Psychology - Biological approach

Brain - Different areas of the brain are linked to different functions, e.g. the frontal cortex is linked to thinking.

Neurotransmitters - Either stimulate or inhibit neurons in the brain, e.g. dopamine, adrenaline.

'General adaption syndrome' GAS - A general response to all stressors that is adaptive (helps the body cope); explains the link between stress and illness.

Three stages - 1. Alarm: stressor peceived, adrenaline released for fight or flight.

2. Resistance: body adapts, apparently copes, but resources are depleted.

3. Exhaustion: initial symptoms reappear.

Research study - Selye (1936) - Three stages of GAS occurred when he exposed rats to various noxious agents (e.g. cold, drugs);demonstrated the non-specific stress response.

Prefrontal lobotomy - Frontal lobe is functionally separated; involved in impluse control and mood. Early methods (e.g. Moniz) were primitive and ineffective.

Stereotactic psychosurgery - Precise location target areas using MRI, e.g. capsulotomy where connections to region near thalamus are severed to relive OCD; also cingulotomy.

Deep brain stimulation - No tissue is destroyed; wires are placed through the brain tissue and high frequency current can be triggered to interrupt brain circuitry. Used successfully with depression. 

Strengths

• A scientific approach - measurable variables enable well controlled, objective research.
• A dterminist approach - casual relationships can be identified.
• Successful applications, e.g. Selye's research led to improved treatment for injured patients.

Weaknesses

• A reductionist approach - complex behaviour is reduced to actions of neurotransmitters and brain activity.
• Nature rather than nurture - ignores other factors such as life experiences and emotions.
• Tend to ignore individual differences, e.g. some people become more stressed than others.

Brain scanning

Enables psychologists to measure brain activity.

• CAT scans take a series of x-rays showing brain structure.
• MRI scans detect brain structure using magnetic detectors, providing detailed information with no radiation.
• fMRI provides a picture of the brain in action.
• PET scans detect chemical and structual information and show the brain in action, but are very expensive and expose patients to radiation

Twin studies

Enable psychologists to estimate the relative contribution of gentic and environmentak factors. High concordance rates for MZ twins demonstarte the importance of nature, especially when compared with DZ twins, also with twins reared apart.

• Strengths: useful information, tells us about nature and nurture.
• Weaknesses: environments the same, twins reared apart share similar environments.