Why might the study of identical (monozygotic) twins be valuable in constructing a model of abnormal behavior? How would dizygotic twins be different?
Identical twins have the same genes. If one has abnormal behavior, then we can assume that the cause is environmental, not genetic.
The study of identical (monozygotic) twins can be valuable in constructing a model of abnormal behavior due to their unique genetic makeup. Identical twins share 100% of their genetic material, as they develop from a single fertilized egg that splits into two. Therefore, any differences in their behavior or traits are most likely influenced by environmental factors. By studying identical twins, researchers can examine how different environments impact the development of abnormal behavior. For example, if one twin develops a mental disorder while the other does not, it suggests that environmental factors may play a significant role.
On the other hand, dizygotic twins, also known as fraternal twins, share only about 50% of their genetic material, like any other siblings. They develop from two separate fertilized eggs. When studying dizygotic twins, any similarities or differences in behavior or traits can be ideally attributed to both genetic and environmental factors. This allows for comparison between the impact of genetics versus environment on abnormal behavior.
By comparing the similarities and differences in behavior between identical and dizygotic twins, researchers can better understand the relative contributions of genetics and environment in the development of abnormal behavior. This information can help construct models that explain the complex interactions between genes and the environment in the manifestation of abnormal behaviors and mental disorders.