THE BIOLOGICAL APPROACH

what is this approach

• most scientific, eg. fMRI to measure

• main assumption is all behaviour is driven by physical or physiological factors. the way we think, feel and behave all have roots in biological functioning

• emphasis on nature (not nurture) in shaping behaviour

what’s the drive for behaviour

genetic factors

biological structure

neurochemistry

4 parts of biological approach

evolution and behaviour

genes and behaviour

biological structures in the brain (neuroanatomy)

neurochemistry and behaviour

1. evolution and behaviour

evolution is the gradual change within a species over several generations in response to environmental pressures

natural selection is the inherited characteristics that enhance survival and are passed into offspring

adaptive is behaviours or traits that will increase change of survival or reproduction

charles darwin 1864

all behaviour is acquired through natural selection and survival of the fittest. it ensures only behaviours that are adaptive will be passed down generations

seligman 1971

biological preparedness of phobias to certain things. innate tendency to create fears of potentially harmful phenomena’s (eg. heights, snakes, spiders) it has survival value

2. genes and behaviour

identifies whether behaviours like intelligence, aggression, personality and mental illness are inherited in the same way as physical characteristics like eye colour. all humans are genetically 99.9% the same but with a unique genotype

genotype vs phenotype

genotype is the unique DNA sequence an individual has or a specific set of inherited genes. each cell contains this copy, 0.1% has human variation

phenotype is observable, physical or physiological characteristics/ expression of traits. these can be influenced by environment and genetics

interactionist approach

nature and nurture (environment and biology) interact with each other

eg. identical twins (monozygotic) are genetically identical, non identical twins (dizygotic) share 50% genetic similarities.

diathesis-stress model is used to explain development of disorders like schizophrenia

genetically inheriting OCD

polygenetic condition and individuals with one of the candidate genes are likely to develop conditions

genetically inheriting schizophrenia

interactionist approach and diathesis stress model. schizophrenia developed due to enlarged ventricles in the brain

3. neuroanatomy

biological structures of the brain, mapping relationship of brain areas to specific functions. identifying areas of brain using case studies, or nowadays brain scanning equipments

Raine et al 1997

used PET scans to identify several areas of murderers brains (who pleaded not guilty due to insanity). reduced activity in prefrontal cortex, amygdala and hippocampus. abnormal asymmetries reduced activity on left and greater activity on right