A01

• This approach focuses on the biological structures and processes inside our bodies which are said to be responsible for our thoughts and behaviour, for example the effect of neurotransmitters or genes on behaviour.

  Psychological traits such as personality, intelligence and mental disorders are inherited the same as physical traits. The genetic basis of behaviour can be explored through twin studies: If the concordance rate for MZ twins is higher than DZ twins for a behaviour, then you can conclude a genetic basis as MZ twins share 100% of their genes while DZ twins only share 50%.
• The genetic make-up is called genotype whereas the way those genes are expressed through physical or psychological characteristics is called phenotype. A person’s phenotype is influenced by both their genotype and their environment.

  Finally, any genetically determined behaviour that enhances an individual’s survival and reproduction will continue in future generations (i.e natural selection). For example, memory evolved because it gave certain advantages (i.e. remembering a poisonous berry) which helped humans survive, reproduce and pass on this trait.