Biological Approach- Assumptions
1. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF DIFFERENT AREAS OF THE BRAIN.
- Research shown - different areas of the brain perform certian functions.
- E.g the occipital lobe controls vision. The hippocampus deals with the ability to form memories.
2. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF HORMONES.
- Action of hormones- controls human behaviour.
- Hormones- chemical substances that circulate the blood, affect target organs- lots are produced but disappear quickly, effecrs are slower than nervous system, but very powerful.
- E.g Testosterone - linked to aggressive behaviour.
3. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF NEUROTRNSMITTERS.
- Human behaviour affected by nervous system. - neurons linked to each other communicate information. Linked by synapse. - neurotransmitters are chemical substances.
- Electrical message from one neuron to another is transmitted across synapse by neurotransmitters.
- E.g seroronin, controls happiness levels.
Biological Approch: Selye's General Adaptation Syn
- Hans Selye- medical doctor- noticed patients displayed same symptoms, whatever illness.
- Suggested that body produces general response to stress. Response- adaptive helps body cope with extreme stress.
1. ALARM REACTION! - Stressor leads to response- hypothalamus sends signal to adrenal gland- adrenaline is released. Causes fight/ flight repsonse.
2.RESISTANCE! - If stress continues- body needs mean of coping with environment- body maintains normal internal functions (temperature)- despite appearance of coping - body is progressively losing resources (adrenaline other hormones like cortisol)
3. EXHAUSTION! - Body can no longer function normally- immune system no longer cope- stress related illnesses- cardiovascular disorder, depression.
Biological Approach- GAS
Selye (1936) - used rats.
- Exposed rats to bad experiences- extreme cold, drugs, excessive excesise, cutting spinal cord.
- Rats responded with GAS.
STAGE 1 : 6-48 hours- lead on to physiological trias- enlargement of adrenal gland, ulcers, shrinkage of the immune system.
STAGE 2 : Return to normal
STAGE 3: Within 1-3 months, return of the phsiological triad.
Biological Approach- Strengths and Weaknesses
- Scientific Approach- clear variables - cause and effect- e.g. recovery rates of psychosugery can be seen.
- Determinist Approach- suggests that elements of the body e.g. hormones cause identifiable behaviour. E.g.high levels neurotransmitter dopamine are suggested as a cause of schizophrenia. - helps mental disorders be treated.
- Reductionist- Reducing complex behaviours in to simple explanations. E.g reducing stress to hormone adrenaline- may cause loss of understanding of mental disorders.
- Individual Differences- Biological studies suggest everyones biological sytem acts in the same way. Nomothetic approach- E.g. male participants used more than female as hormones may affect research. E.g. some people may release more adrenaline in stress that others.
Biological Approach- Methodology
1. BRAIN SCANNING-
Links to Assumptions: Approach suggests behvaiour is caused by brain + nervous system- Biological psychologists look for methods to research this.
- EEG -elcotrodes on scalp- activity on different parts of brain can be recorded. Weakness: Recordings can't specifically indicate source of activity.
- CAT Scans- involves series of x-rays+ combining them to make 2D/3D picture of are a being scanned. Strengths: Higher quality images then x-rays Weaknesses: CAT scans - more radiation than x-rays.
- MRI scans - use of magnetic feild- causes atoms in brain to change alignment when magnet is on, and emit radio signals when magnet is off. Detectors read signals, map structure of brain.
- fMRI scans- gives both anotomical+ functional info - by taking repeated scans of brain. Strengths: More detail than CAT scans, no exposure to radiation. Weaknesses: Takes a long time.
- PET Scans - Giving patient slightly radioactive glucose- most active areas of brain use glucose+ radiation detectors can see radioactive glucose. Strengths: Reveals chemical info e.g. seeing between benign and malignant tumours. Weaknesses: Costly.
Behaviourist Approach - Methodology
2. Twin Studies
Link to Assumptions: Reasearches the influence of genes on behaviour.
- Comparing MZ and DZ twins: MZ twins share 100% of their genes (identical) DZ twins (nonidentical) share max 50% of their genes. E.g. a review of 30 studies (Bouchard and McGue) found 86 % correspondance between MZ twins and 60% for DZ twins in intelligence. Strength: Natural experiment Weakness: Similarities may be due to environmental factors, recent studies show MZ twins are significantly genetically different.
- MZ twins reared apart: separates influence of genetics + environment, Bouchard and McGue found 72% correspondance in MZ twins reared apart. Strenth: Attemps to control shared environment. Weakness: Samples very small.
Biological Approach- Psychosurgery
- How it links to Assumption: The cause of mental illness can be located in areas of the brain.
- Aim: To treat some severe symptoms of mental illness- destroying areas of brain that cause behaviour.
- 40,000 years ago, trepanning- holes in to skull - relieve evil spirits.
- 1930's Moniz developed prefrontal lobotomy- based on treatment aggresive monkeys- behaviour improved when frontal lobe was removed. Moniz used same treatment on humans -icepick.
Types Of Psychosurgery:
- Prefronal lobotomy- destroys connections to prefrontal cortex- mood regulation. Moniz drilled holes in each side of skull and inserting 'ice pick' to destroy nerve fibres. Moniz later refined this by using a leucotome (wire loop) cuts in to white matter in the brain- sevres nerve fibres.(6% fatality rate, severe side effects COMER 2002)
Biological Approach- Psychosurgery
- Stereostatic psychosurgery- more precise technique- MRI's locate exact points, and then connections are carefully carefully. E.g. OCD is associated with thalamus- Capsulotomy surgeon inserts probe in to capsule, heat tips, burn away tiny parts of tissue. (Cosgrove and Raugh 2001 capsulotomy was effective in 67% of OCD patients)
- Deep Brain Stimulation- Doesn't involve tissue destruction- Sugeons place wires in brain- wires connected to battery back implanted in chest- batteries produce adjustable high frequency current that interputs circuit in brain. E.g OCD - if it doesn't work it can be removed. (Mayberg et al 4/6 patients with severe depression experienced 'striking remission' after DBS in frontal cortex.)