Reactivity of what system predicts aggressive behaviour? What other pats of the brain come under this system?
(i) Limbic system
(ii) Amygdala, cingulate gyrus, hypothalamus.
What did Gospic et al. (2011) find?
Found aggressive reactions were associated with a fast and heightened response by the Amygdala.
How is serotonin related to aggression?
In relation to serotonin and aggression, what did Virkkunen et al. (1994) find?
What hormone, found in larger quantities than men, is linked to aggression?
Testosterone.
In relation to testosterone and aggression, what did Dolan et al. (2001) find?
How do animal studies show the influence of testosterone on aggression?
How does the Limbic system explanation exclude other possibilities?
What supporting evidence is there for the role of serotonin?
A part from supporting evidence for the role of serotonin, give a further strength of the neural and hormonal mechanisms in aggression.
1) A plausible mechanism to explain testosterones effects.
- Mazur’s (1985) biosocial model of status (BMoS) suggests changes in testosterone levels following a loss of status in a competition should affect aggressive behaviour afterwards.
What evidence supports Mazur’s biosocial model of status?
A part from the Limbic system explanation excluding other factors, give a further limitation of neural and hormonal mechanisms on aggression.
1) Neural/hormonal explanations research is correlational.
- Studies with humans impossible for ethical issues
- Issues with generalising with animals.
- Other factors overlooked, simply correlation between serotonin and aggression.
In terms of genetic factors in aggression, what twin study supports the role of genetics?
- Concordance rate = MZ of 50%, DZ of 19%
In terms of genetic factors in aggression, how do adoption studies support the role of genetics?
In terms of genetic factors in aggression, how does MAOA support the role of genetics? Describe it.
Why is the MAOA gene nicknamed the ‘warrior gene’ ? Can you explain the evidence that backs this up?
Who found that the most violent domestic abusers had the low-activity MAOA gene?
Give 1 strength of genetic factors in aggression
1) MAOA explanation has support from animal studies.
- Genetic deletion allows researchers to ‘knockout’ single genes on mice so they could observe the effects on aggression.
- Godar et al. (2014) - showed MAOA knockout mice have increased brain serotonin and are hyper aggressive.
= when blocked by a drug –> non-aggressive.
Give 3 evaluative limitations of the genetic explanation in aggression.
1) Difficult to isolate genetic factors.
- Separate environment and genetic factors?
- McDermott et al. (2009) - participants with low-activity MAOA gene behaved aggressively in a lab-based task, but only when they were provoked.
2) Multiple genetic influences.
- Genetic effects quite small, but statistically significant.
- Stuart et al. (2014), along side low levels of MAOA, found low levels of serotonin transporter gene.
3) Findings depends on how aggression is measured.
- Methods differ between studies; include self-reports, observations etc.
- Rhee + Waldman’s study found genetic factors had a greater influence on aggression in self report studies than from parents.
= valid conclusions?
According to the ethological explanation of aggression, in what two ways is aggression beneficial to survival?
1) Reduces competition.
2) Establishes dominance hierarchies - aggression gives a special status.
What does ritualistic aggression mean?
Explain what Lorenz (1966) found in to ritualistic aggression
What is an IRM and what is it triggered by?
What does the Innate Releasing Mechanism (IRM) trigger?
A fixed action pattern (FAP).