The Biological Perspective: Aggression and Free Will

Learning Objectives

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?

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.

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.

we talk about ourselves as if we had the capacity to choose our actions: free will.

Free Will, Moral Responsibility and Psychology

actus reus – the guilty act

mens rea – the guilty mind.

In other words, in law, moral responsibility is generally predicated on intent.

most psychological perspectives deny the existence of free will

behaviourists believe that our behaviour is determined by our conditioning and history of reinforcement.

Freudians believe that our behaviour is determined by unconscious processes.

The biological approach is deterministic in a similar way.

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.

This type of deterministic and reductionist view precludes the idea of choice or agency and, consequently, makes the idea of moral responsibility irrelevant.

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!!

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.

Case 1 – Dawn

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

Dawn is diabetic. Under some circumstances, her blood-glucose level can drop dangerously low, and she becomes hypoglycaemic.

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.

Cases 2 and 3 – Arthur and Colin

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?

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.

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.

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

Discussion question: how significant is it that David was reported to be acting ‘out of character’ in the days immediately prior to the murder?

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.

Case 5 – Sandie

Discussion question: do we view violent women differently to violent men?

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

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

Describe and evaluate how neural (e.g. neurotransmitters) and hormonal (e.g. testosterone) ‘mechanisms’ influence aggressive behaviour.

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

Nelson (1995) reviewed research into how hormones influence aggressive behaviour.

Activity: Why has much of the research on hormonal influences on aggressive behaviour been done on animals?

During puberty aggression increases when androgen levels are higher (especially in males). Animal research further supports these conclusions.

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.

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’.

This ignores the potential for individual difference. Harisson et al (2000)

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.

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’.

. 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.

Q// how might testosterone exert its hormonal and behavioural effects?

There are three possible explanations for the testosterone-aggression relationship:

Testosterone causes aggression. Aggression increases testosterone

secretion. Neither has an effect on the other.

So, it is the aggressive behaviour which appears to drive the testosterone levels, not the other way round (i.e. behaviour-regulating hormone hypothesis).

Kleinesmith et al (2006) showed how testosterone levels change as a result of behaving aggressively.

. 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.

The conclusion from this study was that environmental stimuli such as guns may increase aggressiveness partially via increases in the hormone testosterone.

Activity: Give two strengths and two weaknesses s of this study:

1. 2. 3. 4.

Another fascinating argument involves the ‘middle-ranking monkey’ study. Sapolsky (1997)

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)

Serotonin is a neurotransmitter and research suggests that this chemical influences aggressive and violent behaviour.

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.

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).

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).

Caution must still be used before attributing the cause of aggression to serotonin levels.

Brain structure and aggression

Certain areas of the brain are associated with aggression. In particular, the hypothalamus and amygdale

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.

Amongst humans, if an amygdalectomy (removal of the amygdala) is carried out, it reduces violent behaviour but at the cost of losing emotion!

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

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).

The evidence to date does not conclusively show that this XYY variation does cause increased aggressiveness in males.

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.

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.

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).

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.

A useful way to determine the role of genetics in aggression and rule out environmental factors is Adoption studies.

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

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

This approach suggests that aggression serves an important function in terms of both individual survival as well as procreation potential.

Aggression is advantageous at both the individual and genetic levels.

Newman et al (2005)

Aggressive behaviour by animals

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

Fear Reproduction Hunger Aggression

Lorenz’s Functions

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

Threat displays. Appeasement gestures.

Aggressive behaviour in humans

Freud believed we all possess a powerful ‘death wish’ (thanatos), which is directed outward towards others in the form of aggression.

Fromm (1973)

Benign Aggression Parent defending child from attacker.

Child kicks older sibling.

Malignant Aggression Gang Warfare Ethnic cleansing in Serbia

Tinbergen (1968)

Activity:

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.

The evolutionary perspective suggests that aggression is the result of sexual competition.

A related view suggests that aggression springs mainly from an inherited fighting instinct that human beings share with other species (Lorenz, 1966).

However, Buss (1999) as reminded us that we must not assume all aggression in humans involves males.

Evolutionary explanations of Infidelity

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.

Evolutionary psychology suggests that infidelity triggers different responses in males and females.

Brunk et al (1996)

It is clear that infidelity and subsequent jealousy both contribute to aggressive actions.

Evolutionary explanations of Jealousy

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),

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).

study by Haden and Hojjat (2006) focusing on the aggressive responsiveness in situations of partner rivalry.

Morenz and Lane (1996) observed that ‘murder suicides’

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

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.

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’.

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).

Convergence theory This theory suggested that the

behaviour of a group is a result of like-minded individuals coming together (convergence).

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.

Essentially, this view dictates that crowds are not a passive group of people- in fact, they are a logically thinking mass of individuals.

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.

Group behaviour involves norm-governed 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.

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.

-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.

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.

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).

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.

Evaluation of explanations of group displays in humans

Operationalisation of group behaviour- There is no agreed definition for what constitutes a group display.

Retrospective explanations- The explanations of group display in humans typically involve looking back at past events and explaining them using a particular or theory.

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.