evaluation of dabbs et al 1987 study on aggression

• low sample size of solely prisoners, reducing the generalisability, not applicable to the public
• was a correlational study- as there was no manipulation of variables- therefore we cannot be sure that testosterone causes people to be more violent- perhaps it is the other way round, regularly committing acts of violence could increase testosterone levels, or maybe there is a hidden third factor- such as growing up in a violent, abusive family which may be responsible for increasing both testosterone and the likelihood of committing violent crimes
• no manipulation of extraneous variables- low control of other factors and cannot be sure about establishing cause and effect,