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BIOLOGICAL EXPLANATIONS OF AGGRESSION
1. The role of genetic factors –
A chromosome is an organized structure of DNA and protein that is found in
cells. It is a single piece of coiled DNA containing many genes, regulatory
elements and other nucleotide sequences. Chromosomes also contain DNAbound proteins, which serve to package the DNA and control its functions.
YOU WILL NOT BE ASKED TO EXPLAIN THIS IN THE EXAM, BUT IT MIGHT
BE HELPFUL FOR YOU TO KNOW IT.
Most individuals have
chromosomes (23 from each parent).
X or Y?
Female chromosome =
Male chromosome =
How many chromosomes do most people have?
How many chromosomes does the XYY male have?
It is possible for a male to have an extra Y chromosome.
Sandberg (1961) identified the 47 XYY karotype.
Court-Brown (1965) claimed that 47XYY males were more aggressive than
normal males and should be hospitalised. This incorrect view was accepted by
scientists and was difficult to shift.
How are such misconceptions often spread throughout society generally?
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Theilgaard researched the personality traits of XYY men and compared them
with XY men.
She found that approximately 1 in a 1,000 males are XYY.
The single characteristic was
.
But there seems to be no consistent link between genotype and aggressive
nature.
However, when Theilgaard used Thematic Apperception Testing (such as the
Rorschach test) she found
Give two reasons why this can’t be taken as proof that XYY males behave more
aggressively?
1.
2.
Cairns created aggressive mice and Nelson also created aggressive animals by
selective breeding. This is evidence that genetic manipulation can lead to
aggressive behaviour. Discuss.
Genetics have an influence. Research evidence shows that a greater number of
aggressive behaviours tend to be reported in humans with XYY karotype, but it is
complex as there are other biological influences on behaviours such as
Animal studies have shown that aggression can be passed from one generation
to another. However, there are environmental influences that should be taken
into account such as
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