Biological Approach


The Biological Approach: Assumptions

behaviour can be explained in terms of different areas of the brain 

  • the brain has specialised function based on lobes and hemispheres
  • eg. the occipital lobe deals with visual information while the hippocampus in involved in encoding long term memories 

behaviour can be explained by hormones 

  • hormones ae chemical substances that affect target organs 
  • they are slow acting in comparison to the nervous system but very powerful 
  • eg. testosterone is linked to aggression in both genders, adrenaline causes a fight or flight response 
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Selye's GAS Model (1936)

  • the body produces a general response to stress
  • the response enables the body to cope with stress
  • it is a syndrome as it is a condition that is defined by different identifiable symptoms 

Stage 1: Alarm

  • the threat is recognised and the response is alrm
  • the hypothalamus triggers adrenaline production, and causes a fight or flight response 
  • IN RATS; first 6 to 48 hours, a phsiological triad appears of enlarged adrenal glands, ulcers in the digestive system and shrinkage of the immune system 

Stage 2: Resistance 

  • this is the coping phase 
  • resources are gradually depleted 
  • things are deteriorating 
  • IN RATS: if treatment continued the function of internal organs returned to normal
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Stage 3: Exhaustion 

  • body can no longer remain normal function 
  • the initial symptoms MAY reappear 
  • the adrenal glands are damaged from prior over activity 
  • coritsol production has slowed 
  • stress related illness occurs such as depression and cardiovascual problems
  • IN RATS; after 1 to 3 months the animals lost resistance and displayed the symptoms from the original physiological triad. This is a 'doctrine of non specifity' as it occured in every stressor (noxious agents, excessive excercise, sublethal drugs, spinal shock) 


  • Resources are not depleted in the resistance phas, instead cortisol levels have a negative effect on the function of the immune system whihc is why it fails 
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Link to Assumpions 

  • mentally disordered behaviour has a physical, biological cause 
  • the aim is to alleviate some of the servere symptoms of mental illness by destroying areas which cause abnormal behaviour 


  • practiced by early humans are trephanning 
  • in the 1930s, Egaz Moniz developed the prefrontal lobotomy (practiced in chimps at the time who demonstrated aggressive behaviour)
  • popularised by Freeman with the ice pick technique which simply severs connections and does not remove the lobes like in earlier methods 
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Examples of psychosurgery

Prefrontal Lobotomy (leucotomy)

  • destruction of connections to the prefrontal cortex, this is involved with impulse control 
  • hoped to alieviate distressing thoughts and behaviours 
  • holes drilled into the sile of the skull and nerve fibres destroyed, later a leucotome was used 
  • Comer (2002) 6% of patients show a range of severe side effects such as seizures and lack of emotional responsiveness 

Deep Brain Stimulation

  • no tissue damage 
  • wires placed in brain that are controled by a battery pack in the chest which produce a changeable high frequency current that interupt brain circuitry 
  • use in OCD patients , if it doesnt work it can be turned off
  • Mayberg et al (2005) for 4 out of 6 patients with severe depression, DBS offered striking remission 
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Further Examples

Stereotactic Psychosurgery 

  • more modern and precise technique
  • MRI locates exact points and sever these connections
  • used in OCD, bipolar, eating disorders that do not respons to other treatment 
  • Capsulotomy, surgeous insert probes through skull and down into the capsle where they sever connections to the region , the tips are heated to cauterise the connection 
  • Cosgrove and Rauch (2001) capsulotomy is 67% effective in OCD patients , 55% in Major affective disorder
  • however, this is hard to test as very few patients are treated with this method and there are no control groups which lacks validity 
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Scientific Approach 

  • clear variables that can be measured and tracked
  • e.g. the recovery rates in psychosurgery patients, or how effective the surgery was - Mayberg et al 2005
  • it fulfils the needs of scientific research which means causal relationships are found and psychology can be shown to be a science 

Deterministic Approach 

  • physical elements of the body determine identifiable behaviour
  • e.g. high levels of dopamine are linked to schizophrenia, this can be shown because drugs like amphetamines which increase dopamine levels cause schizophrenic like episodes 
  • if we know what pre determines behaviour, we can alter it and help those who are suffering from abnormality 
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  • reduce complex behaviours to a set of simple factors 
  • means we lose real understanding, need a more holistic approach 
  • e.g. if schizophrenia is purely because of genetic makeup we ignore the role of the enviornment and social situation of the person (Laing 1965) 

Individual Differences 

  • nomothetic approach so ignores our individual makeup
  • uses males rather than females when there are clear differences
  • e.g. flight or flight in males, tend or befriend in females - Taylor (2000)
  • the picture we have of behaviour is therefore wrong
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Methodology: Brain Scanning

Links to Assumptions

the biological approach assumes that behaviour can be explained in terms of activity in the brain, if we see brain activity (seeing different lobes and hemispheres active under different tasks), we can predict behaviour

EEG (Electroencephalogram)

  • early scanning technique
  • electrodes are placed on the pbrain and sense electrical impulses 
  • Derment and Kleitman (1957) used EEG to detect sleep stages, found we are most likely to remember a dream if woken in REM sleep

CAT (Computer Axial Tomography)

  • series of x rays that combine to form a two or three dimensional image
  • dye is injected as a contrast material
  • Useful as they show abnormal brain stricyires and are higher quality than x ray 
  • require more radiation and so can not be used with pregnant women or repeated
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Brain Scanning

MRI scans (Magnetic Resonance Imaging)

  • using magnetic field to change the alignment of atoms and emit different radio signals
  • a dector reads this and turns it into a map of the brain
  • Maguire et al (2000) taxi drivers have enlarged hippocampi and this is an area associated with spacial awareness and direction
  • fMRI provide anatomical and functional information through repeated scanning
  • gives a more detalied image of the soft tissue in the brain than CAT scans and is best in cases where several examinations are needed as it does not have the radiation threat
  • takes a long time and is uncomfortable
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Brain Scanning

PET Scans (Positron Emission Tomography)

  • uses radioactive glucose to see active areas of the brain
  • this reveals chemical information about the brain which is not available in other scans, this means it can distunguish between benign and malignant tumours and is painless
  • extremely costly and is not widely available for research, can only be used a few times
  • Raine et al (1997) used PET scans to show that the amygdala, an area associated with aggression, is more active in violent murderers than the rest of the population 
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Methodology: Twin Studies

Link to Assumptions

there is an influence of genes on our behaviour, by studying twins we can see what influence nature (pure genetics) has on behaviour and nurture (the environment)

Intelligence and Twin Studies 

  • Bouchard and Mcgue (1981) inhertiance of IQ
  • 86% concordance in MZ twins 
  • 60% concordance in DZ twins 

Twins Reared Apart 

  • 72% concordance for twins raised apart 
  • this excludes the role of the enviornment 
  • significiant genetic contribution to intelligence 
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Twins Studies


  • MZ twins are the perfect participants for research on genetic influence as they share all their DNA 
  • allows researchers to make comparisons between genetic and environmental impact 
  • some control over environment in twins reared apart studies 


  • shared ennvironment 
  • identity crisis 
  • even twins raised apart will have been raised in very similar environments 
  • very small sample 
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