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Outline and evaluate one or more biological explanations of
human aggression (8+16 marks)
- Neurotransmitters are chemicals that enable impulses within the brain
to be transmitted from one area to another.
- Serotonin and Dopamine are two neurotransmitters that have been
linked with aggressive behavior.
- Serotonin is thought to reduce aggressiveness by inhibiting responses
to the emotional stimuli. Low levels of serotonin has been linked with
impulsive behaviour such as aggression.
- Some drugs have been found to alter serotonin levels, thus increasing
the chance of aggressive behaviour.
- Mann et al. (1990) gave 35 participants dexfenfluramine, which reduces
serotonin levels. The participants completed a questionnaire; Mann
found an increase in aggression and hostility in males, but not females.
(Consider using this study as A02)
- It has been suggested that there might be a link between dopamine and
- Lavine 1997 stated that an increase in dopamine by the use of
amphetamines has also been linked with aggressive behaviour.
- Furthermore, Buitelaar, 2003; found that antipsychotics, which reduce
dopamine in the brain, have been shown to reduce aggressive behaviour.
- Testosterone is thought to have an influence on aggression due to its
action on brain areas involved in controlling aggression.
- Dabbs et al 1987 measured salivary testosterone in violent and
non-violent criminals. He found criminals with high testosterone to
have a history of violent crime, whereas criminals with lowest levels had
committed only non-violent crimes. (Consider using this study as A02)
- Lindman et al. (1987) found that men who behave aggressively when
drunk have higher testosterone levels than those who did not act
- The challenge hypothesis- Wingfield et al., 1990 proposes that, in
monogonous species, testosterone levels should only raise above the
baseline breeding level in response to social challenges such as
male-male aggression or threats to status. Provided that the threat is
relevant to reproductive competition.
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- Cortisol appears to have a mediating effect on other aggression-related
hormones such as testosterone
- Dabbs et al., 1991 found that high levels of cortisol inhibit testosterone
and so inhibit aggression.
- Vukkenen 1985 found that studies have reported low levels of cortisol
in habitual violent offenders and in violent school children.
- P: To evaluate, evidence to support the role of serotonin in aggression
was found by Scerbo and Raine 1993.…read more
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- P: However there is inconsistent evidence to support the link between
testosterone and aggression.
E: Albert et al., 1995 claim that despite many studies showing a positive
correlation between testosterone and aggression, other studies find no
C: Suggesting that there is no evident link between testosterone and