AGGRESSIVE BEHAVIOR Volume 41, pages 515–525 (2015)

Costly Retaliation is Promoted by Threats to Resources in Women and Threats to Status in Men Shawn N. Geniole1, Cody E. Cunningham1, Amanda E. Keyes1, Michael A. Busseri1, and Cheryl M. McCormick1,2* 1

Department of Psychology, Brock University, St. Catharines, Ontario, Canada L2S3A1 Center for Neuroscience, Brock University, St. Catharines, Ontario, Canada L2S3A1

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.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. What motivates people to act against their own self-interest? In men, what seems to be irrational decision-making in the shortterm may be explained by other long-term benefits; thus retaliation may not be motivated by tangible costs, but instead intangible psychological variables (e.g., status threats). In contrast, there is evidence that women are more sensitive to tangible costs than are men. In Experiment 1, using the Point Subtraction Aggression Paradigm (PSAP), we tested the prediction that in men, the frequency of provocation, and not the monetary loss (tangible cost), would be associated with retaliation, whereas women would be sensitive to the tangible costs. In keeping with the prediction, women (n ¼ 80) who incurred greater tangible costs (irrespective of frequency) retaliated with more costly punishment, whereas men (n ¼ 90) who were provoked more frequently (irrespective of tangible costs) retaliated with more costly punishment. In Experiment 2, we directly investigated whether women were more sensitive to threats to resources and men were more sensitive to threats to status, as suggested by the results of Experiment 1. Women’s (n ¼ 53) retaliation was greater when they reported it to be a means to protect their resources, and men’s (n ¼ 35) retaliation was greater when they reported it to be a means to protect their status. Thus, these results identify psychological variables that guide retaliation that is costly to the actor. Consistent with evolutionary perspectives, concerns about status appear to drive costly retaliatory behavior more so in men than in women. Aggr. Behav. 41:515–525, 2015. © 2015 Wiley Periodicals, Inc.

.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Keywords: dominance; social status; costly punishment; altruistic punishment; aggression; sex-differences; revenge

INTRODUCTION

The saying “To cut off one’s nose to spite one’s face” reflects the common knowledge that people sometimes react to a provocation in ways contrary to their selfinterest. Nevertheless, behavior driven by spite (a.k.a, costly punishment, a form of reactive aggression), which harm the target(s) and the individual actor, were likely maintained throughout evolution because they confer certain benefits (e.g., Gardner & West, 2004; Shaw & Santos, 2012). Aggression that occurs in response to provocation, for example, is often costly to both the target and the aggressor (because of risk of serious injury or death, possible legal ramifications) but may afford certain benefits to the aggressor such as the maintenance of dominance or social rank and the protection of valued resources (Archer, 2009; Campbell, 2006; Daly & Wilson, 1988; Georgiev, Klimczuk, Traficonte, & Maestripieri, 2013). Individuals must be judicious in the use of reactive aggression given its costs, reserving it for situations in which the provocation is particularly threatening and the costs of not responding are greater © 2015 Wiley Periodicals, Inc.

than those of responding (Archer, 2009). Although reactive aggression by definition involves a preceding provocation (Anderson & Bushman, 2002), little is known about the features of the provocation that elicit such costly retaliation from the provoked individual. The Ultimatum Game is the most oft used behavioral assay of costly punishment in laboratory studies. In the Ultimatum Game, one of two players is given a sum of money and decides how the sum is to be split with the second player who then decides to accept or reject the

Contract grant sponsor: Social Sciences and Humanities Research Council (SSHRC). Conflicts of interest: None.  Correspondence to: Cheryl M. McCormick, Department of Psychology and Center for Neuroscience, Brock University, 500 Glenridge Ave, St. Catharines, Ontario, Canada, L2S 3A1.E-mail: [email protected] Received 4 September 2014; Accepted 3 March 2015 DOI: 10.1002/ab.21589 Published online 1 April 2015 in Wiley Online Library (wileyonlinelibrary.com).

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offer. If the offer is rejected, both players receive nothing. Although the rational choice would be to accept any offer (any sum is better than nothing), players seem to act irrationally, often rejecting offers deemed unfair (Fehr & Fischbacher, 2003; G€uth, Schmittberger, & Schwarze, 1982). Unfair offers and costly rejections of these offers are associated with greater activation of the insula (e.g., Sanfey, Rilling, Aronson, Nystrom, & Cohen, 2003) and the amygdala (e.g., Gospic et al., 2011), as well as increased autonomic arousal (e.g., Van’t Wout, Kahn, Sanfey, & Aleman, 2006), suggesting that human costly punishment is driven, in part, by negative emotional reactions to a perceived provocation (see also Yamagishi et al., 2009). The finding that lower offers are rejected more frequently than are higher offers in the Ultimatum Game (e.g., G€ uth et al., 1982) suggests that the costs incurred by a given provocation may be a relevant predictor of costly punishment. Nevertheless, other research suggests that the costs incurred by a provocation have limited utility in explaining costly punishment. In modified Ultimatum Games, for example, in which proposers are forced to choose between two offers (both of which are known to the responder before accepting or rejecting), responders’ decisions to accept or reject depends not only on the offer chosen by the proposer, but also on the alternative offer that the proposer could have chosen, but did not (Falk, Fehr, & Fischbacher, 1999). Specifically, when unfair offers are proposed (eight monetary units for the proposer, two for the responder), responders are more likely to accept the offer if the alternative was more unfair (10 for proposer, 0 for responder) than if the alternative was equal (five for proposer, five for responder). Thus, the absolute monetary values are less important than the fairness and intentions of the proposer. Outside of the lab, evidence from the “real world” also supports the idea that an individual’s costly retaliation to provocation is not necessarily based in the absolute or literal cost of the provocation incurred by the individual. Rather, the provocation may target intangible costs. For example, homicide is often an act of costly punishment that is preceded by provocations that involve no, or little, tangible cost to the killer. Instead, the provocations preceding homicide are often characterized as trivial (e.g., verbal insults; Luckenbill, 1977; and reviewed in Daly & Wilson, 1988). Thus, the finding that provocations can motivate costly punishment in the absence of tangible costs to the provoked individual suggests there may be symbolic qualities of the provocation and/or intangible costs that are threatening and thus promote costly punishment. The motivations underlying costly punishment are likely to be sex-specific. For example, in economic Aggr. Behav.

games, women appear to be more sensitive to the cost of punishing than are men (Eckel & Grossman, 1996), and are more risk averse and less competitive than men (Croson & Gneezy, 2009). Evolutionary theory and sociocultural theories (which are not mutually exclusive) predict such sex differences in behavioral and psychological motivations. Sociocultural theories suggest that women may be more sensitive to tangible costs based on factors such as gender inequality in cultural institutions and social roles (e.g., Fischer & Evers, 2010). According to evolutionary theory, women’s reproductive fitness requires cautious behavior (risk aversion) and attention to resources because of their greater parental investment than men’s and because a long period of dependency of offspring requires that women secure men’s investment of resources (Campbell, 2004). Further, there may be greater selection for harm avoidance in women than men because of higher reproductive costs of aggression and retaliation for women (Campbell, 1999). Consistent with these perspectives, women reported perceiving greater costs associated with aggression than did men (e.g., Archer, Fernandez-Fuertes, & Thanzami, 2010; Rutter & Hine, 2005). In contrast, evolutionary theories posit greater selection pressures for status and dominance in men than in women because of intra-male competition for access to mates (Archer, 2009). Men are thus more sensitive to threats to status (Daly & Wilson, 1988; Wilson & Daly, 1985). Although a loss of resources is typically tangible, a loss of status is typically intangible. Thus, men may be less sensitive than women to the tangible costs associated with provocation. To test this hypothesis of sex differences in sensitivity to tangible costs, we utilized a well-validated behavioral measure of reactive aggression, the Point Subtraction Aggression Paradigm (PSAP, Cherek, 1981), which parallels the Ultimatum Game in that retaliation during the PSAP represents a form of costly punishment because retaliation is costly to the participant. Specifically, throughout the task, participants repeatedly press a button to earn points exchangeable for money. At random intervals, however, a fictitious player steals the points from the participant (i.e., reduces the amount of money the participant will be paid at the end of the task). Participants can respond in one of three ways: They can continue to press the same button and earn points, press a different button to protect their points, or press a third button to steal points from the other player. Although participants can steal points throughout the task, they are told that points stolen are not added to their point tally. Thus, because of the time-limited nature of the PSAP task, and because pressing buttons to steal points detracts from pressing buttons to earn points, stealing points comes at a cost to personal earnings (e.g., Carre, Putnam,

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& McCormick, 2009; Carre, Gilchrist, Morrissey, & McCormick, 2010; Cote, McCormick, Geniole, Renn, & MacAulay, 2013; Geniole, Busseri, & McCormick, 2013). Steal presses can thus be operationalized as a behavioral assay of costly punishment (stealing in response to monetary loss increases monetary loss). A benefit of using the PSAP is that it is dynamic and involves the possibility of numerous attacks and counter-attacks, a feature missing in most studies of costly punishment (Dreber, Rand, Fudenberg, & Nowak, 2008). To test the role of tangible costs of provocation in promoting costly retaliation/costly punishment, we redesigned the PSAP to separate the act of being provoked from the tangible costs incurred by the provocation. Specifically, we used a between-subjects design in which participants were provoked either 10 or 20 times and lost a total of either 10 or 20 points throughout the duration of the task. Based on the hypothesis that the tangible cost (loss of resources) associated with a provocation may be a motivating factor in costly punishment in women, we predicted that greater cost of provocation would increase costly retaliation in women. In contrast, in men, the cost incurred by a provocation may have limited utility in predicting costly punishment, but rather the act of being provoked, in and of itself, may have symbolic qualities that target intangible costs (reviewed above). We thus predicted that in men, greater frequency of provocation would increase costly retaliation more than would an increase in financial cost. STUDY 1. WHAT IS PROVOKING ABOUT PROVOCATION: DOES THE COST ASSOCIATED WITH A PROVOCATION INFLUENCE COSTLY RETALIATION?

Study 1 Methods Participants and recruitment. Undergraduate students (n ¼ 176) were recruited using a departmental online participant pool and received a $5 honorarium for participation at the end of the study, irrespective of their performance on the task. Six participants (three woman, three men) were excluded (technical difficulties or outliers on aggression scores), leaving 80 women and 90 men (M age ¼ 20.19, SD ¼ 3.12; 70% Caucasian, 6% Black, 8% Asian, 16% other). All participants consented to the procedures of the study. Measure and procedure. The procedures of the experiment were approved by the Brock University Ethics Committee. The PSAP was modified from the original version designed by Cherek (1981); who has validated the task extensively as a measure of reactive aggression (Cherek, Moeller, Schnapp, & Dougherty,

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1997; Cherek, Lane, Dougherty, Moeller, & White, 2000). Participants were told they and an opponent of the same sex were playing a computer game, each with the goal of earning points exchangeable for money. The participants did not know that the opponent was fictitious. We used this deception because participants play the PSAP very differently when they are explicitly told they are paired against a computer than against a human, with the main difference being that they steal fewer points from a computer than a human (unpublished observations). Participants had three response options: 100 presses of Button A earned one point; 10 presses of Button B stole a point from the opponent (participants were informed neither they nor their opponent could keep stolen points); and 10 presses of Button C protected the participants’ points for a variable amount of time. The purpose of including the protect option was to enable a response option other than retaliation (see McCloskey, Berman, & Coccaro, 2005) and thus avoid potential demand characteristics. To control experimentally for the number of provocations (points stolen) participants received (see below), Button C had no consequence in the version of the PSAP employed in the present study, although participants were told their points would be protected after 10 presses of Button C for a random time of .5–45 sec. In some versions of the PSAP (e.g., Carre & McCormick, 2008; Cherek, Schnapp, Moeller, & Dougherty, 1996), Button B steal presses also provide a provocation-free interval (although not made explicitly known to the participants), but none was provided here to ensure participants within a given condition received the same number of provocations. Further, whereas in previous research our lab has utilized a version of the PSAP that limited the speed with which participants could press buttons by constraining the minimum inter-press interval to 170 ms (Carre et al., 2009, 2010; Carre & McCormick, 2008; Geniole, Carre, & McCormick, 2011), in the current study we decreased the minimum inter-press interval to 50 ms to allow for more impulsive, automatic button pressing (as in Geniole et al., 2013). The computer screen displayed points earned, and when a point (or fraction of a point) was “stolen” by the opponent, the point counter enlarged, flashed red, and the number decreased by the stolen amount. Consistent with standard versions of the PSAP, participants did not see the point tally of the opponent. The researcher explained the PSAP game and participants then had a 1-min practice round before a single 10-min game session. The PSAP was modified to have four versions in a 2  2 design in which the frequency of, and total financial cost incurred by, provocation were manipulated between subjects; participants were randomly assigned to one of the four Aggr. Behav.

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experimental conditions. In the Low Frequency, Low Financial Cost condition, participants had one point stolen 10 times (frequency ¼ 10 provocations, total cost incurred ¼ 10 points). In the High Frequency, Low Cost Incurred condition, participants had half a point stolen 20 times (frequency ¼ 20 provocations, total cost incurred ¼ 10 points). In the Low Frequency, High Cost Incurred condition, participants had two points stolen 10 times (frequency ¼ 10 provocations, total cost incurred ¼ 20 points). In the High Frequency, High Cost Incurred condition, participants had one point stolen 20 times (frequency ¼ 20 provocations, total cost incurred ¼ 20 points). The Low Frequency, Lost Cost Incurred condition is most comparable to our previous versions of the PSAP in terms of the number of provocations and points stolen in the average session. Before the PSAP game and irrespective of the version to which participants were assigned, participants were told that their point total would be exchangeable for money at the end of the game. The measure of costly punishment used in statistical analysis was the percentage of steal presses (steal presses divided by total presses, multiplied by 100). Percentage of steal presses involved a within-subjects factor of Time involving two levels: Percentage of steal presses before (in the first 45 sec until the “opponent’s” first steal) and after provocation (remaining 9 min and 15 sec of the 10-min round). Thus, the design of the experiment was a 2  2  2  2 (Sex: men vs. women; Frequency of Provocation: low vs. high; Financial Cost of Provocation: low vs. high; Time: pre-provocation vs. post-provocation). Study 1 Results The 2  2  2  2 mixed factorial ANOVA revealed a main effect of Time (F1,162 ¼ 82.31, p < .001, partial h2 ¼.34), indicating that participants used more costly punishment after provocation than before; a two-way interaction involving Frequency and Financial Cost (F1,162 ¼ 5.23, p ¼ .02, partial h2 ¼.03); and two threeway interactions involving Sex, Financial Cost, and Time (F1,162 ¼ 5.44, p ¼ .02, partial h2 ¼.03) and Sex, Frequency, and Time (F1,162 ¼ 4.63, p ¼ .03, partial h2 ¼.03). All other main effects and interactions were not significant (ps > .19). To decompose the two threeway interactions involving sex, two 2  2 mixed factorial ANOVAs were conducted within women and within men separately: the first involved a withinsubjects factor of Time and a between-subjects factor of Financial Cost, and the second involved a withinsubjects factor of Time and a between-subjects factor of Frequency. Within women (n ¼ 80), the mixed factorial ANOVA involving Time and Financial Cost revealed a main Aggr. Behav.

effect of Time (F1,78 ¼ 34.39, p < .001, partial h2 ¼.31) and a Time x Financial Cost interaction (F1,78 ¼ 4.75, p ¼ .03, partial h2 ¼.06; see Fig. 1A), indicating that the increase in costly punishment from pre- to postprovocation was greater for women in the high financial cost (t38 ¼ 4.92, p < .001, Cohen’s d ¼ .78) than in the low financial cost group (t40 ¼ -3.13, p ¼ .003, Cohen’s d ¼ .49). There was no main effect of Financial Cost (p ¼ .27). Within men (n ¼ 90), the analysis revealed only a main effect of Time (F1,88 ¼ 48.79, p < .001, partial h2 ¼.36), indicating that men used more costly punishment after provocation than before (all other ps > .21). Within women, the mixed factorial ANOVA involving Time and Frequency revealed only a main effect of Time (F1,78 ¼ 31.83, p < .001, partial h2 ¼ .29) indicating that women used more costly punishment after provocation than before (all other ps > .27). Within men, the analysis revealed a main effect of Time (F1,88 ¼ 49.81, p < .001, partial h2 ¼.36) and a twoway Time x Frequency interaction (F1, 88 ¼ 4.73, p ¼ .03, partial h2 ¼ .05; see Fig. 1B) indicating that the increase in costly punishment from pre- to postprovocation was greater for men in the high frequency groups (t45 ¼ -6.13, p < .001, Cohen’s d ¼ .90) than in the low frequency groups (t43 ¼ 3.75, p ¼ .001, Cohen’s d ¼ .56). There was no main effect of Frequency (p ¼ .44). 1 Study 1 Discussion The results supported our prediction that women would be more sensitive to the tangible cost of a provocation than would be men. Women showed more costly punishment in response to provocation when the cost incurred by the provocation was high rather than low (irrespective of the frequency of provocation). In contrast, men showed a greater increase in costly punishment when the frequency of the provocation was high rather than low (irrespective of the costs incurred). 1

Although the focus was steal presses, one might also predict sex differences in the use of the other button presses. Because women show greater harm avoidance than men, they may use the protection presses more in response to provocation than do men. Consistent with this prediction, there was an interaction of Sex and Time (p ¼ 0.05), with women showing a greater increase in the percentage of protection presses made after provocation (p < .001, Cohen’s d ¼ .67) than did men (p ¼ .02, Cohen’s d ¼ .29), but Sex did not interact with either Frequency, Financial Cost, or their interaction. The greater increase in use of protection presses of women than men is consistent with women’s concern over resources (e.g., Campbell, 1999) (see also Introduction and Discussion). Because of men’s greater interest in status and competition (Croson & Gneezy, 2009), another prediction is that men would have higher earn presses than women. In keeping with this prediction, the only factor that was significant was Sex: men pressed the earn button more quickly than did women (p ¼ .002, Cohen’s d ¼ .47), and there were no significant interactions.

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Figure 1. Graphical representation (mean þ/ SEM) of the Time x Financial Cost interaction on costly punishment in women (Panel A) and of Time x Frequency of Provocation interaction on costly punishment in men (Panel B). Interaction p-values shown in each graph refer to the post-hoc analyses within sex.

Thus, women and men seem to be sensitive to different situational aspects of the same provoking event, with men sensitive to the frequency of provocation and women sensitive to the financial consequences of the provocation. Although our interpretation is that men’s costly retaliation was likely to be driven by an attempt to protect their status, and that women’s costly retaliation was likely to be driven by an attempt to protect financial resources, we did not directly ask men and women about their reasons for using costly punishment in the task. We therefore conducted a second study in which participants completed the PSAP and then indicated the extent to which costly retaliation was used to protect their status rather than their resources. We predicted that men who used costly retaliation to protect their status would exert more costly punishment throughout the task than would men who used such costly retaliation to protect their resources. Conversely, we predicted that women who used costly punishment to protect their resources would do so more than would women who did so to protect their status. Status and resources are tightly linked and likely share a reciprocal relationship; in other words, a threat to resources may be interpreted as a threat to status and a threat to status may be interpreted as a threat to resources (especially because status can be measured by one’s access to, and ability to control, resources; reviewed in Hawley, 1999). Thus, we had men and women rank the relative importance of retaliating to protect their status versus retaliating to protect their resources. Further, to ensure that costly retaliation was regulated by a desire to protect status in men and by a desire to protect resources in women, and not simply the result of a greater cognitive focus on one of these factors or the other, we also had participants indicate and rank the extent to which they thought about status and resources while being provoked throughout the task. Based on the hypothesis that costly retaliation is regulated by a desire

to protect status in men and to protect resources in women (and not simply a general focus on one of these factors or the other), we predicted that participants’ reasons for retaliation would be a significant factor guiding costly punishment, whereas participants’ thoughts during provocation would not. STUDY 2: ARE MEN’S AND WOMEN’S COSTLY RETALIATION DIFFERENTIALLY INFLUENCED BY THREATS TO STATUS AND THREATS TO RESOURCES?

Study 2 Methods Participants and recruitment. Undergraduate students (n ¼ 101) were recruited using a departmental online participant pool and received a $5 honorarium for participation. Four female participants were excluded (one because of technical difficulties, one because she was an outlier on aggression scores, two because they failed to answer the questions about their reason for retaliation), and 9 male participants were excluded (because they failed to answer the questions about their reasons for retaliation), leaving 53 women and 35 men (M age ¼ 20.12, SD ¼ 3.16; 73% White, 3% Black, 15% Asian, 9% other). All participants consented to the procedures of the study. Measure and procedure. The procedures of the experiment were approved by the Brock University Ethics Committee. To maximize variability in costly punishment but to ensure equivalent provocation conditions for men and for women, we chose the versions of the PSAP in Study 1 that represented the most and least provoking for both sexes [i.e., the condition in which both cost and frequency were low (frequency ¼ 10 provocations, total cost incurred ¼ 10 points) and the condition in which both cost and frequency were high (frequency ¼ 20 provocations, total cost incurred ¼ 20 points), see Study 1 methods]. The condition to which participants were assigned was counterbalanced for each sex. Aggr. Behav.

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Participants’ thoughts while being provoked. Next, participants were asked to rank-order a set of statements of potential thoughts they may have had while being provoked from most to least true. The statements were: “My main thought was about the amount of money I was losing” (resource thought); “My main thought was that the other participant was trying to push me around” (status thought); “My main thought was about making as much money as possible” (resource thought); “My main thought was about performing better than the other participant” (status thought); “My main thought was (please specify)”, which allowed participants to write about and rank any other thought they may have had while being provoked. The statements were ordered to alternate between thoughts about resources and thoughts about status, with the “please specify” statement always last. The order of the statements was also counterbalanced across participants such that the first item was about status for half of the participants and about resources for the other half of the participants. The “Please specify” statement served as a filler and was ignored. Participants were coded as having thought primarily about status if their top-ranking statement of the four remaining statements was about status, or were coded as having thought primarily about resources if their top-ranking statement of the remaining four was about resources. The statements classed as “resources” explicitly mention money, whereas the statements classed as “status” do not; status statements, however were consistent with those in previous studies investigating submissiveness and dominance in human social hierarchies (e.g., Hecht, Inderbitzen, & Bukowski, 1998; Parkhurst & Hopmeyer, 1998). Participants’ reasons for retaliation. Next, participants were asked to rank from most to least true the following statements about their main reason for retaliation: “I wanted to show the other participant I could not be pushed around” (status); “I wanted to discourage the other participant from stealing my money” (resources). Again, the order of these statements was counterbalanced across participants and a filler statement (“I wanted to make the game more interesting by pressing different buttons”) to reduce demand characteristics, which was ignored, appeared between the resource and status statements. Participants were coded as having retaliated primarily to protect their status if they gave a higher ranking to the status statement than to the resource statement, or as having retaliated primarily to protect their resources if they gave a higher ranking to the resource statement than to the status statement. Study 2 Results Sixty-one percent of participants thought more about status than resources while being provoked, whereas Aggr. Behav.

39% thought more about resources than status (this proportion did not differ for men and women; x2 ¼ .46, p ¼ .50). Forty-two percent of participants retaliated to protect status more than to protect resources, whereas 58% retaliated to protect resources more than to protect status (this proportion did not differ for men and women; x2 ¼ 1.02, p ¼ .31). To evaluate the effects of thoughts during provocation and reasons for retaliation on the extent of costly punishment among men and women, a 2  2  2  2 mixed factorial ANOVA was conducted with three between-subjects factors (Thoughts during Provocation: status vs. resources; Reason for Retaliation: status vs. resources; Sex: men vs. women) and one within-subjects factor (Time: pre-provocation vs. post-provocation) on costly punishment (percentage of steal presses). This analysis revealed a main effect of time (F1, 80 ¼ 45.71, p < .001, partial h2 ¼ .36), indicating that participants retaliated more after provocation than before, and a twoway interaction between Sex and Reason for Retaliation (F1, 80 ¼ 5.00, p ¼ .03, partial h2 ¼ .06; see Fig. 2). Posthoc analyses indicated that men who retaliated to protect their status used more costly punishment than did men who retaliated to protect their resources (t33 ¼ 2.06, p ¼ .05, Cohen’s D ¼ .72), whereas women who retaliated to protect their resources used more costly punishment than did women who retaliated to protect their status, although this latter contrast missed statistical significance (t51 ¼ 1.76, p ¼ .08, Cohen’s D ¼ .49) (see Fig. 2). In addition, there was a sex difference in the extent of costly punishment among those who retaliated to protect their status (men > women, t35 ¼ 2.25, p ¼ .03, Cohen’s d ¼ .76), but not among those who retaliated to protect their resources (t49 ¼ 1.56, p ¼ .13, Cohen’s d ¼ .45). All other main effects and interactions were not significant (ps > .47).2 Study 2 Discussion The results of Study 2 support the hypothesis that threats to status and threats to resources differentially motivate male and female costly retaliation. Specifically, men who reported using retaliation to protect their status used more costly punishment than did those who reported using retaliation to protect their resources. Conversely, women who reported using retaliation to protect their resources used more costly punishment than 2 As in Study 1, there was an interaction of Sex and Time (p ¼ .05), with only women showing an increase in the percentage of protection presses made (p < .001, Cohen’s d ¼ 1.08; for men, p ¼ .66, Cohen’s d ¼ .08), but Sex did not interact with either Reason for Retaliation, Thoughts during Provocation, or their interaction. Additionally, number of earn presses differed as a function of Sex: men pressed the earn button more than did women (p ¼ .003, Cohen’s d ¼ .66).

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Figure 2. The mean (þ/ S.E.M.) values of costly punishment (percentage of steal presses) in women and men who reported retaliating to protect their status versus their resources. within women, p ¼ .08; *within men, p ¼ .05; #between men and women, p ¼ .03.

did those who reported using it to protect their status. Therefore, the extent to which men and women used costly punishment depended on different factors, with concerns about protecting status driving male costly punishment and concerns about protecting resources driving female costly punishment. Men and women, however, did not differ in their thoughts during provocation or in their reasons for retaliation; more participants reported thinking about status than about resources during the provocation, and more participants reported retaliating to protect their resources rather than to protect their status. Others have reported sex differences in extent of aggression in the absence of a sex difference in the underlying motivations: In a study by Griskevicius et al., (2009), 48% of men and 45% of women indicated status/reputation concerns for direct aggression and 32% of men and 34% of women indicated these same concerns as the reasons underlying indirect aggression. Nevertheless, men engaged in more direct aggression and women engaged in more indirect aggression. Therefore, men and women do not necessarily differ in their overall reasons for retaliation, but these reasons nevertheless function psychologically to promote costly punishment in men and in women differently. Additionally, participants’ reasons for retaliation contributed to the expression of costly punishment over and above the (non-significant) influence of their thoughts during provocation. Therefore, it is not a general focus on status or resources during the task that promotes costly punishment in men and women. Instead, it is their use of such behavior as a specific means to protect status or resources that promotes costly punishment. By examining these psychological processes

simultaneously (thoughts during provocation and reasons for retaliation), we have isolated participants’ reasons for retaliation as a factor that differentially regulates costly punishment within each sex. General Discussion Given the costs associated with costly retaliation, it may only be worthwhile to use such behavior when the costs of not responding to a provocation are great. Our results suggest that provocations that threaten status may be more threatening than those that threaten resources for men, probably because status may be more strongly linked to survival and reproduction in men than in women. Information about a man’s status, for example, was more important than a man’s attractiveness for women selecting a potential mate (e.g., Li, Bailey, Kenrick, & Linsenmeier, 2002). Men’s fitness varies as a function of their status across pre-industrial (e.g., Von Rueden, Gurven, & Kaplan, 2011) and modern societies, an effect largely driven by the fact that men of lower status are more likely to be childless than are men of higher status (e.g., Fieder & Huber, 2007). As a consequence, some researchers have argued that not responding to threats to status may be, in some circumstances, more detrimental to reproduction for men than is risking their life in an attempt to retaliate and protect their status (Daly & Wilson, 1988). Although this study provides direct support for the link between status threat and costly retaliation, data from other studies have provided some indirect evidence as well. For example, costly punishment is more likely when the decision to do so is made in public (e.g., shared with the experimenter, other research participants) than in anonymity (Kurzban, DeScioli, & O’Brien, 2007; Ma Aggr. Behav.

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et al., 2012), and rejections of low offers in the Ultimatum Game are more likely when the offers are proposed by humans than by computers (e.g., Sanfey et al., 2003). If the decision to retaliate is independent of concerns about status and reputation, costly punishment would be equally likely if it was performed in private versus in public, and if the provocations preceding the costly punishment were delivered by a human versus a computer. Other studies have reported positive associations between rejections of low offers in the Ultimatum Game and baseline concentrations of testosterone (Burnham, 2007; Mehta & Beer, 2010), a hormone sensitive to social competition (e.g., Wingfield, Hegner, Dufty, & Ball, 1990) and dominance (Mazur & Booth, 1998). Rapid increases in testosterone also were associated with costly punishment in the PSAP (e.g., Carre et al., 2009, 2010; Cote et al., 2013; Geniole et al., 2011), and mediated the effect of winning a preceding competitive interaction in one study (Carre, Campbell, Lozoya, Goetz, & Welker, 2013). In another study, rejections of low offers in the Ultimatum Game were correlated with responders’ “assertiveness against imposition” scores, a scale reflecting aversion to being treated as inferior (Yamagishi et al., 2012). Therefore, propensity for costly retaliation was likely to be maintained in men because it prevented the deterioration of status. Retaliation can also facilitate a beneficial reputation (Shaw & Santos, 2012), leading to an increase in future collaboration and trust (e.g., Barclay, 2006; Nelissen, 2008) and, through the maintenance of high status, a decrease in the probability of future provocations (e.g., Archer & Benson, 2008; Doob & Gross, 1968) and a greater likelihood of peer deference (Von Rueden et al., 2011). Additionally, the sensitivity to status over resources in men observed in the present work is consistent with the findings that intrasexual competition in men is associated with more lavish spending and greater debt (Griskevicius et al., 2012), suggesting an insensitivity among men to the cost to personal resources when provoked. Men were also more likely to overbid in auctions when a rival out-group was involved in the auction than when not involved (Van den Bos, Golka, Effelsberg, & McClure, 2013), suggesting that the opportunity for social competition disrupts costbenefit analysis. Unlike men, women used costly punishment to a greater degree when it served to protect their resources than when it served to protect their status. Together with the results of Study 1, these findings from Study 2 suggest that women are more sensitive to provocations that threaten their resources than those that threaten their status. Reviews of studies investigating violence and aggression in women (reviewed in Campbell, 1999) and in other female mammals (Stockley & Bro-Jørgensen, Aggr. Behav.

2011) also conclude that female–female aggression is rooted in the protection and acquisition of resources. Women also tend to be more financially risk-aversive than men (Eriksson & Simpson, 2010; Powell & Ansic, 1997; also see review by Croson & Gneezy, 2009), and show different patterns of brain activations than do men when taking risks (e.g., Lee, Chan, Leung, Fox, & Gao, 2009). Because resources are valuable to reproduction goals in women as they aid in the survival of their offspring (reviewed in Campbell, 1999), costly retaliation in the present work may have been maintained in women because it serves to protect such resources. For example, female-to-female aggression is greater when resources are scarce than when abundant (e.g., Campbell, Muncer, & Bibel, 1998). In addition, women’s increased sensitivity to threats to resources in the current study may be driven by social factors such as the long-standing wage-gap between men and women, with women tending to earn 70% the salary of men (Cool, 2010) and being asked to pay more for cars and to accept smaller increases in salary when they choose to bargain than men (Solnick, 2001). Results based on the Ultimatum Game indicate that both women and men make lower offers to women than to men, and women accept lower offers made by men than by women (Solnick, 2001). Differences in financial resources may thus bias responses to provocations that threaten such resources, leading to a greater sensitivity to, or a lower threshold to, provocations among women. A limitation of the current study is that the effects we reported here are specific to same-sex interactions, and it will be worthwhile in future studies to investigate whether the relationships observed hold when the opponent is of the opposite sex. There is evidence that women are more likely to reject unfair offers from other women than from men, whereas men are less sensitive to gender in economic games (Croson & Gneezy, 2009). Women’s aggressive, competitive, and punitive behavior is more likely to be directed at women than men, which has been proposed to be based in women’s competition for men’s resources (Campbell, 2013). Furthermore, factors other than resources may be important to female reproduction and thus, when threatened, promote costly punishment among women. Sexual reputation, for example, is highly valued by men when selecting a potential mate (see Campbell, 2013). The costs of a woman not responding when her sexual reputation is threatened (through the spreading of rumors, etc.) may thus be greater than the costs associated with retaliation. Although we did not investigate threats to reputation in the current study, such an investigation would be worthwhile. Further, we used a limited number of questionnaire items about status and resources. Although this was done to

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minimize demand characteristics, a broader questionnaire may better capture the constructs of threat to status and threat to resources. Lastly, it will be important to test whether the results extend beyond undergraduate students in North America, as there are cultural differences in the expression of costly punishment (Henrich et al., 2006; Henrich, Heine, & Norenzayan, 2010; Oosterbeek, Sloof, & Van de Kuilen, 2004). CONCLUSIONS

Spite is often cast as a puzzling social behavior given its associated costs. Nevertheless, some provocations may be so threatening that the costs associated with not responding are greater than those of responding. Our results suggest that provocations that are frequent, but not necessarily costly, elicit costly punishment in men and that such retaliation is greater when it serves to protect men’s threatened status than when it serves to protect their threatened financial resources. Conversely, provocations that are costly to the target, irrespective of their frequency, elicit costly punishment in women and such retaliation is greater when it serves to protect women’s threatened resources than when it serves to protect their threatened status. Thus, costly punishment in men and women may result from sensitivity to different environmental cues and psychological aspects of the same provoking event, that is, perceived threat to resources among women and perceived threat to status among men. It is important to note that although many researchers have proposed that status- and/or resourceconcerns differentially guide male and female aggression and costly punishment (e.g., Ainsworth & Maner, 2012; Archer, 2009; Campbell, 1999; Griskevicius et al., 2009; Daly & Wilson, 1988), our studies here are the first to use a manipulation that is not highly gendered and a behavioral measure of costly punishment and retaliation. An important future direction to these studies would be to examine potential mechanisms linking threatened status and costly punishment in men and those linking threatened resources and costly punishment in women. One possibility is that such provocations differentially increase negative emotional states (e.g., anger/rumination, Sell, 2011; Sell, Tooby, & Cosmides, 2009; Denson, 2013), and/or shift the intangible reward (e.g., Carre et al., 2010) associated with retaliation. Future studies may benefit from examining such possibilities. In sum, these studies involved an experimental design (keeping all other contextual factors constant) to show that men and women are provoked by different attributes of the same provocative event. Our results suggest that provocative cues may be represented differently by the sexes; whereas provocation may have been represented

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by men as a threat to status, the same provocation may have been understood by women as a threat to resources. In conclusion, for men, the motivation for costly punishment is about the status, not the money; for women, it may be about the money. ACKNOWLEDGEMENTS

The research was funded by a Social Sciences and Humanities Research Council (SSHRC) grant to CMM. SNG holds an SSHRC Canada Graduate Scholarship.

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