Hormones & Aggression

• what is a hormone?

  Hormones are chemical messengers that transmit information around the body. They are carried in the blood and work all around the body, meaning that they take longer to work than neurotransmitters and often have long term effects on the body/ effect longer term changes. They are produced and secreted by glands and the system of glands is called the endocrine system.
• How do hormones work?

  Hormones affect behaviour and cause physical changes in the body. Different hormones are responsible for different changes like:

  Oxytocin- released from posterior pituitary gland, increases trust between people.

  Testosterone- an androgen (a hormone that develops or maintains male characteristics).
• which hormone is said to be responsible for human aggression and explain why this believed so

  high testosterone levels, paired with low cortisol levels is said to be in charge of human aggression. people with low levels of cortisol are more aggressive because it means that their autonomic nervous system (ANS) is under-aroused: through aggressive behaviour the person attempts to create stressful situations which provoke cortisol release, simulating the ANS.

  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.
• what are the three supporting studies for hormones as an explanation for human behaviour/ aggression?

  Dabbs et al, Tricker et al, Albert et al
• what did Dabbs et al do?

  They tested saliva samples of 692 male prisoners using a correlation design their results were analysed according to the type of crime committed. They found that high testosterone levels in men were more likely to commit crimes involving sex and violence and were more likely to break prison rules than low testosterone males. Men with lower testosterone were more likely to commit acts of burglary and drug use. This concluded that higher levels of testosterone led to more violence.
• evaluate Dabbs' study as supporting evidence for hormones and aggression

  this study is a correlation study as there were no control groups (low validity). This means that it isn't confirmed that testosterone causes aggression- there could be other factors that cause aggression or aggression could cause increases in testosterone. There was also a low generalisability, as the sample of criminals can not be generalised to the target population.
• what did Tricker et al's study consist of/how does it support/ contradict ideas about hormones and aggression?

  : They used a sample of three males and gave them 600mg of testosterone per week for 10 weeks. Half of them were actually given the testosterone, whilst the other half were given a placebo. The participants then filled out anger questionnaires and their families were instructed to rate their aggression. There was a lack of difference between the results of the participants who were given placebos and those who were given testosterone, therefore concluding that testosterone has no effect on aggression.
• evaluate tricker at al shortly

  the study was a double blind trial, so researcher bias was removed. furthermore, participants can't have portrayed demand characteristics
• describe what Albert et al did

  ale rats were castrated, so they no longer produced much testosterone. This led the rats to become less aggressive and less dominant. After this they manipulated the levels of testosterone in the rats through injections and drugs, observing them for any aggressive behaviour like biting. They found that the higher the testosterone, the higher the number of aggressive behaviour- this suggests that when testosterone levels are higher, the organism behaves more aggressively.
• evaluate Albert's study- whether it can be used to support/ contradict hormones as an explanation for aggression

  Albert used a sample of male rats which may not be generalisable to a population to humans. this is because rats are much simpler creatures than humans and have different emotional and cognitive processes
• what are weaknesses of hormones as an explanation for aggression/ human behaviour?

  - Reciprocal model of testosterone suggests that testosterone is the effect of dominance and not the cause of it. This means that direction of causality is an issue, as it could mean that being aggressive causes an increase in testosterone.

  - Most of the supporting evidence/ studies that have been conducted to support this idea have been conducted on small mammals and rodents, making it hard to generalise experimental findings to the surroundings. Brain areas affected by testosterone have different impacts across species- eg: cingulate gyrus in monkeys leads to fear induced aggression, but irritability in cats and dogs.

  - Experimental research cannot be carried out ethically on humans. Some evidence can come from castrated criminals, but this isn't representative because they are atypical.

  - Individual testosterone levels vary across the lifespan, according to environmental status (eg; marriage decreases testosterone, but divorce increases it).
• what is a strength of hormones as an explanation for aggression?

  Basal model suggests that testosterone causes change in a person's dominance, found more likely that males with higher testosterone were more likely to get arrested and use weapons in fights.
• what is a hormone?

  Hormones are chemical messengers that transmit information around the body. They are carried in the blood and work all around the body, meaning that they take longer to work than neurotransmitters and often have long term effects on the body/ effect longer term changes. They are produced and secreted by glands and the system of glands is called the endocrine system.
• How do hormones work?

  Hormones affect behaviour and cause physical changes in the body. Different hormones are responsible for different changes like:

  Oxytocin- released from posterior pituitary gland, increases trust between people.

  Testosterone- an androgen (a hormone that develops or maintains male characteristics).
• which hormone is said to be responsible for human aggression and explain why this believed so

  high testosterone levels, paired with low cortisol levels is said to be in charge of human aggression. people with love levels of cortisol are more aggressive because it means that their autonomic nervous system (ANS) is under-aroused: through aggressive behaviour the person attempts to create stressful situations which provoke cortisol release, simulating the ANS.

  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.
• what are the three supporting studies for hormones as an explanation for human behaviour/ aggression?

  Dabbs et al, Tricker et al, Albert et al
• what did Dabbs et al do?

  They tested saliva samples of 692 male prisoners using a correlation design their results were analysed according to the type of crime committed. They found that high testosterone levels in men were more likely to commit crimes involving sex and violence and were more likely to break prison rules than low testosterone males. Men with lower testosterone were more likely to commit acts of burglary and drug use. This concluded that higher levels of testosterone led to more violence.
• evaluate Dabbs' study as supporting evidence for hormones and aggression

  this study is a correlation study as there were no control groups (low validity). This means that it isn't confirmed that testosterone causes aggression- there could be other factors that cause aggression or aggression could cause increases in testosterone. There was also a low generalisability, as the sample of criminals can not be generalised to the target population.
• what did Tricker et al's study consist of/how does it support/ contradict ideas about hormones and aggression?

  : They used a sample of three males and gave them 600mg of testosterone per week for 10 weeks. Half of them were actually given the testosterone, whilst the other half were given a placebo. The participants then filled out anger questionnaires and their families were instructed to rate their aggression. There was a lack of difference between the results of the participants who were given placebos and those who were given testosterone, therefore concluding that testosterone has no effect on aggression.
• evaluate tricker at al shortly

  the study was a double blind trial, so researcher bias was removed. furthermore, participants can't have portrayed demand characteristics
• describe what Albert et al did

  ale rats were castrated, so they no longer produced much testosterone. This led the rats to become less aggressive and less dominant. After this they manipulated the levels of testosterone in the rats through injections and drugs, observing them for any aggressive behaviour like biting. They found that the higher the testosterone, the higher the number of aggressive behaviour- this suggests that when testosterone levels are higher, the organism behaves more aggressively.
• evaluate Albert's study- whether it can be used to support/ contradict hormones as an explanation for aggression

  Albert used a sample of male rats which may not be generalisable to a population to humans. this is because rats are much simpler creatures than humans and have different emotional and cognitive processes
• what are weaknesses of hormones as an explanation for aggression/ human behaviour?

  - Reciprocal model of testosterone suggests that testosterone is the effect of dominance and not the cause of it. This means that direction of causality is an issue, as it could mean that being aggressive causes an increase in testosterone.

  - Most of the supporting evidence/ studies that have been conducted to support this idea have been conducted on small mammals and rodents, making it hard to generalise experimental findings to the surroundings. Brain areas affected by testosterone have different impacts across species- eg: cingulate gyrus in monkeys leads to fear induced aggression, but irritability in cats and dogs.

  - Experimental research cannot be carried out ethically on humans. Some evidence can come from castrated criminals, but this isn't representative because they are atypical.

  - Individual testosterone levels vary across the lifespan, according to environmental status (eg; marriage decreases testosterone, but divorce increases it).
• what is a strength of hormones as an explanation for aggression?

  Basal model suggests that testosterone causes change in a person's dominance, found more likely that males with higher testosterone were more likely to get arrested and use weapons in fights.
• How quickly do neurotransmitters travel in the body?

  Milliseconds
• Neurotransmitters are restricted to appropriate neurons
• Signaling by neurotransmitters is all-or-nothing.
• Which hormone is associated with aggression and dominance?

  Testosterone
• Which hormone is released in response to stress?

  Cortisol
• Serotonin is associated with mood regulation and reducing aggression