1. Contents What is Individual Differences Psychology? Assumptions Methods of Investigation Core Studies from Individual Differences Psychology: Thigpen and Cleckley (1954) and Gould: A Nation of Morons. (1982) Contributions to Psychology Advantages and Disadvantages Summary

2. Individual Differences An approach to psychology that focuses on how people differ from one another.

3. Assumptions 1) People are unique!

4. Methods of Investigations A whole range of methods. As well as conducting experiments Individual Differences Psychologists use the following methods: Case Study This method involves an in-depth and detailed look at an individual or particular group. It is often used when looking at exceptional cases Participant Observation This method involves the researchers joining a particular social group and making often secret observations over a long period of time. Review Study Looking at previous work and drawing conclusions.

5. Thigpen and Cleckley (1954) A Case of Multiple Personality Aim: To document a case of Multiple Personality Disorder Design: Case Study Participant: A 25 year old woman with Multiple Personality Disorder. Procedure: Information was collected from Eve White. This information included: interview material, psychometric tests and physiological tests. During therapy Eve White’s two other alters (personalities) came out. The Researchers conducted a range of tests on the alters and researchers documented her treatment. Results: Researchers identified three separate alters. Each alter had separate personalities as shown by observations and a range of tests e.g. IQ test scores. The researchers named the alters Eve White, Eve Black and Jane. Eve White was demure, neat, polite and very anxious. Eve Black was the opposite, she was mischievous and had little concern for her husband. Jane was more mature and interesting. She eventually took over from Eve White, but she couldn’t get rid of Eve Black.

6. Gould (1982) A Nation of Morons Aim: To review Yerkes’ work on IQ testing. Design: A Review Study Procedure: Gould reviewed Yerkes’ work. Yerkes conducted a mass IQ testing programme on the American army during the first world war. He claimed that his tests measured native intellectual ability, in other words, intelligence that was unaffected by culture or education. After conducting his tests Yerkes concluded that people from Southern European countries and Africa were less intelligent than people from North America and Northern Europe. Results: Gould reviewed Yerkes tests and claimed that the tests were invalid. Instead of measuring innate intelligence the tests were measuring cultural knowledge and were dependent on fluency of English. This explains why recent immigrants to America did not do very well in the tests. He also identified problems with the way in which the tests had been administered.

7. Contributions to Psychology This area of Psychology has led to a greater understanding of the way we differ from each other. This has been useful in the following areas: 1) The understanding and treatment of usual mental illnesses 2) A greater understanding of different cultural groups. 3) This area has challenged previously ethnocentrically biased research.

8. Advantages and Disadvantages Practical Applications. Particularly in the treatment of the mentally ill. Unlike the rest of Psychology is focuses on how we are different from each other rather than generalising findings to everybody. It is often lacking in scientific rigour. Research methodology can lead to subjective findings. It lacks generalisability. The findings can only be applied to a small group of people. Research is often time consuming and expensive.

9. Summary Individual Differences Psychology looks at the differences between people. It using case study, participant observation and review studies. It has helped further the treatment and understanding of mental illness It has wide applications, but it has been accused of lacking in generalisability.