl who had the puppet) than did males, whereas males were more likely to individually employ direct aggression (e.g., by grabbing the puppet). Observational studies of chimpanzees (Pan troglodytes), one of humans’ closest living genetic relatives, show similar sex differences in social patterns. Male chimpanzees form large groups, whereas females spend more time alone or with only one other female (Langergraber, Mitani, & Vigilant, 2009; Wrangham & Smuts, 1980). Male chimpanzees engage in more direct physical and vocal aggression than do females, but males also cooperate to patrol and defend their community and to raid neighboring communities. Although male chimpanzees fight for dominance, they seldom exclude one another from a group, as they derive strength in numbers during intercommunity interactions (Wrangham, 1999). In contrast, female chimpanzees who attempt to immigrate from neighboring communities frequently become targets of social exclusion by pairs of resident females, apparently because the immigrants pose a competitive threat: Residents risk a loss of resources for themselves and their offspring should a newcomer female and her future offspring settle in their neighborhood (Gilby, Eberly, & Wrangham, 2008; Kahlenberg, Thompson, Muller, & Wrangham, 2008; Lehmann & Boesch, 2009; Townsend, Slocombe, Emery Thompson, & Zuberbühler,
539 2007). When not under competitive threat, female chimpanzees may form one-on-one relationships, but they rarely practice social exclusion (Kahlenberg et al., 2008; Langergraber et al., 2009). Gender differences in human social organization and empirical evidence of exclusion in young children and chimpanzees led us to hypothesize that when confronted with a social threat, females should react with social exclusion more than males do, but that in the absence of a specific threat, females should not proactively use social exclusion more than males do. The existing literature provides little direct evidence supporting our hypothesis. Few studies have examined responses to specific kinds of social threats, and most behavioral studies of children and adults have combined different forms of nondirect aggression, thereby precluding an analysis of the use of social exclusion specifically (e.g., Archer & Coyne, 2005; Card et al., 2008). Studies that have examined emotional, physiological, and neural responses to social exclusion have suffered from a lack of agreement as to how to assess responsiveness to social exclusion (Blackhart, Nelson, Knowles, & Baumeister, 2009). This is reflected in contradictory results: Females responded to social exclusion more strongly than males did in some studies (e.g., Stroud, Salovey, & Epel, 2002), but not in others (e.g., Eisenberger, Way, Taylor, Welch, & Lieberman, 2007; Maner, Miller, Schmidt, & Eckel, 2010). As Blackhart et al. (2009) concluded, behavioral measures remain the clearest measures of responses to social exclusion. Testing our hypothesis behaviorally required us to situate males and females in a competitive context in which alliance formation was a natural possibility and the two sexes would respond identically when alliances were not explicitly exclusionary. To accomplish this, we adopted a method that models ecologically valid decision making in a competitive situation that permits alliance formation. We hypothesized that if an exclusionary alliance was introduced as a threat—even if it had no consequences—females would react by forming exclusionary alliances more often than males would. Participants engaged in a zero-sum game in which they competed for points against two fictitious same-sex opponents using one of three strategies: They could (a) compete alone for the whole payoff, (b) form an alliance with one opponent and share the payoff if the alliance won, or (c) share the payoff with both opponents and avoid competition. Expected payoffs were identical for all three choices. Thus, strategy choice solely reflected individuals’ intuitions about which strategy might be optimal. Using this method in previous studies (Benenson, Markovits, Thompson, & Wrangham, 2009), we found that young adult females and males attempted to compete for the whole payoff when their probabilities of winning alone were high and increasingly chose to form alliances with one opponent as their probability of winning dropped below 50%. Alliances with both opponents were relatively rare and were formed mostly when the probability of winning was low. Under these
540 experimental conditions, males and females showed identical patterns of strategy use. Simply labeling one fictitious character as a potential friend induced both males and females to ally more often with this character than with the other character, a result showing that adults’ strategy choices in the game were subject to the effects of social schemas. In the studies we report here, some participants played the basic version of the game (baseline condition), and others played a version in which we introduced exclusionary alliances. Critically, this modification had no effect on the actual outcome for a participant. For example, in the baseline condition, if the participant chose to compete alone and lost, he or she would receive 0 points. In the exclusionary-alliance condition, if the participant chose to compete alone and lost, the other two players would form an exclusionary alliance, and the participant would receive 0 points. Thus, there was no operational difference between the two versions of the game: The only difference was in participants’ evaluation of the additional threat involved when exclusionary alliances were formed. Researchers studying aggression distinguish between proactive behaviors, which are goal directed and unprovoked, and reactive behaviors, which are triggered by negative events and associated with more responsive threat detection (e.g., Blair, Peschardt, Budhani, Mitchell, & Pine, 2006; Crick & Dodge, 1996). The design of the following studies allowed us to distinguish between these two forms of behavior. Our previous analysis (Benenson et al., 2008) indicated that females react to social threats with social exclusion but do not employ social exclusion proactively. Thus, we hypothesized that when confronted with an exclusionary alliance, females would react by forming alliances with another player more often than males would. When there was no threat of an exclusionary alliance, we did not expect to find significant sex differences in use of exclusion.
General Method All participants attended a college in Montréal, Québec, Canada, and participated individually under identical conditions. More than 95% were White, and all were French speaking and from lower-middle- to middle-class backgrounds. No participant was included in more than one study or condition. Each participant was seated at a computer and told that he or she would be competing for money (maximum of $5) in a 28-round game against two same-sex opponents (who were depicted as cartoon figures). On each round, the participant competed for 100 points. The participant’s personal strength, or probability of winning all 100 points in a round when competing alone, varied randomly between rounds from 20% to 80% (in 10% increments). Over the course of the 28 rounds, each participant played four times at each level of personal strength. On every round, the sum of the player’s level of personal strength plus the levels of strength of the two opponents equaled 100%, with the levels of the two opponents’ strengths apportioned unequally. At the end of the 28 rounds, all players received a minimal payoff. Additional payoffs were given only
Benenson et al. to the players who had received more points than both of their opponents and varied in proportion to the amount by which they beat the player with the second highest amount of points. No winnings were announced until after the game had ended. On each round, the player was informed of his or her level of personal strength and the two opponents’ levels of strength. The participant’s choices depended on the condition. In the baseline condition, the participant was given the following three choices: •• Compete alone, with the participant’s level of personal strength indicating his or her probability of winning the 100 points (compete-alone choice). •• Form an alliance with either of the opponents, with the participant’s level of personal strength and the allied opponent’s strength summed to generate their combined strength (their combined probability of winning the 100 points). If the alliance won, the 100 points would be divided between the alliance members in proportion to their relative strengths (allywith-one-player choice). •• Form an alliance with both opponents to avoid competing and automatically divide the 100 points according to the assigned strength of each player. This option guaranteed a payoff for everyone (three-wayalliance choice). Levels of strength and the possible results of these three choices were clearly demonstrated using specific examples. Critically, in a given round, the three choices produced identical expected payoffs, although players were not told this explicitly. To facilitate understanding and increase the ecological validity of the game, we depicted the player and two opponents with three identical same-sex cartoon faces labeled “Me,” “A,” and “B” and on each round indicated the corresponding strength, or probability of winning, above each face.
Study 1 Participants A total of 41 females and 42 males (average age = 21 years 4 months) participated in this study.
Method and procedure In this study, half the participants were assigned randomly to the baseline, no-exclusion condition, in which instructions were exactly as described in the General Method. The other half were assigned to the full-exclusion condition, in which instructions were modified to describe any potential alliance of two players as exclusionary. Thus, in the full-exclusion condition, participants were told that if they chose to compete alone, they would run the risk of being excluded by the other two players: “If you choose to compete alone, your two
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Social Exclusion opponents will form an alliance and exclude you if they win. Thus, if they win, you will be excluded and will not receive any points.” In addition, they were told that if they formed an alliance with either of their opponents, this would exclude the third player: If you and your partner win, the third player will be excluded and will not win any points. If your alliance wins, you will divide the 100 points proportionally with your opponent in relation to your assigned strengths. If you and your partner lose, you will not win any points and the third player will win 100 points. The third choice (forming an alliance with both of the other players) was described in exactly the same way as in the baseline condition.
Results We first examined the number of times out of four that each participant chose to ally with one player at each level of personal strength. A repeated measures ANOVA on the dependent variable with gender and condition as independent variables and level of personal strength as the repeated factor yielded significant main effects of condition, F(1, 79) = 4.11, p < .05, ηp2 = .049, and personal strength, F(6, 74) = 31.15, p < .001, ηp2 = .716, and a significant interaction between condition and gender, F(1, 79) = 7.07, p < .05, ηp2 = .082. The effect of personal strength precisely mirrored previous findings (Benenson et al., 2009). Participants increasingly formed alliances with another player as their personal strength waned, with the effect leveling off at strengths below 40%. Least squares means contrasts were used to analyze the
Condition × Gender interaction. Across all 28 trials, the mean number of times that an alliance with one other player was chosen was significantly higher for females (M = 19.14, SD = 6.23) than for males (M = 14.64, SD = 5.21) in the fullexclusion condition, whereas there was no gender difference in the no-exclusion condition (females: M = 13.85, SD = 4.87; males: M = 15.35, SD = 3.91; see Fig. 1). Females were more likely to form their own exclusionary alliances when the possibility of exclusionary alliances was explicit than when such a possibility was not mentioned. In contrast, males responded to the full-exclusion and no-exclusion conditions as if they were identical. Next, we examined choices to form three-way alliances. Our analysis showed a significant main effect of personal strength, F(6, 74) = 9.07, p < .01, ηp2 = .424, and a significant Gender × Condition interaction, F(1, 79) = 7.95, p < .01, ηp2 = .091. Overall, participants chose to form a three-way alliance quite rarely, on fewer than 10% of the trials. This option was chosen at a rate higher than 10% only when personal strength was less than 40%. Females were significantly less likely to form three-way alliances in the full-exclusion condition (M = 1.52, SD = 3.03) than in the no-exclusion condition (M = 3.80, SD = 3.86), whereas males did not show a significant difference between conditions (full exclusion: M = 3.36, SD = 4.14; no exclusion: M = 1.60, SD = 1.79). Analysis of how often participants chose to compete alone (note that the frequency of this choice was constrained by frequencies of choosing the other two strategies) showed a main effect only of personal strength, F(6, 74) = 40.03, p < .001, ηp2 = .764; use of this strategy declined as personal strength decreased. Note that females competed alone somewhat less in the full-exclusion condition (M = 7.33) than in the no-exclusion condition (M = 10.35), although the difference was not significant.
Females Full Exclusion
3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
4.0
No Exclusion
Number of Alliances
Number of Alliances
4.0
Males
80 70 60 50 40 30 20
Personal Strength (%)
Full Exclusion No Exclusion
3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 80 70 60 50 40 30 20
Personal Strength (%)
Fig. 1. Results from Study 1: mean number of choices (out of four) to ally with one player as a function of personal strength (probability of winning alone) and condition (full exclusion vs. baseline, with no exclusion). Results are presented separately for female and male participants.
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Thus, as hypothesized, females were more sensitive than males to the threat of social exclusion, even though it did not affect their chances of winning, and they modified their strategy use correspondingly, choosing to form an exclusive alliance significantly more often than males did at all levels of strength. The frequency with which females chose to form exclusive alliances significantly reduced their use of three-way alliances, and somewhat lowered their use of the competealone strategy. In contrast, males showed no significant differences in strategy choice between conditions.
greater tendency than males to use exclusion as a proactive strategy.
Study 2
A total of 20 females and 20 males (average age = 21 years 6 months) participated in Study 3.
As previously stated, researchers studying aggression distinguish between proactive and reactive behaviors. In this study, we examined the possibility that females use exclusion proactively; that is, we tested the possibility that, compared with males, females more often choose to form exclusionary alliances when there is no provocation to do so.
Participants A total of 21 females and 21 males (average age = 21 years 9 months) participated in Study 2.
Method and procedure In this study, the choice to ally with one other player was explicitly described as exclusionary, with the target of exclusion being the third player (i.e., the description of this choice was the same as in the full-exclusion condition of Study 1). Neither of the two other choices mentioned exclusion. Thus, in the description of the compete-alone choice, there was no mention that the other two players would attempt to form an exclusionary alliance against the participant.
Results Using a repeated measures ANOVA with gender as the independent variable and level of personal strength as the repeated factor, we analyzed the number of ally-with-one-player choices at each level of personal strength. This analysis yielded only a significant main effect of personal strength, F(6, 35) = 6.44, p < .001, ηp2 = .525. As before, participants increasingly formed alliances with one other player as their personal strength waned, with the effect leveling off at strengths below 40%. There were no gender differences in the number of allywith-one-player choices, F < 1 (females: M = 12.67, SD = 6.22; males: M = 13.81, SD = 6.08). Examination of use of three-way alliances yielded no significant effects. Analysis of the compete-alone strategy showed only a main effect of personal strength, F(6, 33) = 10.34, p < .001, ηp2 = .546. Females and males showed the same profile of strategy use when the ally-with-one-player choice resulted in the participant forming an exclusionary alliance. In other words, females showed no
Study 3 In our next study, we tested the hypothesis that females’ differential responses to exclusion are reactive, or due to the threat of being excluded.
Participants
Method and procedure In this study, instructions stated that if the participant chose to compete alone, the two other players would form an exclusionary alliance against the participant (i.e., the description of this choice was the same as in the full-exclusion condition of Study 1). The two other choices did not mention exclusion. Thus, the choice to form an alliance with one player was not explicitly described as a choice to exclude the third player.
Results Using a repeated measures ANOVA with gender as the independent variable and level of personal strength as the repeated factor, we analyzed the number of ally-with-one-player choices at each level of personal strength. This analysis yielded significant main effects of personal strength, F(6, 33) = 9.61, p < .001, ηp2 = .636, and gender, F(1, 38) = 4.70, p < .05, ηp2 = .110. Again, participants increasingly formed alliances with one other player as their personal strength waned, with the effect leveling off at strengths below 40%. Females chose the ally-with-one-player strategy significantly more often (M = 17.65, SD = 7.29) than did males (M = 12.90, SD = 6.54). Analysis of the three-way-alliance choice showed no significant effects. Analysis of use of the compete-alone strategy showed only a main effect of personal strength, F(6, 73) = 16.44, p < .653, ηp2 = .636. Thus, there were no significant sex differences in the number of choices to form a three-way alliance or to compete alone, although both of these strategies were used slightly less often by females than by males. Results showed exactly the same pattern as found in the full-exclusion condition in Study 1. Figure 2 presents the number of trials on which male and female participants chose to ally with one other player in the exclusion conditions of Studies 1 through 3.
Study 4 Results of Studies 1, 2, and 3 showed that females’ differential responses to exclusion were reactive; that is, females adjusted their strategy choices more often than males did when participants were the potential target of an exclusionary alliance.
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Social Exclusion
Mean Number of Alliances
21
Females
Males
19 17 15 13 11 9 7 5
Full Exclusion (Study 1)
Proactive (Study 2)
Reactive (Study 3)
Condition Fig. 2. Male and female participants’ mean number of choices (out of 28) to form an alliance with one other player in the exclusion conditions of Studies 1 through 3.
However, females might have been reacting to the possibility that when they competed alone, their opponents would enter into an alliance, and it may have been only the alliance, not social exclusion, that threatened females. In order to examine this possibility, we presented 23 females and 19 males (average age = 22 years 3 months) with a version of the game in which the instructions indicated that when participants chose to play alone, the two other players would simply form an alliance (rather than a specifically exclusionary alliance). No mention of exclusion was made in the descriptions of any of the choices. As in the baseline condition, results showed no gender differences in the frequency with which participants chose any of the three response options (Fs < 1 for all strategies).
General Discussion In two studies, adult human females, compared with males, were more likely to react to the possibility of social exclusion by socially excluding a third party, even when social exclusion did not affect payoffs. When the threat of an exclusionary alliance was not present, females and males selected identical strategies. These results are consistent with findings from studies of 4-year-old children and chimpanzees in which females were more likely than males to respond to social threats by forming exclusionary alliances (Benenson et al., 2008; Kahlenberg et al., 2008). Our findings complement previous results suggesting heightened responses to social exclusion among females, at least on some physiological measures (Stroud et al., 2002). However, males also respond negatively to social exclusion (Eisenberger et al., 2007). Future research is therefore necessary to determine whether females and males differ in their cognitive evaluations of the degree of threat posed by social exclusion and to establish whether the sexes exhibit different physiological responses to social exclusion.
Although our studies demonstrate that females employ social exclusion as a response to the threat of social exclusion more often than males do, future research is needed to compare sex differences in behavioral reactions to a variety of social threats, including direct aggression and other forms of nondirect aggression. Results from our studies and prior research are consistent with the idea that females and males have different default behavioral reactions to threats. As their primary competitive strategy to combat any social threat, females may attempt to form an exclusionary alliance, whereas males may endeavor to unilaterally and directly dominate an opponent (Benenson, 2009; Benenson et al., 2008). The game we used in our studies provides clear methodological advantages, but it lacks the richness of real-world contexts. It is possible that gender differences might be even greater in a natural setting than they were in our studies. Given that females tend to form strong one-on-one bonds, an alliance between a female’s friend and a third female might appear to be exclusionary and hence threatening, producing a spiraling exclusionary cycle. Furthermore, in real-world group contexts such as occupational or recreational settings, females may exhibit greater sensitivity than males to threats of social exclusion, and such sensitivity could lead females to favor one alliance partner over other group members (Benenson & Heath, 2006). Although females are typically characterized as being less competitive than males (Archer, 2009; Bem, 1974), studies using nuanced definitions of competition and aggression suggest that females and males respond to competition differently and employ different competitive strategies (Björkqvist, 1994; Crick & Grotpeter, 1995). If social exclusion is recognized as a distinct competitive strategy, reputed sex differences in competitiveness may need to be reevaluated. 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.
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