Psychology is commonly defined as 'scientific' study of human behaviour and cognitive processes. Broadly speaking the discussion focuses on the different branches of psychology, and if they are indeed scientific. However, it is integral in this to debate to understand exactly the major features of a science, in order to judge if psychology is in fact one. There must be a definable subject matter - this changed from conscious human thought to human and non-human behaviour, then to cognitive processes within psychology's first eighty years as a separate discipline. Also, a theory constructio…