• Home   /  
  • Archive by category "1"

Biological Explanations Of Aggression Essay Writing


Aggression is a form of self-assertion (putting yourself forward or standing up for yourself). However, it is done through causing harm to yourself, to other people or to your environment. This can be physical harm involving breakages and bruises or mental harm, involving fear and anxiety. Physical aggression is violence and social aggression includes rumour spreading, insults and breaking off friendships. Threatening someone is aggressive because it causes them fear and anxiety, even if no violence occurs.
Aggression can take many forms but it is defined as any action that is aimed at causing either physical and/or psychological pain to oneself to others or to objects in the environment. The expression of aggression can occur in a number of ways, including verbally, mentally and physically - Charlotte Thomas (2012)
There are two camps when it comes to the psychology of aggression: the nature camp and the nurture camp.

Nativists (nature) argue that aggression is innate - it comes from within us. We are born with aggressive urges which never entirely go away, although self-discipline and a good upbringing might help us to control or re-direct these urges.
Nurturists (nurture) argue that aggression comes from our environment and no one is born aggressive. Aggressive behaviour is learned or else produced by social pressures. Put anyone in the right situation and they will behave aggressively, but anybody's aggressive behaviour can be reduced or removed if they are put in better surroundings.
  • In the Social Approach, Milgramshows how an authority figure will produce aggression (delivering electric shocks); Sherifshows how out-group discrimination turns into aggression in the Robbers Cave study
  • In the Learning Approach, Bandura shows how aggression is transmitted through aggressive role models; it may also be conditioned through reinforcement (Skinner)or association (Pavlov)
  • Although the Edexcel course doesn't cover it, the Cognitive Approach would also explain aggression, either as a rational choice (weighing up the costs and benefits to get what you want) or as faulty thinking (failing to appreciate the costs of aggressive behaviour)
Do we teach boys sports like rugby so that they can get rid of their innate aggression safely and productively... or are we teaching boys to be aggressive who wouldn't be otherwise?


The nativist view is that aggression is a response that is produced in the brain. There is evidence to support this from animal studies, brain scans on humans and case studies of individuals with brain damage.
Amazingly, Gage survived the accident, thanks to treatment from Dr John Martyn Harlow. However, his personality greatly changed. In his case study, Harlow reported that Gage became
fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires - John Harlow (1868)
After he died, 12 years later, Gage's skull was preserved and studied. Modern computer-assisted design has reconstructed the damage to his brain: it was damage to the frontal lobe, which is responsible for decision-making and self-restraint.
Before the shootings, Whitman had visited 5 doctors and a psychiatrist for help with his urges.
I talked with a Doctor once for about two hours and tried to convey to him my fears that I felt overwhelming violent impulses
The psychiatrist noted in his records that Whitman was "oozing with hostility". When an autopsy was carried out after the shootings, Whitman was found to have a brain tumour the size of a pecan nut pressing on his amygdala. A Commission that investigated the case concluded that this brain damage may have been responsible for Whitman's behaviour.


As the Phineas Gage case suggests, the brain's frontal lobe plays an important part in decision-making and self-restraint. In particular, a region called the pre-frontal cortex seems to be particularly important. If it is damaged or malfunctions, aggression is a possible side-effect.

Another brain structure that plays a role in aggression is the corpus callosum that links the left and right hemispheres. The two hemispheres need to communicate over long-term planning and thinking through consequences. Damage to the corpus callosum might also lead to more reckless behaviour.

In the Classic Study by Raine et al. (1997), brain scans of a group of murderers revealed they had much less activity in the frontal lobe and corpus callosum compared to a control group of non-murderers.
It's important to note that damage to the frontal lobe or corpus callosum doesn't create aggression itself. It just makes you less self-controlled and more inclined to act on the spur of the moment, especially in unfamiliar or confusing situations. This MAY turn out to mean aggressive behaviour, but it doesn't have to.


The limbic system is a sub-cortical area - part of the "old brain" that we share with other animals. It is also the brain's emotion centre where our most basic urges and desires (appetite, sleep, sex drive, fear) are regulated. For example, the thalamus is the brain's "switchboard" which receives signals and sends messages out to all the other areas. The hypothalamus has an important role in producing hormones.

However, the most important part of the limbic system for understanding aggression is the amygdala. The amygdala takes information from the thalamus and interprets it as a threat or not; it produces fear or aggression, the famous "fight or flight" response. Of course, if the amygdala malfunctions, then things which are threatening will not produce a fear response - or else harmless events will be interpreted as a threat, producing aggression.  The case of Charles Whitman might be an illustration of this.
This 10-minute video looks at the link between the amygdala and the pre-frontal cortex. It also includes Adrian Raine talking about his famous study.
The relationship between the amygdala and the frontal lobe is very important. If the pre-frontal cortex is healthy, then willpower can resist the amygdala's urges of fear or aggression. In Adrian Raine's murderers, the amygdala behaved erratically and the pre-frontal cortex was under-active - a dangerous combination.
Animal studies also support the link between the limbic system and aggression. John Flynn carried out studies on cats in the 1960s, using electrodes to stimulate the amygdala directly. Egger and Flynn (1963) introduced a rat to the cat's cage and found that the two animals would ignore each other. However, when the amygdala was electrically stimulated, the cat immediately attacked and killed the rat. This is predatory aggression. Egger & Flynn found that stimulation of a different part of the amygdala caused the cat to ignore the rat and attack the experimenter! This is affective (emotional or fear-based) aggression.


Over 19 sessions, you can see that mouse aggression varied a lot, but after castration it clearly drops. When the mice are injected with 150 micrograms of testosterone a day, their aggression creeps back up to the old levels.
A study of prisoners (James Dabbs et al., 1987, 1995) found testosterone levels were higher in those who had been convicted of a violent crime. Those with high testosterone levels were rated higher by other prisoners for being "tough".
Mazur & Booth (1998) review studies showing that men with higher levels of testosterone are more likely to:
  • divorce, or remain single
  • be arrested (for offenses other than traffic violations)
  • to buy and sell stolen property
  • incur bad debts
  • use a weapon in fights

Mazur & Booth report a study of 2,100 male Air Force veterans who received four medical examinations over a ten year period: testosterone levels fell and remained low with marriage, and rose with divorce. These results are consistent with Mazur & Booth's reciprocal model: testosterone varies with a person's dominance. Unattached males need to be socially dominant in order to attract mates so testosterone levels rise when a male is single. This explains why single/divorced males are more likely to be convicted of crimes, even when the statistics are adjusted for individuals with certain characteristics like calmness and empathy being more likely to marry in the first place (Ryan King, 2007).
Another hormone linked to aggression is cortisol. Cortisol is a hormone produced in the adrenal glands. While it is responsible for "waking us up" in the morning, its main job is managing stress levels. Cortisol seems to inhibit aggression, the same way that testosterone increases it (Van Goozen et al., 2007). Virkkunen (1985) report low levels of cortisol in violent offenders and  Tennes & Kreye (1985) report low levels of cortisol in aggressive school children.
People with lower levels of cortisol are more aggressive because it means their autonomic nervous system (ANS) is under-aroused; aggressive behaviour is an attempt to create stressful situations which provoke cortisol release, stimulating the ANS.
There's also evidence linking aggression to HIGH levels of cortisol (eg. Gerra et al., 1997). Clearly, cortisol is complicated and does a lot of different things in the brain.
Animal studies also support the link between hormones and aggression. Rachel Adelson (2004) used rats as test subjects and used electricity to stimulate the hypothalamus; this led to the release of a stress hormone called corticosterone, which is part of the aggressive response. 

If the rats had their adrenal glands removed and couldn't produce their own hormones, their aggression faded. However, when they were then injected with corticosterone, the hypothalamus activated. This shows a "feedback loop" in aggression: the hypothalamus triggers the release of the hormone but the hormone also activates the hypothalamus. This might explain the phenomenon of rage, when aggression spirals out of control.


Serotonin is a neurotransmitter linked to mood and sadness. Treatment for depression often involves medicines that boost serotonin levels in the brain. However, low serotonin levels are also associated with increased aggression. This is because serotonin seems to inhibit aggression.
Dee Higley et al. (1996) studied rhesus monkeys living wild on an island. The researchers used behavioural observations of the monkeys fighting and leaping from trees. They also took samples of spinal fluid from the monkeys to measure 5-HIAA levels. 5-HIAA is a chemical that is produced by the re-uptake of serotonin, so high levels of 5-HIAA means high levels of serotonin. If serotonin inhibits aggression, you would expect aggressive monkeys to have low levels of serotonin, and therefore low levels of 5-HIAA (because there would not be need for much serotonin re-uptake).
The poor monkeys with low levels of serotonin got themselves killed jumping off trees and attacking older, bigger monkeys. Basically, being jerks.
There is also a link between dopamine and aggression. Dopamine is a neurotransmitter linked to attention and pleasure. Increased dopamine levels are associated with increased aggression and anti-psychotic drugs (which reduce dopamine levels in people suffering from schizophrenia) seem to reduce aggressive moods and behaviours.
Ferrari et al. (2003) studied the link between neurotransmitters and aggression in rats. They allowed a rat to fight every day for 10 days at approximately the same time. This was done by introducing an "intruder rat" into the test rat's cage. On the 11th day, no intruder rat was introduced. The researchers measured the levels of serotonin and dopamine in the test rat's brain. The test rat’s dopamine levels had increased and serotonin levels decreased, because it was anticipating a fight.

This study also links in with Classical Conditioning. The rat had been conditioned to fight at a certain time each day and its brain chemistry had altered to prepare it for aggressive action. It also illustrates brain plasticity, since the rat's brain chemistry changed, showing that the brain adapts to what we experience.
A famous example is Phineas Gage, an American railway worker who suffered a terrible accident in 1848. The railway workers used dynamite to make the ground flat for laying the rail tracks, but an unexpected explosion nearly killed Gage. It blasted a "tamping iron" (a metre-long iron nail) through Gage's skull; the iron entered through Gage's cheek, passed through his brain and shot out of the top of his head.
Another case study is Charles Whitman, a Texan marine who, in 1966, murdered his family then shot a dozen strangers in a killing spree, before taking his own life. Whitman left a suicide note:
I don’t really understand myself these days. I am supposed to be an average reasonable and intelligent young man. However, lately (I can’t recall when it started) I have been a victim of many unusual and irrational thoughts.
Testosterone is the hormone linked to aggression. Testosterone is produced in spurts, so the testosterone levels can rise suddenly and have an effect within minutes. It also varies seasonally in some animals, which is why red deer become aggressive in the mating period in the Spring. Males produce more testosterone than females (although female ovaries do produce testosterone) - and this is an explanation for why males are are aggressive than females on average.
Castration reduces testosterone levels in males. Wagner et al. (1979) castrated mice and observed that aggression levels dropped. When the castrated mice are injected with testosterone, their aggression levels (measured by biting attacks on other mice) rose back to pre-castration levels. This clearly suggests that testosterone is a cause of aggression in mice and may cause aggression in humans too.
The researchers found a negative correlation between 5-HIAA and aggression: aggressive monkeys had lower levels of 5-HIAA (and therefore of serotonin too); less aggressive monkeys had higher levels.

Low 5-HIAA/serotonin was associated with high risk-taking behaviour, such as aggression towards older, larger animals and taking long leaps from tree to tree. Many died as a result of this.


Sexual Jealousy

Sexual jealousy is a powerful cause of aggression, which is why it is the plot of so many great stories.
Sexual feelings also come from the limbic system. As part of its job in regulating emotions, the amygdala handles trust and intimacy. It is responsible for helping us recognise familiar faces and feel secure around people we are on intimate terms with. Sexual jealousy (when we feel insecure around people we are intimate with) is also produced by the amygdala.

Of course, some people just get unhappy when they are jealous; they don't get mad. Jealous rage seems to require hormones as well, such as testosterone in men. Testosterone is produced in the testes but the message to increase production comes from the pituitary gland in the brain, just beneath the limbic system.

Mazur & Booth (1998) showed how testosterone rises in men who need to show their dominance; this includes single males and males in failing relationships. If jealousy makes men feel insecure in a relationship, their body will start to produce more testosterone to prepare them to assert their dominance and this can make them aggressive.

One of the conclusions from all this is that the best way to reduce male aggression is to marry men off! This is the conservative idea that "men are civilised by marriage". A similar idea, popular with people of a different political outlook, is that the best way to reduce male aggression is to give more power to women.
Since violence is largely a male pastime, cultures that empower women tend to move away from the glorification of violence and are less likely to breed dangerous subcultures of rootless young men - Stephen Pinker (2011)
However, not everyone agrees that men need to be tamed. Schacht et al. (2014) carried out a meta-analysis of 20 studies into male violence in different countries. They found "that violence was equally likely to be associated with extra women as with extra men." Nine studies showed more violence in societies where men outnumbered women, and nine showed the opposite. Two studies were not conclusive.
Social Aggression

Not all aggression is physical aggression. There is also teasing, name-calling, rumour-spreading socially excluding people. Social aggression has two components:

  • Indirect aggression, which is covert (hidden), such as spreading malicious gossip
  • Relational aggression, which is overt (in the open) but non-physical, such as breaking off a friendship, pulling faces or “bitchiness”

Statistics on bullying show that 30% of children may be the target of it at some point in time (Analitis et al., 2009). A study by Atlas & Pepler (1998) revealed that other children were present in 85% of all bullying episodes on a school playground, yet these bystanders intervened to stop the bullying just 15% of the time.

Gordon Ingram (2014)shows that young children show more physical aggression than social aggression, but, as they grow into adolescence, this reverses and social aggression (gossiping, rumour-spreading) dominates.

Brendgen et al. (2015) considers this as part of the Biological Contemporary Study:  young children don’t have the verbal or social skills to practise social aggression, but they acquire these once they start school. The Brendgen study goes on to show a genetic connection in twins that links to social aggression as well as physical aggression.
In Shakespeare's play "Othello", the conniving servant Iago drives his master Othello mad with jealousy by making Othello think his beautiful young wife has given her handkerchief to another man. It all ends BADLY.



Human and animal studies support the idea that there are brain structures linked to aggression, in particular the limbic system which generates aggressive impulses and the pre-frontal cortex which inhibits aggressive impulses. Animal studies like those carried out by John Flynn in the 1960s clearly show the role of the limbic system in producing different sorts of aggression. Ferrari's research on rats illustrates how dopamine and serotonin are linked to aggression in rats. These animal studies are backed up by human studies, like Raine et al. (1997) which also suggests the amygdala and pre-frontal cortex are linked to murder, and case studies like Charles Whitman whose brain tumour may have produced his uncontrollable aggression.

Since the 1990s, this research has been supported by new brain imaging techniques like PET and MRI. These scans show a correlation between unusual brain activity and aggressive or antisocial behaviour, such as Adrian Raine's observation that there was 11% less activity in the pre-frontal cortex of patients suffering from Antisocial Personality Disorder compared to a Control Group.

This evidence supports the nativist viewpoint that aggression is innate, present from birth and an unavoidable (and even a positive) part of human behaviour.

Generalising from animal studies to humans is full of difficulties. Animals do not have the same pre-frontal cortex as humans (it is smaller, for example) and may not be capable of planning or self-awareness.

Animals also express their behaviour through dominance or submission. It is possible that researchers are confusing dominant behaviour with aggressive behaviour. This would be a validity problem with the animal model if one sort of behaviour is being mistaken for another. In fact, there may be very little aggression in animal behaviour:
The overwhelming impression one gets from watching animal disputes is of remarkable restraint and self-control. The spilling of blood is not the norm - it is a rare event  - Morris (1990)
If this is true, humans may be much more aggressive than other animals, especially when social aggression (which cannot easily be observed in animals) is taken into account.

Although brain imaging techniques are reliable, there may be validity problems with these too. This is because the same structures in the brain (and the same neurotransmitters) seem to do different jobs. For example, the amygdala regulates both aggression and fear. Dopamine is associated with both pleasure and aggression and both high and low levels of dopamine are linked to aggressive behaviour.
The Exam Board expects you to compare the biological explanation of aggression with the Freudian explanation of aggression. Freud's ideas are explained on another page. For now, I'll compare and contrast the biological explanation with the empiricist explanation that aggression is learned.
There are many studies supporting the idea that aggression is a learned behaviour. Bandura's "Bobo Doll" studies show that children imitate the aggressive behaviours they see in role models. Classical and Operant Conditioning both offer explanations for aggressive behaviour.
  • Classical Conditioning shows that aggression is an unconditioned response to some stimuli (like threat) but may become a conditioned response to a neutral stimuli (like social embarrassment, unfamiliar people or drunkeness). This ties in with the Biological Approach because it assumes that unconditioned aggression is an instinctive response, but conditioned aggression is learned.
  • Operant Conditioning shows that aggression is learned through reinforcement, either positive reinforcement (aggressive behaviour may bring you admiration and respect) or negative reinforcement (aggressive behaviour may make unpleasant things stop, by scaring people away).

Strict Behaviourists like B.F. Skinner would argue that ALL behaviour is learned and that human beings are born as tabula rasa (a bank slate), with aggression being added later.

Biological determinists would argue that ALL behaviour is hereditary and that human beings are born with a genetic destiny they cannot help but obey.

Most psychologists take a middle way between these extremes. Genetics gives us predispositions to behave a certain way, but we can resist these impulses if we try. We learn specific behaviours, but our genes give us broad instructions that affect what we learn and how easily we learn it.
  • For example, Watson & Rayner conditioned Baby Albert to fear a white rat, but their experiment depended on the fact that Albert found something naturally frightening (a loud noise).
11-minute video (part 1 of 4) looking at different theories of aggression, nativist and empiricist

If the nativist viewpoint is correct, then aggressive behaviour is natural and unavoidable. It might be possible to identify people with extreme aggression at an early age, either by genetic screening, testing for testosterone or serotonin levels or by trying to identify those with an under-active pre-frontal cortex or malfunctioning amygdala. These individuals could be carefully monitored and perhaps kept away from jobs or roles where they might present a danger to the public (working with children or in hospitals, for example). There might be some jobs that would suit them well (the Armed Forces, perhaps, or contact sports like boxing or rugby).
This viewpoint easily turns into EUGENICS, which is the belief that some people are biologically inferior and should be prevented from having children. This is an ethical debate that psychologists must consider.  This will also be discussed as part of the Key Question for the Biological Approach.
Another application of the nativist view of aggression is the use of drugs to control behaviour and reduce aggression. For example, young people with ADHD (Attention Deficit Hyperactivity Disorder) can behave aggressively. They are often treated with drugs like Ritalin to control their behaviour.
Many people feel there are ethical problems with controlling people through drugs, especially young people who might suffer side effects from the medication.

Interestingly, Ritalin works by (among other things) boosting dopamine levels to help children with ADHD to concentrate. High dopamine levels are normally associated with increased aggression. This illustrates the problems with linking dopamine to aggression and indeed with linking any biological process to aggression in a straightforward way. The exact effect dopamine has depends on a lot of other factors.

If the nativist viewpoint is mistaken, then identifying people based on biological tests and discriminating against them is grossly unfair. Not everyone with high testosterone levels is a violent person. This ties in with the objection that biological characteristics often relate to several different behaviours. High testosterone levels might make one person aggressive but another person hard-working and energetic. High dopamine levels are associated with aggression in some people, but good memory and cheerfulness in others.

The nurturist viewpoint would argue for the importance of education and counselling to help people manage their emotions and behave more appropriately. Techniques like Token Economy Programmes have been developed to do this based on the Learning Approach. Bandura's research suggests removing aggressive role models from TV and film might help reduce imitative aggression. However, if some people are driven by biological urges they cannot control (perhaps like Charles Whitman), then no amount of education or therapy will help them.

Most psychologists adopt an interactionist approach, accepting that aggression is produced by nature and nurture. This is the view taken by Mara Brendgen; even though her twin study suggests that physical and social aggression both have a biological connection, she concludes that education at an early age may help children control their behaviour better.

The idea of brain plasticity suggests that the brain changes based on experience. If so, then learning can change brain chemistry. This is illustrated in Ferrari et al.'s study of fighting rats.

How to write a 8-mark answer

Evaluate and apply the biological explanation of aggression. (12 marks)
  • A 12-mark “evaluate” question awards 4 marks for describing biological processes leading to aggression (AO1), 4 marks for applying biology to aggression (AO2) and 4 marks for evaluation (AO2). You need a conclusion to get a mark in the top band (7-8 marks).

Biologically, aggressive responses come from the brain's limbic system, which handles also our basic drives and emotions. In particular, the amygdala regulates fear and anger.
Aggression may also be due to a failure of the pre-frontal cortex to restrain aggressive urges. THe pre-frontal cortex handles decision-making and self-control.
Aggression may also be caused by a failure in the corpus callosum, because this enables the left and right hemispheres to communicate which is important for long-term thinking.
Finally, low levels of serotonin are associated with aggression; serotonin is linked to sadness and the ability to inhibit (restrain) your feelings.

Young children can be physically aggressive because they have not yet developed the cognitive skills to handle frustration and disappointment.
As they go through school, children switch to being socially aggressive rather than physically aggressive. This may involve verbal bullying and "being mean".
Brendgen's twin study found a genetic link for both types of aggression. MZ twins were more likely to be aggressive if their twin was aggressive.
Children with the gene for aggression may be counseled to help them show their feelings in less hurtful ways.

Biological explanations of aggression are backed up by studies like Raine et al., which use brain imaging to show parts of the brain that are less active in aggressive people.
Explaining aggression biologically runs into the problem that biological processes can lead to different behaviours. For example, the amygdala regulates aggression and fear.
The nurturist approach focuses instead on how we learn aggression from our environment. You can see this in studies like Bandura, Ross & Ross, where the children imitate the aggression they observe.
Although drugs can calm people with Antisocial Personality Disorders, the biological approach doesn't offer useful therapies like counseling which can help aggressive people manage their anger.

An interactionist approach includes both learning and biology. Because of brain plasticity, our brain structure may change because of our experiences, making us more or less aggressive than we were to start with.

  • Notice that for a 12-mark answer you don’t have to include everything about the biology of aggression. I haven’t mentioned the other parts of the limbic system, testosterone or the role of serotonin. But it is a balanced answer - one third description, one third application and one third evaluation.

Aggression Revision Notes

by Bruce Johnson published 2017

Exam Advice

You MUST revise everything - because the exam board could choose any question, however, it does make sense to spend more time on those topics which have not appeared for a while.

Exam Tip:

With these particular questions there is a sizeable risk that people don’t understand the difference between the questions, and then write about the wrong thing. Make sure you know which is which, for example do you understand the difference between “Genetic explanations” and “Neural and hormonal explanations”, and do you have a model essay for each?

Section 1: Neural and Hormonal causes of aggression.


• The Limbic System (including the Hypothalamus and Amygdala) tends to act as an alarm system triggering aggressive response to certain types of threats.

• Giving testosterone to new-born female mice made them act like males with increased aggression, when given testosterone as adults. However, control females only given testosterone as adults did not react in this way (Edwards ,1968).

This suggests that testosterone masculinises androgen-sensitive neural circuits underlying aggression in the brain.


Research in Greece found that removing the amygdala reduced aggressive incidents by between 33% and 100%, although the sample was small – 13 patients.

The Phineas Gage study provides evidence that brain damage may have an effect on personality including aggression.


• The PET-1 Gene is linked to the production of the hormone serotonin, which inhibits (i.e. stops) aggression. Damage to the gene, in mice, raises aggression. [sometimes referred to as “Knockout Mice] (Deneris, 2003).

• Drugs increasing serotonin production lead to reduced levels of aggression, suggesting that low levels of serotonin are linked to increased aggression (Delville et al., 1997).

• Rats selected for reduced aggression levels had higher serotonin and greater levels of serotonin related activity than wild, more aggressive counterparts (Popova et al., 1991).

• Research shows a relationship between low levels of serotonin and violent behaviors, suggesting that a lack of serotonin is linked to aggression (Linnoila & Virkunen, 1992).

• Lidberg et al. (1985) compared serotonin levels of violent criminals with non-violent controls, finding the lowest levels of serotonin among violent criminals.


Most evidence linking low levels of serotonin and aggression is only correlational and does not indicate causality.


• Giving the hormone testosterone to new-born female mice made them act like males with increased aggression, when given testosterone as adults.

However, control females only given testosterone as adults did not react in this way, suggesting that testosterone masculinises androgen-sensitive neural circuits underlying aggression in the brain (Edwards ,1968).

• Testosterone affects certain types of aggression in animals, such as intermale aggression as a defence response to intruders, while predatory aggression is not affected (Bermond et al., 1982).

• Van Goozen (1997) conducted a natural experiment on trans-gender sex-change patients. This is one of the few cases where research was actually carried out on humans.

Findings revealed testosterone levels governed aggression. Males receiving testosterone suppressants became less aggressive. Females receiving testosterone became more aggressive.

• Aggressive Boys, violent criminals, military offenders all had high levels of testosterone (Dabbs, 1996).


Individuals with elevated testosterone levels exhibit signs of aggression, but rarely commit aggressive acts, suggesting that social and cognitive factors play a mediating role (Higley et al., 1996).

Dabbs and Morris (1990) 'Blocked pathways to success' study: When a rich boy with high testosterone came home from the army he was less likely to get into trouble, but when a poor boy with high testosterone came home he was more likely to get into trouble.

This suggests testosterone doesn’t simply cause aggression, but it makes aggression more likely as a response to frustration.


• The fearlessness Theory: Stress, caused by the hormone cortisol may inhibit aggression through fear. So individuals with lower levels of cortisol are less inhibited, more inclined to take risks and act impulsively (Raine, 2002).

• Low cortisol leads to Sensation seeking behavior, especially in males (Zuckerman, 2010).

• Low levels of Cortisol in delinquent teenagers with conduct disorder (Fairchild, 2008)

General Criticisms of Neural and Hormonal Research


Much of the evidence is only correlational and may not prove causation. It isn’t clear whether hormones promote aggression, or aggressive behavior stimulates homrone production.

Comparative – much of the work on hormones and neurotransmitters has been done on animals and may not apply to humans so easily.

Reductionist: Sees only biological factors, overlooking social issues such as de-individuation Heredity / Environment: Biological theories tend to overlook the effects of socialisation and other environmental issues, such as environmental stressors.

Deterministic: Assumes humans have no choice and will follow primitive behavior patterns.

Section 2: Genetical Origins of Aggression.

Genes alone do not control aggression, rather they affect the production of hormones and neurotransmitters which in turn affects aggression. So you will also draw upon your knowledge of biological factors, but you MUST show a link to genetics for each one.

Basic Evidence of Genetic Influences on Aggression


• Animal studies show instinctive patterns of behavior including aggressive behavior. If a whole species has a similar level of aggression then it must have a genetic basis.

• Twin studies have shown that twins have similar levels of aggression.

Using old Danish police records Christiansen (1977) demonstrated that levels of criminality showed a stronger correlation between identical twins – with the same genes – than between dizygotic twins.


However criminality is not always the same as aggression.

Genetical Research on Serotonin


• PET-1 Gene is linked to serotonin production which inhibits aggression. Damage to the gene in so called “knockout mice” raises aggression. Mutations in humans can have the same effect (Deneris, 2003).

• Acts of impulsive aggression, such as domestic violence, have a genetic link to the serotonergic system, suggesting that many genes may be involved in aggression (New et al., 2003).

Genetical Research on MAOa - The Warrior Gene


• MAOa is an enzyme which helps with the re-uptake of neurotransmitters including serotonin. Humans with the MAOa L gene (L is for Low) have a lack of MAOa enzyme. Without this enzyme to recycle it the level of serotonin may become depleted.

• When researchers found the MAOa-L gene present in 56% of New Zealand Maori men it was nicknamed “The Warrior Gene”. Poa {2006] criticised this term as unethical - i.e. racist.

It was later found that the gene is present in 58% of African American men and 36% of European men, so it is actually a mainstream genetic variation with adaptive advantages associated with risk taking.

• A Dutch family has long history of aggression, and a genetic inability to process serotonin due to lack of MAOA (Brunner, 1993)

• Caspi et al (2002): Interaction of MAOA problem AND abusive childhood led to aggression. If boys with the MAOa – L gene suffered abuse in childhood , they were 3 times more likely to be aggressive when they reached adulthood.

Genetical Research on Testosterone


• Bogaert et al. (2008) established that variations in male testosterone levels are inherited – and therefore genetic.

• Giving testosterone to newborn female mice made them act like males with increased aggression, when later given testosterone as adults. Females only given testosterone as adults did not react in this way, suggesting that testosterone masculinises aggression systems in the brain at birth, it’s not just an environmental issue (Edwards, 1968).

• Rissman et al. (2006) investigated Sry, a gene leading to the development of testes and high androgen levels in males. Male and female mice with and without the gene were tested. The Sry gene was associated with high levels of aggression, suggesting that genes and hormones interact and that sex chromosome genes also have a role.


• Rissman et al. (2006) investigated Sry, a gene leading to the development of testes and high androgen levels in males. Male and female mice with and without the gene were tested. The Sry gene was associated with high levels of aggression, suggesting that genes and hormones interact and that sex chromosome genes also have a role.

• The Super-Male hypothesis (Sandberg, 1961) suggested the XYY Gene led to aggression. Later research by Alice Theilgard [1984] did show that 16 men out of 30,000 sampled had the xyy gene and that these were slightly more aggressive and slightly less intelligent but this is such a rare mutation that it does not explain aggression in the general population.

General Criticisms of Genetic Research


Comparative – much of the work on genes has been done on animals and may not apply to humans so easily. However, the experiments which have been done on mice relate to chemicals and genes which are very similar.

Reductionist: Danger of seeing only biological and overlooking social psychology issues such as de-individuation. Tends to overlook the effects of socialisation and other environmental issues, such as environmental stressors. Genetic factors do not work in isolation but interact with environmental factors as well.

Deterministic: Assumes that humans have no choice and will follow quite primitive behavior patterns.

Section 3: Ethological Explanations of Aggression.


Ethology is where we learn about human psychology from studying other animals.

• Conrad Lorenz believed that aggression was an innate adaptive response – something which had evolved in humans and animals to help them survive.

    • To see off predators: For example a group of hissing geese can drive off a fox, even though the fox would probably win a straight fight. If the geese survive, then the gene which led to that aggressive response will be passed on.

    • To get resources: Lorenz also suggested that much aggression was aimed at members of the same species, when competing for territory or sexual partners, but some animals are so fierce they could easily damage each other when fighting for dominance; Eg. Wolves, Stags, Lions.

This would be maladaptive – bad for the species. Therefore they fight until one backs down, not to the death, just to establish who is stronger and who is weaker.

This creates a society in which each individual knows their place. They have evolved ways of warning others to back off: Dogs bark and snarl, cats hiss, apes beat their chest or wave sticks about.

Niko Tinbergen called these Fixed Action Patterns [FAP]

Fixed Action Patterns [FAP]


Lea [1984] analysed FAPs and identified 5 features:

  1. Stereotyped – behavior follows a certain pattern each time.
  2. Universal all the animals in that species use the same type of threat.
  3. Innate: all the animals in that species seem to be born with it and don’t have to learn it.
  4. Ballistic: Once it starts it cannot simply be stopped.
  5. Specific triggers seem to set it off.


Breland and Breland found that animals tend to revert to instinctive behavior regardless of training. This would support the FAP theory.

It could be argued that some behaviors are learned in the environment – but maybe not all. Dogs can been trained by hunters, army and police to act in particular ways.

Eibesfeldt (1972) tried to identify human FAPS such as smiling to show non-aggression, however he found that our culture changes so quickly that cultural differences in signs can change more quickly than evolutionary patterns. Rude words and hand signs can change, so not evolutionary. Humans are certainly capable of developing new ways of expressing aggression – such as cyber bullying!

Innate Releasing Mechanisms [IRM]


• Creatures have evolved an instinctive response to certain signs. [Like a red rag to a bull!]

Eg. Male sticklebacks will respond aggressively to the red underbelly of a rival male – but not to a female who does not have the red underbelly.

The Hydraulic Model of instinctive behavior [Lorenz 1950]

It may be easier to understand and remember the hydraulic model if you compare it to a toilet ! The water level gradually fills up till you flush it - then it has to be filled up again.


• Lorenz said that all creatures build up a reservoir of Action Specific Energy – you could call it “pent up aggression”. When the Innate releasing mechanisms [IRM] trigger the Fixed Action Pattern [FAP] all the aggression is fired off.

Once it is out of the system the animal is less aggressive again till the level of Action Specific Energy has built up again.


This explanation was probably an example of Lorenz trying to adapt Freudian ideas to animals! Freud wrote about the build-up of sexual energy [Libido] and Lorenz applied a similar idea here.

This theory fails to explain premeditated aggression and bearing grudges.

Holst [1954] found that instead of getting it out of the system , aggressive action could feed back to make the person more angry and increasingly more aggressive.

Arms et al. [1979] found that watching violent sport did not flush aggression out of the system but tended to increase it. Bushman does not agree with idea of Catharsis – says that aggression may lead to more aggression.

Section 4: Evolutionary Explanations of Human Aggression.

The central idea of this topic is that for aggression to be an adaptive feature it has to serve a purpose.


• David Buss has identified 7 adaptations of aggression in humans:

• Self Defence

• Reputation to ward off future aggression

• To achieve status – more allies less enemies

• Get and keep better share of resources. Pinker (1997) states aggression evolved in men to compete for women. This may have been the MAIN reason for aggression as there was no other property worth fighting over as we evolved.

• Deny own resources to children of rivals

• To prevent other males sharing the prime females

• Prevent partner being unfaithful. For example, sexual jealousy may have evolved to ensure that men pass on their own genes rather than allowing other males access to their mate.

This is aggression between different groups, such as warfare and gangs.


Buss states human males have evolved cognitive bias towards organised aggression: E.g.

    • Cognitive bias to expect attack

    • Cultivating tough reputation

    • Use of vengeance as a deterrent

    • Strategies for planning and timing an attack

    • Deception and the ability to detect deception

Cosmides and Tooby, the Military Contract: Men will only fight if those who share the rewards also share the danger. Other animals are not bright enough to work this out.

This is aggresion within a single group, mainly linked to male rivalry and sexual jealousy.


• Daly and Wilson: Male – Male aggression among young men is common in all human cultures – suggesting it is evolutionary.

• Pinker (1997) suggests aggression evolved in men to compete for women. This may have been the MAIN reason for aggression as there was no other property worth fighting over as we evolved. Through most of evolution there was no money, no real property, so women were the only target of aggression.

• Potts and Hayden (2008): War and aggression aimed to control women’s mating habits since development of farming made inheritance of land important. Jealousy has evolved as a male response to the threat of infidelity. Jealous males are determined to pass on their OWN genes.

• Daley and Wilson (1988): Men may use jealousy and violence to control partners sexual behavior Violence is not intended to kill but may have that result. E.g. Fertile young women 10 times risk of domestic violence.

General Criticisms of Evolutionary Research


Ethics: Waller says : Violence , Xenophobia and even genocide are adaptive, but this is very deterministic and unethical.

Ethics and Gender: Critics feel this theory could be used to justify violence against women. Buss himself always points out that we are not controlled by our genes, we have inherited the ability to learn and to choose.

Reductionist: Is this an over-simplification? Are there other issues which promote aggression such as culture or Individual differences in testosterone and cortisol.

Heredity & Environment: Are environmental factors a greater cause of aggression?

    • Environmental stressors, heat, noise etc

    • Cortisol levels in pregnant mother

    • Childhood abuse and neglect

Deterministic: Evolutionary explanations may seem to suggest that aggression is natural but Figuerdo [1995] suggests jealousy and domestic violence are context specific not inherent, women are less likely to be victims of domestic violence if they have several brothers in town, so aggression can be controlled.

Section 5: Social-Psychological explanations of Aggression.

In the 1960s Social learning theory seen as a challenge to behaviorists Suggested children learn things even without doing them, through observational learning and modelling.

Exam Tip: If the question asks about Social learning Theory it is not enough only to write about the Bobo Doll experiment. That was only one experiment – not the whole theory.


• behaviorists believe learning occurs through experience followed by either punishment or reward. “Social Learning Theory” challenges that approach.

• The central idea of social learning theory is that people do not need rewards to learn aggression, they may copy the behavior of others, but this is less likely of they see the other people being punished.

Bandura states children learn by imitation, and are more likely to copy depending on:

  • The actual behavior of the role model
  • The status of the person copied
  • The closeness / immediacy of the person
  • How well we understand what is happening

Bobo Doll experiments: Children copied adults

Contributory factors:

  • Similarity: boys will copy boys, family links and groups etc.
  • Presentation: How close, live, immediate the violence was
  • Warmth: If the model was more friendly towards the subject
  • Prestige: If the model had high status
  • Appropriateness: If the behavior was “appropriate.

Vicarious reinforcement: (i) Adult was rewarded children slightly more likely to copy; (ii) adult was punished children were much less likely to copy.

Disinhibition: People are more willing to do things if they see that others are already doing them.

Bandura’s conclusions: Aggression is not inevitable. Children observe aggressive behavior in others, but how they act may depend on what the consequences of aggression were, particularly for those they use as role models.


Positive Criticisms of Bandura

Huge implications for society -provides a key to understanding causes of good and bad behavior. Based on clear research in lab and followed up by many studies into TV violence, video games etc.

Negative Criticisms of Bandura

Experiment was in a lab – may lack ecological validity.

Children may have known that the Bobo Doll was designed for punching and therefore more open to suggestion, also they may have been aware of the experiment from other children in the group.

These are both examples of demand characteristics.

Media Implications

Viewing violence may cause children to develop cognitive scripts which involve violence in dealing with situations.

A danger that media violence makes children more desensitised, more hardened to acts of violence in real life.

Social Theory: De-Individuation


• The central idea of this theory is that humans have a natural tendency to be aggressive if they think they can get away with it. Being disguised, or part of a crowd, will therefore lead to increased aggression.

• Festinger (1952) invented the term “Deindividuation”, defined by Fraser and Burchell (2001) “A process whereby normal constraints on behavior are weakened as persons lose their sense of individuality.”

Contagion Theory: Starting point for deindividuation

  • Le Bon 1896: People in groups become infected with a kind of group hysteria and act in ways they would not do on their own.
  • Blumer 1939: Circular reaction where the people add to the crowd and the crowd fires up the people.

• Zimbardo (1969): An electric shock experiment, similar to the classic Milgram study, found that disguised students were more likely to shock others – supports deindividuation.

• Deiner Et Al (1976) Studied 1300 American children “trick or treating” on Halloween. Children in disguised or in a large group behaved worse. Supports deindividuation theory.

• Mullen (1986) studied lynch mobs. The greater the number of people tended to correlate with the level of violence.


Gergen 1973: Deindividuated persons in dark areas became more affectionate. Therefore de-individuation need not always lead to aggression

Postmes & Spears (1988): Deindividuated people are not necessarily aggressive - Crowds may be happy and good natured – as at pop festivals

Tajfel (1981): Reduced private self awareness. Taking on the values of groups we belong to – which may be peaceful or aggressive

Johnson and Downing: some people in Nurses uniforms and some in Ku Klux Klan outfits.

De-individuation led to better, more caring behavior by the nurses which suggests de-individuated people get into the role more and the role may not be aggressive.

Zimbardo: Stanford Prison experiment saw students adopting to perceived roles.

Emergent Norm Theory & convergence theory

These ideas can be used as criticisms of de-individuation. They suggest that groups or sub-cultures come together because they have some sort of similarity, (convergence) then establish their own norms (emergent norms). Often one person, or a few people will behave in a certain way which others like - so they copy. This argues against de-individuation and the faceless crowd, it does not imply aggression will result. A very good example would be the hippy culture of the 1960’s

The Frustration-Aggression Hypothesis


• Aggression is a result of frustration. Frustration is any event or stimulus that prevents an individual from attaining a goal and it’s accompanying reinforcement quality (Dollard & Miller, 1939).

• Displaced Aggression [Dollard 1939] You cant kick the boss, so you kick the cat. Like Lornez, Dollard thought that getting aggressive cleared the mind of frustrations [a Catharsis] and life could then go on as normal.

• Berkowitz (1989 ) updated version known as “Negative – affect theory”. Frustration is just one factor, others may include feeling uncomfortable [eg. Heat, Reifmann [1991]] - but could also be noise or loud music Certain cues may increase the tendency towards aggression such as seeing a weapon on the table – Berkowitz used a baseball bat in experiments. Also if the problem is unexpected the individual is less likely to control their aggression.

• So, the level of aggression will depend on:

  • how much you really want to achieve the goal
  • Whether you understand that there is a good reason for the problem
  • How expected / unexpected the frustration was


Bandura (1973) Frustration may lead to aggression if that has worked for someone in the past and they have internalised that way of dealing with problems.

Harris (1974) Found that people at the front of a cue were less aggressive if someone pushed in, whereas people at the back of a long cue were feeling a greater sense of frustration and therefore mad a bigger fuss.

Wright and Klee (1999): Societies will be more stable and peaceful if they have systems which allow clever or hardworking people to rise to the top. Otherwise a strong but angry working class will develop, filled with people who resent being “kept down”.

Brown (2001) - holidaymakers became more aggressive when frustrated by delays.

Priks (2010) has tried to explain football violence this way. Supporters seem much more likely to misbehave when their team is losing.

Mallick and McCandles found that people were much less aggressive when given a reason for the frustration. Doob and Sears [1939]: people felt angry when a bus went by without stopping. But people were less angry if the bus had a sign saying out of service [Pastore 1952]

The danger is that it justifies deviant behavior: Plenty of people suffer injustice or unfairness and do not turn to violence. Therefore there must be some additional factor, such as a biological dimension, to explain why some people turn to violence or aggression when faced with problems and others don’t.

Section 6: Institutional Theories of Aggression.

The situational approach: prisons make people aggressive – it’s the situation to blame.

The dispositional approach: prisoners are aggressive people who make the prison violent.

The Situational Approach: Sykes’ (1958) Deprivation Model


• Some institutions have harsh living conditions, such as prisons, army camps, refugee camp This is less of a problem if the deprivation is for a good reason; if you were on a “round the world yacht race” or a mountaineering trip you have positive attitudes to keep you going.

• Some institutions, deprive people of things they want:

  • liberty,
  • autonomy,
  • goods and services,
  • sexual relationships,
  • security

• This deprivation causes stress and frustration which leads to an aggressive sub-culture. But this only applies to places with harsh conditions: E.g. in prison, army, refugee camp etc. Less likely to be a problem if the deprivation is for a good reason; Eg. fitness & diet camp.


  • The general environment becomes dangerous and aggressive.
  • Some people retreat, back down, hide in their cells.
  • Others compete in order to get what they want.
  • Getting a tough reputation is very important in order to get respect and not be a victim.


Support for Situational Model

McCorkle (1995) In a study of 317 United States prisons, poor facilities and overcrowding were found to influence levels of violence.

Franklin (2006): Age and overcrowding led to aggression, with younger inmates (18-30) being most aggressive in conditions of overcrowding. Her Majesty’s Prison Woodhill: Major improvements at this prison included less noise, better ventilation, attractive views and especially less crowding. This led to a massive improvement in behavior in the 1990s.


Harer and Steffensmeir (1996) found that age, race and criminal background were the only variables which affected levels of aggression. This strongly argues for the importational model, not the deprivation model.

The Situational Approach: Dysfunctional Institutionsl


Another situational argument is that the prisons themselves are dysfunctional. Milgram believed that people are loyal to the hierarchy of the organisation, but sometime the hierarchy encourages cruel behavior.

Much of Milgram’s thinking was influenced by events of the holocaust in Germany. Here the institutional aggression was on the part of the guards, rather than the prisoners.

The Stanford Prison Experiment

Zimbardo found that ordinary students became aggressive and cruel when they took on the role of being a prison guard. At the time of the Zimbardo experiment there were many prisons in the united states where conditions were extremely poor, violent and overcrowded. Some even used the prisoners as slave labour on prison farms. Zimbardo’s experiment strongly supports the situational approach.

Historical Context

At the time of the Zimbardo experiment there were many prisons in the united states where conditions were extremely poor, violent and overcrowded. Some even used the prisoners as slave labour on prison farms. Zimbardo’s experiment strongly supports the situational approach.

Features of dysfunctional Power Systems (Zimbardo)

  • Isolated from the outside world
  • Own set of values
  • Cohesive group; guards don’t question orders
  • Under pressure to act quickly
  • Difficult situation to manage
  • Out-group seen as troublemakers

Dispositional Explanation: The Importation Model


• A prison is a violent place because aggressive people are in there. Their aggressive attitudes become part of its nature. It’s a dispositional approach because everything depends on the attitudes of the prisoners. This may also apply to other groups and institutions; The army / Extreme political groups / Street gangs.

Irwin and Cressy 1962: People who are sent to prison already have well established criminal behavior patterns. Prisoners were often gang members before going to prison and their loyalties and relationships are continued in the prison environment.

They also have certain learned patterns of behavior – “The code of the Streets”. They may also have problems which cause problems with relationships. E.g, Lack of self-control - Delisi (2011); Impulsive, anti-social - Wang & Diamond (2003).


Support for Irwin and Cressy / importation model

Men who were members of gangs before they went to prison are more likely to be involved in violent offences whilst in prison. Drury and Delisi (2011)

Mears (2013) believed that the code of the street is imported into prison and is the fundamental cause of aggression.

Poole and Regoli 1983: Violence before prison was the best indicator of violence inside prison. This supports the importation model.

Fischer (2001) Segregating gang members inside prison, so that they did not come into conflicts with other gangs, led to a 50% reduction in assaults.

Criticism of Importation Model

Delisi (2004) found that gang members were NOT more violent than other prisoners. However, this is a rather weak piece of research as it does not allow for the fact that those gang members had already been segregated away from other gang members. The importation model does not really explain why some organisations act aggressively when they are made up of good people supposed to act sensibly. Police officers, school teachers, traffic wardens, psychiatric nurses, and salesmen are all members of organisations which have sometimes been accused of acting in an aggressive way and yet these are very law abiding people who joined those organisations willingly and for good reasons.

Exam Tip

In January 2012 there was a short question (4 marks) which just said; Describe one experiment which investigated Institutional Aggression. A short summary of Zimbardo was all that was needed.

Section 7: Media influences on aggression.

Exam Tip: Many criticisms can be made of the methodologies used in studying the link between Media and Aggression. Click here for AO3 suggestions on this unit.

In recent years computer games have replaced film as the target of claims that children are taking on immoral attitudes and copying violence. Especially those involving violence, especially first person “shoot-em-ups” “Grand Theft Auto” is a very good example.


• Five psychological theories could be mentioned to support the view that repeated exposure to video game violence may lead to real life aggression:

• 1. Learning theory [Skinner]

Everything you have ever learned about Operant Conditioning can be beautifully applied to this argument. The computer game is the world’s most effective “Skinner Box”.

The human is conditioned to think in patterns which have been pre-programmed into the machine. Basic ideas are taught in the basic levels and behavior is constantly shaped to conform to the rules of the game. Every act, every single click on the mouse, is instantly rewarded, by the computer’s response. Mistakes are instantly punished.

• 2. Learning theory [Bandura]

Attention  retention  production  motivation

Individuals model the aggressive acts in the game. Some characters, and some types of behavior, are more likely to be copied because they are seen as attractive and appropriate etc. There is no sense of real punishment for making mistakes – just game over and start again. This creates disinhibition, individuals unconsciously feel that if they commit aggression they will not be punished.

• 3. Social Cognitive Observational Learning Theory [an updated version of Bandura]

Psychologists have identified certain mechanisms which explain why we learn and copy behavior:

  • Schemas: Models which help us understand the world [Grebner 1994]
  • Normative beliefs: social rules and explanations [Guerra Et. Al.]
  • Cognitive Priming: What connects to what in the brain [Berkowitz, Huesmann]
  • Cognitive Scripts: A pattern of behavior we have ready to deal with certain situations

So the films don’t suddenly turn a person violent, but they might slowly cause the development of anti-social attitudes. This could be more effective in certain types of people [not very intelligent, have no positive role model, feel hard done by in life].

• 4. The General Aggression Model [Anderson and Dill]

This model brings together elements of Social learning and Cognitive Priming Theory and suggests that if we live in a violent environment – such as a war zone, we will adapt to it, our thoughts, feelings and actions will be based around violence and that is how we will survive. But could over-exposure to gaming have the same effects?

Evidence for General Aggression Model: Meta-Analysis Findings: Anderson et al. [2004] 35 studies examined Found that video game violence exposure is related to: increases in aggressive affect, cognition and behavior increases in physiological arousal; decreases in helping behavior.

• 5. Neurological Effects

Ritterfield and Mathiak [2006] -- Participants were subjected to a functional magnetic resonance imaging scan whilst playing a violent video game. It appeared to suggest that emotional areas of the cortex are to some extent “switched off” during the game, perhaps an adaptive mechanism which permits an animal to focus on survival. This is the same as happens when engaged in real acts of violence.


• Cognitive priming is based on the idea that memory works through association. It therefore contends that events and media images can stimulate related thoughts in the minds of audience members. For example, if we have often seen clowns throwing custard pies at one another, then when we encounter a custard pie in real life we may think about throwing it at someone.

• A schema is a model of what we think normally happens. We assume that our parents will feed us and our friends will be pleased to see us because that is what normally happens.

• A cognitive script is a way of dealing with a situation. We have learned that in a hotel restaurant we sit down and wait to be served, but in a burger bar we line up at the counter.

• Berkowitz thinks watching violent movies could lead to storing schemas and cognitive scripts which involve aggression EG. the students in the Stanford Prison experiment had never been in a real prison but they may have had a schema based on movies they had seen. EG. Students who play “Grand Theft Auto” might develop a cognitive script for what to do when traffic lights turn amber. This may be different from the way their Grandma drives!

• Priming means that a particular event, or an image or even a word may be associated with these thoughts. We call that a trigger. When we encounter the trigger we may respond in the way we have been primed. EG. a football comes bouncing towards me - without thinking I put out my foot to stop it or kick it back, but if it’s a cricket ball I would pick it up and throw it back. I am primed to respond differently to the cricket ball. So Berkowitz argues that we learn anti-social attitudes from the media and these are associated with certain triggers.


Steve Berkowitz [1984] did an experiment involving an argument in an office. In condition A there was a baseball bat on the side of the desk. In condition B there was a badminton racquet. Berkowitz found the presence of the baseball bat led to more aggressive responses.

Bushman [1998] Participants who had watched a violent film responded more quickly to aggressive words than those who had watched a non-violent film.

Anderson and Dill [2000] Found that playing a violent computer game led to more aggressive thoughts. They claimed that even playing the game just once could be having this effect, although the effect might only be short term.

Zelli [1995] found that cognitive priming could be used to make people suspicious of the intentions of others. This in turn led the people who had been primed to act in a more aggressive manner.

Murray [2007] – used fMRI scans to study children’s brains when watching violent and non-violent TV programmes. Violent films led to increased activity in those areas which deal with emotion, arousal and attention – not surprising – but also in the areas used to store episodic memory. This supports the suggestion that children can store scripts.

Atkin [2003] found that priming was more pronounced when the media was more realistic. However this may not simply mean it “looked better” it might relate to how much the participant believed it was realistic.


• Media violence triggers biological [physiological] changes, specifically a general arousal, similar to how people respond to a real life threat [flight or fight]. If the level of fear is too much we may feel.

• In the natural world a certain level of natural fear should make people hold back from violent situations. The desensitisation argument suggests that if children watch too much violence on TV they will be less scared and therefore more open to aggressive activity.

• People become less likely to notice violence, or in real life. They have less sympathy for victims of violence. They have less negative attitudes towards violence. [Mullin and Linz 1995]

Measuring desensitisation

• Desensitisation can be monitored by physical indicators of stress, such as heart beat and galvanic skin response. [Linz 1989]

• Carnagey [2007] found that experienced computer gamers show less of a reaction to a film of real life violence.

Effects of Desensitisation

• Bushman and Anderson [2009] found that desensitisation made people less likely to help others in unpleasant situations.

• Dolf Zillman suggested that if we survive real life danger we feel good afterwards [winners] During an action movie we feel excited and stimulated. Later we want that excitement again but we become de-sensitised so we need more scary films to get us excited. This could transfer to seeking violence in real life.


• Normally we act in certain ways because we have been socialised to know what is right and wrong. We get aroused and excited by a film or a game and this causes us to lose our inhibitions, acting in a more extreme manner till the excitement dies down.

• Long term Disinhibition: Too much violent TV can change our actual moral values so that we see more violent standards of behavior as acceptable. One aspect of this is that we often see acts of violence going unpunished in movies or games and this could lead to disinhibition.

Individual factors [Collins 1989] make disinhibition more or less likely:

  • Violent home background
  • Physical punishment of children
  • Younger viewers
  • Children with low intelligence
  • Children who believe their heroes are realistic
  • Children who believe the media reflects real life

• Disinhibition less likely if Strong family norms against violence or where adults discuss issues from the film with their children.

About the Author

Bruce Johnson is an A-level psychology teacher, and head of sixth form at Caterham High School

→A-level Home Page|Memory Revision|Social Influence Revision |Attachment Revision|Psychopathology Revision|

Was this article useful? Please help us improve by giving feedback below

→A-level Home Page|Memory Revision|Social Influence Revision |Attachment Revision|Psychopathology Revision|

One thought on “Biological Explanations Of Aggression Essay Writing

Leave a comment

L'indirizzo email non verrà pubblicato. I campi obbligatori sono contrassegnati *