1. What is Personality? Unit 1 – Making sense of other people.
Topic 3 – Development of personality

2. Lesson objectives By the end of the lesson you will be able to;
Define personality.
Define temperament.
Describe the studies of temperament carried out by Thomas, Buss and Polmin, and Kagan.
Evaluate the studies on temperament carried out by Thomas, Buss and Polmin, and Kagan.

3. Keywords.
Personality – The thoughts, feelings and behaviours that makes an individual unique. Temperament – The genetic component of personality. Longitudinal study – A study carried out to show how behaviour changes over time. Monozygotic twins – Twins developed from one fertilised egg. Dizygotic twins – Twins developed from two separately fertilised eggs.

4. Starter activity Describe the personalities of the people in the 4 photos below.

5. Defining Personality and Temperament.
Personality is made up of thoughts, feelings and behaviours that make a person unique. It therefore comes from within the individual and remains reasonably constant. This means that the person is the same in different situations. Personality can develop over the years as a result of experience. Temperament refers to the inherited aspects of personality. Therefore it describes the way in which the individual responds to the environment. This stays constant throughout life. Understanding temperament can be important in helping people recognise situations they find difficult. (i.e. create coping mechanisms).

6. Thomas, Chess and Birch (1977)
Aim – To discover whether ways of responding to the environment remain stable throughout life. Method – They studied 133 children from infancy to early adulthood. The children’s behaviour was observed and their parents interviewed. The parents were asked about the child’s routine and its reaction to change. Results – They found that the children fell into 3 types: easy, difficult and slow to warm up. The easy children were happy, flexible and regular. The difficult children were demanding, inflexible and cried a lot. The slow to warm up children did not respond well to change or new experiences to begin with, but once they had adapted they were usually happy. Conclusion – These ways of responding to the environment stayed with the children as they developed. Thomas, Chess and Birch therefore concluded that temperament was innate.

7. Evaluation
This is one of a few longitudinal studies of temperament allowing the researchers to support the view that temperament is innate. This is because if the children still show the same reactions to situations as they get older, this would suggest it is inborn response. The draw back of longitudinal studies, however, is that some participants could drop out partway through, which could affect the results.
The children were from middle class families in New York. This means the results cannot be generalised to other social classes.
The parents may have been biased in the answers they gave in the interviews. They may have given answers that they thought showed their children in the best possible light.

8. Buss and Plomin (1984)
Aim – To test the idea that temperament is innate.
Method - They studied 228 pairs of monozygotic twins and 172 pairs of dizygotic twins. They rated the temperament of the twins when they were 5 years old. They looked at 3 dimensions of behaviour;
Emotionality – How strong the child's emotion response was.
Activity – How energetic the child was.
Sociability – How much the child wanted to be with other people.
They then compared the sores for each pair of twins.
Results – There was a closer correlation between the score of the monozygotic twins than between the dizygotic twins.
Conclusion – Temperament has a genetic basis.

9. Evaluation
This study supports the view that temperament is innate. This is because monozygotic twins, who are genetically identical, were more similar in the 3 situations that the dizygotic twins.
Monozygotic twins are treated in very similar ways. The correlation between scores could therefore be explained by their environment rather than by their genes.
Research on twins cannot be generalised to the whole population because not everyone is a twin.

10. Kagan and Snidman (1991)
Aim – To investigate whether temperament is due to biological differences. Method – Kagan and Snidman studied the reactions of 4 month old babies to new situations. For the first minute the baby was placed in a seat with the caregiver sitting nearby. For the next 3 minutes the caregiver moved out of the baby’s view while the baby was shown different toys by the researcher. Results – 20% of the babies showed distress by crying, vigorous movement of arms and legs and arching the back. They were classed as high reactive. 40% of the babies showed little movement or emotion. They were classed as low reactive. The remaining infants fell somewhere in between. In a follow up study, 11 yrs later, Kagan and Snidman found there was still differences in the way the 2 groups reacted to new situations; the high reactive were shy while the low reactive were calm. Conclusion – They concluded that these 2 temperaments are due to inherited differences in the way the brain responds.

11. Evaluation
Kagan and Snidman used a large sample, which means its easier to generalise their results to the whole population.
The research took place in an experimental setting. This is a controlled environment that would have been unfamiliar to the children taking part in the study. Therefore they may have behaved differently from usual because they were in a strange place.
Behaviour was observed and recorded. The researchers may have missed some important behaviours or recorded them inaccurately. This would have affected the results.