Evaluation of Raine et Al

Reliability is also high in the experiment as there were many controls put in place, such as the specific time gap between the injection and taking the PET scan of 32 minutes. All participants were also subject to the same tasks before the scan was produced. This means that the experiment could be repeated in order to gain similar results which would give it reliability. This is also strengthened by the fact that PET scanning was used, as it is a scientific method where procedures are controlled which can be repeated to check for consistent results.

The findings describe the brain differences but do not explain them. It could be that such differences were present from birth and are biologically given. However, it could also be that such differences came about from environmental influences and that, although they are biological differences, they are not caused biologically. The findings also do not tell us if the murderers are responsible for their behaviour due to the brain differences.

The researchers looked at some extraneous variables that may have affected the…