Strength The biological approach adopts scientific methods for investigation using measures which are largely objective (not subject to opinion) such as brain scanning and measuring biochemical levels. It is possible to accurately measure biological and neural processes in ways not open to bias therefore supporting the biological approach as it is based on reliable data.

weakness It is one the strongest supporters of the nature perspective in the nature-nurture debate as it argues for genetic influence on behaviour. However, what the biological approach does not take into account is that twins and family members are exposed to the same environment. This means that findings could just as easily be interpreted as supporting nurture rather than nature as it could be that the behaviour has been learned through the environment rather shared through genes.

strength  A real strength of the biological approach is its real- world application. Increased understanding of biochemical processes in the brain has led to the development of psychoactive drugs that treat serious mental illnesses such as depression (anti-depressants increase serotonin production). Although these drugs are not effective in all patients, they are revolutionised treatment for many. This is a strength of the biological approach as it means that sufferers are able to manage their condition and live relatively normal life, rather than remain in hospital.

weakness It is argued some of the explanations are too simplistic and do not do the complexity of human behaviour justice. This means they are reductionist as they can often fail to acknowledge the role of the environment in behaviour.

weakness  The biological approach is determinist in the sense that it sees human behaviour as governed by internal, biological causes over which we have no control. This is a criticism of the biological approach as it says we are purely governed by our genetics and don’t have any control over our behaviour which is untrue.