Studied by 0 peopleThe Evolution of Cooperation
•People commonly make personal sacrifices towards their friends and in man different ways. Acts of friendship pose an evolutionary puzzle: Natural selection is inherently competitive (you want to be the one that survives and reproduces), and sacrifices are costly to those who make them, but they benefit the people who these sacrifices are made for
•How could patterns of friendship and altruism have evolved?
The Problem of Altruism
•Your friends are not your genetic relatives, so any cost you incur for a friend results in a loss to you
•How could altruism among nonrelatives have evolved, given the competitive adaptations that tend to be produced by natural selection?
The Problem of Altruism (pt. 2)
•Social exchange, a form of cooperation, occurs across human cultures and is found frequently in hunter-gatherer cultures
•Other species, such as vampire bats, also engage in forms of social exchange
•Other primates also engage in reciprocal helping - help each other to get help back
A Theory of Reciprocal Altruism
•This theory states that adaptations for providing benefits to non-relatives can evolve if the delivery of benefits is returned or reciprocated at some point in the future - we help other people to get help in return; social insurance; you get more back than what you gave through reciprocal altruism
•Those who engage in reciprocal altruism tend to out-reproduce those who do not
Cooperation Among Non-Humans - Food Sharing in Vampire Bats
•For vampire bats, survival depends on food - blood from other animals (horses and cattle), colony is mostly composed of females and their offspring, the bat’s abilities to feed increases with age and experience
•Failure at feeding can quickly lead to death (they can go without blood for only 3 days) - failure is common so failure at feeding is a constant threat to the species
•They give regurgitated blood to their friends - do this non-randomly, those from whom they’ve received blood in the past (i.e. friends); have to be able to differentiate between their bats and keep track of who gave them blood in the past, more likely to give blood to those who they were seen for the most time with rather than those who they did not spend as much time with
•Research documents reciprocal altruism in vampire bats (Wilkinson, 1984)
Chimpanzee Politics
•Cooperative alliances are central to the lives of chimps
•They engage in reciprocal exchange of grooming and food sharing - services are given roughly equal to those that they receive in the long-run, males will groom females and play with the offspring, alpha males will chase or bite a female if she is associating with an enemy, after the threat is gone, the males will become friendly towards the females
•Alliances form not just between males but also between the sexes
•Cooperative alliances are central to the lives of chimps
•They engage in reciprocal exchange of grooming and food sharing - services are given roughly equal to those that they receive in the long-run, males will groom females and play with the offspring, alpha males will chase or bite a female if she is associating with an enemy, after the threat is gone, the males will become friendly towards the females
•Alliances form not just between males but also between the sexes
Cooperation & Altruism Among Humans - Social Contract Theory
•Developed to explain the evolution of cooperative exchange in humans, with special attention to how humans have solved the problem of cheating - possibility of cheating poses a threat to cooperation
•Over evolutionary time, cheaters thrive more than cooperators - benefit in two ways (benefit from what has been given and has not been affected by costs to receiving)
•Reciprocal altruism can only evolve if organisms have mechanisms for detecting and avoiding cheaters; researchers have outlined 5 such cognitive capacities - mental strategies (Cosmides & Tooby, 1992).
Capacity 1: Recognition of Individual Humans
•“If you give me a benefit and I get lost in a ‘sea of anonymous others,’ you will be vulnerable to being cheated. You must be able to identify me and remember me as distinct from all other people” (Axelrod & Hamilton, 1981).
Capacity 2: Recalling History of Interactions
•Breaks down into several different abilities: One must be able to remember whether a person with whom they’ve interacted was a cooperator or a cheater
•One must be able to keep track of who owes what to whom = requires an accounting system for keeping track of the costs you’ve occurred and who has been helped - expect something in return
•Failure to keep track - susceptible to being cheated, no way of knowing if the benefit has been returned
Capacity 3: Ability to Communicate Values
•If your friend fails to understand what you want, how can they provide the benefits you need?
•If you fail to communicate your anger to a cheater, you might be vulnerable to being cheated in the future. Important that people communicate values so that we can try to guarantee that we won’t be cheated in the future
Capacity 4: Ability to Model Values of Others
•If you can detect when people are needy and what they need, the benefit you provide can be tailored to that need
•By understanding the desires and needs of others, you can tailor your exchanges to maximize the benefits you provide, making the other person more indebted to you
Capacity 5: Ability to Represent Costs & Benefits
•Humans can and do exchange an astonishing array of items - tools or weapons, food, shelter building, assistance in fights, information on enemies
•For this reason, evolved mechanisms of social exchange cannot be pre-wired to represent and negotiate for specific items = have to be able to have more flexible cognitively
•We must be able to understand and cognitively represent the costs and benefits of a wide range of items
Do People Remember Cheaters?
•Memory plays a major role in cheater detection as people remember the faces of known cheaters, especially low-status cheaters, better than they remember the faces of known cooperators (Mealy et al., 1996)
•Memory for cheaters may partly depend on their rarity in the population (Bell & Buchner, 2009; Buchner et al., 2009)
•Cheaters will be remembered best if the cheater is rare versus common, better face recognition for non-altruistic people versus altruistic people
Attentional Biases & Predictions of Cheating
•People show automatic attentional biases toward the faces of people who had previously failed to cooperate during a game (Vanneste et al., 2007)
•Even after a brief interaction, people are reasonably accurate at predicting who will cooperate and who will not (Chang & Wilson, 2004). Upon meeting someone for the first time, you are pretty good at determining if a person is trustworthy versus cheating - trusting your gut
The Detection of Prospective Altruists
•Once a cheater-detection adaptation has evolved in humans, selection will favor co-evolved adaptations to avoid being detected as cheaters (deception) - leads to subtle forms of cheating
•Humans have evolved an adaptation to this problem: The ability to detect the genuineness of altruistic acts (Brown & Moore, 2000)
Other Research on Altruist-Detection
•Altruistic dispositions can be detected even from witnessing very brief video clips (Fetchenhaur et al., 2010)
•In one study, participants were asked to view a silent video of somebody doing something random, we can pick up on subtle cues that allow us to determine whether or not a person is altruistic. Another study used a questionnaire in which participants were asked to answer questions and rank themselves based on the statements that were provided. Those who ranked ver high versus very low were brought in for interviews and recorded. After the interview, the audio was removed and people were asked to detect who they found trustworthy versus untrustworthy
•The facial cue of genuine (spontaneous) smiles is a valid cue to altruistic and cooperative dispositions (Mehu et al., 2007)
Indirect Reciprocity Theory
•People who perform altruistic acts advertise a propensity for generosity and cooperation - others might glean this information through gossip, etc.
•The benefit to the altruist does not come directly from the person who receives the altruistic act, but rather from others who witnessed or heard about the person behaving generously
•Might help us explain why we help others when gaining nothing in return and why we help others when others are watching
Risk Pooling, Social Insurance, & Need-Based Transfers
•Need-based transfer systems- in risk or volatile environments (modern hunter-gatherer societies, our evolutionary history), forming special types of friendships can be a form of social insurance against catastrophe
•The Massai of East Africa have such a system, called osotua - best friend system, not the same as reciprocal alturisim (freely given) but rather that each person is expected to help each other
•Less needed in environments that are predicted and stable
Costly Signaling Theory
•The logic behind costly signaling is that individuals display acts of altruism (giving to charities, hosting lavish parties) to signal that they are excellent potential allies. Those who are able to display these signals are oftentimes wealthier in comparison to those with little resources, who are not able to express the costly signals of altruism
•Several studies show that group members who endure pain for the benefit of the group are awarded more benefits and held in higher esteem (McAndrew & Perilloux, 2012a; 2012b)
Empirical Tests of Costly Signaling
•One study found that when volunteering anonymously, most participants chose the least taxing charity work from a set of options. But, when volunteering publicly, many more chose the costly charity work
•Those who chose the costliest altruistic investment in the public condition experienced a boost in their social reputation and popularity among the group
•In other words, when you’re not in front of other people, you take the path of least resistance, but when in front of others you will chose the most difficult to boost social status and reputation
Prosocial Signaling & Altruist Value
•Altruists are good at finding each others and are more likely to be surrounded by those who are helpful in value
•Another study examined one form of costly signaling, prosocial signaling, as indicated by the percentage of meat a hunter typically shared with others (Bird & Power, 2015)
•Prosocial signalers were most often sough after as cooperative hunting partners
Positive Assortment
•Associating with some people but all, as they try to avoid people who don’t help or provide in return for the benefits that are bestowed on them
•People preferentially associate with and form relationships with a subset of other individuals
•In inclusive fitness, people assort/ associate based on genetic relatedness.
•In reciprocal altruism, people assort based on who returns benefits to those who have benefited them in the past.
•In indirect reciprocity, people associate with groups of people who have reputations as good cooperators.
•In need-based transfer systems, people form special friendships based on willingness to help.
•In costly signaling, people associate with those who have demonstrated benefit-bestowing capacities through showing costly honest signals of resource-holding potential
Emotions Involved in Cooperation
•One emotion that is particularly relevant is gratitude
•One evolutionary psychologist explored a wider array of emotions in reciprocity and violations of reciprocity (Brase, 2017).
•He found that people express anger toward those who could help but fail to do so.
The Psychology of Friendship - Introduction
•When a person insists on immediately replaying us for a favor, we interpret this as a sign of a lack of friendship (Shackelford & Buss, 1996) - we don’t want to just help out our friends but we will reach some reward later ….
•We want to help our friends just because they are our friends, not because we will reap some later reward
•Evolutionary psychologists argue that we should pay attention to people’s intuitions, because they provide a cue that friendships might not be based solely on reciprocal exchange (Tooby & Cosmides, 1996)
Defining Altruism According to Costs Incurred
•Altruism is not considered to have occurred unless the individual incurs a cost
•But what if we reconsider the definition? Rather than focusing on incurring cost, why not focus on the evolution of adaptations designed to deliver benefits to others?
The Banker’s Paradox
•Bankers who loan money to people are at risk of costs, such as the fact that a larger number of people seek loans than any bank has money to lend
•Bankers must decide to whom they should loan money, and those who need money most desperately are precisely the same people who are the poorest credit risks
The Banker’s Paradox in an Evolutionary Context
•Each person has a limited amount of help to dispense to others
•People should be able to evaluate whether someone they help will be willing and able to repay them in the future
Becoming Irreplaceable
•A replaceable person– someone who provides benefits that are readily available from others– is more vulnerable to desertion than someone who is irreplaceable, even if these two friends provide benefits to you.
•The loyalty of your friendship should be based in part on how irreplaceable each friend has become
Becoming Irreplaceable (pt. 2)
•Promote a reputation that highlights one’s unique or exceptional attributes
•Be motivated to recognize personal attributes in others
•Cultivate specialized skills
•Seek out people or groups that value what you have to offer and what others in the group tend to lack
•Avoid social groups in which one’s attributes are not valued or are provided by others
•Drive off rivals who offer the same benefits you offer
Fair-Weather Friends
•It’s when you are really in trouble that you find out who your true friends are
•Fair-weather friends are there only when times are good, whereas when things are difficult, these friends might not be there to support you
•According to evolutionary theory, selection should fashion mechanisms to differentiate true friends from fair-weather friends
•Receiving help during a difficult time is the best way to determine who your true friend is as if they are giving of themselves during this time, these friends are incurring a cost on themselves
The Dilemmas of Modern Living
•We suffer from a relative scarcity of critical events that would allow us to accurately assess whether our friends are deeply engaged in our welfare or not (true friends versus fair-weather friends)
•Loneliness and a sense of alienation might stem from the lack of critical assessment events that tell us who our true friends are/ who are deeply engaged in our welfare
Factors that Determine Your Choice of Friends
•Number of slots already filled
•Evaluate who emits positive externalities- beneficial side effects that exist simply as the result of someone’s presence
•Select friends who are good at anticipating your needs
•Select friends who consider you to be irreplaceable
•Alliance hypothesis- a key function of friendship is to assemble support groups that can come to your aid in social conflicts
•Select friends who want the same things you want
Costs & Benefits of Friendship
•Despite the potential benefits, friends sometimes become our competitors or rivals
•One study of female friendships found that the less attractive member of the pair perceived more mating rivalry within the friendship than the more attractive of the pair (Bleske-Rechnek & Lighthall, 2010)
Opposite-Sex Friendships
•Opposite-sex friendships offer a benefit that same-sex friendship generally lacks: the potential for mating
•Men evaluated the potential for sexual access to their opposite-sex friends as significantly more beneficial than did women (Bleske & Buss, 1997)
Opposite-Sex Friendships (pt. 2)
•For women more than men, a function of opposite-sex friendship is to provide protection
•Another hypothesis is the opposite-sex friendships function to provide information about the opposite sex
Same-Sex Friendships
•Men and women will perceive mating rivalry as a potential cost of same-sex friendships
•Men and women both reported intrasexual rivalry over mates in their same-sex friendships, although not at high rates
Cooperative Coalitions
•Cooperative coalitions are alliances of more than two individuals for the purpose of collective action to achieve a particular goal (e.g., hunting, defense, building shelters)
•Coalitions can face two serious problems that can undermine them: defection and free-riding
Punitive Sentiment
•Evolved as a solution to the free-rider problem– a desire to harm “slackers’ in the group
•It could have two distinct functions: Increase the chance that a reluctant member of the group will contribute and damage the free-rider’s fitness relative to those who participate fully (Price et al., 2002)
Altruistic Punishment
•Those who punish free-riders incur a cost; it takes time, energy, and effort to punish someone, and punishers risk retaliation
•Punishing others could be an evolutionary altruistic act in the sense that it provides a benefit to the whole group at a cost to the individual doing the punishing
Cultural Group Selection
•Describes a process by which certain culturally transmitted ideas spread because of the competitive advantages they provide to the social groups holding them
•Altruistic punishment that is beneficial to the group could spread in this manner
Reputational Benefits
•Altruistic punishers are more often sought out for cooperative relationships because they are perceived as being more trustworthy than those who fail to punish non-cooperators (Barclay, 2006)
•The presence of an audience increases the rates of punishing non-cooperators (Kurzban et al., 2007)
Competitive Altruism
•Competing to be seen by others as great contributors to the group (Roberts, 1998)
•Competing for reputations as being highly generous to others in the group (Barclay, 2013)
•Self-interested but unlike free-riders, don’t impost costs on the group
Ostracism or Shunning
•Those who shun individuals who either fail to help or fail to punish non-cooperators maintain a good reputation
•People who shun free-riders save the cost they would incur by helping them, so those who punish by shunning directly benefit (Fehr, 2004)
Aggression and Warfare - Introduction
•Of the more than ten million species of animals, chimps and humans are the only two species to show male-initiated coordinated groups that support each other to raid neighboring territories and lethally attack members of their own species; warfare-like behaviors, filled with types of rivalries; Spartans and Athenians, the Crusades, predominantly male-dominated aggression, initiated when they have bigger groups than the ones they are attacking
•Coalitions- groups in which members support each other in a mutual quest to aggress against others
Co-Opting the Resources of Others
•Humans, historically, stockpile resources that historically have been valuable for survival and reproduction, including fertile land, access to fresh water, food, tools, and weapons.
•Aggression to co-opt resources can occur at the individual (one person takes from another person)or group level (one group takes from another group); the threat of aggression is often enough to secure resources from others.
•Men often form coalitions for the purposes of forcibly co-opting the resources of others.
Defense Against Attack
•Victims of aggression stand to lose valuable resources. They might also suffer injury or death = impedes survival and reproduction
•They might also lose in the currency of status and reputation.
•Aggression can be used as a defense against attack
Inflicting Costs on Intrasexual Rivals
•Another adaptive problem involves vying for access to valuable members of the opposite sex
•Aggression and derogation of competitors are common; bully kicking sand in the face of a weaker male’s female - verbal assault, beatings, and even killings, derogating competition, cyberbullying on social media, bar fights that can escalate into someone dying
•Because evolution operates according to reproductive differences, a reproductive cost inflicted on a rival can translate into a relative reproductive benefit for the perpetrator.
Negotiating Status & Power Hierarchies
•Another hypothesis is that aggression functions to increase one’s status or power within existing social hierarchies. Example: men who expose themselves to danger in warfare are considered brave and fearless which elevates their status within a group
•Aggression does not lead to status elevation in all groups; in some groups, it can result in a status decrement (i.e., a loss); example: a professor punching another professor in the face
Deterring Rivals from Future Aggression
•Cultivating a reputation as aggressive individual might function to deter aggression from rivals and other forms of cost infliction from others; deterrent from taking from individuals who are physically formidable or strong as it could lead to beatings or assault
•Aggression and the reputation for aggression can act as deterrents, helping to solve the adaptive problem of others attempting to co-opt one’s resources and mates.
The Context-Specificity of Aggression
•Aggression is not a unitary, monolithic, or context-blind strategy; rather, it is highly context specific, triggered only in situations that resemble those in which our ancestors confronted certain adaptive problems for which aggression was an effective solution.
•Adaptive benefits must also be evaluated within the context of costs. One of the strongest findings in aggression research is that aggression tends to cause retaliatory aggression, which can sometimes lead to escalating cycles of aggression and counter-aggression.
Reputational Consequences of Aggression
•Cultures and subcultures differ in whether aggression enhances or diminishes status; when you’re in the context of a culture of honor, such as “cultures of honor,” for example, failure to aggress when insulted can lead to status loss (Nisbett, 1993).
Retaliation
•Another dimension of cost pertains to the ability and willingness of the victim to retaliate; in the context of bullying, a bully will often target those who cannot or would not stand up for themselves. However, the presence of extended kin is one context of cost that moderates the manifestation of spousal abuse (Figeredo, 1995) = hypothesized to have something to do with retaliation aggression
Why Are Men More Violently Aggressive Than Women? - Introduction
•Of homicides committed in Chicago between 1965 and 1980, 86% were committed by men (Daly & Wilson, 1988); of these, 80% of the victims were also men.
•In all cultures, men are overwhelmingly more often the killers and the majority of the victims.
Evolutionary Model of Intrasexual Competition
•Begins with the theory of parental investment and sexual selection: In a species in which females invest more heavily in offspring than males, females are a valuable resource; there is a ceiling on reproduction that is higher for men than for women
•This leads to differences in the variances in reproduction between the sexes. The differences between the haves and have-nots are greater for males than females
•Selection favors riskier strategies within the sex that shows the higher variance; species that show higher variance in the reproduction of one sex compared to the other tend to be sexually dimorphic (i.e., different in size and shape) across a variety of physical characteristics; the more intense this difference, the more dimorphic they are, example: elephant seals (males are much larger than the females)
Effective Polygyny
•Means that some males gain more than their “fair share” of copulations while other males are shut out completely; we see this in chimp species (chimp politics). This leads to more ferocious competition within the high-variance sex.
•Polygyny selects for risky strategies, including those that lead to violent combat/conflict with rivals; when males gain more than their fair share, the other males have to engage and challenge the alpha males to gain access to the females
Violence
•Homicide data reveal that men who are poor and unmarried are more likely to kill compared with their more affluent and married counterparts (Wilson & Daly, 1985).
•There are two sides to the use of aggression: Aggression by a male to gain access to multiple mates and aggression to avoid total reproductive failure.
Risk Taking in Mating Contexts
•Selection, in some contexts, filters out those who fail to take risks.
•Males are often the perpetrators of violence because they are the products of a long history of mild but sustained polygyny characterized by risk strategies of intrasexual competition for access to females.
Female Aggression & Violence
•Women also engage in aggression, and their victims are also typically members of their own sex
•In studies of verbal aggression, women to engage in verbal aggression/ slander the physical appearance of their rivals or suggest that their rivals engaged in promiscuous sexual activities
•Selection may operate against women who take the large physical risks entailed by aggression
The Recalibration Theory of Anger
•The recalibration theory proposes that feeling and expressing anger functions to increase (recalibrate) the value that the target of your anger places on your welfare (Sell et al., 2009).
•Individuals with a superior ability to inflict costs (i.e., a man’s upper body strength) and confer benefits (i.e., a woman’s physical attractiveness) should be more prone to anger.
•The theory thus predicts that physically formidable men and physically attractive women should be more prone to anger and experience a greater sense of entitlement than their less formidable or attractive counterparts
Testing the Recalibration Theory of Anger
•Stronger men (but not stronger women) reported more proneness to anger, a more frequent history of fighting, and a greater sense of entitlement than physically weaker men.
•Attractive women and men both reported the above findings, although these effects were stronger for women than men.
Sex Differences in Same-Sex Aggression
•Several sources of evidence are available regarding sex differences in same-sex aggression:
•Body differences in design for combat, meta-analyses (combined studies) of sex differences in aggression, homicide statistics, studies of bullying, and evidence from aboriginal communities and tribal societies that are more similar to those that lived in our evolutionary history
Body Differences in Design for Combat
•Compared to women, men have 61% more total muscle mass, 75% more upper-arm muscle mass, 91% greater upper-body strength, taller and heavier bodies, thicker jaw bones, stronger bones, greater bone density in their arms, higher muscle-to-fat ratio, broader shoulders, and even thicker skin (Lassek & Gauline, 2009; Sell, 2012); men also show greater interests in using their bodies in activities that allow them to utilize these physical benefits such as boxing, karate, wrestling, etc.
Meta-Analyses of Sex Differences in Aggression
•An effect size, in this context, refers to the size of the sex difference. An effect size of 0.80 may be considered large, 0.50 medium, and 0.20 small.
•Research shows the following effect sizes in aggression, all of which show greater male scores: Aggressive fantasies (0.84), physical aggression (0.60), imitative aggression (0.49), and willingness to deliver electric shock to others in an experiment (0.39).
Same-Sex Homicides
•Daly and Wilson (1988) compiled same-sex homicide statistics from 35 different studies representing a broad span of cultures from downtown Detroit to tribal communities in Uganda. The results of the research showed that in every culture, the rate at which men kill other men far exceeds the rate at which women kill other women.
•“There is no evidence that women in any society have ever approached the level of violent conflict prevailing among men in the same society” (Daly & Wilson, 1988, p. 149); men are overwhelming the aggressors and the victims
Same-Sex Bullying in Schools
•In reports of bullying others, one study showed that 54% of middle school boys reported engaging in bullying, whereas only 34% of girls did
•Among older-aged high school students, 43% of the boys but only 30% of the girls reported bullying others
•In the high school sample, 36% of the boys but only 9% of the girls reported being physically hurt by a bully; 10% of boys but only 6% of girls reported having their belongings taken from them
•In terms of verbal aggression, 74% of girls, reported others have called them nasty names, whereas only 57% of the boys reported this form of bullying
•Bullying in males takes the form of physical aggression versus for female bullying which focuses more on verbal aggression
An Australian Aboriginal Community
•An anthropologist recorded and coded 793 aggressive episodes and found that men, overwhelmingly resorted to more dangers aggression than women did
•Of the 93 episodes in which a weapon was used, all but 2 were used by men.
The Young Male Syndrome
•Young men appear to be the most prone to engaging in risky forms of aggression. Wilson and Daly (1985) call this the young male syndrome.
•Over the course of our evolutionary history, a young man seeking a wife had to display formidable physical prowess to impress others and deter rival men from hindering his sexual quests = (one of the rationales behind young male syndrome)
Cultivating a Reputation
•Competitive success or failure early in life might have been a strong determinant of reputation, which could affect a man’s lifetime survival and reproductive success
•Displays of violence by young men are almost invariably performed in the presence of others; suggests that they are not only to try and get rid of a rival but also to form a formidable reputation among others
Contexts Triggering Men’s Aggression
Against Men - Marital and Employment Status
•In a study of Detroit homicides in 1982, only 11% of the adult men in the area were unemployed that year, but 43% of the victims and 41% of the perpetrators were unemployed (Wilson & Daly, 1985), overwhelmingly over half the statistics were unemployed in context of the results
•In the same study, 73% of the male perps and 69% of the victims were unmarried, contrasted with only 43% of the same-age men in the area. Thus, lacking resources and being unable to attract a long-term mate appears to be context linked with male-male homicides
Contexts Triggering Men’s Aggression
Against Men - Status and Reputation
•One of the key motives of male-on-male homicide is the defense of status, reputation, and honor in the local peer group; sometimes these things start out as trivial aggressions but then becomes more aggressive if one things their status is being jeopardized
•Humans evolved in small-group living in which status and reputation were vital to a man’s access to mating opportunities
Contexts Triggering Men’s Aggression
Against Men - Sexual Jealousy & Intrasexual Rivalry
•A summary of 8 studies of same-sex killings involving “love triangles” documented that 92% were male-on-male homicides and only 8% were female-on-female homicides (Daly & Wilson, 1988, p. 185).
•Rivalry and competition over women can also trigger nonlethal aggression (Buss, 1988c).
Contexts Triggering Women’s Aggression Against Women - Verbal Aggression
•Women tend to use indirect aggression, notably gossip, much more than physical aggression in their competition with other women (Hess & Hagen, 2006).
•Although women and men engage in similar levels of verbal aggression, however the content of the derogation differs (Wyckoff et al., in press); women more likely to derogate competitors in terms of physical appearance and sexual promiscuity, men use verbal aggression to talk about competitors potential lack of resources
Other Studies of Female Aggression
•In a study of high school girls, female aggression was found to stem from motives such as jealous rivalries, competition over boys, and the desire to be included among the “desirable” group of other women (Owens et al., 2000). Social aggression among a tribal group in Bolivia focused on failing to reciprocate food sharing, failure to get mate attraction, etc.
Sexual Jealousy & Mate Guarding
•Women are more indirectly aggressive to attractive women who are dressed provocatively than to those dressed conservatively (Vaillncourt & Sharma, 2011)
•Attractive women are often subject to harsher forms of aggression from other women (Leenaars et al., 2008). Has to do with mate guarding - women become jealous of other women and become protective and aggressive to try and protect their resources (mates and their resources)
Contexts Triggering Men’s Aggression Against Women - Sexual Jealousy Among Men
•Much of men’s non-sexual violence against women is directed at spouses, mates, or girlfriends and sexual jealousy appears to be the major cause.
•Sexual jealousy is also a key context for spousal homicide and the most common cause across cultures (Daly & Wilson, 1988).
Contexts Triggering Men’s Aggression Against Women - The Age of Female Victims
•Young girlfriends and wives are far more likely to be killed than older ones (Daly & Wilson, 1988; Shackelford et al., 2003). This is because youth is a powerful cue to a woman’s reproductive value, it makes sense that male sexual jealously would be especially targeted toward young women.
•It is also likely that younger women are more often the objects of desire by other men, so male sexual jealousy might be activated by the heightened presence of potential mate poachers.
Contexts Triggering Men’s Aggression Against Women - Controlling the Sexuality of Female Partners
•One study looked at over 8,000 women, of whom 277 had been assaulted by their husbands within the past year (Wilson et al., 1995).
•“Autonomy-limiting” items were positively linked with violence perpetrated by husbands against their wives.
•Men who commit violence against their wives typically display an inordinate amount of jealousy and controlling behavior (Easton & Shackelford, 2009).
Contexts Triggering Women’s Aggression Against Men - Defense Against Attack
•Extreme aggression such as spousal homicide is much less frequently perpetrated by women, but it does occur
•The contexts are almost always linked with one of two factors: the women is defending herself against a husband, or when a woman sees no way out of the coercive grip of her husband (Daly & Wilson, 1988).
Warfare - The Evolutionary Psychology of Warfare
•War is an intensely cooperative venture (Tooby and Cosmides, 2010).
•The benefits, in fitness currencies, have to be sufficiently high to overcome the risks of injury and death
•Tooby & Cosmides have 4 essential conditions that must be met for warfare adaptations to have evolved.
The Long-Term Gains Must Outweigh the Costs + Coalitions Must Believe They Will Be Victorious
•The average long-term gain in reproductive resources must be sufficiently large to outweigh the reproductive costs of engaging in warfare over evolutionary time.
•Members of coalitions must believe that their group will emerge victorious.
Coalitional Members Must Share the Benefits
•The risk that each member takes and the importance of each member’s contribution to the success must translate into a corresponding share of the benefits.
The “Veil of Ignorance”
•Men who go into battle must be cloaked in a “veil of ignorance” about who will live or die.
Evolutionary Theory of Warfare Predictions
•The evolutionary theory of warfare leads to specific predictions:
•Men, but not women, will have evolved psychological mechanisms designed for coalitional warfare
•Sexual access to women will be the primary benefit that men gain from joining male coalitions
•Men should panic and flee when death appears to be imminent
Evolutionary Theory of Warfare Predictions (pt. 2)
•Men should be more likely to go to war when their odds of success appear high, such as when the number of men in their coalition greatly exceeds the number of men in the opposing coalition
•Men should have evolved psychological mechanisms designed to enforce the risk contract– that is, to detect and punish cheaters, defectors, and traitors
•Men should have evolved psychological mechanisms that function to detect, prefer, and enlist men in the coalition who are willing and able to contribute to its success
Men Engage in Warfare
•The fact that men form coalitions for the purposes of killing men in other coalitions is observed across cultures (Alexander, 1979; Chagnon, 1988; Wrangham & Peterson, 1996).
•In no culture have women ever been observed doing this.
Men Spontaneously Assess Their Fighting Ability
•Men should have evolved distinct psychological adaptations that lead them to evaluate the conditions in which it is wise to go to war; one such mechanisms if the self-assessment of one’s fighting abilities relative to other men.
•Research suggests that men assess their fighting abilities significantly more frequently than women (Fox, 1997).
Men’s Adaptations To Facilitate Success in War
•Men exceed women in upper-body strength: The average man is nearly twice as strong as the average woman in chest, shoulder, and arm strength
•Men show superiority in throwing distance and accuracy and also in navigating through strange territories
Evolved Adaptations for Success in Warfare 1
•Bioarcheological evidence of mass graves from tens of thousands of years ago that contain mostly male skeletons (Walker, 2001)
•The high male mortality rate due to warfare and homicide in traditional cultures
•Lab studies of simulated war games find that men are substantially more likely than women to attack another country, even without provocation (Johnson et al., 2006).
Evolved Adaptations for Success in Warfare 2
•Men are more likely than women to form strong ingroup/outgroup distinctions and derogate outgroup members (McDonald et al., 2012).
•Men are more likely than women to hold outgroup stereotypes, especially under conditions of threat from outgroups (Schaller et al., 2003).
•Men’s groups are more rigidly hierarchical than women’s groups (van Vugt, 2006).
Evolved Adaptations for Success in Warfare 3
•Men, compared to women, show a particularly strong bias against outgroups, especially toward male outgroup members (Navarrete et al., 2009; Navarrete et al., 2010).
•Lab studies in which people are threatened by an outgroup member show that men, but not women, subsequently show more prejudice and discrimination toward the other group (Yuki & Yokota, 2009)
•Sports violence by groups of fans is nearly exclusively a male activity (Newson et al., 2018; see also Lopez, 2017).
Evolved Adaptations for Success in Warfare 4
•Men locate weapons more quickly than do women in complex visual arrays (Sukikowski & Burke, 2014)
•Boys typically prefer competitive warlike games more than girls (McDonald et al., 2012); this gender difference also shows up in the world of computer games.
What is Sexual Conflict?
•A conflict between the evolutionary interests of individuals of different sexes
•Evolutionary interests boil down to “genetic interests”
•Whenever the genetic interests of a male and female diverge, sexual conflict can ensue
•Example: There’s two people on a first date and the male wants to have sex after the first date whereas the female doesn’t so this is a sexual conflict
•Example: Women wants to go to party without husband to look for a potentially better mate whereas her husband doesn’t want her to go out. This is an example of conflict between freedom of mate choice versus mate guarding
Major Forms of Sexual Conflict
•Conflicts over the occurrence and timing of sex
•Sexual aggression and defenses against it
•Jealous conflicts that arise from potential “mate poachers”
•Signals of infidelity
•Mate guarding that limits a partner’s behavior by preventing full freedom of mate choice
•Conflict over access to resources
Short-Term Sexual Strategies Conflict
•Many sources of conflict between the sexes can be traced to evolved differences in sexual strategies.
•Men, far more than women, have evolved a stronger desire for sexual variety (short-term mating strategies, desires manifest themselves include seeking sexual access sooner than women would prefer)
•Women have evolved to be more discriminating in short-term mating (females may want to delay sexual intercourse, for example)
•Clearly, the sexes cannot simultaneously fulfill these conflicting desires. This is an example of strategic interference.
Strategic Interference Theory
•Occurs when a person employs a particular strategy to achieve a goal and another person blocks successful enactment of that strategy (i.e. delay of sexual intercourse until she feels emotional closeness, but the male continues to try to pressure her, this is a blockage of her successful mating strategy)
•The strategy of an individual of one sex can interfere with the strategy of an individual of the other sex
Applying Strategic Interference Theory
•Conflict can pervade all relations between the sexes (conflict in workplace, conflict on dating scene, and conflicts that can occur inside and outside of a marriage)
•Sexual harassment is one form of strategic interference in the workplace
•Deception on the dating scene
•A man who deceives a woman of his marriage status or a women deceiving a man about her age
•The key point is that strategic interference is predicted to pervade interactions between the sexes
•Evolutionary psychologists argue that this will pervade interactions between males and females
“Negative” Emotions: Anger & Distress
•Are psychological solutions that have evolved in part to solve the adaptive problems posed by strategic interference (Buss, 1989b).
•Negative emotions = uncomfortable emotions but are still functional in dealing with these problems. They focus our attention on problematic events, mark those events for storage in memory, and lead to action to eliminate the source or strategic interference and what is causing us anger or stress; adaptive
Predictions from Strategic Interference Theory
•Predicted to occur when members of one sex violate the desires of members of the opposite sex. Historically, this prevented our evolutionary ancestors from going through with their sexual strategies and could have impaired our sexual/ reproductive success
•Negative emotions represent evolved solutions to the problems of strategic interference, alerting people to the sources of interference and prompting action to counteract it
Qualifiers of Strategic Interference
•Conflict serves no adaptive purpose in this context. Not adaptive for members of the other sex to get into conflicts
•The metaphor of the “battle between the sexes” is misleading; unification cannot occur between all members of one sex- implies that men and women are unified in their interests, when this is not always the case, men can’t be united all together because they are competing for similar resources and vice versa; they can form alliances but this doesn’t rule out the conflict between members of the same gender according to evolutionary psychology
Conflict About the Occurrence and Timing of Sex - Introduction
Differences of timing about mating/sex - sexual conflict over the optimal timing for sexual reproduction, amount of investment before sex, frequency of sex over the course of the relationship, and the amount each invest in offspring
Note
Flashcard