influence of genes on behaviour

Question 1

genetic inheritance

Answer 1

Our genetic inheritance comes from our parents, this can explain why we may share both physical and psychological characteristics with our parents.
However, although genes contain the blueprint for particular characteristics, how they develop or are expressed in a particular individual depends on the complex interaction between nature and nurture.

Question 2

twin studies

Answer 2

One way psychologists study the interaction between nature and nurture is through twin studies.
Monozygotic (MZ) or identical twins share 100% of each other’s genes.
Dizygotic (DZ) or non-identical twins share 50% of DNA - the same as regular siblings.

Question 3

concordance rates

Answer 3

Psychologists look at concordance rates, these are the percentage of both twins displaying the same characteristics. The expectation is that if a characteristic is inherited there will be a higher concordance rate in MZ twins.
Schizophrenia - 48% concordance rate for MZ twins, 17% concordance for DZ twins.
Bipolar depression - 40% concordance for MZ twins, 7% concordance for DZ twins.
Anorexia nervosa - 23% concordance for MZ twins, 9% concordance for DZ twins.
However if characteristic were wholly inherited, concordance would be 100%