The Biological Perspective:
Aggression and Free Will
Learning Objectives
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Objectives
Identify some issues with explaining aggressive
behaviour in a purely biological way
Differentiate between the social psychological
theories of aggression and the biological
perspective
Describe the main assumptions of the biological
perspective
Outline some of the biological factors that may be
involved in aggressive behaviour
Discuss the issue of free will in relation to biological
perspectives on aggression
Is Aggression Part of Human
Nature?
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Since the end of World War II there have been
about 30 days on which a war was not taking place
somewhere on the planet.
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Other animals with which we share a common
ancestry, such as chimpanzees, have also been
observed to engage in intergroup aggression that
looks a great deal like warfare.
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we talk about ourselves as if we had the capacity to
choose our actions: free will.
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Free Will, Moral Responsibility
and Psychology
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actus reus – the guilty act
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mens rea – the guilty mind.
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In other words, in law, moral
responsibility is generally predicated
on intent.
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most psychological perspectives deny the existence
of free will
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behaviourists believe that our behaviour is
determined by our conditioning and history of
reinforcement.
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Freudians believe that our behaviour is determined
by unconscious processes.
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The biological approach is deterministic in a similar
way.
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Genetics and the possibility that certain behavioural
tendencies are inherited.
The nervous system, and the way that certain behaviours are
linked to the functioning of particular parts of the brain.
Chemical influences, and the way that substances such as
neurotransmitters and hormones (and their analogues, drugs
and toxins) can alter the functioning of the brain.
What these have in common is that they are governed by
physical processes that follow the laws of physics.
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This type of deterministic and reductionist
view precludes the idea of choice or agency
and, consequently, makes the idea of moral
responsibility irrelevant.
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However society as a whole (psychologists
included) carry on as if people do make
choices about their actions and can be held
responsible for the consequences
However!!
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there are circumstances where we
(and the law) accept that biological
processes have overridden ‘free will’,
and that a person should not be held
liable for the consequences of their
actions.
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Case 1 – Dawn
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Discussion question: what
immediate assumptions might we
make about Dawn’s behaviour? If
Dawn had stabbed her husband,
would we hold her responsible?
Dawn contintued
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Dawn is diabetic. Under some circumstances, her
blood-glucose level can drop dangerously low, and
she becomes hypoglycaemic.
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Dawn’s blood-glucose level drops, her cerebral
cortex, the part of the brain responsible for
planning, reasoning and ‘rational’ behaviour starts
to shut down. However, her limbic system, a more
primitive part of the brain involved with responding
to threats and aggressive behaviour, carries on
functioning. Its aggressive impulses can no longer
be controlled by the cerebral cortex.
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Cases 2 and 3 – Arthur and Colin
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Discussion question: if someone
claims to have committed a criminal
act, such as homicide, whilst
asleep, is it our first instinct to
believe them? How could we test
their claim?
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Frontal cortex (thinking, planning, rational
behaviour) is inhibited whilst the person
sleeps.
At times, sensory and motor cortex (areas
associated with movement and sensation)
are highly stimulated, leading to the
experience of dreaming.
The limbic system (emotion) is often
activated whilst we dream.
The pons paralyses us to stop us from
acting out our dreams.
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Psychologists who examined both Arthur and Colin
agreed that both were suffering from sleep
disorders. In Arthur’s case, he suffers from night
terrors. In this disorder, people tend to have very
strong negative emotions whilst asleep, on which
they are inclined to act.
They may lash out in their sleep and are sometimes
violent, but often have no recollection of this when
they wake up. In Colin’s case, it was decided that
he was suffering from REM behaviour disorder.
This is rarer and often more dangerous than night
terrors.
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A Patient came to a local sleep laboratory because he was keeping
his family awake all night with shouting and acting out his dreams.
His wife was forced to sleep in a different room not only so she could
get some sleep, but also because she feared for her own safety. The
patient managed to fall out of bed on a nightly basis, often injuring
himself in the process. He was a war veteran and would often dream
he was trying to avoid enemy attack. Thinking that it would help, he
purchased a hospital bed with railings. Still he managed to climb out
over top of the railings and fall to the floor. The patient then had to
resort to sleeping on a mattress on the floor. When he was monitored
in the sleep lab during overnight testing, and he entered REM sleep,
muscle tone activity was detected when it should have been absent.
Talking, laughing, shouting, flailing of the arms and kicking of the legs
were all observed. He nearly fell head first out of the bed on several
occasions. The patient has been prescribed a medication which will
make his muscles relax during REM sleep so that he will no longer
act out his dreams. To update, the patient is now doing fine and is
sleeping in his own bed again. (Orr, 2003)
Case 4 – David
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Discussion question: how significant
is it that David was reported to be
acting ‘out of character’ in the days
immediately prior to the murder?
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At his trial, David’s defence argued
that his behaviour had not been under
his control. Shortly before his
behaviour changed, David had
accidentally been exposed to a high
concentration of an organophosphate
pesticide called carbaryl.
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Case 5 – Sandie
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Discussion question: do we view
violent women differently to violent
men?
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Whilst examining her history when preparing her
defence, her defence team noticed that her violent
outbursts seemed to occur at regular monthly
intervals.
Discussion question: psychologists are divided on
the question of whether pre-menstrual syndrome is
a useful construct. Apart from the ambiguous nature
of some of the evidence, some have argued that it
paints a picture of women as ‘inherently
pathological entities’ who are slaves to their biology.
What do you think of this view
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Your task
Aggression is an area where the theories which have been put
forward form a nature - nurture debate. Some theorists think
that aggression is something which we all have, instinctively,
and which we need to release; while others consider it as
something which arises as a result of environmental
circumstances. Based on your understanding of the topic so
far, complete the task below:
Write a 300 word discussion on how aggression can be seen
as a product of both ‘nature’ and ‘nurture’. There may well be
sections in your text book to help you.
Lesson Objective
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Describe and evaluate how neural
(e.g. neurotransmitters) and hormonal
(e.g. testosterone) ‘mechanisms’
influence aggressive behaviour.
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The role of testosterone (hormonal)
This focuses on biochemical
influences on aggressive behaviour.
Testosterone has been shown to be
correlated with outward displays of
human and non-human animal
aggression
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Nelson (1995) reviewed research into
how hormones influence aggressive
behaviour.
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Activity: Why has much of the
research on hormonal influences on
aggressive behaviour been done on
animals?
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During puberty aggression increases
when androgen levels are higher
(especially in males). Animal research
further supports these conclusions.
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Wagner et al (1979) show that if a male
mouse is castrated, overall levels of
aggression tend to reduce. If the castrated
mouse receives testosterone aggression
levels increase.
Activity: Give 2 problems with this
research:
1.
2.
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Simpson (2001) argues that
‘testosterone is only one of a myriad of
factors that influence aggression and
the effects of environmental stimuli
have at times been found to correlate
more strongly’.
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This ignores the potential for individual
difference. Harisson et al (2000)
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Testosterone does have a role to play
in this complex formula of human
aggression. Huston et al (2007)
The Basal Model of Testosterone is
a model which suggests that an
individual’s level of testosterone
influences their level of dominance.
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Mazur and Booth (1998) who, after
reviewing a number of studies in this
field, concluded that men with higher
levels of testosterone ‘are more likely
to divorce, or remain single, be
arrested for offences other than traffic
violations; to buy or sell stolen
property; to incur debts; and to use
weapons in fights’.
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. The Reciprocal Model of
Testosterone, suggests that
testosterone levels vary with the
person’s dominance. The level of
testosterone is the effect of, and not
the cause of, the dominance.
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Q// how might testosterone exert its
hormonal and behavioural effects?
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There are three possible explanations
for the testosterone-aggression
relationship:
Testosterone causes aggression.
Aggression increases testosterone
secretion.
Neither has an effect on the other.
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So, it is the aggressive behaviour
which appears to drive the
testosterone levels, not the other way
round (i.e. behaviour-regulating
hormone hypothesis).
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Kleinesmith et al (2006) showed how
testosterone levels change as a result of
behaving aggressively.
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. There were two conditions:
Half the Pp had to dismantle and
reassemble a pellet gun, which looked like a
Desert Automatic handgun.
The other half were given the board game
Mouse Trap to assemble.
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The conclusion from this study was that
environmental stimuli such as guns may increase
aggressiveness partially via increases in the
hormone testosterone.
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Activity: Give two strengths and two
weaknesses s of this study:
1.
2.
3.
4.
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Another fascinating argument involves
the ‘middle-ranking monkey’ study.
Sapolsky (1997)
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It seems that testosterone doesn’t
cause aggression, but it may
exaggerate the aggression that is
already there as a result of other
factors.
Role of serotonin (neural)
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Serotonin is a neurotransmitter and
research suggests that this chemical
influences aggressive and violent behaviour.
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Davidson et al (2000) suggested that
serotonin may provide an inhibitory function
so that when comparing violent criminals to
non-violent ones, the levels of serotonin
found in violent criminals were markedly
lower.
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Serotonin has effects all over the body.
It would seem that ‘low levels of
serotonin in the brain can result in
impulsive behaviour, aggression,
overeating , depression, alcohol abuse
and violent suicide’ (Lenard, 2008).
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Linnoila and Virkkunen (1992) who
reported that low levels of serotonin
are linked to ‘impulsivity and explosive
acts of violence’. In some clinical trials,
tryptophan and Desyrel 5HTP (a
serotonergic drug) has been given to
juvenile delinquents to reduce their
aggressive tendencies (Morand et al,
1983).
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Caution must still be used before
attributing the cause of aggression to
serotonin levels.
Brain structure and
aggression
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Certain areas of the brain are
associated with aggression. In
particular, the hypothalamus and
amygdale
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the 1960s, Flynn found that
stimulating the lateral hypothalamus in
cats made them more likely to show
‘predatorial aggression, but when the
medial hypothalamus was stimulated
‘vicious attack behaviour’ was more
likely.
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Amongst humans, if an
amygdalectomy (removal of the
amygdala) is carried out, it reduces
violent behaviour but at the cost of
losing emotion!
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Activity: Use the your text books and the
internet to investigate what happened to
Phineas Gage and write in your own
words:
1. What happened to Phineas Gage?
2. Critically evaluate whether this case
study provided support for the argument
that brain structure influences
aggression (make sure you explain your
answer).
The role of genetics in
aggression
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While most people have 46
chromosomes (23 from each parent), it
is possible for a male to have an extra
Y chromosome, making them XYY.
This XYY genotype has in the past
been correlated with aggression
(Court-Brown, 1965-67).
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The evidence to date does not
conclusively show that this XYY
variation does cause increased
aggressiveness in males.
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According to Sapolsky (1997), genes are
the ‘hand behind the scenes’, directing
testosterone actions.
1. Genes determine how much testosterone
or oestrogen is produced and how quickly it
circulates around the body.
2. Genes determine the synthesis of
testosterone receptors, and how many and
how sensitive such receptors are.
3. Genes control our behaviour via the
messenger testosterone.
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Scientists became interested in a gene called
monoamine oxidase A (MAOA) when they
discovered by chance in 1995 that mice that lacked
it suffered serious anger management problems.
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The same gene had previously been implicated in
human aggression when it was found that members
of a Dutch family whose men suffered from
excessive bouts of aggression carried a rare MAOA
gene mutation (Cases et al, 1995).
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One way to study the possible genetic
influence on aggression is to use twin
studies.
Berkowitz (1993) reports that studies in the
1930s using these methods found an
average concordance rate of 75% for MZ
twins and 24% for DZ twins. This suggests
that genetics do influence crime rates,
including aggression but does not rule out
environmental factors.
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A useful way to determine the role of
genetics in aggression and rule out
environmental factors is Adoption
studies.
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Mednick et al (1984) followed some 14,000 adoptees and
found:
that the boys with no criminal parents, either adoptive or
biological, had a baseline rate of criminal conviction of 14%.
If the adoptive but not the biological parents were criminals,
boys still had a conviction rate of only 15%.
If the biological but not the adoptive parents were criminal, the
rate increased to 20%
If both the adoptive and biological parent were criminal, the
rate increased to 25%.
This study does seem to suggest then that aggression is likely
to be biologically determined.
The Evolutionary Approach
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Objectives
Define natural selection
Demonstrate links between natural selection
and human aggression
Describe how jealousy and threat of
infidelity can lead to aggressive behaviour
Evaluate the evidence that human
aggression is the result of evolutionary
pressures
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This approach suggests that
aggression serves an important
function in terms of both individual
survival as well as procreation
potential.
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Aggression is advantageous at both
the individual and genetic levels.
Newman et al (2005)
Aggressive behaviour by
animals
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Animals do not necessarily try and kill
other animals in their fights; their aim
is to get the attacker to back down or
submit, and they will only use physical
force if necessary.
Lorenz (1966)
Main Drivers
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Fear
Reproduction
Hunger
Aggression
Lorenz’s Functions
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It would ensure that only the strongest
and fittest were selected.
It would ensure survival of the young.
It would help to distribute a species in
a balanced was as animals would
have their own territories.
ritualised behaviour
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Threat displays.
Appeasement gestures.
Aggressive behaviour in
humans
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Freud believed we all possess a
powerful ‘death wish’ (thanatos), which
is directed outward towards others in
the form of aggression.
Fromm (1973)
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Benign Aggression
Parent defending child from attacker.
Child kicks older sibling.
Malignant Aggression
Gang Warfare
Ethnic cleansing in Serbia
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Tinbergen (1968)
Activity:
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In pairs think of three examples of
human aggression in the news
which was ultimately rooted in a
desire to harm another:
1.
2.
3.
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The evolutionary perspective suggests that
aggression is the result of sexual
competition.
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A related view suggests that aggression
springs mainly from an inherited fighting
instinct that human beings share with other
species (Lorenz, 1966).
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However, Buss (1999) as reminded us
that we must not assume all
aggression in humans involves males.
Evolutionary explanations of
Infidelity
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Q// what is infidelity?
A// the process of being unfaithful with your
partner, which ultimately includes having
sexual relationships with someone other
than your partner.
Buss et al (1992) argue that this would
naturally lead to the showing of behaviours
that would reduce and eliminate the threat.
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Evolutionary psychology suggests that
infidelity triggers different responses in
males and females.
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Brunk et al (1996)
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It is clear that infidelity and subsequent
jealousy both contribute to aggressive
actions.
Evolutionary explanations of
Jealousy
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According to Cascardi et al (1995),
when Pp of studies are asked to
explain the causes of the aggression in
the relationship, jealousy is the most
commonly attributed cause.
reinforced by Canary et al (1998),
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However, it may be that some violent
males lack effective ways of mediating
and responding to situations of
jealousy, compared to non-violent
males (Holtzworth et al, 1991).
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study by Haden and Hojjat (2006)
focusing on the aggressive
responsiveness in situations of partner
rivalry.
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Morenz and Lane (1996) observed
that ‘murder suicides’
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Evolutionary theory explains jealousy
as the desire to keep one’s mate.
Males have a tendency to show male
tending and guarding activities
including the showing of aggressive
activities to avoid sexual infidelity,
whereas females display such
behaviour less frequently.
Group display of aggression
in humans
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Group display in this context refers to
displays of aggressive behaviours by
groups, which are sometimes
described as three or more people
gathered for a common purpose. In
this case, for an aggressive purpose.
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Contagion theory
Le Bon (1896) argues that the
atmosphere of the group causes
contagion and ‘group members fall
under the influence of a collective
mind’.
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Deindividuation theory
According to this theory, we sometimes
lose a sense of our identity by being in
a large group, or crowd, such as a
mob or army (i.e. deindividuation).
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Convergence theory
This theory suggested that the
behaviour of a group is a result of likeminded individuals coming together
(convergence).
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Emergent-norm theory
Turner and Killian (1957) argued that
crowd behaviour as such is ‘normless’.
So where an individual has no norms
to follow, as the situation is unique,
they look to see what other people are
doing and base their behaviour on
that.
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Essentially, this view dictates that
crowds are not a passive group of
people- in fact, they are a logically
thinking mass of individuals.
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They argue that crowd behaviour is neither
irrational nor entirely predictable. Groups of
similar people gather together for some
collective purpose (say, to cheer on their
respective team), but this may change
during the course of the match day and
specific factors (e.g. referees decision or
policing the crowd) may alter the norms
within the crowd.
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Group behaviour involves normgoverned behaviour which is rational.
Such groups processes are governed
by NSI- that is people act in a
compliant way, motivated by seeking
approval and avoiding punishment of
the group.
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Evaluation
+ve This theory is useful in that it
appears to combine both the
Convergence and Contagion theory as
one. It suggests that group behaviour
is a combination of like-minded
individuals, anonymity, and shared
emotion that leads to group behaviour.
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-ve However, this theory has been
criticised for the idea that certain
distinctive individuals shape the
group’s norms and instead of crowd
behaviour being explained in terms of
the personalities of all the participants
it is tied to the personality of a
dominant few.
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Social Identity theory (SIT)
Reicher (1987) argued that group behaviour
involves inter-group (between different
groups of people) behaviour, such as
opposing sports fans, confrontations with
the police etc. Reicher believed that even in
the absence of direct confrontation there is
often a symbolic confrontation between the
group and some other group or agency.
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SIT propose that norms form within groups
due to the relationship they have to an
outgroup (people who are not members of
the group). Groups have existing norms for
outgroup members and inductive inferences
from the behaviour of other ingroup
members (key members may start throwing
bottles, which may be taken as normative
behaviour in that instance).
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Evaluation
This theory can certainly explain how
people change their behaviour
according to group membership and
the situation they find themselves
confronted with. It can also explain
how the same groups can behave
differently in different situations.
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Evaluation of explanations of group
displays in humans
Operationalisation of group
behaviour- There is no agreed
definition for what constitutes a group
display.
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Retrospective explanations- The
explanations of group display in
humans typically involve looking back
at past events and explaining them
using a particular or theory.
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Activity: Using one or more of the above
theories on group displays in humans explain
the following specific examples:
1. Booing responses to a referee’s decision in a
football match.
2. Standing up of all spectators when the
national anthem is played in a rugby match.
3. Chanting a players name in a tennis match.
4. Rioting following a football match.
5. Lynchings of black people by Klu Klux Klan
members.