The word ‘psychology’ has its origin in two Greek words ‘psyche’ and ‘logos’. The word ‘psyche’ in Greek language refers to ‘spirit’ or ‘soul’ and the word ‘logos’ refers to ‘discourse’ or ‘study’. During earlier times it was considered as a discipline which deals with the study of the soul.

In the following sections we will try to understand all the components which collectively define psychology.

(a) Study of experience: Psychologists study a variety of human experiences which are mainly personal or private in nature. They may range from experiences of dream, conscious experiences at different stages of life and experiences when the consciousness is altered through meditation or use of psychedelic drugs. The study of such experiences helps the psychologist to understand the personal world of the individual.

(b) Study of mental processes: Psychology as the study of mental processes tries to investigate the activities happening in the brain which are primarily non physiological in nature. These mental processes include perception, learning, remembering and thinking. These are internal mental activities which are not directly observed but inferred from the behavioural activities of the person. For example, we can say that somebody is thinking if he or she displays certain activities related to finding solution to a mathematical problem assigned to him or her.

(c) Study of behaviour: The range of behaviours studied in psychology is very broad. It includes simple reflexes (e.g. eye blinking), common response patterns such as talking to friends,

verbal reports about feelings and internal states and complex behaviours such as handling computers, playing piano and addressing a crowd. These behaviours are either observed directly through naked eyes or are measured through instruments.They are generally exhibited verbally or nonverbally (e.g. facial expression) when an individual reacts to a stimulus in a given situation. Thus in psychology the main unit of investigation is the individual human being an his or her experiences, mental processes and behaviours.