Psychology is defined as the following:
1) science of behavior and mind, embracing all aspects of conscious and unconscious experience as well as thought.
2) an academic discipline and a social science which seeks to understand individuals and groups by establishing general principles and researching specific cases.
Even before Psychology was named as such, people have been observing, thinking, and implementing behavior based on their own understanding as well as other influential factors. However, there has been no established criteria or principles that differentiate it from other social sciences. Thus, the long past.
The short history began when Psychology was determined as a social science that is different from other social sciences like philosophy. During those times, the study of behavior among people have been done according to the established principles and criteria of psychology.