Psychology etymologically can be defined from two Greek words psyche , which means "soul" or "mind", and logos which means "study of”. Psychology therefore can be understood as the study of mind or as the science of mind. Psychology studies the relationship between the mind and brain. Though originally started with human beings today we have animal psychology. Research uses animals to a great extent and draw parallels to human beings. Psychology is used to gain knowledge about various spheres of human activity including problems individuals face in daily life. Psychology is also used to gain knowledge on treating mental illness .

Psychology uses various tools to gain insight into human behavior, one such tool is comparison. Although the word Psychology is derived from the Greek word ‘psyche', psychology does not specifically study only about the soul. It covers a wide area of human behavior. The most common definition used to define psychology is ‘ the science of behavior and mental processes' .

Psychology though is a science; it differs from other sciences like sociology, anthropology, economics, and political science. As opposed to other sciences, psychology involves studying the behavior of individuals (alone or in groups) rather than the behavior of the groups . The same applies for biology and neuroscience. A clear differentiating line that marks off psychology from biology and neuroscience is that psychology not only studies about the neural response produced by the system but studies about the overall behavior of the system.

The first person who called himself a psychologist was Wilhelm Wundt. He opened the first laboratory for psychology. This laboratory was opened in 1879. Though a lot of terms were discussed and thousands of psychological questions were raised (for more details please refer ‘ De Memoria et Reminiscentia or "On Memory and Recollection" written by Aristotle), psychology emerged as a separate field only recently.