refers to the way that biological psychologists try to reduce behaviour to a physical level and explain it in terms of neuron's, hormones, brain structure etc.
don't really involve scientific testing so can become vague.
-e.g humanistic psychology tends to be criticised for its lack of empirical evidence. by considering various factors about an individuals behaviour it becomes hard to see which one is most influential, making it harder for the development of therapy.
this is a limitation as the holistic approach makes it difficult to help individuals in the real world.
-in order to conduct well controlled research we need to operationalise the variables. making it possible to conduct experiments/ record observations in a way that's reliable.
-e.g. research on the SS operationalised variables such as separation anxiety.
-this puts psychology on equal grounds with the natural sciences.
-e.g. the reductionist approach may only consider the influence of genetics on depression, completely discarding any other factors such as past experiences, trauma etc.
-these genetic explanations do to analyse the social context within which the behaviour occurs.