EVOLUTIONARY EXPLANATIONS OF AGGRESSION

27 Feb

SPECIFICATION: EVOLUTIONARY EXPLANATIONS OF HUMAN AGGRESSION, INCLUDING INFIDELITY AND JEALOUSY

An evolutionary explanation of aggression focuses on enhancing survival and reproductive success. While aggression can be risky, mainly when directed at members of your species, certain aggressive behaviours have been naturally selected because they solve adaptive problems.

In other words, aggression may offer a survival advantage, even when used against others in the same group. Below are some of the evolutionary functions of aggression that may explain why it has persisted across time and cultures:

Gaining territory and resources: i.e., children bullying others for money or toys, adults mugging and warfare.
Defending against attacks: aggression to prevent losing resources and status necessary for reproductive fitness, e.g., “stick up for yourself,” defending territory.
Inflicting cost on same-sex rivals: competition for resources and mates, e.g., men fighting over women.
Negotiating status and power hierarchies: aggression to gain dominance or prestige, e.g., gang violence to “prove oneself.”
Deterring rivals from future aggression: reinforcing an aggressive reputation, e.g., threatening gestures.
Deterring mates from infidelity: aggression used to ensure long-term partner loyalty and paternity certainty, e.g., partner control

OVERVIEW OF GENDER AND CRIMINALITY IN THE UK AND USA

According to the Ministry of Justice’s 2022/23 Criminal Justice Statistics, men still commit more crimes and more violent crimes than women.

Although men and women make up roughly equal proportions of the UK population, men accounted for:
- 85% of all arrests
- 74% of defendants prosecuted
- 95% of the prison population
- Only 5% of prisoners are women

These figures have remained fairly consistent over the last decade, showing that men are disproportionately involved in serious offences such as violence, robbery, and sexual crime.

SEXUAL OFFENCES

Around 98% of sexual offenders are male
Fewer than 2% of those convicted of sexual offences are female (MoJ, 2022)

WHO ATTACKS WHO?

MALE OFFENDER / MALE VICTIMS: ~65%
- This reflects high rates of male-on-male aggression, especially among young men.
- ONS homicide data (2021) supports this: most male victims are killed by other men.
- Daly & Wilson (1988) explained this pattern using evolutionary psychology: sexual rivalry and status competition drive much of male-male violence.
- Male homicide offending tends to peak in the early 20s, which correlates with testosterone levels.
MALE OFFENDER / FEMALE VICTIMS: ~22–25%
- Much of this falls under domestic abuse and femicide.

EVOLUTIONARY PERSPECTIVE ON MALE-MALE VIOLENCE

Classic research by Daly and Wilson (1988) found that cross-culturally, male-on-male homicide is by far the most common form of lethal aggression in humans.

Sexual jealousy and status competition account for a large proportion of these killings.
Males are likelier to kill rivals or those who threaten dominance, particularly around mate access.
Homicide peaks in men’s early 20s, when testosterone levels are highest (AO3 biological explanation).
Unmarried and low-status men are disproportionately represented among offenders (Wilson & Daly, 1985).

FEMICIDE STATISTICS (UK)

According to the Femicide Census (2021):

On average, a woman is killed by a man every 3 days in the UK
In 2018, 149 women were killed by 147 men
In 2022, 141 women were killed by male suspects in the UK (Femicide Census)
A current or former partner killed 61% (91 women)
39% were killed by acquaintances, family members, or strangers.
The rest were killed by sons/stepsons (8%), acquaintances (10%), strangers (7%), or others.
Only 6% of femicides were committed by strangers.

Of those 91 killed by partners:

41% had separated or taken steps to separate
30% were dead within the first month of separation
70% were dead within the first year
Around 15% of victims were over 66 years old at the time of their death.

OTHER NOTABLE FINDINGS

Overkilling (using excessive violence) was found in 56% of cases
68% of femicides occurred in the woman's home
52% of perpetrators had prior histories of violence
16% of men were known to use pornography or prostitution
3% of men had previously killed a woman

WOMEN WHO KILL

8–10% of all homicide offenders are female.

Of those female offenders, about 70–90% of their victims are male (depending on the country and study).
That means only about 7–9% of total homicides involve a female offender killing a male victim.
Female-on-female homicide is very rare — around 1–3% of total homicides, globally.

Women are more likely to commit crimes of necessity, such as theft or fraud, and are far less likely to commit violent acts. When women do kill, the motive is more often self-preservation (e.g. escaping abuse) than dominance or rivalry.

Women are more likely to kill in self-defence, particularly in cases of chronic domestic abuse.

In rare cases, motives involve mental illness, retaliation, or protecting children.
Some studies also link female homicide to coercion by male partners (e.g., being forced to take part in crime)

SOURCES

Ministry of Justice: Criminal Justice Statistics (2023)
Office for National Statistics: Homicide in England and Wales (2021)
Femicide Census: UK Women Killed by Men Report (2021)
Daly, M. & Wilson, M. (1988). Homicide
Wilson & Daly (1985) Sex, Evolution and Behaviour

SEXUAL JEALOUSY AND EVOLUTIONARY THEORY

Mate Protection in Other Primates
Evidence from other great apes suggests that jealousy evolved as a mate protection strategy to maintain low levels of female promiscuity. For instance, a single Silverback gorilla can guard and monopolise up to eight females, achieving reproductive dominance. As a result, gorillas face minimal sperm competition and have relatively small testes for their body size. By contrast, humans have slightly larger testes, suggesting greater sperm competition. This implies a heightened evolutionary need for vigilance over a mate’s fidelity, with jealousy likely evolving as a by-product of this mate competition (Jones, 2006).

SEXUAL JEALOUSY: SEX DIFFERENCES

The evolutionary theory of sexual jealousy explains the different emotional reactions men and women have toward infidelity. From a fitness standpoint, men are most concerned about sexual infidelity, while women are more distressed by emotional betrayal (Harris, 2004). David Buss (1995) attributes these differences to evolved neural mechanisms that guide sex-specific emotional responses.

PATERNITY UNCERTAINTY

Male jealousy is widely considered an evolutionary response to paternity uncertainty (Barrett et al., 2002). Males invest time, resources, and care into offspring and, in turn, want to ensure that those children are biologically theirs. Unlike maternity, which is always specific, paternity is inherently uncertain due to internal fertilisation and concealed ovulation in women (Alexander & Noonan, 1979; Strassmann, 1981; Daly et al., 1982). Human females do not show visible signs of fertility, which may have evolved to encourage long-term male investment through pair bonding and commitment (Alexander & Noonan, 1979).

In societies with low paternity confidence, men tend to invest more in their sisters’ children, whose genetic link is assured (Gaulin & Schlegel, 1980). Across cultures, historical evidence suggests that men have consistently demanded paternity assurances before committing resources to child-rearing (Barrett et al., 2002).

CULTURAL CONTROL OF FEMALE SEXUALITY

To secure paternity certainty, cultures have developed practices that aim to control female sexual behaviour. Barrett et al. (2002) describe these as “honour and shame” systems, in which family status is tied to female chastity. This control tends to increase with social status, where male investment in offspring is greatest (Dickeman, 1979).

Examples include:

Pre-marital virginity requirements
Modest dress codes (e.g. under Islamic law)
Chaperoning in public (ancient China)
Foot binding
Female genital mutilation (Sub-Saharan Africa)

These customs serve to limit women’s mobility, sexual autonomy, and access to other potential mates, ultimately preserving paternity certainty for their partners (Dickeman, 1979).

PHENOTYPIC RESEMBLANCE AS PATERNITY REINFORCEMENT

Because paternity cannot be confirmed at conception, post-birth cues also play a role in maintaining paternal investment. Phenotypic resemblance is one such cue. Studies have shown that mothers often emphasise how much a newborn resembles the father to reinforce their perceived genetic connection (Daly & Wilson, 1982; Regalski & Gaulin, 1993). In Canadian maternity wards, mothers commented more on father–infant resemblance than mother–infant resemblance (Daly & Wilson, 1982), a trend also observed in Mexico (Regalski & Gaulin, 1993).

Such remarks may be strategic, strengthening paternal bonds and encouraging continued male investment, even without biological certainty.

Evidence from the other great Apes suggests that jealousy is a mate protection strategy to maintain low levels of female promiscuity. A single Silverback Gorilla can protect up to eight females as his own, thus gaining a reproductive monopoly. As a result, gorillas do not have much sperm competition and, therefore, have tiny testes relative to their stature. On the other hand, humans have slightly larger testes relative to stature but still have small testes compared to other apes. This suggests that humans have somewhat more sperm competition, and therefore have more reason to be suspicious of a mate’s interest in another. Jealousy likely evolved as a byproduct of this mate competition (Jones, 2006).

The evolutionary theory of sexual jealousy seeks to explain differences in jealousy between sexes from a biological/evolutionary standpoint. Responses differ between men and women because the two sexes have different needs for maintaining fitness. For women, when a man is unfaithful in a relationship, it is emotional infidelity that is cause for concern, while for men, it is physical sexual infidelity (Harris 2004). David Buss states that this difference comes from how men's and women’s brain circuits guide emotional reactions (Buss 1995).

Sexual jealousy and paternity uncertainty

The consensus among biologists regarding the reason for male sexual jealousy is concern over paternity confidence for existing and future offspring (Barett et al. 2002). The male partner invests paternal care (time, energy, affection, resources) in a female to ensure reproductive success. He only wants to invest parental care in his offspring (Barett et al. 2002). While maternity is unmistakable, paternity is less certain when internal fertilisation exists (Daly et al, 1982) and there is concealed ovulation in females (Alexander and Noonan, 1979; Strassmann, 1981). Human females are unique in that ovulation is nearly impossible to detect. Women, therefore, may be receptive to fertilisation at any point in their ovulatory cycle (Alexander and Noonan 1979). If paternal investment were unlikely, advertisement of ovulation would likely increase copulations at fertile points in her cycle and the likelihood of securing a competitive male (Alexander and Noonan 1979, Strassmann 1981). Where paternal investment is likely, concealed ovulation might oblige males to commit to a companion relationship, thereby minimising the risk of the males finding other mates, while also ensuring paternity confidence in the offspring (Alexander and Noonan 1979, Strassmann 1981). A study by Gaulin and Schlegel (1980) shows that males are much less likely to invest in their partner’s offspring in societies with low paternity confidence. Instead, they will invest in their sister’s children- a genetic relationship that is guaranteed. Historically, human males have demanded assurances that offspring are genetically related before they invest in a child (Barett et al, 2002). This is a common occurrence bridging most human cultures and societies. Barett et al (2002) argue that sexual jealousy is a demonstration of men’s desire to control the sexual behaviour of women to guarantee paternity certainty, thereby ensuring they are investing in their offspring.

Throughout history, the control of female sexual behaviour has been manifested in many different ways. Barett et al (2002) describe these systems as “honour and shame systems” where the “honour and prestige of a lineage is premised on the chastity of its daughters”. The intensity of these cultural codes tends to increase with social status; this supports the assumption that higher-ranking males tend to invest more in the paternal care of their offspring (Dickeman 1979). These cultural practices are a collection of contexts where men control female chastity and fidelity, reduce female mate choice, and promote the institutional seclusion and incapacitation of women (Dickeman 1979). Dickeman (1979) illustrates specific examples of sexual control, including: the insistence that women are virgins before marriage, “modest” dress restrictions under Islamic law, foot binding and chaperoning in public in ancient China, and cliterodectomy in Sub-Saharan Africa. Each of these cases represents a cultural framework constructed to control women’s exposure to other people, mobility, or sexual behaviour, thereby helping ensure paternity certainty for husbands and potential fathers (Dickeman 1979).

Since paternity is not guaranteed, males do not only rely on female sexual fidelity and the timing of conception, but phenotypic resemblance can also support or undermine paternity certainty (Daly and Wilson 1982). After a child is born, females are inclined to express confidence in paternity through comments about the child's likeness to the father (Daly and Wilson 1982, Regalski and Gaulin 1993). Daly and Wilson (1982) showed that in Canadian maternity wards, mothers are especially inclined to comment more often about the physical similarities between the father and the infant than the similarities between the mother and the infant. Similar results have been found through a study in Mexico, where paternal resemblance was more often alleged after a birth than maternal resemblance, and the mother is responsible for most of these comments (Regalski and Gaulin 1993). Paternal confidence can be manipulated, and often mothers will attempt to strengthen the bond between a father and child by citing their relatedness and phenotypic similarities (Daly and Wilson 1982).

Female Sexual Jealousy and Parental Investment

Female aggression

Until recently, relatively little attention was focused on female aggression. Campbell (1999) argues that

lower rates of aggression by women reflect not just the absence of masculine risk-taking but are part of a positive female adaptation driven by the critical importance of the mother's survival for her reproductive success."

After choosing a mate, females bear the brunt of child production. Not only does the woman have to produce and carry the baby, but in Western society, she remains responsible for raising him or her. Because offspring are at such a high cost for the female, the male’s resource contribution could mean life or death for her and her child, weighing significantly on her fitness potential (Schutzwohl, 2008). If a woman knows or suspects that her husband is being unfaithful, she will be more concerned that he is sharing his resources with another woman, rather than making another baby (Schutzwohl, 2008). As a result, for females, emotional infidelity is significantly more vexing than sexual infidelity. In a study done to determine the behavioural differences between men and women in terms of jealousy, researchers found that women were most upset when they found out, or suspected that their mate had given a gift to another woman, closely followed by spending time with another woman, and spending time thinking about another woman (de Weerth, 1993). These are considered the worst offences because the man is giving away the monetary resources and the time he could use to support his child. In the same study, women also self-reported more overall jealousy in relationships than men. This is likely due to the parental investment costs females incur – females have more to lose with an unfaithful spouse (De Weerth, 1993).

Aggression and Jealousy in Females

Contrary to statistics on spousal abuse in which men are the abusers (de Weerth, 1993), women are more likely to report that their hypothetical sexual jealousy would manifest itself as anger and physical aggression. While both sexes reported experiencing sexual jealousy in relationships, as well as an interest in discussing the reasons for the infidelity, significantly more surveyed females claimed that they would cry, and then act aggressively toward their unfaithful spouse. Women also claimed that they would feign indifference as well as attempt to make themselves more physically attractive to their mate (De Weerth, 1993).

Women will direct their jealousy toward their rival female, even though their husbands are unfaithful. As a result, when a woman is around a suspected rival female, she is more likely than a male counterpart to announce that her companion is “taken” and go out of her way to enhance her appearance to her spouse (Schutzwohl, 2008).

Gregory White found that women are likelier to attempt to induce jealousy in their partner for some gain. Women who considered themselves in “low-power” positions in their relationships reported inducing jealousy in hopes that their partner would spend more time with them or pay more attention to them (White, 1980). White believes that the inducement of jealousy is a manipulation of power on the female’s part, using the partner’s jealousy to gain influence in the relationship (White 1980).

A01 Research

Female-female aggression

Female aggression is more verbal against other women to maintain status and reduce the attractiveness of competitors, especially by using verbal criticism of the physical unattractiveness of other females and their promiscuity (for men looking for long-term mates with sexual fidelity) to lower their appeal in the eyes of men.

(Buss and Dedden, 1990).

Daly and Wilson (1985) found that in 58 out of 214 cases of murder studied in Detroit in 1972, jealousy was the primary motive of the uxoricide.

In another sample of 80 murders where the victims were married or cohabiting, the victims were 44 husbands and 36 wives. This suggests violence is similar in both genders, contradicting evolutionary theory, which suggests females have more to risk by being aggressive, e.g., they can’t look after their children.

29% of these conflicts arose from sexual jealousy (Daly and Wilson). However, some critics have argued that the husbands’ deaths occurred out of self-defence. This data is not scientific and correlational. Caution must also be applied to defence pleas, as most females would cite this as it carries a lesser sentence.

Data collected by Bellis and Baker (1990) showed that their biological father does not father 7-14% of children.

A common way to test whether an innate jealousy response exists between sexes is to use a forced-choice questionnaire. This questionnaire asks participants "Yes or No" and "Response A or Response B" questions about specific scenarios. For example, a question might ask, "If you found your partner cheating on you, would you be more upset by (A) the sexual involvement or (B) the emotional involvement?". As the name implies, one is forced to choose between the two options. Many studies using forced-choice questionnaires have found statistically significant results supporting an innate sex difference between men and women. Furthermore, studies have shown that this observation holds across many cultures, although the magnitudes of the sex difference vary within sexes across cultures. The main differences are that men are more sexually jealous and females are more emotionally jealous, which supports evolutionary theory.

Typical questions include: Would you prefer your partner to have sex with another person whilst thinking of you, or have sex with you whilst thinking of someone else?

Or that your partner has formed an intense sexless friendship with another woman, or had sex as a one-night stand.

Men generally choose the latter and women the former.

A02: Although forced-choice questionnaires show a statistically significant sex difference, these findings are questionable when the entire body of work on sex differences is considered. When methods other than forced-choice questionnaires are used to identify an innate sex difference, inconsistencies between studies begin to arise. For example, in a study by Sangrin & Guadango (2005), the authors found that women sometimes report feeling more intense jealousy in response to both sexual and emotional infidelity. The results of these studies also depended on the context in which the participants were made to describe what type of jealousy they felt and the intensity of their jealousy. From this study, it is clear that context plays a role in the responses men and women give researchers and, therefore, how sex differences are interpreted.

GROUP DISPLAY AND WAR

Group displays of aggression are defined as situations where at least three people join together for a common purpose, such as to be aggressive. These groups frequently see themselves as a distinct unit or in-group.

Hardin (1972) introduced the related concept of tribalism: "Any group of people that perceives itself as a distinct group, and which is so perceived by the outside world, may be called a tribe. The group might be a race, as ordinarily defined, but it need not be; it can just as well be a religious sect, a political group, or an occupational group. The essential characteristic of a tribe is that it should follow a double standard of morality - one kind of behaviour for in-group relations, another for out-group”.

Individuals in a group behave far more aggressively than on their own

Examples of group displays of aggression:

Mobs and crowds (especially at sporting events)
Lynch mobs
Criminal organizations
Urban gangs,
Motorcycle gangs,
Football teams,
Pre-state warrior societies
Contemporary armies
Mafia (Some forms of human violence involve an accurate assessment of the risk of injury (e.g. the Mafia are reputed to wait for a numerical advantage before they attack their victim).

Keywords:

In groups: In sociology and social psychology, in-groups and out-groups are social groups to which an individual feels as though he or she belongs as a member or (for out-groups) to which they feel contempt, opposition, or a desire to compete. People tend to hold positive attitudes towards members of their groups, a phenomenon known as in-group bias. In-groups can be formed for any reason: shared ethnicity, religion, belief, culture, school, gender, sexual persuasion, location, nationality, political organisation (ANYTHING, pretty much). Sometimes members are not consciously aware that they are even part of in-groups. Tribes are a good way to describe in-groups and out-groups, and even though we often think of tribes as primitive, they very much apply to in-groups and out-groups, too.

Xenophobia: Xenophobia is defined as the "hatred or fear of foreigners or strangers or of their politics or culture" It comes from the Greek words ξένος (xenos), meaning "stranger," "foreigner", and φόβος (phobos), meaning "fear." Examples are: An in-group towards an out-group, including a fear of losing identity, suspicion of its activities, aggression, and desire to eliminate its presence to secure a presumed purity. ".

Belligerence: A belligerent is an individual, group, country, or other entity that acts in a hostile manner, such as engaging in combat. The word belligerent comes from Latin, meaning "to wage war." Unlike the colloquial use of the word "belligerent" to mean aggressive, its formal use does not necessarily imply that the belligerent country is an aggressor.

A01 Theory

Evolutionary Theory

Like most behaviours, group displays of aggression can be examined in terms of their ability to help an animal reproduce and survive. Humans may use group displays of aggression to gain and secure territories and other resources, including food, water, (oil), mating opportunities, and to achieve high status in their social groups (thus obtaining the best females). Researchers have theorised that group displays of aggression and the capacity for murder are products of our evolutionary past.

Risking your life in a group display of aggression may seem maladaptive. Still, it is also maladaptive to be killed by an enemy or have your family, friends, tribe, females, or resources killed or taken away. Likewise, it is also maladaptive not to seek opportunities to try and gain resources when times are hard (famine, lack of females, etc.). Thus, those who aggressed in groups survived and passed down this trait to their offspring (natural selection).

Xenophobia, belligerence, and bravery (see key terms for explanation) are thought to be key personality traits that are naturally selected for group displays of aggression.

Xenophobia is a fear of strangers. It is thought to be adaptive for humans to be xenophobic, as it would have made them suspicious of different tribes that may have taken away their resources.

Xenophobia

• Wilson (1975) - Xenophobia appears in ‘virtually every group of animals displaying higher forms of social organisation.’

• Natural selection favoured genes that caused more extraordinary altruism to members of their group, but were intolerant of outsiders.

• Shaw and Wong (1989) - suspicion of other groups advantageous - avoid attack - more offspring survive

• Mac Donald (1992)- adaptive to exaggerate negative stereotypes about outsiders - overperception of threat, less costly

According to Patrick (1915), ’man the fighting animal’ had evolved out of conditions of never-ending conflict between races, with the continuous extermination of the unfit. Survival in this constant struggle had been the product of order and mutual aid within groups, but with fear, hatred, and the rule of might dominating between groups. Read (1920) said that hominids and early humans formed hunting packs inclined to be aggressive toward all outsiders. "Wars strengthened the internal sympathies and loyalties of the pack or tribe and its external hostilities, and extended the range and influence of the more masculine and capable tribes". Wrangham & Peterson (1996) note that the underlying psychology of our ancestors is no different for urban gangs, motorcycle gangs, criminal organisations, American football teams, pre-state warrior societies, and contemporary armies: "Demonic males gather in small, self-perpetuating, self-aggrandising bands. They sight or invent an enemy ’over there’ - across the ridge, on the other side of the boundary, on the other side of a linguistic or social or political or ethnic or racial divide. The nature of the divide hardly seems to matter. What matters is the opportunity to engage in the vast and compelling drama of belonging to the gang, identifying the enemy, going on the patrol, participating in the attack"

In other words, man commits group aggression in many different guises: lynch mobs, war, ambush, persecution of minority groups, but it all boils down to the same thing: protection of resources or attack to secure more resources. Most modern forms of group aggression will occur when there is economic uncertainty and will be xenophobic, e.g., persecution of Jews WW2; the Oil in the Iraqi War; the persecution of Bosnians by Serbs; the slaughter of native Indians by Americans, etc, the lynching of blacks by whites after the abolition of slavery.

Some of these group displays of aggression will be displayed as a war, and others will be ambush attacks, lynching or persecution. Most evolutionary psychologists do not see the different kinds of displays of group aggression as vital because they see the reason behind any group display of aggression as the same, e.g., survival.

The Evolutionary approach shows us how understanding group displays fits better with natural selection and behaviour that has evolved to ensure the group's survival better. Group displays make membership costly; thus, partaking in them increases commitment and group solidarity. This is an adaptive advantage, as such solidarity allows unified groups to defend and compete against other groups.

A disadvantage, however, is that in societies with stricter religious displays, this tends to lead to a greater level of intergroup conflict also (Roes & Raymond)

Group displays of aggression also raise status with women and allow men to gain access to women either by stealing them or taking sexual privileges by force. Both have evolutionary advantages

A01 Research

Status with women

(Chagnon 1968)

• Success in battle > high status

• Successful warriors had more wives and children

• Young men who had not killed were rarely married.

Females as a resource

Pinker (1997) – In WW2, Germans raped women in concentration camps.

• More than 20,000 Muslim girls and women raped as part of genocide programme in Bosnia.

• The aim was to make the women pregnant and raise the children as Serbs, or terrorise them into fleeing the land (Allen 1996)

• In Yanomamo of the Amazon rainforest, frequent fighting between villages over the abduction of women.

Sports events & xenophobia
Xenophobia is the hatred or fear of foreigners or strangers or their politics or culture. Natural selection has favoured genes that cause group members to be altruistic towards members of the group and intolerant towards outsiders, leading to suspicion of strangers and avoiding attack by outsiders. Overexaggerating the stereotypes of outsiders helps survival, as seeing an exaggerated threat is safer than underestimating a danger.

In Italy in the 1980s, there was an increase in openly racist, anti-semitic, extreme right-wing groups such as the Northern League. The racism was seen particularly openly and vigorously among football crowds, with the effect that the open displays of xenophobia increased the cultural identity of supporters by highlighting the differences between Northern and Southern Italians (Podaliri & Balestri, 1998).

Foldesi (1996) found that violent displays among a small core of Hungarian football crowds led to an increase in violent and racist (against gypsies, Jews and Russians) outbursts by spectators.
A02: Sporting groups

However, football violence may not be an act of naturally selected xenophobia, but more an organised behaviour by hooligans to gain peer acceptance and a sense of personal worth (Marsh, 1978).

Victory in matches also brings status to fans.

• Cialdini et al (1976) ‘basking in reflected glory’ – after a university football team had performed well, students more likely to wear university scarves and sweaters.

Marsh (1978) – football hooliganism is the human equivalent of ‘ceremonial conflict’ in animals.

• Exclusively male, ritualised symbolic aggression restrained by the desire to minimise harm and death.

ANALYSIS

Synoptic links for evolutionary displays of Human Aggression
Imposed etics and ethnocentrism
Explanations of human aggression tend to focus on an industrialised Western point of view and fail to consider the individuality and differences of other cultures. Judging another culture in terms of the researcher’s culture creates an imposed etic.

Groups of humans are not always aggressive.
Groups of humans are not always aggressive, and crowds do not always lead to aggression. Cassidy et al. (2007) researched behaviour during the Hindu festival of Mela, which has crowds of up to 50 million people. Crowds behaved well and showed increased pro-social behaviour, which starkly contrasts with the self-aggression displayed by Shiite Muslims, for example. This also indicates that crowd behaviour and collective living can promote non-aggressive behaviour.

A single theory to account for aggression
No single theory seems to account for group displays of human aggression adequately. The power-threat hypothesis, costly signalling theory, and xenophobia have all been suggested as causes. However, many other theories may also contribute. Other factors that could lead to group aggression include biological factors and personality dispositions. Deindividuation could also account for group behaviours, for example, the extreme behaviours of lynch mobs could be explained as individuals losing their sense of responsibility and instead adopting the group's behaviour. In deindividuation, individuals would never behave that way outside of a group setting, but in a crowd, they often do.

Sports crowds emulate war. Is it a form of sublimation? It is only seen in contact group sports, not group sports like cricket. It is only the working class, though.

Is the rape of women in war a group display of aggression or dominance. ¼ of black Caribbean have a white male ancestor because of rape by slave masters.

Psychology as a science. Impossible area to research scientifically, especially war. Must rely on anthropological and historical evidence, with the best correlations.

Paints a depressing picture of humankind, are we so intrinsically xenophobic and primed for war?

Deterministic? According to ET theory, most men have no choice. They will want to aggress against their outgroups, but it is not their fault. They may not try to change.

Alpha-biased theory.

Reductionism

It does not explain peaceful countries or conscientious objectors. Also, why are some groups of people more belligerent than others, and some not belligerent at all?" Other factors must be involved: SLT, biology, genes, operant Conditioning, cultural norms, etc. For example, Shaw & Wong’s theory. Given that band-level and tribal peoples were all more or less xenophobic, where does the vast variation in belligerence stem from? Factors such as the intertribal political gatherings, ecological constraints, cultural traditions and mores, historical contingencies, societal configurations, and individual cognitions and inclinations are highly complex.

Shaw and Wong seem to believe that many nonbelligerent primitive peoples existed (besides the Eskimo, Semai, and Siriono they mention), and many of them still exist.

Inclusive fitness may account for xenophobia and kin group warfare", Somit (1990) commented, "but I find it unpersuasive when stretched to explain nationalism, patriotism, and contemporary warfare. I doubt, for example, that very many of the millions of soldiers who died during the last two great wars were motivated to any significant degree by the desire, conscious or unconscious, to maximise their inclusive fitness". Little weight is given to the personal ambitions and animosities of those in high office, political rivalries, dynastic aspirations, or the capacity of the regime to compel and persuade military service.

Only a few ultimately decide to take up arms and go to war (Somit, 1990).

Many anthropologists do not acknowledge an evolutionary background to war, adhering to Margaret Mead's famous dictum, “War is only a cultural invention.” Ferguson (1984) is the most outspoken advocate of this position, arguing that war has not been a regular occurrence throughout human history, but most likely became a social institution in Mesopotamia some 8,000 years ago and has been reinvented many times and in many places since.

For the evidence of historical wars (wars in recorded human history) - to illustrate human ’war proneness’ - Shaw & Wong quote the ’magical’ figures of 14,500 wars during the last 5,600 years of recorded history, with peace comprising only 8% of the entire history of recorded civilisation. However, these figures have been shown to be a hoax or a mystification (Jongman & Van Der Dennen, 1988). It is one of those myths that have acquired the status of ’scientific fact’ due to the uncritical quoting of ’authoritative’ sources. Jongman & Van Der Dennen have shown that these imaginary figures have no factual basis. Wars and warlike actions have been, were, and are highly exceptional (and primarily marginal) events (despite the history books which capitalise on war and the rumours of war).

Leakey (1967) suggested that the humanisation of man, especially the development of speech in the last quarter of a million years of human evolution, turned man against man. The characteristically human aspect of aggression, says Leakey, is that it is organised and premeditated. This requires abstract speech.

Evolutionary theory can explain tribal warfare, where there are few casualties and great rewards.

• But in recent human history, prolonged warfare has resulted in significant losses on both sides.

• Wrangham (1999) – military incompetence results from adaptive self-deception.

• Positive illusions about winning will improve

Alternative theories as A03

Sigmund Freud. He suggested that the mindset of an individual differed from their mindsets when in a crowd. He argued for a ‘merging of minds’ within the same opinion groups, leading to reduced behavioural inhibitions. However, his ideas – like most of his theories – were criticised for the lack of use of the hypothetic deductive method. He didn’t test his ideas using investigations arising from a hypothesis.

The slaying of a man is scarcely held by the law of any people to be of itself a crime. Still, on the contrary, it has been regarded as an allowable or praiseworthy act under certain conditions, especially in self-defence, war, revenge, punishment and sacrifice. Yet, no known tribe, however low and ferocious, has ever held that men may kill another indiscriminately, for even the savage society of the desert or the jungle would collapse under such lawlessness. Thus, all men acknowledge some law of "thou shalt not kill", but the question is how this law applies... The old state of things is well illustrated in the Latin word hostis, which, meaning originally stranger, passed naturally into the sense of enemy. Not only is slaying an enemy in open war looked on as righteous, but ancient law operates on the doctrine that slaying one’s tribesman and slaying a foreigner are crimes of quite different order, while killing a slave is but a destruction of property (Tylor, 1871).

The question of why males are the warriors in group displays of aggression has been addressed by many, who believe the hypothesis that raiding-type warfare evolved as a high-risk/high-gain male-group display of aggression for reproductive strategy (or, arguably, even as a parental investment strategy).

Reproductive success is the only criterion in the currency of evolution. Male and female organisms have evolved different strategies for optimising their reproductive success. For males, females are generally the limiting resource: for human males, women are the highly strategic “good” (always in short supply) that can convert the other resources controlled by the males into offspring.

Section Three: Topic Five: Evolution and human aggression

Evolutionary explanations of human aggression, including infidelity and jealousy

Introduction just to remind you why males and females are different:

Evolutionary psychologists have developed a theory to explain the origins of differences between men and women which are caused by early release of Testosterone. Evolutionary psychology is the well-developed theory explaining sex differences (Wood & Eagly, 2002). From the evolutionary perspective, human sex differences reflect the pressure of differing physical and social environments between females and males in primeval times. It is believed that each sex faced different pressures and that the differing reproductive status was the key feature in life at that time. This resulted in sex-specific evolved mechanisms that humans carry with them--these are the causes of sex-differentiated behaviour. The two sexes developed different strategies to ensure their survival and reproductive success. This explains why men and women differ psychologically: They tend to occupy different social roles (Eagly & Wood, 1999). Evolutionary psychologists explain sex differences as based on differing parental investment. Because women invest greatly in reproduction of offspring, they have developed traits that help improve the chances that each offspring will survive. Men are less concerned with reproduction and are less choosy about mates and more concerned with hunting, sex, defending and attacking.

Evolutionary reasons for aggression

A01 theory:

The Evolutionary approach to explaining aggression sees aggression in terms of its ability to increase survival chances therefore to enhance reproductive success.

Q) How can aggression improve survival chances?

A) Aggressive behaviour has evolved to serve adaptive problems of social living such as:

· Gain territory and resources i.e. children bullying others for money or toys, adults mugging and warfare.

· Defending against attacks: aggression to prevent loss of resources and status necessary for reproductive fitness i.e. “stick up for yourself, defending territory

· Inflicting cost on same sex-rivals: aggression between same sex members to aid in the competition for resources and mates i.e. men fighting over women.

· Negotiating status and power hierarchies: aggression to gain prestige and dominance among same-sex members i.e. gang violence to “prove oneself” to aid sexual selection by opposite sex members i.e. women attracted to dominant and powerful men.

· Deterring rivals from future aggression: aggression to maintain dominance and fear in others i.e. making threatening gestures, reinforcing aggressive reputation, maintaining an aggressive appearance

· Deterring mates from infidelity: aggression against opposite-sex members to maintain fidelity of desired long-term mates and ensuring paternity i.e. wife-battering

All this has meant men is predestined to be aggressive.

The Evolution of Male on Male Homicide. Homicide (murder) is the most extreme form of aggression. The vast majority of murderers and their victims are men (Buss & Shackleford, 1997). Aggression resulting in homicide can also be explained in evolutionary terms. One factor that may lead to homicide is increased male-male competition, a response which occurs when there's a lack of resources or difficulty attracting long-term mates. Wilson & Daly analysed homicides in Detroit and found that 43% of male perpetrators were unemployed (lack of resources) & 73% were unmarried (lack of relationship). A02: This suggests a lack of resources (unemployment leads to less money, less food, poorer housing etc.) and the inability to have a long-term relationship lead to increased social competition and men murdering men. This research supports ET. Correlation though?

Homicide can also be due to sexual jealousy. Daly & Wilson found that 92% of murders occurring in 'love triangles' were male-male, suggesting that male sexual jealousy is a key motivator of same-sex aggression and homicide.

A02: If, as is suggested above, homicide is an evolved behaviour then it is very likely that the ability to defend against murder has also evolved, such as being able to read the signs of homicidal intent. This would make homicide a very risky and dangerous behaviour to engage in (Duntley & Buss, 2004), and so it is likely that selection favours the ability of people to deceive others, e.g. the ability to hide homicidal intent from an intended victim.

A01: Wilson and Daly found that another reason that men kill men is to defend their status in a peer group. In our evolutionary past, loss of status could be harmful for survival and reproduction. Even though status is largely irrelevant for survival nowadays, it is an evolved behaviour that is passed on genetically.

Sexual jealousy is a further motivator in male-male homicide. A meta-analysis of 8 studies of same-sex killings involving love triangles found that 92% were male-male and only 8% were female-female (Daly & Wilson, 1988).

More A01 Research crime statistics

Sexual jealousy produces more male-male homicides than female-female

An earlier study found murders tended to be age related too, with males peaking in their early 20s. A02: This coincides with Testosterone production in teen males.

Daly and Wilson (1985) found that in 58 out of 214 cases of murder studied in Detroit in 1972, jealousy was the primary motive of the uxoricide.

In another sample of 80 murders where the victims were married or cohabiting, the victims were 44 husbands and 36 wives. This suggests violence is similar in both genders contradicting evolutionary theory which suggests females have more to risk by being aggressive, e.g., can’t look after their children.

Predisposing factors for murder (Daly & Wilson 1988). Nature of murder Frequency

Male offender/male victim 65.3%

Male offender/female victim 22.7%

Female offender/male victim 9.6%

Female offender/female victim2.4%

Source: FBI supplementary homicide reports 1976-2005

A02:

Daly & Wilson…..a closer look!!

The results illustrate:

1. Men alone are not restricted to murder.

2. Different reasons were given for murder by men & women.

3. Men are more likely to kill a love rival or those who threaten their dominant position (ET says because of paternal uncertainty)

4. Women are more likely to kill through self-defence e.g. murdering partner who sexually abused them.

These findings are seen as supporting the ET theory on aggression Cross-culturally, human violent aggression and homicide is far more common in males, against other males (Daly and Wilson, 1988).

Also, if homicide has evolved then we would expect all people to behave in a similar way, however 3 different people may react to the same situation in 3 different ways – e.g. one may beat his unfaithful wife, the second may murder her, and the third may just get drunk. And evolution cannot explain why some cultures require violence to attain social status, whereas in others it leads to irreparable reputational damage (Buss & Shackleford, 1997).
Wilson & Daly (1985)

A02:

It is hard to prove ET theory and male aggression. Most people would not acknowledge that according to ET we are predetermined to fight because we adapted certain behaviours that were crucial to our survival in the EEA research is difficult to conduct and mostly relies on questionnaires/interviews of suspects/perpetrators. This method would be invalid as for example, a gang member in fight is not going to realise he was fighting to obtain status necessarily. He may give another reason like revenge or a petty incident that spiralled out of control. ET explanations are post hoc, after the event has occurred so it hard to prove the reason behind aggression is linked to ancient ancestor survival behaviour and not for instance social learning theory or poverty.

We have to be cautious about defendant’s reasons for aggression as they may use stories that help them in court. They are therefore unreliable.

You can’t study this area scientifically with humans as it is unethical to orchestrate. Therefore we have to rely on retrospective data and crime statistics which do not show cause and effect.

Infidelity and Jealousy

Some back ground information in case you forgot……..Evidence from the other great Apes suggests that jealousy is a mate protection strategy designed to maintain low levels of female promiscuity. A single Silverback Gorilla can protect up to eight females as his own, and is thus able to gain a reproductive monopoly. As a result, gorillas do not have a great deal of sperm competition, and therefore have very small testes relative to stature. Humans on the other hand, have slightly larger testes relative to stature, but still have small testes compared to other apes. This suggests that humans have somewhat more sperm competition, and therefore have more reason to be suspicious of a mate’s interest in another. Jealousy likely evolved as a byproduct of this competition for mates (Jones, 2006). Please see other evidence of how unfaithful females are in your relationship booklet (e.g., misattributed paternity 1 in 10, etc.)

The evolutionary theory of sexual jealousy and aggression seeks to explain differences in jealousy between sexes from a biological/evolutionary standpoint. Responses difference in men and women because the two sexes have different needs in order to maintain fitness. For women, when a man is unfaithful in a relationship it is the emotional infidelity that is cause for concern, while for men it is physical sexual infidelity (Harris 2004). According to David Buss, this difference comes from the way men and women’s brain circuits guide their emotional reactions (Buss 1995).

Sexual jealousy and paternity uncertainty

The consensus among biologists regarding the reason for male sexual jealousy and aggression is concern over paternity confidence for existing and future offspring (Barett et al. 2002). The male partner invests paternal care (time, energy, affection, resources) in a female to ensure reproductive success, and in turn, he wants to invest parental care only in those offspring who are his own (Barett et al. 2002). While maternity is unmistakable, paternity is less certain when internal fertilization exists (Daly et al 1982) and there is concealed ovulation in females (Alexander and Noonan 1979, Strassmann 1981). A study by Gaulin and Schlegel (1980) shows that in societies where paternity confidence is low, males are much less likely to invest in their partner’s offspring, and instead they will invest in their sister’s children- a genetic relationship that is guaranteed.

Barett et al (2002) argue that sexual jealousy and aggression is a demonstration of men’s desire to control the sexual behaviour of women in order to guarantee paternity certainty- thereby ensuring they are investing in their own offspring.

Through history, the control of female sexual behaviour has been manifested in many different ways. Barett et al (2002) describes these systems as “honor and shame systems” where the “honor and prestige of a lineage is premised on the chastity of its daughters”. The intensity of these cultural codes tend to increase with social status; this supports the assumption that higher ranking males tend to have a larger investment in the paternal care of their offspring (Dickeman 1979). These cultural practices are a collection of contexts where men control female chastity and fidelity, reduce female mate choice, and promote the institutional seclusion and incapacitation of women (Dickeman 1979). Dickeman (1979) illustrates specific examples of sexual control including: the insistence that women are virgins before marriage, “modest” dress restrictions under Islamic law, foot binding and chaperoning in public in ancient China, and cliterodectomy in Sub-Saharan Africa. Each of these cases represents a cultural framework constructed to control women’s exposure to other people, mobility, or sexual behaviour - thereby helping ensure paternity certainty for husbands and potential fathers (Dickeman 1979).

Applying this theory directly to aggression
A man can never be certain that he is the father of his wife’s children unless he prevents her having relationships with other men. This can explain why male sexual jealousy is often cited as a cause of domestic violence. In many countries it is seen as acceptable to murder an adulterous wife or her lover, e.g. among the Nuer people of East Africa, a man who commits adultery is likely to be killed by his lover’s husband, and only 35 years ago in the USA a man who killed his wife’s lover while in the act would have a legal excuse for murder and be unpunished.

According to Daly & Wilson (1988), men have evolved different strategies to deter their partners from committing adultery, ranging from vigilance or direct guarding (watching their every move – e.g. asking who they talk to on the phone, stopping them going out with friends, reading texts etc.) to violence. All of these are the result of male jealousy and paternal uncertainty (being unable to be certain he is the father of her children).

Buss (1988) argues that males have developed strategies for mate retention. These include direct guarding (restricting her movements) of the female and negative inducements to prevent her straying (financial control, threat of violence if they are unfaithful or even so much as look at another man, etc).

A01 Research and A02 Commentary: Wilson et al (1995) found support for the link between sexual jealousy, mate retention and violence. In a questionnaire, women who indicated that their partners were jealous and did not like them talking to other men were twice as likely to have experienced violence from their partners (72% of these needing medical attention).

A01 Research Shackleton et al (2005) also demonstrated the link between mate retention, jealousy and violence. They surveyed 461 men and 560 women who were all in committed heterosexual relationships. The men answered questions about their use of mate retention techniques, and the women were asked about their partners’ use of mate retention techniques and how violent their male partners were. There was a positive correlation found between men who used mate retention techniques of direct guarding and negative inducements and their use of violence. Men also tended to use emotional manipulation as a mate retention technique. The women’s results confirmed this as there was also a positive correlation between those that had jealous partners and being the victims of violence.

A01 Theory: If men can prevent female infidelity by giving their partners positive benefits to stay then they are less likely to be violent, but men who are unable to provide positive benefits are more likely to become jealous and violent leading, according to Daly & Wilson (1988), to the unintended killing of the woman (uxorocide – wife killing). A02: However the unintentional nature of uxoricide is challenged by Shackleford et al (2000). They analysed 13,670 uxorocides and found that younger women were most at risk which, as the women were in their reproductive prime, presents a problem for them being unintentionally killed. A better explanation (The Evolved Homicide Module Theory; Duntley & Buss, 2005) might be that when a woman is unfaithful, not only does the man lose a partner, but another man also gains a partner. By killing his partner the man at least prevents his competitor gaining a reproductive advantage over him.

A02:

• Some critics feel that evolutionary explanations justify violence by men against women as natural and inevitable.

• The evolutionary perspective offers an explanation of how aggressive behaviour due to suspicions of infidelity may arise as a result of natural selection. An important implication of research into sexual jealousy and violence is that mate retention techniques (e.g. direct guarding and negative inducements) can be the early signs of a violent man. Educating people in these danger signs can reduce the likelihood of women becoming victims of violence.

• Determinism: Pre-disposed to be jealous and violent yet only a small proportion of males do this. Does not blame a person though. Not their fault they are jealous and aggressive. Should they be punished?

•

• This theory is very damming towards males yet if ET was accepted scientifically it may excuse males? Perpetuates gender stereotypes.

• Is EP relevant in individualistic societies? EG. Women are more equal. Paternity tests, contraception, women can look after themselves now. Moreover there is evidence that women are more sexually liberated and that males do expect virginity.

• Reductionism reduces the complexity of aggression to adaptions learnt in the EEA. Other factors? Upbringing, culture, norms. For example, psycho dynamic theories suggest aggression towards wives/girlfriends is more to with troubled upbringing and complexes with the mother.

• Psychology as a science: Murder rates stats are not scientific nor are defence pleas. Although there are many instances of man’s control of women (veiling, stoning, name calling etc. see previous discussion above and under parental investment, the research is non-scientific .Therefore caution must be applied when using such data.

• The explanation of uxoricide as being a consequence of sexual jealousy cannot account for the fact that younger women are at much greater risk of uxoricide regardless of their partner's age. The finding that men kill their wives when they're most reproductively valuable contradicts evolutionary logic. However, the evolved homicide module theory explains this by pointing out that a partner's infidelity carries a double loss for a male. He loses a partner (which damages his reproductive fitness) and another male gains his partner, increasing his own fitness.

• A problem for these evolutionary explanations of aggression is that most studies of infidelity have focus solely on men's retention strategies and violence against women. It has been argued that women practise retention strategies and carry out assaults on their partner as often as men do. This would suggest that our current understanding of mate retention strategies is limited due to this gender bias.

• Another problem with this perspective is that the social environment is constantly changing, so having flexible and behaviour that is responsive to these changes would be more adaptive than having a fixed set of behaviours. Because of this, using retention strategies and violence may not be adaptive in some cases.

• This understanding has a real-world application. The use of mate retention strategies can be seen as an early indicator of potential partner violence. It therefore has value in alerting others to intervene before actual violence against the partner can occur.

• .There are limitations to this evolutionary explanation, such as the fact that there are individual differences. This approach cannot explain why some men react differently to the same stimulus. This suggests that violence is not a universal response to sexual jealousy, and thus that it is not completely evolutionary.

• This perspective is also unable to explain why, if this is a universal human response to these situations, there are cultural differences in the importance of violence. For example, among the Yanomamo of South America, male violence is required to attain status, but among the! Kung San of the Kalahari, aggression only leads to reputational damage.
Much research makes use of questionnaires and surveys to collect data Surveys are a self-report method and therefore has inherent difficulties with collecting reliable and valid data. If a man is asked to complete a questionnaire asking how violent he is towards his partner, then it is most likely that he will distort the truth due to his desire to appear more socially desirable than he actually is (social desirability bias). Similarly, a woman may be less likely to accurately report her partner as abusive if she fears recriminations from him, or she may even choose to deny the truth about his behaviour because acknowledging it could mean the end of her relationship with him. Questionnaires and surveys may not therefore reveal the true extent and nature of male jealousy.

• Research into infidelity is gender biased
The evolutionary argument for infidelity states that it is something a man must prevent a woman from doing, and does not really acknowledge the fact that men may be just as unfaithful as women. This is heavily gender biased and does not reveal the true nature of male and female infidelity. Moreover there are instances where females do commit aggression against other females and males when they believe their partner is being unfaithful.

• Nature nurture debate
Evolutionary explanations argue that behaviour has evolved through gene selection and is therefore biological. If jealousy and uxoricide were really evolved responses to female infidelity and determined by genes, then we would expect all men to behave violently to women, but clearly they do not. There must, therefore, be an alternative explanation that takes into account the fact that men may have naturally aggressive responses to female infidelity, but that also explains why many men do not behave violently and others do. Social learning theory may account for this as violent men may have grown up with violent role models, and have learned to be violent by observing them.

A Level exam tips: Answering exam questions (PSYA3 AQA A specification)
Outline and evaluate research into sexual jealousy as a cause of human aggression (24 marks)
8 AO1 marks come from outlining the evolutionary debate in terms of men never being able to be certain that they are the father of a child, and needing to ensure that they are not subject to cuckoldry. Outline male behaviours to control women. Outline uxoricide as an accidental killing when control has gone too far. Also explain that men may kill other men because of social competition including competition for a mate.

16 /3AO2 marks come from evaluating and discussing the research. Describe studies supporting the argument that men need to control women and the sort of behaviours they use to do so. Illustrate the link between male jealousy, mate retention and violence using research studies (e.g. Shackleton et al). Discuss the alternative argument to the accidental nature of uxoricide and state why it may be an intentional act. Discuss the problem for the evolutionary argument in that not all men act the same way in the same situation. Remember to build in synoptic links including the problem with questionnaire and survey research, and the gender biased nature of research into infidelity.

Essay Example of A01: outline evolutionary explanations of elements of aggression such as infidelity and jealousy.

Aggression in men has an adaptive value. Men are more likely to experience sexual jealousy because of their fear of cuckoldry. Because men are more prone to parental uncertainty, they risk unwittingly investing resources in children who aren't their own. Sexual jealousy and the aggression which it can cause, therefore, evolved to deter females from sexual infidelity and hence minimise the risk of cuckoldry.

To do this, men have evolved retention strategies to deter mates from infidelity. This includes direct guarding, in which a male is especially vigilant to their mate in order to restrict her sexual autonomy. Retention strategies can also include violence against the woman. In extreme cases, an unintended consequence of this evolutionary behaviour may be her death (uxoricide).

Topic Six: EVOLUTIONARY EXPLANATIONS OF Group Display of Aggression in Humans (E.g., aggression in groups not as individuals): Note this topic must be answered from an evolutionary perspective:

Why do some people behave aggressively when in a group situation? In the USA between 1882 and 1968 there were an estimated 4,742 lynchings in which mobs with up to 15,000 members tortured, castrated, mutilated, dismembered, burned alive, and hanged black victims. The lynchings were often organised and advertised in advance. The ‘crimes’ committed by the victims were often as ridiculous as ‘looking for work out of place’ or ‘insulting a white man.’
Group display and War

Group displays of aggression are defined as a situation where at least three people join together for a common purpose, e.g. to be aggressive. These groups frequently see themselves as a distinct unit or in-group.

Individuals in a group behave far more aggressively than on their own

Examples of group displays of aggression:

· Mobs and crowds (especially at sporting events)

· Lynch mobs

· Criminal organizations

· Urban gangs,

· Motorcycle gangs,

· Football teams,

· Pre-state warrior societies

· Contemporary armies

· Mafia (Some forms of human violence involve an accurate assessment of the risk of injury (e.g. the Mafia are reputed to wait for a numerical advantage before they attack their victim).

Key words:

In groups: In sociology and social psychology, in-groups and out-groups are social groups to which an individual feels as though he or she belongs as a member or (for out-groups) to which they feel contempt, opposition, or a desire to compete. People tend to hold positive attitudes towards members of their own groups, a phenomenon known as in-group bias. In-groups can be formed for any reason: shared ethnicity, religion, belief, culture, school, gender, sexual persuasion, location, nationality, political organisation (ANYHING pretty much). Sometimes members are not consciously aware they are even part of in-groups. Tribes are a good way to describe in-groups and out-groups even though we often think of tribes as being primitive they very much apply to in-groups and out-groups too.

Xenophobia: Xenophobia is defined as the "hatred or fear of foreigners or strangers or of their politics or culture" It comes from the Greek words ξένος (xenos), meaning "stranger," "foreigner" and φόβος (phobos), meaning "fear." Examples are: An in-group towards an out-group, including a fear of losing identity, suspicion of its activities, aggression, and desire to eliminate its presence to secure a presumed purity. ".• Wilson (1975) - Xenophobia appears in ‘virtually every group of animals displaying higher forms of social organisation.’

• Natural selection - favoured genes that caused greater altruism to members of their own group, but intolerant of outsiders.

• Shaw and Wong (1989) - suspicion of other groups advantageous - avoid attack - more offspring survive

• Mac Donald (1992)- adaptive to exaggerate negative stereotypes about outsiders - overperception of threat less costly

Belligerence: A belligerent is an individual, group, country or other entity which acts in a hostile manner, such as engaging in combat. Belligerent comes from Latin, literally meaning "to wage war". Unlike the colloquial use of belligerent to mean aggressive, its formal use does not necessarily imply that the belligerent country is an aggressor.

Rebecca Sylvia

I am a Londoner with over 30 years of experience teaching psychology at A-Level, IB, and undergraduate levels. Throughout my career, I’ve taught in more than 40 establishments across the UK and internationally, including Spain, Lithuania, and Cyprus. My teaching has been consistently recognised for its high success rates, and I’ve also worked as a consultant in education, supporting institutions in delivering exceptional psychology programmes.

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