Task 1: for each of the following statements, identify whether it is a strength or a weakness for evaluating the link between biology and aggression: 1. Animal studies that have involved damage to or removal of the amygdala offer evidence for its link with aggression. 2. Studying the human brain is difficult and can be very risky, so there is no way of making sure areas of the brain are linked to aggression. 3. Animals and humans are different in many ways, so animal research suggesting a link between the brain and aggression may not be applicable to humans. 4. The case study of Charles Whitman (1966) are evidence for its link with aggression in humans. 5. Case studies are unreliable, as the reason for an individual’s aggression may be unique to that individual. 6. Aggression could equally be explained by the way children copy the media. 1

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Essentially the argument is Neural 1.Brain abnormalities Hormonal 1.High levels of testosterone..... are associated with aggression 3

Hormones & agrression What is a hormone? A hormone is a chemical produced by the body that sends messages to organs of the body via the bloodstream. What is the role of testosterone in the body? Testosterone is a male sex hormone produced in the testes and secreted by the adrenal gland which is needed to produce sperm. Testosterone is also involved in the development of the male reproductive organs and produces male features, such as facial hair and a deep voice. It is also said to be involved in aggression. Hormones & aggression

Hormones and Aggression - Testosterone Beeman (1947) and Wagner et al (1979) castrated male mice and found that aggressiveness reduced. He later injected the mice with testosterone which re- established their aggressiveness. Castration has since been used as a method for making domestic and farm animals more manageable.

Aggression in animals 3) In animals, what happens when they are injected with testosterone or have their testes removed? 4) Define castration.

Aggression in humans Psychologists can take blood from humans to see what levels of testosterone they have and compare this to how aggressive they feel or act. Some correlation studies (studies that see if there is a link between 2 variables) have found a relationship between high testosterone levels and questionnaire results showing greater reported aggression. It is not certain though whether testosterone causes increased aggression or aggression causes increased testosterone

Testosterone is also clearly related to aggression in humans. Dabbs et al (1987) – salivary testosterone levels were able to differentiate between 89 violent and non-violent criminals. The more testosterone the more violent their crime. Dabbs et al (1995) – measured testosterone in saliva of 692 adult male prisoners. Found higher levels in rapists and violent offenders than in burglars and thieves. Dabbs et al (1996) – looked at 12 fraternities (a social club for male undergraduates) in 2 universities. Members of fraternities with highest levels of testosterone were described as boisterous and macho, those with lowest were attentive and helpful. Those frat boys at it again…

Male aggression and testosterone 1) Why is it that males in almost every culture are more aggressive than females?

The same effects of testosterone are also found in women. Dabbs et al (1988) – female prisoners. Testosterone highest in cases of unprovoked violence but lowest where violence was defensive (eg. In domestic abuse cases) Other research has found conflicting results, but this is to do with the operationalisation of ‘aggression’.

Sex and Testosterone Dutch psychologist Stephanie VanGoozen & colleagues (1995, 1997) studied people undergoing sex change operations: – Women changing to men got testosterone injections – became more aggressive and sexual – Men changing to women got testosterone suppressants – became less aggressive and sexual

Aggression in humans 6) How can testosterone levels be measured? 7) What are correlation studies?

Recap  In almost every culture, males are far more aggressive than females; could this be because of testosterone (male sex hormone)?  Testosterone is secreted by the adrenal glands and testes and is needed to produce sperm, develop the male reproductive system and produce male features e.g. facial hair, deep voice etc.  Women also have testosterone but males produce more of it (10 times more!)  Animal research has shown that injecting testosterone increases levels of aggression whilst removing the testes decreases levels of aggression.  Castrating a male animal lowers its testosterone level making it less aggressive.  If that animal is then injected with testosterone its aggression level is restored to normal.  This is strong evidence that testosterone is responsible for aggression.  Can we say the same about humans? It is unethical to deliberately increase the testosterone level in men.  Psychologists can take blood from humans to see what level of testosterone they have and compare it to how aggressive they feel or act. Some correlation studies have found a relationship between high testosterone levels and questionnaire results showing greater reported aggression. However, it is not certain whether testosterone causes increased aggression or aggression causes increased testosterone.

Task 2: For each of the following statements, decide whether it is true or false In animals, there is no clear cause and effect relationship between testosterone and aggression. 2. Human studies show a relationship between aggression and testosterone in correlation studies. 3. All humans with high testosterone levels are aggressive. 4. Correlation and animal studies have weaknesses. Animal studies may not apply to humans, and correlation studies just look for relationships and are not direct evidence. 5. If testosterone is the cause of aggressive behaviour, are all men more violent than women? 6. This explanation of aggression completely ignores the huge impact of upbringing and social circumstances on our behaviour.

Task Read through your textbook and the rest of these slides on the role of testosterone on aggression Using the information, create a table of evidence for and against hormones as the cause of human aggression

AO3 Evidence conflicting on role of testosterone Studies showing positive correlation small samples and self-report measures Studies mainly correlational (eg. Wagner) so not possible to conclude that testosterone causes aggression Also testosterone not always associated with negative characteristics: improved sporting and spatial abilities also been found 16

AO3 Need to distinguish between aggression & dominance Issue relates to the internal validity if the research as studies may be measuring different things, making comparison of results difficult 17

AO3 issues Gender bias evident as most research done on males (animals and humans) whereas it is known that there are differences between the genders in androgens Also cultural bias as most research conducted in western countries 18

AO3 debates Physiologically reductionistic to just consider role of biochemistry alone Also need to consider genetic factors Also need to consider the contribution of environmental factors such as situational cues, temperature, noise, overcrowding, and the role of learning 19

AO3 application/conclusion Clearly a very important & useful area of biopsychological research and theory as aggression associated with many anti-social phenomena in society, eg. numerous forms of crime, violence If the role of biochemistry can be understood it can perhaps be treated or managed Although there would be ethical issues associated with giving people drugs simply to alleviate aggression (ie. for social control), or male castration, even if it may be in the interests of multiple parties Could perhaps be treated more ethically through diet (tryptophan) and exercise 20

Evaluate the role of hormones on aggressive behaviour (12 marks) 21

Point – A strength of the argument that hormones are associated with aggression come from animal studies. For example… Evidence- Comment – Therefore this suggest that testosterone has a large role to play when explaining aggression. Point – However, on the other hand…. 22

Reductionism (nature) being too simple – use nurture argument Problems with generalising Problems with causation (is it the aggression that caused the increase in testosterone or the other way round?) 23