What is behavioural psychology? How to use it

Behavioural psychology also referred to as behaviourism in some quarters, attempts to establish links between human behaviour and the external world. It is based on the assumption that all human behaviour is a direct consequence of external stimuli. In other words, the discipline holds that there can be no behaviour without external stimuli. Indeed, advocates of this approach prefer "behaviour" to the more purposeful "action." Understandably, this view has come under some criticism, mainly because it seems to suggest that human behaviour is a mere reaction.