Ever since Psychology came to be studied as a separate branch of human knowledge, its nature has been defined differently by different experts.
(a) Psychology as the Science of Soul
The word, “Psychology” is derived from two Greek words, “Psyche’ which means soul (atma) and ‘logos’ which means ‘talk about’ or ‘study’ of. So, the term means the ‘study of soul’. But, to define Psychology as the ‘science of soul’ is to defeat the very meaning of ‘science’.
The nature and origin of soul are not known and thus ‘soul’ cannot be put to any scientific study. Soul is a metaphysical concept. Its basis is theology and accepts no logic. In this sense, Psychology becomes more of a religious pursuit than a scientific one. Modern psychology, as James says, is ‘a psychology without a soul”.
(b) Psychology as the Science of Mind
In the 18th Century, Psychology was understood as the ‘study of mind’ or the ‘study of mental processes’. But soon it was felt that the term ‘mind’ is as vague as the term ‘soul’. There are three mental processes which are always going on in each individual. These are Cognitive, i.e., thinking, reasoning, knowing; Affective, that is, feeling; Conative, that is, doing or motor activities. These three mental processes can be studied by an individual himself. They are subjective, personal and private. Again, the view that Psychology can study ‘mind’ in its totality, is only half-truth.
A man in the street looks upon mind as some agent which thinks, feels, wills and does many other things. Tetchier is against this view. He says that mind is itself, not has, thoughts, feelings and wills. ‘Mind’ is only a short-hand name for all the mental processes.
Thus the truths about the nature of ‘Mind’ have been interpreted subjectively, from person to person. So, to say that Psychology is the ‘study of mental processes’ is incomplete or one-sided because through this we cannot know the mental processes of other individuals. So, this definition is subjective, half-truth and very personal.
(c) Psychology as the Science of Consciousnes
Still later, Psychology was defined as the “Science of consciousness”. The term ‘consciousness’ means our immediate awareness of any object. It is, to put simply, ‘mind- now’. William Wundt and William James said that man is a conscious animal and because of this, he acts and reacts towards his environment. But, this definition, too, was rejected as one-sided.
The scope of psychology is not only limited to the conscious level but also extends to the sub- conscious and unconscious mind. These form the major portions and exert important influence on the behaviour of a person.
It was Sigmond Freud, a psycho-analyst, who brought to the fore-front the concept of unconscious mind. He said that mind has got three layers, viz., conscious, subconscious and unconscious. Bradley also remarked that much lies at the back of our mind. To say that Psychology is ‘the study of conscious mind’ is to narrow down the area of the science.
(d) Psychology as the Science of Behaviour
The latest concept of Psychology is in terms of behaviour-conscious or unconscious. In this sense, Psychology may be defined as the scientific study of behaviour and adjustment. J.B. Watson, an exponent of the behaviouristic school of psychology, supported the view that Psychology is the science of behaviour.
Now the question arises: what are the activities which are include in the term ‘behaviour’? In the present contexts the term ‘behaviour includes all activities which are easily observed and which cannot b easily observed. Activities as walking, writing, speaking can be easily; observed while such activities as seeing, hearing, remembering, reasoning! Memorizing etc. cannot be easily observed. Both these types of activities are covered by the term behaviour as used in the definition of psychology; given above.
The second term used above is adjustment. This term refers to the process by means of which the human organism becomes favorably relate to the various elements of its surrounding environment, both human and non-human. Moreover, an analysis of the patterns of human behavior: will reveal that most of the activities of the individual are of a type that would be classified as adjustments.
Behaviour is the external expression of our mental processes According to Drever; behaviour is the response (R) of the organism stimulus (S) or a situation or situations of life. The response may b simple or complex. Usually, it is the complex response which is termed as behaviour. Psychology as the science of behaviour studies the tot response of the organism to different situations of life. In this sense, psychology studies behaviour- physical as well as mental, normal as well as abnormal, child behaviour as well as adult behaviour.
Again, behaviour manifests itself in three domains-Cognitive, Affective and Conative. Cognitive behaviour involves knowing and thinking; Affective behaviour refers to the feeling aspect and involves emotional experiences, instinctive reactions etc.; and Conative behaviour is dominated by motor activity.
Many other psychologists like Watson, Pillsbury, Skinner, Munn, Crow and Crow have defined Psychology as a positive science of behaviour.
In the light of what we have said above, Psychology may be defined as a positive and empirical science dealing with mental life and its external expression (behaviour). In the words of Garret: “Psychology is the study of human behaviour and its subject-matter is what people do and how and why they do.” McDougall has also defined Psychology as “the positive science of conduct and behaviour.” It is the science which aims “to give us better understanding and control of the behaviour of the organism as a whole.”
The changing concept of Psychology has been aptly described by Woodworth in these words:
“First Psychology lost it soul, then it lost its mind, then it lost consciousness, it still has behaviour of a kind.”