Biological Theories Flashcards
What are the two types of biological theories
Genetic
Physiological
Name one example of an biological genetic theory
Jacobs XYY
Twin Studies
What is Jacobs XYY theory based on
The XYY syndrome -
Male has an extra Y chromosome
What does Jacob saying having an extra Y chromosome make them
More aggressive
What can XYY males be referred to as
Supermales
A case example supporting Jacobs XYY theory
John Wayne Gacy
Give 2 advantages of Jacobs XYY theory
Found they were more XYY men in the prison population compared to general public
Tries to explain why XYY men may commit more aggressive crimes - John Wayne Gacy
Give 2 disadvantages of Jacobs XYY theory
Not all men with XYY commit crime or aggressive acts
The theory ignores environment factors e.g. upbringing
Name one example of a physiological theory
Sheldon
What did Sheldon theory focus on
Somatotypes (body types)
Name the three different body types Sheldon focused on
Mesonorphic
Endomorphic
Ectomorph
Which body type did Sheldon label as criminal
Mesomorphic
Describe mesomorphs
Muscular and hard
More aggressive
Describe endomorphs
Fat and soft
Tend to be sociable and relaxed
Describe ectomorphs
Thin and fragile
Are restrained
Give 2 advantages of Sheldons theory
Had a control group of 200 college students to compare criminals to
Other studies seem to support this theory to some extent - Putwain and Sammons
Give 2 disadvantages of Sheldons theory
Ectomorphs and endromorphs can also be criminals
Body types are fixed throughout life and can change
Name the two types of twins and how much DNA they share in the twin studies
Monozygotic - 100%
Dizygotic - 50%
What do twin studies look for
Concordance rates between twin siblings
What do many studies suggest about concordance rates in the twin studies
Higher in monozygotic than dizygotic twins
An example of a theorist who found higher concordance rates in MZ twins for criminal behaviour
Lagne
Give 2 advantages of Twin Studies
Provides a good natural experiment - nurture is kept constant
Highly true to life - nothing in manipulated
Give 2 disadvantages of Twin studies
Not representative - small sample
Very deterministic
Twins aren’t always exposed to the same environmental influences
