Specification
- The use of twin studies to investigate genetic relatedness and aggression.
- List A from Social Psychology
Twin studies are used in psychology to investigate the relative importance of genetic and environmental factors in the development of various traits, behaviors, and disorders. This is achieved by comparing the similarity of traits and disorders among identical twins, who share 100% of their genes, to fraternal twins, who share only 50% of their genes on average.
The basic idea behind twin studies is that if identical twins are more similar in their traits, behaviors, and disorders than fraternal twins, then this suggests that genetics plays a stronger role in the development of these characteristics than the environment. On the other hand, if identical twins are not more similar than fraternal twins, this would suggest that the environment plays a stronger role.
How can twin studies be used to study aggression?
One way to use twin studies to study aggression is to conduct a retrospective or prospective twin study. The researcher would collect data on the level of aggression in both identical and fraternal twins, and compare the similarity of aggression between the two groups. If identical twins are more similar in their aggression levels than fraternal twins, this would suggest that genetics plays a stronger role in the development of aggression. On the other hand, if identical twins are not more similar than fraternal twins, this would suggest that the environment plays a stronger role.
Another way twin studies can be used to study aggression is by conducting a concordant or discordant twin study. A concordant twin study would investigate the degree of correlation between identical twins for aggression, while a discordant twin study would investigate the degree of dissimilarity between identical twins for aggression. If identical twins are more concordant in their aggression levels, this would suggest that genetics plays a stronger role in the development of aggression. If identical twins are more discordant in their aggression levels, this would suggest that environmental factors play a stronger role.
Evaluation
- It is important to note that twin studies have limitations, such as the assumption that identical twins have the same environment, which is not always the case, and that the twin pairs are not representative of the general population.
- Additionally, twin studies can not infer causality and genetic effects can be difficult to disentangle from environmental effects.
- The predisposition of aggression is not 100% twin studies are not able provide conclusive evidence of genetic influences on human behaviour.
- Twin studies have small sample sizes as twins are not common, so findings may not be representative of a wider population.
Past Paper Questions
- Identify which sample of twins has a higher genetic relatedness between aggression and antisocial behaviour. (1) June 2016
- Explain one strength and one weakness of the twin study method. (4) June 2016
- Vanessa researched genetic relatedness and aggression. She used a twin study to determine if aggression was linked to genes. Describe how Vanessa might have carried out a twin study to investigate genetic relatedness and aggression. (4) January 2019
- Explain one weakness of using twin studies to investigate genetic relatedness. (2) January 2019