Aggression

Aggression in psychology refers to behaviours that could harm yourself, others or could affect objects in the environment.

The limbic system, serotonin, testosterone and cortisol research.

The hypothalamus, the amygdala, and the hippocampus.

Decreased levels of serotonin reduce self-control and may increase impulsivity. This includes behaviours such as aggression.

The Warrior Gene (MAOA), serotonin, testosterone, cortisol and gender.

The monoamine oxidase A (MAOA) gene codes for the production of the enzyme involved in breaking down neurotransmitters in the synapses between neurones. This is especially true for serotonin, although it affects other neurotransmitters, such as dopamine and norepinephrine. When variants of this gene occur, it can result in lower production of the enzyme, causing neurotransmitters to remain in the synapse for longer, resulting in brain dysfunction.

Social learning theory, involving the Bobo Doll and Bandura, De-individuation, and the frustration-aggression hypothesis.

Children can learn aggressive behaviours through observation alone.

The situational approach, involving the Sykes deprivation model, the dysfunctional institution, and the importation model.

It suggests that prisoners are violent and aggressive outside of prison, so when they are in prison, they bring that aggression with them, and this is why prisons tend to be places full of aggression and violence.

These include TV, Films, computer games and books.

Cognitive priming relies on schemas and cognitive scripts. These are the building blocks of the mind and automatic thoughts. Schemas exist to tell us what should happen based on previous experiences, and cognitive scripts are the way our body responds to this new or old situation based on these experiences.

If someone is exposed to violent acts or emotions frequently, they may become desensitised to it, and view it as normal, despite societal views on it. They no longer have strong emotional responses to a distressing stimulus, and may not be as empathetic as a result.

Ethology is where we study animals and then translate the results and try to explain behaviours and psychology by linking them to humans. It’s a comparative study of nonhuman animals in their natural environments.

Fixed action patterns, coined by Lorenz, are an ethological term used to describe instinctive behaviours in a species, usually a reflexive action in response to a stressor.

Aggression is adaptive, and inter and intragroup aggression.

If the last piece of meat for an animal is being fought for by a competing animal, an aggressive act to secure it would increase the first animals chance of survival, and the second animals chance as well. Aggression is an adaptive response to ensure survival through acts like these. 

Aggression is any behaviour that intends to harm others psychologically or physically.

 The Papez circuit.

The hypothalamus, the hippocampus, the amygdala, and the cingulate gyrus. (There are more components, however we care about these areas for the exam!)

The amygdala is considered the emotional centre of the brain, particularly for fear and threatening stimuli.

The hypothalamus regulates emotional responses and the autonomic nervous system (ANS).

This is primarily involved in long term memories.

The fight or flight response starts in the amygdala and can involve aggression. As these components are involved in mood regulation and emotional responses, it stands to reason that they are essential in the regulation of aggression.

It is a neurotransmitter.

Serotonin is a mood regulator, affecting aggression if it is too low. Low levels of serotonin are correlated with aggressive behaviours.

Testosterone is an androgen that is important in the development of the body, especially in males.

Some consider this so, as it is directly related to aggressive and dominant behaviours, particularly in males.

The Basal Model: This suggests that testosterone changes a person’s level of dominance.

The Reciprocal Model: This suggests testosterone levels are determined by a person’s standing in their social hierarchy, which determines their dominance levels.

It is said to be the ‘stress hormone’.

This theory suggests that stress caused by cortisol can inhibit aggression through fear. Lower levels of cortisol mean behaviours are less inhibited.

Papez, in 1937.

It processes it hierarchically.

The amygdala, the hippocampus, the hypothalamus, and the cingulate gyrus. (There are more components, but these are important for the exam!)

It is involved in the formation of long-term memories and learning. It is also involved in spatial awareness and navigation.

It is crucial in regulating the autonomic nervous system (ANS), which regulates emotional responses. Damage here can cause inappropriate responses to perceived threats.

It is the emotional centre of the brain, processing fear-inducing and threatening stimuli and how they are linked/associated with memory. It integrates emotions with motivational behaviours.

Regulating aggression, emotional responses to pain, communication and maternal bonding, amongst other functions.

The fight or flight response.

Aggressive behaviours.

In this study, the amygdala was surgically removed to reduce aggression in violent individuals. However, it affects emotion overall and suggests the amygdala is linked to aggression but is not the cause.

In the ultimatum game, there was a heightened response by the amygdala in response to rejected, unfair offers, more noticeably in males than females.

The research suggests there’s an association between the two. However, the studies only show a correlational link between aggression and the limbic system. It is not a direct cause.

Issues with beta bias. Although there were structural differences in the aggressive, reoffending inmates, they could not apply it to females, as the study was a small sample size of males.

It inhibits it to help regulate aggression.

It is a neurotransmitter in the central nervous system and a hormone in the peripheral nervous system.

Mood regulation and feeling relaxed, calm, and happy.

An inhibitory effect.

Sleeping, digestion, eating, healing wounds.

Tryptophan.

When serotonin levels are normal, it helps inhibit impulsive, aggressive behaviours received from the amygdala.

It cannot control or regulate impulsive, aggressive behaviours properly.

Decreased levels of serotonin cause a reduced inhibitory effect, affecting the OFC and causing more impulsive and aggressive behaviours.

Lowering serotonin levels resulted in weakened communication between the amygdala and frontal cortex. Their studies suggest that low serotonin levels are the reason why the frontal cortex struggles inhibiting and controlling the amygdala's aggressive impulses.

Those with IED had exaggerated amygdala reactivity and diminished OFC activation to angry faces, compared to the controls. The findings show an amygdala-OFC dysfunction in response to processing angry faces, supporting the connection between the OFC and the amygdala.

Serotonin is associated with melatonin synthesis.

It can cause insomnia.

You have little or no aggressive behaviours and can feel relaxed and in control of your emotions.

No, context matters. Both the individual and their social environment affect the aggressive behaviours, even with abnormal serotonin levels.

It is an androgen and an anabolic steroid. It is a hormone.

In the gonads and the adrenal cortex.

Testosterone enables the development of male characteristics, and secondary ‘male’ characteristics such as muscle and skeletal growth, as well as body hair and facial hair.

When there is not enough testosterone in the body, especially for males undergoing puberty, the development of male characteristics is affected, such as hair growth on the body and face, as well as affecting healthy sexual development.

Anger, verbal aggression, dominance, competitiveness.

Testosterone activates the amygdala, enhancing its resistance to regulation from the prefrontal cortex (PFC), and increasing its emotional reaction to stimuli.

Cortisol and serotonin.

The Basal Model of testosterone suggests that testosterone changes a person’s level of dominance.

Testosterone is determined by a person’s standing in their social hierarchy, which determines their dominance levels.

They measured testosterone levels in prisoners. Those who had committed violent crimes or had a history of aggressive behaviours had higher levels of testosterone compared to those who didn’t have this history.

They measured the testosterone levels in the saliva of 89 prisoners: 9 out of 11 inmates with low testosterone levels had committed nonviolent crimes in their past, whereas 10 out of 11 inmates with high testosterone levels had committed violent crimes in their past.

High levels of testosterone are positively correlated with levels of dominance.

Increased levels of anger/aggression.

Men who were going through a divorce had higher testosterone levels than those who were still married.

Cortisol is a steroid hormone that acts on the body in multiple ways, usually in stress response.

In the adrenal glands.

The pituitary gland, which the hypothalamus controls.

Controls stress responses in the body, affects blood sugar levels, regulates metabolism, influences blood pressure and heart rate, and affects inflammation.

When stressed, cortisol levels rise and increase heart rate, blood pressure (through narrowing blood vessels), and glucose levels in the blood. It activates the flight or fight response.

Cortisol acts as a hormonal modulator of aggression.

Testosterone.

Cortisol inhibits testosterone.

Lower cortisol levels have been linked to higher aggression levels, as it isn’t inhibiting testosterone.

This theory suggests the stress caused by cortisol can inhibit aggression through fear. Lower levels of cortisol mean behaviours are less inhibited.

Startle-elicited blinks were significantly lower in DBD children for all slides. The more delinquent the DBD children were, the lower their startle response was during negative slides. The study suggests a form of deficit in the DBD’s children fearing modulation capabilities.

Among male violent offenders, those who were habitually violent and had antisocial personalities had low cortisol levels compared with other violent offenders, antisocial personalities who did not habitually commit violent crimes, and male clinicians.

In rats, when stimulating their aggression centres in the brain, there was rapid, positive feedback between the adrenocortical stress response (the fight-or-flight mechanism; your body anticipating action due to stress) and a brain mechanism controlling aggression.

Among boys screened for aggressive or violent behaviour from childhood to adulthood, those with conduct disorder (CD, a form of DBD known to be the more physically aggressive subgroup) had higher cortisol levels than boys without CD.

It suggests aggression is biologically controlled and ignores the nuances of human nature.

It is a neurotransmitter.

Normal levels of serotonin in the orbitofrontal cortex (OFC) correlate with greater self-control levels. Decreased levels of serotonin usually mean a person acts more impulsively.

Serotonin synthesis, serotonin transportation/uptake, and serotonin receptors/degradation.

No. Genes may not directly affect behaviour, but how genes act on the regulators, i.e., the neurotransmitters that influence behaviours, are how they affect behaviours.

The amino acid tryptophan.

Tryptophan hydroxylase (TPH).

Monoamine oxidase A and B (MAOA and MAOB).

For mice who had their MAOA gene deleted, serotonin concentrations increased ninefold, as MAOA could no longer break down the serotonin in the mice’s brains. Adult male mice showed increases in aggressive behaviours.

The TPH gene was not the only one in the genome that affects serotonin synthesis. TPH affects serotonin levels in the blood, periphery tissues, and pineal gland. TPH2 is what affects serotonin levels in the brain.

In this study on mice, the TPH2 gene was genetically altered (knockout mice) to see its effects on serotonin and aggression. They changed a particular section of the allele from C to G on the gene. Mice who had the original C gene had higher levels of 5-HT. These mice were more prone to attacking other mice if they intruded on their territory.

In this study, the serotonin transporter (5-HTT, or SERT) was knocked out, and they assessed the aggression level of these mice in cages. The SERT deficient mice were less inclined or slower overall with attacking the intruder than the controls.

Brunner et al. (1993) assessed a Dutch family and found a genetic issue causing a mutation in the structure of the MAOA gene. 14 affected men had complex behavioural issues (related explicitly to aggression) and were affected by a syndrome of borderline mental retardation.

Women with specific genotypes had higher levels of 5HIAA (a byproduct of the breakdown of serotonin) than men. Similarly, African Americans with particular genotypes had higher levels of 5HIAA, too, when compared to Caucasians.

In this case, it means the gene in these mice has been altered/deleted or knocked out.

No. It is causal in its relation to mood regulation, but not for aggression. It is only correlational.

We refer to the monoamine oxidase A gene when talking about the MAOA gene.

The MAOA gene codes for producing the enzyme MAOs (monoamine oxidases), involved in breaking down neurotransmitters in the synapses between neurones.

The gene is found on the X chromosome.

The gene codes for enzymes that break down neurotransmitters such as serotonin. If the gene cannot do this properly, these neurotransmitters are left in the synaptic cleft for longer and affect a person’s mood.

Dr. Rod Lea.

Aggressive behaviours, risk-taking, addiction issues, and psychiatric disorders are associated with the warrior gene.

56% of the Mãori men had this MAO-30bp-rpt allele, almost double that of Caucasian men analysed in a different study.

There was a point mutation in the MAOA structural gene (specifically the eighth axon). This changed how this gene coded for the enzyme production, which caused issues with the breakdown of neurotransmitters.

The behaviours of the men in Brunner et al. (1993) consisted of impulsive aggression, arson, and attempted rape.

‘Obviously, this means they are going to be more aggressive and violent and more likely to get involved in risk-taking behaviour like gambling.’

Lea suggested this was due to the nature of the Mãori men’s past; they had to engage in many risk-taking behaviours, such as migration and fighting for survival, which has led to aggressive behaviours in the present, modern-day, and a genetic bottleneck.

The MAOA gene is fundamentally linked to mood due to producing enzymes that deal with neurotransmitters. Mood and behaviours will also be affected if the gene is affected. This suggests a genetic component to behaviour and moods, particularly aggression, and validates the genetic research on the MAOA gene.

They found that the MAOA gene was important in moderating the effect of maltreatment. If children had a genotype that expressed high levels of MAOA, they were less likely to develop antisocial behaviours after suffering maltreatment.

McDermott et al. (2009) found in their study that the MAOA gene is not explicitly tied to aggression, even in low provocation conditions. Instead, it predicts aggressive behaviours in high provocation situations.

Yes, the ‘warrior gene’ is unethical as it has racial overtones that unfairly describe a race of people as aggressive due to their genetic makeup.

It is an androgen and anabolic steroid.

A neuroendocrine system is a group of neurones, glands, and other tissues that regulate homeostasis (this is the normal, steady, and optimal state of the body).

This metabolic arousal results in the expression of aggression through mobilising the body’s muscles.

The Leydig cells in the testes produce testosterone (remember, testosterone is produced in the gonads for both sexes).

The NR2F2 gene.

They found the sex steroid concentrations (testosterone, etc.) and the body composition factor had significant heritability, with testosterone being the highest. They concluded that these two factors are under strong genetic control.

In twins whose blood levels (especially testosterone) were measured, the familial influence was more significant in MZ twins than in DZ twins, which was true for all measurements except SHBG.

They proved that specific genes influence aggressive behaviours by identifying a mutation in the MAOA gene.

Although aggression in humans does have a biological root in defensive aggression, it’s not dependent on hormones such as testosterone.

In men, 60% of the variance in testosterone levels is heritable, despite the father-son resemblance issues. This finding suggests that genetic factors are expressed differently in adolescence and adulthood. In women, it was 40%.

Around 60% of the variation in testosterone levels were due to genetic factors. The genetic contribution to AHA (anger, hostility, aggression) syndrome was approximately 23% to 53%, which is a moderate heritability level.

Overall, they said that testosterone and aggression traits seem to have a solid genetic basis. However, there is a lack of evidence for genetic relation between the two, so it needs further investigation.

Archer found overall that higher levels of testosterone in adults were usually indicators of higher levels of aggressiveness.

Those who had committed violent crimes or had a history of aggressive behaviours had higher testosterone levels than those who didn’t have this history.

This is the normal, steady, and optimal state of the body.

Gender is a term that refers to the scale between masculinity and femininity.

Gender, unlike the biological sex, is affected by social and cultural norms.

Boys use more physical aggression. In proportion to their overall aggression scores, girls use more indirect aggression. Both genders use direct verbal aggression equally. 

The person subjected to it may not easily identify indirect aggression.

According to Björkqvist (2018), indirect aggression is a form of social manipulation intended to psychologically and/or socially harm the person. This aggression can be through gossip, manipulating social standings within a group, or even excluding a person altogether.

Overall, they found that girls used more indirect aggressive behaviour than boys who used different means. Social hierarchy was ‘tighter’ amongst girls, making it easier to manipulate relationships and harm those subject to indirect aggression.

Older girls had greater overall use of indirect aggression. Boys used more direct means of aggression. They thought it was physical, differing from the girl’s preference of verbal.

They included more ages, ranging from 8, 11, to 15-year-olds.

Indirect aggression wasn’t as present in 8-year-old girls but was prominent in 11-year-old girls.

They found that girls mostly used indirect aggression, similar to the previous studies, across nations and ethnic groups.

They applied the studies to different countries to establish if the gender differences in aggression were cross-cultural.

No. They were equally indirectly aggressive. Girls just preferred this method of aggression, and boys preferred more direct methods.

According to multiple studies, boys overall had higher scores and aggression levels than girls.

Card et al. (2005).

They found the existence of the super-male chromosome.

Yes, as aggression is an innate releasing mechanism to ensure the survival of either species.

Yes, it is an instinctual process that is passed on, rather than learnt, an innate releasing mechanism (IAM).

No. Most of the time, members of the same species will avoid fighting to death as this is counterproductive.

Baring their teeth, hissing, raising the hair on their backs, growling. Yes, it is an example of FAPs.

It refers to warning behaviours all members of the same species display when aggressive or defensive (baring teeth, hissing, growling).

To secure territory, food, and mating rights.

Innate releasing mechanisms are ‘innate’, evolved responses to specific stimuli, in the sense that they exist within the animal as an inherited trait rather than a learnt one.

Isolated infant monkeys recognised threatening poses when shown images of other monkeys. Despite never being taught to do so by their mothers, they reacted defensively. They had innate responses to threatening stimuli.

Innate releasing mechanisms are the inherited behaviour that inhibits aggression until the animal is exposed to external stimuli. When this happens, the animal displays a pre-programmed behaviour in response to it. This behaviour is known as the fixed action pattern (FAP).

• Not comparable to humans (free will, premeditated aggression). 
• Not universal across the human species. 
• Not genuinely known if animals are being aggressive or just trying to survive.

Southern white men reacted more aggressively to a confederate man who called them names after bumping into them than northern men. This reaction suggests a cultural difference in aggression.

Fixed action patterns (FAPs) are instinctive behaviours in a species. They are a sequence of actions that respond to a stressor or cue (stimulus). FAPs are innate (not learned) and must be performed to their fullest extent, even when the stimulus is no longer present.

Konrad Lorenz.

Innate releasing mechanisms (IRMs) are instinctive responses evolved and passed on rather than learned – a hard-wired mechanism of the brain that acts as a release, in a sense. When an animal encounters a particular stimulus or event, it responds through a series of behaviours. These behaviours represent a neural network in the brain that responds to specific stimuli and triggers a specific sequence of actions directly responding to the stimulus.

Stereotyped, complex, universal, triggered, released, unaffected by learning. 

FAPS follow a particular pattern and are unchanging. They are rigid and highly predictable, ‘stereotypical’.

FAPs are not just a reflex and can be a set pattern of behaviours occurring in specific orders, in complex patterns.

FAPs are found throughout the species in response to a specific threat.  

FAPs that have been triggered must be completed, even if the stimulus that triggered it is no longer present (also known as ballistic).

FAPs are a response to a specific stimulus, as in, it only occurs in certain scenarios. It is a response to a particular ‘releaser’.

FAPs are not learnt from the parent, apparent from the first instance of a FAP.

Somewhat, yes. There are genetic components to fixed action patterns, as genes influence behaviours to some extent. Fixed action patterns are behaviours innate in the species, not learnt from outside sources. 

During the mating season, sticklebacks turn their bellies red and establish nesting territories. They are also aggressive toward other males to increase their chances of mating with females. Tinbergen placed wooden objects with and without a red underside near a male stickleback. The male stickleback was aggressive to the red underbelly objects, but not the objects without the red underbelly. 

In their retrieval of displaced eggs, greylag would extend the neck over the egg and use the underside of its beak to roll it back into the nest upon noticing the egg. Even if the egg were moved, it would not stop this action; it had to complete the FAP. 

Monkeys isolated from their mothers as infants were shown pictures of threatening and non-threatening poses of other monkeys. They reacted defensively to threatening pictures, even though they had never learnt this behaviour. Their defences were innate. 

Humans are subject to societal and cultural influence and evolve rapidly in behaviour, adapting to the situation at hand. The studies on animals do not apply to humans. 

Innate releasing mechanisms (IRM) are neural networks in the brain that react to a specific stimulus to elicit a particular response.

They trigger a fixed action pattern (FAP).

Innate releasing mechanisms are the hard-wired neural network within the brain that recognises a stimulus and then trigger the fixed action pattern. Fixed action patterns are a sequence of actions triggered BY the innate releasing mechanism. 

Nick Tinbergen, after expanding on the work of Konrad Lorenz.

Yes, by being innate they are born within the animal and are instinctive as a result. 

An egg would have been displaced from the nest. The goose would first notice the egg (sign stimulus) and then extend its neck over it, so the egg is under the beak. Using the underside of the beak, the goose would then roll the egg back into the nest. 

Yes.

Yes, as long as the object was similar in size, shape, and weight to an egg, it would elicit the same response in the goose. 

Innate is an instinctive behaviour that is there when the animal is born. The young can perform something innate without having to learn it.

Orthoptera, a species of insects that use sound to communicate (mating reasons.)

This is not easy to establish, so we cannot confidently say yes or no. It is harder to identify in humans, but some examples are the knee-jerk reaction and yawning. Society and cultural norms affect human behaviours too much. 

They are reductionist, ignore human free will, and it is hard to measure intent in animals truly, so we cannot say if an IRM or FAP is due to aggression. 

Upon seeing a red underbelly of another stickleback, male sticklebacks will begin a fixed action pattern of aggressive behaviours in response. 

This is the object or stimulus that triggers an innate releasing mechanism and fixed action pattern. 

No.

The hydraulic model of instinctive behaviour is a concept Konrad Lorenz developed to demonstrate the release of pent-up aggression in animals (innate releasing mechanisms), specifically by showing a reservoir of motivation/aggression. A sign stimulus releases this reservoir to cause fixed action patterns to specific stimuli.

Konrad Lorenz (1950).

It ties them together to show how aggression builds up and is released in an animal.

Freud’s work. 

He believed it was inevitable, particularly for males, as they are biologically programmed to fight for survival. 

It is the pent-up aggression accumulating in the reservoir. 

The weight releases, resulting in the release of aggression and fixed action patterns.

It is where aggression levels lower in an animal following the release of pent-up aggression. 

To appear threatening, Siamese fighting fish puffed up in response to stimuli that looked like other male fish – a fixed action pattern.

In vacuum activity, pent-up aggression is released in the absence of the sign stimulus. 

True. The reservoir then builds up again in the hydraulic model. 

It fails to consider the ability to learn and adapt fixed action patterns during development in animals. 

True. 

Arms et al. (1979) found aggression and hostility in male and female spectators of sports increase rather than decrease after viewing the events. However, this was not the case for the non-competitive events.