Psychology has become a very important and popular subject today. It deals with many problems of everyday life. Psychology helps us to understand the behaviour of people around us, to find out why they behave differently and what forces are responsible to make them so different from others.

It tries to explain wide array of factors involved in what we human beings do. The principles explained by psychology give us a rational basis of understanding of what we and others do. Psychology has been defined in many ways. In ancient days people were analysing the behavioural aspects on the basis of philosophy. They believed that there is a soul in every individual and this is responsible for all our activities.

This view led to the opinion that the subject matter of psychology must be the study of soul. But this definition could not answer the questions regarding the existence of soul and its accessibility for study. This condition led to a new definition by Greek philosophers who defined psychology as a ‘science of mind’. But this definition was also rejected on the same grounds as soul was rejected.Later, Wilhelm Wundt a psychologist who established the first psychological laboratory at the University of Leipzig in Germany defined psychology as the study of consciousness. EB Titchener the disciple of Wundt, proposed the method of Introspection to study consciousness. But because of its subjectivity and unscientific method of study, this definition was also rejected.

Gradually, as a result of the development of scientific outlook people started thinking on scientific basis and began to define psychology as a science of behaviour. Finally, it is JB Watson (1913) defined psychology as a science of behaviour of human as well as animal beings.

Scope of Psychology:

Psychology deals with the origins, development and change of behaviour. It deals with similarities and differences among people, with the occurrence of expected behaviour as well as unexpected behaviour. Equally so it is concerned with the non-occurrence of expected behaviour. It is concerned with behaviour which is observable and unobservable, conscious and unconscious, with the behaviour of individuals as well as groups and with the influence of individuals on the behaviour of one another.

It may also be said that psychologists are concerned not only with the actual day-to-day behaviour but also with the unique products of human activity like dreams, art, literature, mythology, folklore and all other products of human behaviour.

By analysing and studying these products, psychologists have tried to understand the motivational processes and other factors which might have influenced the production and creation of these activities. In recent years, psychologists have also extended their interest to studying political philosophies, ideologies and forms of government.

All this has naturally resulted in the expansion of the scope of psychology. Psychology is applied everywhere in the home, at the school, at the hospitals, in factories and offices, in the armed forces and in all imaginable situations involving the behaviour of human individuals alone or in a group.The subject of psychology which was mainly developed by philosophers from their armchairs, progressed to laboratories and is today studied and applied in all walks of life.

Methods of psychology :

The aim of science is to use scientific method to collect information in the form of verifiable data. Different sciences use different methods that are suitable for the investigation of their subject-matter. However, all of them have one thing in common, in the sense that, they aim at a very high objectivity in the collection of facts and precise description of the phenomena under investigation.

When discussing the methods used by psychology, we must be sure that they fulfill scientific requirements. The complexity of the subject-matter with which psychology deals is quite obvious. The behaviour of the individual is something that varies not only from person to person but also from time to time.

Such variations in behaviour, obviously, are less subject to accurate and objective observation and description than the subject-matter of many sciences like physics, chemistry, biology etc. In spite of these difficulties, psychologists, have tried to confine themselves to the requirements of objectivity, which characterize the methods of science. Like other sciences, psychology also uses several methods to study its problems.