The goal of psychology is to understand and explain behavior, that is, to isolate the reasons for the observed behavior. This process involves not only the formulation of the theories which are organized and consistent with known facts, but also development of hypotheses about relationships which are yet to be proved. A theory is also supposed to help us make reasonable guesses when we don’t know. Explanation is, in fact, the real basic field of research in psychology. The psychologist may be able to describe and measure anxiety. In principle, almost anyone with reasonable intelligence and relevant reference books may diagnose and treat any mental disease, without knowing what caused that disease. Basic psychology is an attempt to understand in detail many significant issues, including the processes of mental illness. The fundamental knowledge and skill involved in reading the basis of interaction between motivation and performance.