The word "Psychology" was referred to the study of the mind currently it is defined as a science that studies the behaviour of man and other living beings. Man is essentially a living organism. Psychology is primarily concerned with the responses of these organisms to their outside world. The organism takes stimuli from the environment which interact with its mind and organic system and which in turn, respond to these stimuli. Hence psychology may be considered to be a biological science if we describe it in terms of stimulus, organism and response.