Biological approach


Biological assumptions

Different areas of the brain:

  • Different areas of the brain specialised to certain functions.
  • Cerebral cortex associated with higher cognitive functions and divided into 4 lobes. Frontal lobe responsible for fine motor movement. Occipital lobe associated with vision.


  • Neurones=electrical cells that make up the nervous system
  • Neurone communicates with another at the synapse where the message is passed on by chemical messangers, neurotransmitters.
  • Neurotransmitters are released from presynsptic vesicals and bind to receptors on the postsynaptic membrane.
  • Dopamine: associated with rewards
  • Serotonin: associated with sleep and arousal
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Selye's GAS model

  • Display a universal repsonse to all stressors. General Adaptation Syndrome.
  • Links stress with illness. Stress lowers physiological resources which lowers organisms resistance to infection.
  • S1: Alarm reaction: Stressor is recognised. Hypothalamus triggers production of adrenaline to prepare for the fight ot flight reaction. S2: Resistance: Body finds a mean of coping. S3: Exhaustion: Body systems can no longer continue and initial symptoms reappear.
  • Discorvered this when working in a hospital. All patients had loss of apitite, pains and aches.
  • Selye exposed rats to unpleasant stimuli, Cold, surgical injury, cutting o the spinal chord and lethal doeses of drugs. Syndrome developed in 3 stages. S1=6-48hrs. Physiological traid, enlargement of adrenal glands, ulcers in the digestive system and shrinkage of the immune system. S2: Appearance and function fo organs returned to normal. S3: Lost resistance. Physiological traid reappears.
  • Concluded theres a non-specific response to any demand upon the body. Observed in rats similar to the general defense mechanism linked to illness.
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  • Surgical proceudre perfomed ont he brain with the aim of treating mental disorders. May involve destorying sections of the brain or severing fibres so areas of the brain are seperated. Linked ot assumption that areas of the brian links to different behaviour.
  • Prefrontal lobotomy: Destruction of frontal lobe fibres. Aims to alleviate symptoms of OCD and schizophrenia. Easrly methods, Moniz, whi drilled a hole into the skull to destory finbres with an ice pick were unsuccessful. Comer (2002) found that lobotomies have a fatality rate of 6% and a range of side effects including brain seizures and lack of emotions.
  • Stereotactic psychosurgery: MRI used to pinpoint sections fo the brain so fibres can be desotryed selectively. OCD and depression. Capsulotomy where surgeons insert probes through top of skull to destory connections near hypothalamus to treat OCD. Cosgrove and Rauch (2001) capsulotomy was effective in 67% of pateints and 55% with severe symptoms.
  • Deep brain stimulation: Wires implanted in brain with no tissue destoryed and connected ot a battery pack in the chest. High frequency distrupts brian activity.
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Strengths and weaknesses


  • Assumptions are behaviour explained in terms of the brain, hormones and neurotransmitters - Biological explanations have clear variables that can be tracked and examined. Enables psychologists to conduct scientific research. E.g. psychosurgery based on research that links brain with aggression.

Successful applications:

  • Selye - understanding of stress and illness. Further research of people recover less quickly if stressed- changed hospitals to reduce anxiety in patients.
  • Treatment of metal disorders - E.g psychosurgerya and chemotherapy


  • Simple. Behaviour reduced to hormones, neurotransmitters and the brain. E.g. Stress reduced to hormone adrenaline. Loose understanding of real meaning.

Ignores differences:

  • Nomothetic approach and makes generalisations. Assumes peoples biological systems work the same. However, research is male biased.
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Brain scanning:

  • Assumption of different parts of the brain associated with different functions
  • EEG: Electrodes places on scalp and electrical activity recorded. Used in Derment and Kleitman (1957) study on different stages of sleep.
  • CAT: X-rays combined to form 2d or 3d image. Useful for revealing abnormalities as has a high quality picture. However, high radiation.
  • PET: Radioactive glucose ingested and shows on active parts of the brain. Raine (1997) used PET scans to compare brain activity in murderers and normal individuals. Found difference si the amygdala which has been previously associated with aggression. Different stypes of tumors can be recognised however expensive and patient exposed to radiation.

Twin studies:

  • Influence of genes on behaviour
  • MZ twins share 100% of genes so perfect participants for investigating genes on behaviour. However, reared in the same environment and when reared apart, reared in similar environments in terms of social class. Difficult to conclude that only genetics have an influence on behaviour.
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