P1 - Biological Approach - Genetics and Behaviour Flashcards
genes, genetic similarities, evolutionary explanations
what is a gene?
basic physical and functional unit of hereditary which is made of DNA. Some genes act as instructions to make proteins
what is human behaviour influenced by?
genes and environment
what is the study we use for genes?
Brunner
what is the study we use for genetic similiarities?
Brunner
what is the study we use for family/kinship studies?
Brunner
what is the study we use for twin studies?
Coccaro
what is MAOA
its a gene to make an enzyme called MAOA, which is responsible for breaking down serotonin.
it sweeps up any serotonin left in the synaptic gap
if this enzyme doesnt work, there would be a build up of serotonin, where people become immune to it and need more to have a normal level
on the x chromosome
MAOA-L - less MAOA is produced, brain becomes insensitive to the calming effects of serotonin
what is the background to Brunner 1993
a large dutch family
several women sought genetic counselling as certain males in their family were prone to aggressive and impulsive outbursts. one raped his sister, arson, run over employers.
geneists at the university hospital said it ran in males due to the x chromosome
what is the aim of Brunner 1993?
to explain behaviour of a large familys of which males were affected by abnormal violent behaviour
who are the participants in Brunner 1993
5 men from the same family
what was the procedure of Brunner 1993?
data collected from genetic material from the family from a urine sample
what were the findings of Brunner 1993?
low levels of MAOA enzyme and a mutuation was found on the x chromosome on the gene responsible for producing MAOA
what was the conclusion for Brunner 1993?
the defect in the gene causes the mental disabilities which would lead to violent behaviour
why do we use families for genetic similarities?
family studies provide a way to examine the relationship between genetics and behaviour. If a certain trait is influenced by our genes, close relatives should also display that behaviour.
link genetic similarities to brunner
Brunner uses genetic similarities to identify a genetic influence for aggression as the five males who all displayed aggressive behaviour in one family were also found to have the same genetic mutation on the x chromosome, supporting evidence for the MAOA genes.
link kinship/family studies to Brunner
Brunner uses participants from the same family to establish that MAOA gene has a role in aggression as all males from the same family display similar similar aggressive behaviours and have the same genetic mutation on their x chromosone.
why do we use twins in genes in research?
its one of the possible ways to study the correlation of genetic inheritance and behaviour is through twins.
what are the difference in twins?
monozygotic twins - share 100% DNA, as egg is split
dizygotic twins - share 50% of DNA as 2 seperate eggs fertilisied by 2 seperate sperms
what is the concordance rate?
presence of the same trait in both members of a pair of twins
what is the aim of Coccaro et al 1997
to investigate monozygotic vs dizygotic twin pairs
who are the sample of Coccaro et al
american male veterans
182 MZ and 118 DZ
what is the procedure of Coccaro et al 1997
examined for concordance of criminal behaviour.
measured using the BDHI, which is a questionaire designed to assess hostile behaviours, direct/indirect assualt, verbal, irritability
what are the findings of Coccaro 1997
MZ - 50% concordance for direct physical assualt, with 19% DZ
verbal aggression MZ - 28%, DZ - 7%
what is the conclusions of Coccaro et al?
supports role of genetics in aggression as twins were genetically identical were more likely to display criminal behaviour than DZ twins
what is evolutionary psychology?
behaviour can be explained by appeal to the internal psychological mechanisms
what is intersexucal selection?
making themselves attractive to the other sex
becomes a competition to attract a mate
intrasexual selection
occurs between same sex
direct competition between individuals of same sex to maintain the ability to pass on their traits
what study do we use for evolutionary explanations?
wedekind
aim of wedekind et al 1995
to determine whether MHCs would affect mate choice
procedure of Wedekind 1995
sample: 49 females, 44 males from Uni of Bern, Switzerland. different courses
- men were asked to wear a tshirt for two days and keep it in a plastic bag at night. scent free soap, no deodrants, no perfumes, no tobbacco, no alcohol, no spicy food, no sex
- 2 days later, women ranked the 7 tshirts through a cardboard smelling hole
- 2 weeks after menstruation
- nasal spray for two weeks
- 3/7 similar MHC, 3/7, different MHC 1/7 control
ranked odours of tshirts for intensity and pleasantness
what were the results from Wedekind 1995
women scored male body odours as more pleasant when the MHC was different
what was the conclusions of Wedekind
women preffered odours of men with a different immune system as it would increase the health of their potential babies.
link Wedekind to evolutionary explanations
MHC genes make molecules that enable immune system to recognise pathogens. the more diverse the MHC genes of the parents, the stronger the immune system of the offspring. We have evolved the strategy of being able to smell who has a different version of the MHC gene to us
