Temperament - Thomas, Chess and Birch (1977)
Aim: Discover whether ways of responding to the environment remain stable throughout life.
Method: -Studies 133 children from infancy to early adulthood. -Childrens behaviour was observed and their parents were interviewed. -Parents were asked about the childs routine and its reactions to change.
Results: -Children fell into 3 different types: Easy, difficult or slow to warm up. -Easy = happy, flexible and regular. -Difficult = demanding, inflexible and cried a lot. -Slow to warm up = respond well to change or new experiences to begin with but once they had adapted thehy were usually happy.
Conclusion: Ways of responding to the environment stayed with the children as they developed. Thomas, Chess and Birch therefore concluded that temperament is innate.
Evaluation for the study Thomas, Chess and Birch
-Children were from middle-class families living in New York. Therefore, the results cannot be generalised to other social classes.
-Parents may have been biased as they may have wanted to present there children in the best possible way.
-Participants could drop out partway through, which could affect the results.
Temperament - Buss and Plomin (1984)
Aim: Test the idea that temperament is innate.
Method: -Studied 228 pairs of monozygotic twins and 172 pairs of dizygotic twins. -Rated the temperament of the twins when they were 5. Looked at 3 dimensions of behaviour: -Emotionality (how strong the childs emotional response was) -Activity (how energetic the child was) -Sociability (how much the child wanted to be with other people)
Then they compared the scores for each pair of twins.
Results: Closer correlation between the scores of the monozygotic twins than between the scores of the dizygotic twins.
Conclusion: Temperament has a genetic basis.
Evaluation for the study Buss and Plomin
-Supports the view that temperament is innate.
-Research carried out on twins cannot be generalised to the whole population because not everyone is a twin.
-Monozygotic twins are treated in very similar ways. The correlation between their scores could therefore be explained by their environment rather than by their genes.
Kagen and Snidman (1991)
Aim: Temperament is due to biological differences.
Method: -Studies reactions of 4 month - old babies to new situations. -First minute, baby was placed in a seat with the caregiver sitting nearby. -Nextt 3 minutes the caregiver moved out of the baby's view while the baby was shown different toys by the researcher.
Results: -20% of babies showed distress by crying,vigorous movement of the arms and legs and arching of the back = high reactive. -40% of babies showed little movement or emotion = low reactive. -The remaining infants fell somewhere between the two.
Conclusion: These 2 temperaments are due to inherited differences in the way the brain responds.
Evaluation for the study Kagen and Snidman
-Used a large sample which makes it easier to generalise their results to the whole population.
-Research took place in a experimental setting. 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 which would affect the results.
Aim: Personality of 700 servicemen.
Method: -Each Soldier completed a questionnaire. -Eysenck analysed results using a statistical technique known as factor analysis.
Results: Indentified 2 dimensions of personality: extroversion and inteoversion and neuroticism - stability.
Conclusion: Everyone can be placed along these two dimensions of personality. Most people lie in the middle of the scale.
Evaluation for the study Eysenck
-Only described a limited number of personality types.
-Used questionnaires to test personality and the answers people gave could have been based on their mood at that time.
-Believed personality is genetic. This does not consider the idea that personality can change as a result of experience.
APD - Raine et al (2000)
Aim: Support the theory that abnormalities in the prefrontal cortex cause APD.
Method: Magnetic resonance imaging (MRI) was used to study 21 men with APD and a control group of 34 healthy men. - They were all volunteers.
Results: APD group had an 11% reduction in prefrontal grey matter compared with the control group.
Conclusion: APD is caused by a reduction in the brains grey matter.
Evaluation for the study Raine et al
-Supports the biological explanation that APD is caused by an abnormality in the brain.
-Only studied males so their findings may not relate to women with APD.
-His participants were volunteers, so may not have been representive of all people with APD.
Situational causes of APD - Farrington (1995)
Aim: Development of offending and anitsocial behaviours in males studied from childhood to the age of 50.
Method: -Carried out a longitudinal study of development of anitsocial and offending behaviour in 411 males (all lived in a deprived,inner-city area of London). -First studied at 8 and were followed up until the age of 50. -Their parents and teachers were also interviewed. -Seaches were carried out at the Criminal Records Office to discover if they, or members of their family, had been convicted of a crime.
Results: -41% of males were convicted of at least one offence between the ages of 10 - 50. -Most important risk factors for offending were criminal behaviour in the family, low school achievement, poverty and poor parenting.
Conclusion: Situational factors lead to the development of anitsocial behaviour.
Evaluation for the study Farrington
-The study was not a controlled experiement so factors that were not considered could have affected the offending behaviour of the males studied eg: biological factors were not investigated.
-Researchers in this study interviewed males, parents and teachers. When people are taking part in surveys they can give socially desirable answers.
Elander et al (2000a)
Aim: Investigate the childhood risk factors that can be used to predict anitsocial behaviour in adulthood.
Method: -Investigated 225 twins who were diagnosed with childhood disorders. -Interviewed them 10-25 years later.
Results: Found that childhood hyperactivity, conduct disorders, low IQ and reading problems were strong predictors of APD and criminality in adult life.
Conclusion: Disruptive behaviour in childhood can be used to predict APD in adulthood.
Evaluation for the study Elander et al
-They looked at twins. Therefore, genetics, rather than situational factors, may have affected their behaviours.
-Participants were asked to describe experiences from their childhood, which they may have remembered wrongly.