Neural, Hormonal & Genetic Mechanisms in Aggression (AQA A Level Psychology): Flashcards
Exam code: 7182
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Define aggression.
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Cards in this collection (40)
Define aggression.
Aggression is behaviour intended to harm another person who is motivated to avoid that harm.
Which brain region is most associated with aggression?
The limbic system, first linked to emotional behaviour by Papez (1937) and revised by MacLean (1952).
Name three structures of the limbic system.
Any three of the cingulate gyrus, septal area, hypothalamus, fornix, amygdala and parts of the hippocampus.
The most important limbic structure in aggression is the , whose reactivity predicts aggressive behaviour.
The most important limbic structure in aggression is the amygdala, whose reactivity predicts aggressive behaviour.
What did Gospic et al. (2011) find using the Ultimatum Game?
Rejecting unfair offers was accompanied by a fast, heightened amygdala response. A benzodiazepine halved rejections and reduced amygdala activity.
How does serotonin normally affect aggression?
It has inhibitory effects. Normal levels in the orbitofrontal cortex are linked to greater self-control, so decreased serotonin increases impulsive aggression (Denson et al., 2012).
What did Virkkunen et al. (1994) find?
Violent impulsive offenders had significantly lower levels of the serotonin metabolite 5-HIAA than violent non-impulsive offenders, plus more sleep irregularities.
True or False?
Coccaro et al. (2007) found increased orbitofrontal cortex activity in aggressive psychiatric patients.
False.
Activity was reduced, disrupting the cortex's impulse-control function and increasing aggression.
True or False?
Testosterone is a neural mechanism of aggression.
False.
Testosterone is a hormonal mechanism, part of the endocrine system. Neural mechanisms relate to the brain and nervous system.
Why is testosterone the main hormone associated with aggression?
Males secrete more testosterone and display more aggression. As an androgen, it regulates social behaviour via brain areas implicated in aggression.
What did Giammanco et al. (2005) demonstrate?
Experimental increases in testosterone raised aggression in several animal species, and castration reduced it.
Dolan et al. (2001) found a positive correlation between testosterone and aggression in 60 male offenders in UK hospitals.
Dolan et al. (2001) found a positive correlation between testosterone and aggression in 60 male offenders in UK maximum security hospitals.
What did Mehta and Josephs (2006) find?
Of losers whose testosterone rose after losing, 73% rechallenged their opponent. Of those whose testosterone dropped, only 22% did.
What did Klinesmith et al. (2006) find?
Male students who interacted with a gun rather than a toy showed greater testosterone increases and added more hot sauce to water for another student.
How does Berman et al. (2009) provide non-correlational evidence?
Participants given paroxetine, which enhances serotonin, gave fewer and less intense shocks than a placebo group, though only those with a history of aggression.
What did Dabbs et al. (1995) find in prisoners?
Violent criminals had higher testosterone than those who committed theft and violated more rules, particularly those involving confrontation.
True or False?
Neural and hormonal research on aggression is mostly experimental.
False.
It is mostly correlational, for ethical reasons, so cause and effect and third variables cannot be established.
What do neural and hormonal explanations ignore?
Social and environmental factors such as upbringing, education and substance abuse.
Neural and hormonal explanations are , reducing aggression to brain structures and chemical imbalances.
Neural and hormonal explanations are reductionist, reducing aggression to brain structures and chemical imbalances.
Why do biological explanations of aggression raise questions of responsibility?
They suggest aggression is biologically determined, challenging free will and accountability in legal and moral contexts.
What do genetic explanations assume about aggression?
It results from inherited traits adapted across generations because of their evolutionary usefulness, e.g. for survival.
Twin studies suggest heritability accounts for about % of the variance in aggressive behaviour.
Twin studies suggest heritability accounts for about 50% of the variance in aggressive behaviour, the rest being environmental.
Why are MZ and DZ twins compared in genetic research?
MZ twins share 100% of their DNA and DZ around 50%, while both are raised in the same environment, so greater MZ similarity implies genetic influence.
What did Coccaro et al. (1997) find?
For direct physical assault, concordance was 50% for MZ twins and 19% for DZ twins.
What did Rhee and Waldman's (2002) meta-analysis find?
Genetic influences accounted for 41% of the variance in aggression and antisocial behaviour in adoption studies, in line with twin studies.
True or False?
In adoption studies, similarity to adoptive parents suggests genetic influence.
False.
Similarity to biological parents suggests genetic influence. Similarity to adoptive parents suggests environmental influence.
Define monoamine oxidase A (MAOA).
MAOA is an enzyme that 'mops up' neurotransmitters, especially serotonin, after transmission, breaking them down to be recycled or excreted.
True or False?
The MAOA gene codes for serotonin.
False.
It codes for the MAOA enzyme that breaks serotonin down. A dysfunctional gene alters enzyme activity, which affects serotonin levels.
Why does disrupted serotonin matter for aggression?
Serotonin balances mood, so low or disrupted levels may be a factor in affective disorders such as depression and in aggressive behaviour.
What did Frazzetto et al. (2007) find?
Higher antisocial aggression was linked to the low-activity MAOA variant, but only in men who had experienced significant childhood trauma, a gene-environment interaction.
What did Stuart et al. (2014) find?
Men with the low-activity MAOA gene were the most violent perpetrators of intimate partner violence, inflicting the worst injuries.
What did Mertins et al. (2011) find?
In a money-distributing game, men with the high-activity MAOA variant were more co-operative and made fewer aggressive moves.
What did Brunner et al. (1993) find?
28 males from a Dutch family with impulsive violent behaviour had abnormally low MAOA and the low-activity gene, though one family limits generalisation.
Why is biological evidence for genetic explanations considered valid?
Saliva samples and DNA analysis are objective and can be measured by researchers blind to aggression scores.
Why do twin and adoption studies produce robust data?
They tend to use large samples, such as Rhee and Waldman's 51 studies, generating robust quantitative data.
Why is measuring aggression a problem for genetic research?
Methods differ (self-report, parent and teacher reports, observation). Rhee and Waldman found genetic effects larger with self-reports, making valid conclusions hard.
In Stuart et al.'s study, IPV was also associated with the serotonin transporter gene .
In Stuart et al.'s study, IPV was also associated with the serotonin transporter gene 5-HTT, so genetic effects are small and involve other genes.
What did Vassos et al. (2014) find?
No association between any single gene and aggression. Hundreds of genes interact in complex ways, casting doubt on the search for single candidate genes.
How does Caspi et al. (2002) support an interactionist approach?
Environmental triggers like childhood trauma interact with genes, so aggression is shaped by both genetic vulnerability and experience.
Why do genetic explanations raise questions of moral responsibility?
They imply biological determinism, so it is unclear whether someone carrying a so-called 'warrior gene' can be held fully accountable.
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