Development of personality

Development of personality

1. Key words

   • Personality - the thoughts, feelings and behaviours that make an individual unique.
   • Temperament - the genetic component of personality.
   • Monozygotic twins - twins developed from one fertilised egg.
   • Dizygotic twins - twins developed from two separately fertilised eggs.
   • Extroversion - a personality type of people who look to the outside world for entertainment.
   • Introversion - a personality type of someone who is contented with their own company.
   • Neuroticism - a personality type for people who highly emotional and show a quick, intense reaction to fear.
   • Psychoticism - a third dimensions identified by Eysenck. People who score high on this dimension are hostile, aggressive, insensitive and cruel.
   • Antisocial personality disorder - a condition in which the individual does not use socially acceptable behaviour or consider the rights of others.
   • Amygdala - part of the brain involved with emotion.
   • Prefrontal cortex - the very front of the brain. It is involved in social and moral behaviour and controls aggression

2. Case Studies

   • 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 were interviewed. The parents were asked about the child's routine and its reactions to change.
         • Results - They found that the children fell into three types: 'easy, 'difficult' or 'slow to warm up'. The 'easy' children were happy, flexible and regular. The 'difficult' children were demanding, inflexible and cried a lot. The children that were 'slow to warm up' 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 is innate.
     • Evaluation
       • Lacks population ecological validty. The children were only sampled from middle class so the results cannot be generalised to other social classes.
       • The experiment is said to be bias because the experimentors relied on the parent's opinion and they may have had bias answers in interviews.
   • Eysenck(1947)
     • Aim - To investigate personality difference between people.
       • Method - 700 servicemen completed a questionnaire. Eysenck analysed the results using a statistical technique know as factor analysis.
         • Results - He identified two dimensions of personality: extroversion, introversion and neuroticism - stability.
           • Conclusion - Everyone can be placed along these two dimensions of personality. Most people can lie in the middle of the scale.
     • Evaluation
   • Kagan and Snidman(1991)
     • Aim - To investigate whether temperament is due to biological differences.
       • Method - Kagan and Snidman studied the reactions of four-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 three 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 the arms and legs and arching of 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 between the two. In a follow-up study, 11 years later, Kagan and Snidman found there was still a difference in the way the two groups reacted to new situations; the high reactives were shy while the low reactives were calm.
           • Conclusion - Kagan and Snidman concluded that these two temperaments are due to inherited difference in the way the brain responds.
     • Evaluation
       • This study lacks population validity because the experiment was only conducted on twins, so the results may not be generalizable to the wider non-twin population.
       • They used a large sample of participants meaning they gathered a large range of results to analyse.
       • This was a longitudinal study so that the behavioural changes can be seen over time however, it is likely that some of the participants dropped out over time, affect the results.
   • 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 five years old. They looked at three dimensions of behaviour. Emotionality - how strong the child's emotional response was. Activity - how energetic the child was. Sociability - how much the child wanted to be with other children. They then compared the scores for each pair of twins.
         • Results - They was a closer correlation between the scores of the monozygotic twins than between the scores of dizygotic twins.
           • Conclusion - Temperament has a genetic basis.
     • Evaluation
       • This study lacks population validity because the experiment was only conducted on twins, meaning that the results cannot be generalised for the wider non-twin population.
       • They used a large sample size gaining a wider range of results to analyse.
       • This was a longitudinal study so the behavioural changes could be seen over time however it was likely that some participants dropped out over time which would have affected the results.

Images and files in the map