Psychology may be defined as the study of man—his behavior and mind. The triangle of man, behavior and mind encompasses the whole domain of human activity and life.
In the simplest terms the psychology may be defined as the study and analysis of behaviors. It is the most quoted and appropriate definition of psychology. What is behavior? Behavior is wide term and includes anything a person or animal does that can be observed in some way or the other. The grand characteristic of behavior is that unlike mind and thoughts, feelings and emotions it can be seen and observed
The language and deeds of person are of paramount importance from psychology point of view. What a man says, or communicates says through the medium of language. What he does, the acts of his doings involve five human senses and other body organs. The mental processes are always active behind his seeing and doing i.e. the behavior of the person. The trinity of man, his actions—behavior and mental processes form the basis of psychology. Now we can draw the conclusion that psychology is the study of man his behavior and mind. Man and his behavior are observable entities but mind is unseen. There standsa mind or mental processes behind the working and doing of human beings. In this way in the perspective of human behavior the internal mental events and processes can be studied as they manifest themselves through what man does or people do—behavior it is through the medium of behavior we can actually study and understand the mental processes going on unhidden in the dark.
There is mental process behind every action and behavior of man. The aim of every psychologist is to reach this mental process through the varied and weird behavior. The failure of the psychologist to understand and study the human behavior, these unseen mental processes will remain unstudied and unobserved. The whole psychology has evolved from the ability of the psychologist to study these unseen mental processes. So mind and behavior are two focus points of psychology. The journey is both ways from mind to behavior and behavior to mind
When psychology is defined as “science of behavior,” it does not exclude mind from its purview. What a person does—his behavior is the avenue through which his internal mental processes and events can be studied. We can also say that human behavior is the reflection of his mind processes. The human behavior is confirming the existence of mind which many skeptics are denying. In easiest terms psychology may be defined as study of man his behavior and mind. These three exist in dialectical relation of being influenced and influencing each other and not in absolute isolation.