Methodology of the Biological approach Biological approach Two

Methodology of the Biological approach

Biological approach Two types of methodology Animal experiments Twin studies

Animal Studies In which approach did we come across this method before? ____________ The behaviourist approach Which study in the biological approach used this method? Selye (1936) ______ How about Moniz?

Animal studies Why are animals studies used in the biological approach? Allow us to investigate the biological basis of behaviour in a way which would unethical to do on humans Allows high levels of control: scientific

Key Features Controlled conditions IV and DV Extraneous variables limited Nomothetic Drug testing and lesions

Evaluation of animal studies Complete the boxes firstly from memory in brief bullet points. When you think you have all the evaluation points, check the information on page 11. Add anything that you missed.

Twin studies Looks for similarities between twins Bio approach is interested in the effect of genes. Twins are a great way to do this

Twin Studies What are the two types of twins? How are they formed?

MZ Monozygotic 1 sperm, 1 egg Splits into two embryos Therefore twins are identical Always same gender

DZ Dizygotic 2 sperms, 2 eggs Twins share a womb, but are no more genetically similar than other siblings Non-identical (fraternal) twins Can be the same or different gender

Key features Traits: intelligence, aggression, mental illness Calculate a concordance between twins on particular trait (0 -100%) Compare identical with non identical twins Ideal is identical twins raised apart

Example of a Twin Study Bouchard and Mc. Gue (1981) Studied the inheritance of IQ What is IQ? They compared the IQ scores of different types of twins who were reared together and separately. They were looking for the genetic basis of IQ by using concordance rates

Bouchard and Mc. Gue (1981) RELATIONSHIP Identical twins reared together Identical twins reared apart Non identical twins reared together Siblings reared together Non identical twins reared apart Siblings reared apart IQ TEST Concordance 86% 76% 55% 47% 35% 24%

Bouchard and Mc. Gue (1981) What can we conclude from these results about the effect of genes on IQ?

Twin studies Psychologists have utilised twin studies to investigate a wide range of behaviours. It has been found that there may be a genetic basis for many mental illnesses such as alcoholism, schizophrenia, Alzheimer’s, autism and mood disorders. Read the strengths and weaknesses

Timed essay Read the exam focus Highlighter task (like last time)