Biological Approach
Assumptions
Genetics: genes an individual possesses influence behaviour
Evolution: Behaviour evolves in the same way as physical characteristics
CNS: brain is the main focus when explaining behaviour as it is seen to the the origin of how the world is seen and acted upon.
Biochemistry: varying levels of chemicals found in both the brain and he body hormones are related to behaviour.
Genotype: an individuals genetic make up which occurs at conception and provides the genetic code for how that individual will develop - eye colour and hair colour.
Phenotype: Expression of an individuals genetic makeup which can be influenced by the environment - height.
Hereditary is the process where characteristics are passed from one generation to the next. Genes carry out the instructions for a particular trait and biological psychologists believe that behavioural characteristics such as intelligence and personality are inherited in the same way as physical characteristics.
Twin Studies
Concordance rates on MZ and DX twins were recorded. Schizophrenia - MZ 48% DZ 17%. Bipolar MZ 40% DZ 5-10%.
(-) Concordance rates in MZ twins are never 100%. Behaviour is not solely caused by genetics so the environment factors must have some role to play.
Adoption Studies
Concordance rates of behaviour between adoptive child and their biological parent. 50% with biological parent but 0% with adoptive parent.
(-) Difficult to claim that high concordance rates suggest that the behaviour is purely genetic. Spent time with biological parent before adopted so is difficult to establish similarities are due to behaviour or learnt before adoption.
Maternal love: chances of women's offspring surviving and passed on through generations - adaptive
Mate preferences: males prefer women who present characteristics of fertility so she is more likely to give birth.
Aggressive: improve survival rates and increase access to resources. Helps protect territory.
Neurotransmitters: the transmission of chemicals is via the cerebral fluid through chemicals which include neurotransmitters. Synaptic transmission.
Evaluations
(+) successful treatment: Created drugs such as antidepressants and anti anxiety drugs. Effective during psychological abnormalities.
(+) Scientific method: brain scans are largely objective. Use of sophisticates imaging has increased the precision and objectivity of research in this area.
(+) Non-human participants: easy to control and manipulate - establish cause and effect.
(-) Over simplistic and takes nature side: ignores environmental environmental factors
(-) Reductionist: explain complex behaviour by reducing it down to its smallest component - genes and hormones.
(-) Deterministic: behaviour is a product of external influences and we cannot control our own processes.