Lessons 01 - 05

Question 1

Aggression definition

Answer 1

Range of behaviours that can result in both physical and psychological harm to oneself, other people or objects

Question 2

Proactive aggression

Answer 2

Based on the term ‘cold blooded’
Planned method

Question 3

Reactive aggression

Answer 3

Based on the term ‘hot blooded’
Unplanned method angry, impulsive

Question 4

What are neural mechanisms?

Answer 4

Structures (neurons, neural circuits, regions of the brain) or substances (neural transmitters, hormones) that regulate aggression

Question 5

Neural explanations

Answer 5

The limbic system - how a person responds to environmental threats
Involves the amygdala, hypothalamus and hippocampus.
Is hierarchical (signals passed from lower systems to higher systems)
The limbic system connects to the cingulate gyrus (responsible for attention on emotionally significant events), and the prefrontal cortex (involved in forward planning)

The hypothalamus regulates the autonomic nervous system, which regulates responses to emotional circumstances. Damage = inappropriate aggressive responses.
The amygdala is responsible for attaching emotional significance to sensory information.
Damage to the prefrontal cortex will reduce the inhibition of the amygdala, resulting in higher levels of aggression

Question 6

Serotonin

Answer 6

It slows down and calms neural activity (inhibits the firing of the amygdala)
Low levels mean people can’t control their impulsive and aggressive behaviour. Lower levels affect our response to external stimuli, meaning a person can become aggressive easily.

Question 7

Evaluation of neural mechanisms in aggression

Answer 7

(+) Research support. Kluver and Busy (1939) removed the main areas of the limbic system from Rhesus monkeys. They showed an absence of emotional, motor and vocal reactions, and also lost the social understanding (tried to fight the more dominant members). They became more aggressive
(+) Technological advances. Wong et al. (1997) did MRI scans of 19 violent males, the volume of the amygdala was significantly smaller.
(-) BUT small sample, only done with men (gender bias, specifically beta bias)
(+) Supports the role of neurotransmitters. Ferrari et al. (2003) let 11 male rats fight with each other for 10 days at a specific time. On the 11th day, they didnt, and found that dopamine levels increased by 65% and serotonin levels were reduced by 35%. Changed the rats brain chemistry.
(-) BUT cause and effect? Lowers the validity.
(-) Research uses animals. Can the findings be extrapolated? Despite having similar neural structures, we don’t know if processes are the same
(-) Mann et al. (1990) gave a drug (dexfenfluramine, which reduces serotonin levels) to 35 adults, who then did a questionnaire. Aggression rose amongst males, not females, showing gender differences and the problems of beta bias

Question 8

Hormonal mechanisms
Testosterone

Answer 8

Male sex hormone, promotes muscle strength, and is responsible for the sex drive. Thought to influence aggression from young adulthood.
Sapolsky (1998) found that removing the source of testosterone resulted in lower levels of aggression.
Men are more aggressive than women (men have more testosterone)
Ages 21-35 is when testosterone concentrations are at the highest, and there is an increase in male-on-male aggression.
Carre and Olmstead (2015) found that testosterone concentrations fluctuate rapidly in the context of changes to the social environment. Changes to levels increases amygdala reactivity.

Question 9

Hormonal mechanisms
Progesterone

Answer 9

A female ovarian hormone that can increase mood. Is a natural antidepressant. Levels vary during the ovulation cycle.
Ziomkiewicz et al. (2012) found a negative correlation between progesterone levels and self-reported aggression.
Low levels of progesterone are linked to increased aggression.

Question 10

Evaluation of hormonal mechanisms in aggression

Answer 10

(+) Research support about testosterone. Wagner (1979) castrated mice (removed testes) and their aggression levels went down.
(+) Gianmanco et al. (2005) agrees. In male Rhesus monkeys, there is an increase in testosterone and aggression levels during mating season.
(-) Lack of generalisation in animal studies to humans. Also, studies may only provide support for correlations, nor for cause and effect. Does not confirm if testosterone causes aggression

Question 11

Genetic factors in Aggression
Genetics

Answer 11

Genes consist of DNA strands, that produce ‘instructions’ for features. Genes are inherited (transferred from parent to offspring).
Most people have 23 pairs of chromosomes, male (XY) or female (XX). Early psychologists believed the genetic cause of aggression was the Y chromosome.
‘Super males’ have XYY. Court-Brown (1965) studied 314 super males, who all had an increased likelihood of aggressive behaviour (he said they should be hospitalised)
More recently, psychologists have used selective breeding in animals to support the idea that aggression is transmitted from parent to offspring

Question 12

Genetic factors in Aggression
Twin studies

Answer 12

Coccaro et al. (1997) studied male adult twins.
Concordance rates:
Physical assault:
- MZ (100% DNA) = 50%,
- DZ (50% DNA) = 19%
Verbal assault:
- MZ = 28%
- DZ = 7%
Suggests a genetic component

Question 13

Genetic factors in Aggression
Adoption studies

Answer 13

Rhee and Waldman (2002) carried out a meta-analysis of adoption studies of direct aggression and antisocial behaviour and found genetic influences accounted for 41%

Question 14

Genetic factors in Aggression
Candidate genes

Answer 14

MAOA gene, responsible for the production of the protein monoamine oxidase, which allows the metabolising of noradrenaline, serotonin and dopamine
Too much adrenaline - hypersensitivity in the fight or flight response.
MAOA-L gene is a low-activity variant, which means people are likely to be aggressive.
Lea and Chambers (2007) found that 56% of Maori men had this (compared to 34% of Caucasians), and they are known for being ferocious warriors

DYSFUNCTIONAL MAOA GENE:
- High levels of dopamine = increased likelihood of feelings of reward when aggression is carried out
- Low levels of serotonin = lack of inhibition over impulsive behaviour
- High levels of noradrenaline = overreaction to perceived threats

Question 15

Evaluation of the genetic factors in aggression

Answer 15

(+) Abundance of research. Coccaro et al (1997) and MZ/DZ twins study, supporting the role of nature in aggression
(+) Godar et al. did selective breeding by removing the MAOA gene in mice. These mice showed increased aggression and abnormal levels of serotonin, showing the relationship between genes and neurotransmitters. When the mice were given fluoxetine (to raise serotonin levels), their aggression levels went back to normal
(+) Brunner (1993) found that 28 violent criminals possessed the MAOA-L gene, further supporting the genetic explanation
(+) Stuart et al. (2014) found that 97 men who has been involved with severe domestic abuse had the faulty MAOA gene.
(-) Not all research supports the XYY gene causing aggression. Theilgaard (1984) found that XYY causes an increase in height, not in aggression, shows we cannot make generalisations as there is no link shown here
(-) Twin studies lack validity. MZ twins have 100% same DNA and are also reared the same way, and DZ twins may not be. Twin studies may be unintentionally measuring environmental influences also

Question 16

Ethological explanations of aggression

Answer 16

Looks at innate behaviours of animals (to help understand human behaviour).
A key ethologist is Lorenz
Aggression is seen in all animal species and is adaptive. It is beneficial (can help survival by protecting resources, and establishing dominance hierarchies).
Lorenz (1996) said aggression is often ritualistic; e.g. ‘teeth baring’ has the effect of deterring without physical harm
Aggression is the result of an evolved automatic biological response in the brain. Animals have a built-in neural structure (Innate Releasing Mechanism IRM) that when exposed to specific stimuli, will cause the release of an automatic behavioural response (Fixed Action Pattern FAP)

EXAMPLE: when a dog sees a cat running (the running is the IRM), they have an instinctive response to chase (FAP)

Question 17

Six main features of FAPs

Answer 17

• STEREOTYPED or relatively unchanging sequences of behaviour
• UNIVERSAL, found in every individual of its species
• INNATE, unaffected by learning
• BALLISTIC, once triggered the course cannot be altered
• SINGLE PURPOSE, behaviour only happens in a specific situation
• A RESPONSE TO AN IDENTIFIABLE STIMULUS

Question 18

Evaluation of ethological explanations of aggression

Answer 18

(+) Strong research. Tinbergen (1951) did an experiment with male sticklebacks. In mating season, they get a red spot on the underside. When they see the red spot (IRM) on another male in their territory, they attack (FAP). He tested this with a wooden model. Red spot means attack, no spot, they would not attack
(-) Assumes behaviour is innate, so it should be the same across cultures. Nisbett (1996) found that South American males would be more likely to respond aggressively when insulted, compared to white North American males. Shows cultural differences
(-) Aggression is not always ritualistic. Goodall (2010) studied chimpanzees. They waged a brutal war and slaughtered members of neighbouring groups. This ‘systematic slaughtering of another group by a stronger group’ is hard to explain from an ethological standpoint (risk of injury is high and is not adaptive)
(-) Not all FAPs are fixed. Variation in a species means we should look at ‘model action patterns’ instead. These are instinctual but also differ between individuals. Differences are down to training, or species differentiation

Question 19

Evolutionary explanations of sexual jealousy

Answer 19

Jealousy comes from paternal uncertainty and the fear of ‘cuckoldry’ (raising another man’s child). Investment in the offspring would be a waste of resources.
Men in the past who avoid cuckoldry are more reproductively successful. So psychological mechanisms have evolved to increase anti-cuckoldry, so sexual jealousy is experienced more strongly in males than females. This leads to aggressive strategies to keep their partners from ‘straying’

Question 20

Sexual jealousy
Mate retention strategies

Answer 20

• Direct guarding: involves the male being vigilant over a partner’s behaviour (checking where they are going, tracking them)
• Negative inducements: threats with dire consequences (“I’ll kill myself if you leave”)
• Physical violence: Wilson et al. (1995) asked women to repost mate retention strategies. Measured in terms of how they agree with statements (e.g. ‘he insists on knowing where you are at all times’). Women who agreed with these statements were twice as likely to experience physical violence. 73% required medical attention. 53% feared for their lives

Question 21

Evolutionary explanations of bullying

Answer 21

Bullying occurs because of a power imbalance. Our evolutionary ancestors used it as an adaptive strategy to increase chances of survival by promoting their health and creating opportunities for reproduction.
Volk et al. (2012) found that characteristics associated with bullying are attractive to females (dominance, strength). Bullying behaviour would be naturally selected. May be beneficial to the bully’s health (being ‘tough’ would mean they’re less likely to be the victim of aggression and would experience that stress)

Question 22

Evolutionary explanations
Female bullying

Answer 22

Often takes place in a relationship and is used to control the partner and prevent infidelity. Ensures the partner continues to provide resources for offspring. Campbell (1999) said behaviour is naturally selected because of enhanced reproductive success

Question 23

Evolutionary explanations
Warfare

Answer 23

Smith (2007) said that human warfare originated to obtain valuable resources and also to attract mates. Displays of aggression and bravery are attractive to females.
In the past, male warriors tended to have more sexual partners, and more children. This suggests a direct reproductive benefit.
Aggression also increases status for warriors (more respect)

Question 24

Evaluation of evolutionary explanations of human aggression

Answer 24

(+) Explains the gender differences. Campbell (1999) argues that it is not adaptive for a female with children to be physically aggressive as she puts their lives at risk. A more adaptive strategy is verbal aggression, men use physical aggression
(+) Real life application to reduce bullying. One strategy to reduce bullying is to address and question why a bully does it. This can lead to anti-bullying strategies (show the bully the costs of bullying)
(-) Does not explain cultural differences. Thomas (1958) studied the Kung San people in Botswana and called them ‘harmless people’. They had negative attitudes towards aggression; individuals who did show aggression lost their status and respect within the community. This shows how cultural and societal norms are more powerful in shaping aggression than evolutionary reasons.
(-) Biologically determinist. By suggesting aggression is inevitable and therefore not our fault, it implies it is acceptable. This will not sit well in a court of law as it ignores the role of free will and may not be relevant in the real world.