AGGRESSION AS AN ADAPTIVE RESPONSE
To read up on aggression as an adaptive response, refer to pages 177–187 of Eysenck’s
A2 Level Psychology.
Ask yourself
 Is it “natural” for men to be aggressive in their pursuit of sexual partners?
 Does jealousy take different forms in men and women?
 Why are football crowds sometimes very violent but crowds watching other
team sports are not?
What you need to know
EVOLUTIONARY
EXPLANATIONS OF
HUMAN AGGRESSION
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Infidelity and
jealousy
Rape
GROUP DISPLAY IN
HUMANS
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Warrior displays
Football findings
LYNCH MOBS
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Explanations
Findings
Evolutionary Explanations of Human Aggression
Evolutionary explanations of behaviour focus on the fact that all species have
evolved behaviour that best enables them to pass on their genes. Obviously it is
necessary to survive in order to pass on genes so species have evolved behaviour
that increases survival chances, but it is the passing on of genes that is the main
force in shaping behaviour. We will now consider how aggressive behaviour may
have evolved in order to help humans to do this.
Infidelity and Jealousy
Obviously the passing on of genes involves having children. For human females this
is biologically a costly business involving 9 months of pregnancy, breast-feeding,
and prolonged care if the child is to survive. Males invest far less—a few easily
replaced sperm. The mating strategies for females and males, so the theory goes, are
therefore likely to be very different. Females need to choose their mate very
carefully since they do not want to waste valuable resources raising children with
poor quality genes. They therefore need to be fussy and coy in order to attract a
mate who will care for them whilst they are pregnant and raising the child.
Aggressive behaviour is not particularly useful to them in the selection of a mate:
they do not need to compete; it is the females who do the choosing.
The situation for males is very different. It is in their interest (in terms of evolution)
to mate with as many females as possible. However, since females are fussy, they
have to compete to be chosen by her and aggression may be part of this. Certainly, in
some mammals, males fight for the right to mate with females. In human society it is
a little more complex but females may well favour males who show that they are
strong and capable of defeating others, since, in evolutionary terms, this means they
will provide her child with good quality genes. So this may account for why males
are generally more aggressive than females.
Evolution can also account for feelings of jealousy but the precise form that this
jealousy takes is different for males and females. Females are certain that they are
the mother of a child and therefore they are not at risk of wasting valuable
resources in raising children who are not their own. Males, on the other hand, have
no such certainty and could, if they are not careful, spend their resources raising
children who are not biologically theirs. Bearing this in mind, the form that jealousy
takes in males and females is likely to be different. Men are likely to be jealous of
women being unfaithful to them. This helps to account for some aggressive
behaviour in men both towards their partner (if they think she might be unfaithful)
and towards any potential rivals. A woman, on the other hand, needs a man to be
committed to her in order that she has the necessary resources to raise her children.
She is more likely to be jealous of any emotional feelings he has towards other
women as this presents a danger that he will leave her for another woman. This may
lead her to show aggression towards any women whom she perceives as being a
rival for her partner’s affections. The theory argues that she will not be as concerned
with her partner having sex with another woman just as long as he remains with her
and devotes his resources to her.
Evaluation
 Evolutionary explanations are post hoc and therefore lack scientific
validity. Since there is no way of researching our evolutionary past the
explanations of human social behaviour are post hoc (made up after the
event). Although evolution is a fact, the way in which it shapes behaviour is
not at all clear and is based on speculation. Since the explanations cannot be
verified or falsified, they do not fulfil Popper’s key criteria of what constitutes
a science. On this basis the explanations lack scientific validity.
 Reductionist and deterministic. Evolutionary theories are reductionist as
they focus on one factor only (the gene) when other emotional, social,
cognitive, behavioural, and developmental factors are highly relevant to
jealousy and the tendency to be unfaithful. The evolutionary explanations are
oversimplified accounts at best. They are also deterministic as they suggest
that the genes control behaviour, which ignores the free will of the
individual.
 Some of the explanation is plausible. The suggestion that female jealousy
and aggression towards rivals may deter other women from poaching their
partner appears to be a reasonable assumption.
 Specific aggression will be determined by social norms. Nevertheless, the
way in which jealousy is translated into aggressive action depends on the
norms of the particular society.
 Some of the explanation is not plausible. A female directing aggression
towards her partner if she thinks he has been, or is tempted to be, unfaithful
may drive him away and is therefore not an adaptive response.
Rape
Rape is an aggressive behaviour that involves sex with an unwilling partner. We will
consider two evolutionary hypotheses to account for rape.
Mate deprivation hypothesis. This hypothesis states that rape is perpetuated by
males who cannot otherwise obtain a sexual partner and is a last ditch attempt to
pass on their genes. This hypothesis suggests that men who resort to rape are likely
to be unmarried men who have few resources and have been unsuccessful in
attracting a mate. They are also jealous of successful males. The rape victim would
be of child-bearing age and healthy.
Maladaptive version of male sexuality. According to evolutionary theory, males
are easily aroused and are prepared to have impersonal sex (because this is the best
strategy for passing on their genes). They compete for females and use strategies to
persuade them to have sex. The hypothesis based on rape being a maladaptive
response suggests that some men who have an unusually strong sex drive use rape
as a means of obtaining a partner and that this behaviour is simply an extreme
version of normal male sexual behaviour. Unlike mate deprivation hypothesis, this
hypothesis suggests that rapists come from all socio-economic groups. They would
not be suffering from jealousy and may be partnered. The rape victim would have
the same characteristics as in the mate deprivation hypothesis—healthy and of
child-bearing age.
RESEARCH EVIDENCE
 Alcock (1993, see A2 Level Psychology pages 179–180) analysed rape victim
data and found that the majority of victims were of child-bearing age, as
predicted by both hypotheses.
 Myhill and Allen (2002, see A2 Level Psychology page 180) found that far
more rape victims were aged between 16–19 years than over the age of 45
years. Although this supports the view that rape victims are of child-bearing
age, the fact that some rape victims were post-menopausal does not support
evolutionary theory.
EVALUATION
 Supporting evidence. There is evidence that men from low socio-economic
groups commit disproportionately more rapes than those from higher socioeconomic groups. However, it is possible that fewer rapes by high status men
are reported. Rape victims very often do not report rapes and they may
consider that, for various reasons, a conviction is less likely to be secured
against a respectable, professional man.
 Contradictory evidence. Myhill and Allen (2002) also found that the
majority of rape victims were from low socio-economic groups. This
contradicts evolutionary theory since males should seek a mate who has
good resources for rearing their child.
Characteristics of rape victim do not fit the hypotheses. As mentioned
earlier, the fact that women past child-bearing age are sometimes rape
victims does not fit with either of the two hypotheses.
 Alternative hypothesis. The psychodynamic approach offers an alternative
theory: that rape represents hostility towards women in general and is not
motivated, either on a conscious or unconscious level, by the desire to
reproduce. Rather the behaviour results from childhood experiences of
inconsistent or inadequate mothering and the consequent use of such
defence mechanisms such as denial, displacement, and projection. There is
certainly evidence that rape is motivated more by aggression than by a desire
to have children.
GROUP DISPLAY IN HUMANS
“Group display” refers to displays of aggressive behaviour by groups that are
gathered together for the specific purpose of behaving aggressively.

Warrior Displays
Military marches are a prominent display of might and prowess. They serve as a
warning to any other groups that may be considering an attack as well as a
reassurance to the home nation that it is well protected.
Aggression in Sports Crowds, Including Football Crowd Aggression
Research on 26 of the 119 football programs in the top division of USA for 2004–
2005 showed a substantial increase in aggressive acts in the host team’s community,
especially if the result was unexpected.
RESEARCH EVIDENCE
 Phillips (1986, see A2 Level Psychology page 182) observed behaviour in the
three days following championship boxing matches. He observed a
significant increase in homicide rates during that time.
 Widmeyer and McGuire’s (1997, see A2 Level Psychology page 182)
observations found rather different behaviour. They observed behaviour
during 800 hockey matches and believe that most aggression is more of a
display than actual contact. They only found increased aggression among
teams that met frequently.
 Marsh, Rosser, and Harré (1978, see A2 Level Psychology pages 182–183)
argue that actual contact aggression during football matches is not the norm.
Their view is supported by police records and participant observation so it is
quite robust.
 There is evidence, however, that a small minority of football “fans” are no
such thing—they are people who gather together for the specific purpose of
being aggressive. They include middle-class people, respectable in everyday
life, who gather themselves together in a group known as a “Firm” in order to
meticulously plan fights at matches at which they anticipate there will be
violence between the home and away teams. Members talk of the thrill and
addictive nature of the violence.
EXPLANATIONS
 Social learning theory argues that this violence may be caused by imitation of
role models, of the footballers themselves, or players seen in the media.
These role models fulfil several of the criteria that increase the likelihood of
them being imitated: they have high status, are perceived as successful, and
are greatly admired.
 The frustration–aggression hypothesis could explain violence following an
unexpected loss by one team.
 Aggression is simply a display and does not include much actual aggression.
Sport (notably football) attracts individuals who are not fans but who seek
out an opportunity for violence.
EVALUATION
 Social learning theory. There is evidence that violence increases on game
days that involve football, boxing, and North American hockey games but not
other sports such as rugby games in the UK. The lack of coherence casts
doubts on the validity of social learning theory as an explanation here unless
it could be shown that the players in some sports are perceived as more
successful and admired role models than players in other sports. However,
it’s quite possible that it is the social norm rather than the role models that
are influencing behaviour. So, for example, it may be the social norm to be
aggressive at a football match but not at a cricket match.
 The frustration–aggression explanation. This states that when people are
frustrated they become aggressive. This could explain the reaction of
supporters if their team unexpectedly lost, especially if the winning team’s
supporters taunted them. Aggression could also help restore some selfesteem.
 Aggression is a display rather than actual violence. There is evidence that
much aggression involves loud chants, abusive language, and rude gestures.
Whereas these count as aggression, they do not constitute actual violence.
They signify strength and the ability to humiliate but do not involve contact
aggression. Haley (2001, see A2 Level Psychology page 184) and several
official reports argue that actual violence is exaggerated, often by the media.
Ritualised aggression is just that, a display of aggression that involves all
manner of threats but is carefully orchestrated and never intended to involve
actual harm.
 Sport attracts violent individuals. Research on “Firms” supports this idea.
However, the studies just recounted in the last explanation contradict it.
They show that, in many cases, there is little violence. In addition, “Firms”
only account for a very small minority of football fans.
Lynch mobs
A lynch mob is a collection of people who intend to take a person in order to kill
them (sometimes in a tortuous manner) without recourse to legal action. There
have been many dreadful accounts of these lynchings, which are often associated
with racism in the Southern States of the US but occur in other parts of the world.
There are several explanations of lynching as follows. The first two are social
psychological theories, the third one is psychodynamic:
 The Sociological Power Threat Hypothesis: This argues that minority groups
are perceived as a threat to the economic wellbeing of the majority and are
blamed for any misfortunes. Lynchings are one way of retaliating.
 The Psychological Self-Attention Theory suggests the larger the number of
hostile and angry people who gather when something bad happens, the
greater the likelihood of a lynching atrocity.
 Lightweiss-Goff (2007, see A2 Level Psychology page 184) offers a
psychodynamic explanation of lynchings, which are viewed as the result of
sublimated aggression. Sublimation is a defence mechanism that involves the
redirection of innate impulses into a learned response, one that is usually
socially acceptable (though only acceptable to a small minority in this case).
With respect to lynching, it allows pent-up innate aggression from thanatos
to be released onto the victim of the lynching.
 A United Nations report on lynchings in Guatamala blamed their previous
human rights violations and poverty.
RESEARCH EVIDENCE
 Leader, Mullen, and Abrams (2007) have analysed data from US lynchings
and found that there is a positive correlation between numbers of African–
Americans in the country and number of lynchings. This supports the
frustration–aggression hypothesis in general and specifically Sociological
Power Threat Hypothesis. Other factors to consider are that large crowds can
produce crowd deindividuation and the fact that victims are black may result
in dehumanisation of them by a white lynch mob.
EVALUATION
 Contradictory evidence for United Nations view. Mendoza (2006, see A2
Level Psychology page 185) reported that lynchings were not related to
poverty and only very loosely related to human rights violations. However,
the lack of legal services did have a relationship. This may indicate that
frustration at not being able to access legal procedures may be a contributory
factor.
 Further support for the frustration–aggression hypothesis. Contrary to
the findings above in respect to poverty, Hovland and Sears (1940, see A2
Level Psychology page 185) did find that lynchings were positively correlated
with poverty in cotton-growing areas of the United States. The frustration
resulting from poverty may trigger lynchings with the victim acting as a
scapegoat.
 Lack of empirical evidence for psychodynamic view. The idea that
aggression involved in lynchings is caused by the release of pent-up
aggression in which the ego collapses and liberates the id is not one that can
be empirically verified. Like all psychodynamic perspectives, it involves
hypothetical constructs and ideas that cannot be verified or refuted.
SO WHAT DOES THIS MEAN?
One way of considering aggression is to view it as a response that helps people (and
non-human animals) adapt to their environment and pass on their genes. It is likely
that behaviour as well as bodies have evolved to best adapt to their particular
ecological niche but once an attempt is made to explain all behaviour in this way, it
becomes highly speculative. It is quite possible, with the benefit of hindsight, to
explain almost any behaviour (including non-aggression) in a way that fits the
evolutionary model but these explanations lack scientific validity as they have no
empirical evidence to back them and no predictive power. In terms of how science
works, they are not scientific.
Human behaviour is complex and shaped by experience. It is moulded by learning,
social norms and, according to the psychodynamic approach, by unconscious
motivation. We need to take account of all of these explanations if we are to account
for all types of aggression. The variety of aggressive response is so broad, including
ritual displays of aggression, that it is unlikely that a single approach can explain it
all and multi-perspective is necessary.
OVER TO YOU
1. Describe and evaluate the evolutionary explanation for aggressive behaviour. (25
marks)