Genetic factors for aggression (Biological explanations) Flashcards
What main areas can you draw upon in questions regarding genetic factors?
The MAOA gene and Twin/Adoption studies.
What is the role of the MAOA gene?
The MAOA gene codes for an enzyme which breaks down a series of neurotransmitters. These are dopamine, serotonin, and noradrenaline.
Give a basic account of the role of dopamine and serotonin in aggression (combined).
Imbalances in levels of these neurotransmitters leads to aggression.
What two studies support the role of the MAOA gene in aggression?
Brunner (1993) and Caspi (2002).
Outline Brunner’s study and findings from 1993.
Brunner looked into a family who were reported to highly aggressive males. He found they were all suffering from a defective MAOA gene. As a result, he found high levels of the highlighted neurotransmitters in urine samples taken from the males.
Outline Caspi’s findings from 2002. He found results which both support and confound with the MAOA model.
He found that there was only a significant increase in aggression levels if the defective gene was couple with severe maltreatment at childhood.
Give two negative IDA points for the MAOA gene theory.
Nature vs nurture and determinism.
Give the negative Nature vs Nurture IDA point against the MAOA gene theory.
Give the negative Nature vs Nurture IDA point against the MAOA gene theory.
Give the negative determinism IDA point against the MAOA gene theory. This includes a real life case.
The theory suggests that those who have the defect will be aggressive. It gives them an alibi to commit violent crimes. Bradley Waldrop managed to avoid the death penalty for double murder as a result of pleading determinism.
What state was Waldrop tried in?
Tennessee.
What did Mason & Frick find in their 1994 study? What form did this study take?
A meta-analysis of twin and adoption studies which found genes only count for about 50% of aggression.
What did Mcguffin & Gottesman find in their twin study?
MZ concordance of 87% and DZ concordance of 72%.
What did Coccaro find in his twin study?
Found genes accounted for 40% of aggression.
Why is Coccaro’s study highly useful?
It measured pure aggression and not just anti-social behaviour, thus giving it high internal validity.
What did Hutchings & Medinck find in their twin study?
14,000 twins. There was a high concordance of conviction for kids and their biological fathers.
