Psychology - Biological approach - Summary

• 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, adrenline.

General adaption syndrome - GAS

A general rersponse to all stressors that is adaptive (helps the body cope); explains the link between stress and illness.

Three stages 

1. Alarm: stressor perceived, adrenaline released for fight or flight.
2. Resistance: body adapts, apparently copes, but resources are depleted.
3. Exhaustion: intial 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.

Stereotatic psychosurgery

Precise location of target areas using MRI, e.g. capsulotomy where connections to region near thalamus are severed to relieve OCD; also cingulotomy.

Deep brain stimulation (DBS)

No tissue is destroyed; wires are placed through the brain tissue and high frquency current can be triggered to interrrupt brain circuitry. Used successfully with depression.

Strengths

• A scientific approach - measurable variables enable well controlled, objective research.
• A determinist approach - causal relationships can be indentified.
• 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.
• Tends 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 genetic (nature) and environmental (nurture) factors. High concordance rates for the MZ twins demonstrate the improtance of nature, especially when compared with DZ twins, and also with twins reared apart.

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