biological theory of agression - hormone testosterone Flashcards
(11 cards)
What are hormones?
· Hormones are chemical messengers that transmit information around the body through the blood stream.
· They are involved in the regulation of our physiology and behaviour including breathing, temperature, metabolic rate, reproduction, stress, growth and development, sleep and mood.
· They are produced and excreted by glands and this system of glands is called the endocrine system.
What is testosterone?
Testosterone is an androgen meaning that it is a chemical that develops or maintains male characteristics.
We all have testosterone in our bodies but it is present in a much greater degree in a much greater degree in the average male the compared to females.
Antenatal (in the womb) exposure to testosterone has an organising effect on the developing brain.
During the critical period immediately following birth testosterone sensitises certain neural circuits. It stimulates cell growth in areas of the hypothalamus and amygdala (which, as we have seen, have a role in the perception and reaction to environmental threats which includes aggressive responses)
What is the evidence for hormone theory?
Male rodents will be castrated (remove the testicles) which stops the production of testosterone
Their behaviour is compared to control rodents e.g under control conditions like threat and competition for mates
The issues with using evidence from animal experiments is that animals are different as they won’t be able to reason with their aggression due to the lack of cortical folds
Hawke 1951
Looked at case studies of convicted sex offenders who had been castrated.
There have been cases where convicted sex offenders have been chemically castrated and this led to the removal of aggression and a loss of sex drive.
Dabbs et al 1987
Looked at
89 male prisoners who had been convicted of either violent crime or non-violent crime and measured the amount of testosterone in their salvia.
Inmates with higher testosterone concentrations had more often been convicted of violent crimes. 10 out of 11 inmates with the highest testosterone concentrations had committed violent crimes. Inmates rated ‘tougher’ by their peers were higher in testosterone.
89 prisoners, measured saliva. Inmates with higher testosterone concentrations had more often been convicted of violent crimes ( 10 out of 11 inmates with the highest testosterone concentrations had committed violent crimes). Inmates rated as ‘tougher’ by their peers were higher in testosterone.
Mazur 1983
Looked at aggression and testosterone levels across the lifespan.
Testosterone levels increase during the early teens and there is strong positive correlation with aggressive behaviour and inter male fighting.
Testosterone levels increase during the early teens and there is a strong positive correlation with aggressive behaviour and inter- male fighting.
Dual hormone hypothesis
- hormonal causes of aggression are much more complex that the role of a single hormone implies
- one theory highlights the role of a second hormone - cortisol - secreted by the adrenal glands to protect the body against the effects of stress
- this suggests there is an interaction between systems responsible for regulating aggression and the stress response
- Carre and Mehta (2011) claim that high levels of testosterone lead to aggressive behaviour only when cortisol levels are low. When cortisol is high, testosterones influence on aggression is blocked
- this may be a better predictor!!!!
EVIDENCE
Dabbs et al. Measured saliva of 89 male prisoners and found 10 out of 11 prisoners with high levels of testosterone were involved in violent crime
* this validates the hormonal explanation of aggression and supports the role of nature in the development of aggressive acts
However, Dabbs can only be used to understand aggression in the criminal population and may not generalise to individuals outside this setting e.g measuring aggression in ‘normal’ individuals
The impact of testosterone on aggression can be measured under a scientific framework using objective tools e.g saliva. Therefore gives some credibility to the explanation
APPLICATION
Drug treatment of offenders I.e if aggression is chemically controlled then we can produce a drug treatment which influences the hormonal mechanism and reduces aggressive behaviours.
Maletzy (2006) - found that a testosterone lowering drug reduced level of sexually aggressive behaviours in some offenders.
Therefore, we can have positive application in society.
e.g Hawke - there have been cases where convicted sex offenders have been chemically castrated and this led to the removal of aggression and a loss of sex drive.
STRENGTHS AND SHORTCOMINGS
Reductionist - assumes aggression can be broken down to hormones and doesn’t take into account other factors.
That said, it is useful to be reductionist, allows researchers to isolate variables such as hormones which are related to aggression which can lead to treatment.
Many studies of hormonal influences on human aggression are correlation. This is sensible for ethical and practical reasons but we cannot establish a casual relationship and therefore it is not as scientific.
It is difficult to determine testosterone levels as we have ‘baseline’ and ‘fluctuating’ levels - some may argue the baseline is less important. Therefore, questions if valid indicator of testosterone levels in relation to aggression.
Testosterone explanations do not asses the role of the hormone implies different types of the hormone in different types of aggression e.g physical and social aggression.
ALTERNATIVE
Testosterone explanations of aggression do not take account of the role of nurture in the development of the behaviour.
Social learning theory would suggest that..
This highlights the difficulty in reducing complex behaviours to simple explanations
