Mind is the faculty by which one is aware of surroundings and by which one is able to experience emotions, remember, reasons and make decisions. Mind is an abstract component which arises out of the CNS and develops along with other developments in the human body. It has two components namely physiological and psychological. So it involves organs, faculties and qualities of various sorts. The brain is the organ, intelligence is the faculty and consciousness is the quality. Behavior is the way in which someone behaves. Behavior means all the convert and overt activities of human beings that can be observed. It may be cognitive (knowing), affective, and psychomotor (doing). There is an interaction of mind and body in behavior which effects of the body on mind, i.e. physically identifiable events on psychological functioning on behavior for example taking stimulants (caffeine, nicotine) increases CNS activity particularly by enhancing dopamine activity, and increases alertness, suppress appetite, etc. similarly effects of mind on body can influence physical functioning and behavior. For example effects of stress, the body may respond to stress by producing excessive stress hormones (catechol amines and corticosteroids) leads to increased heart rate, increased blood pressure, increased oxygen intake, increased mental activity, increased skeletal blood flow, decreasing splanchnic blood flow, etc. and increasing cortisol-increasing gluconeogenesis, increases proteins and fat metabolism, increased aldosterone—sodium and water reabsorption, decreased urine output, and increased thyrodine—increasing metabolic rate. Every individuals development into a unique personality is determined by a very complex process of interaction between his heredity and his environment through time, each level of development depending partially on the levels previously reached. The process by which heredity continues to function after birth is called maturation. An instinctive behavior pattern which is inborn, appears full-blown upon the first occasion that an adequate stimulus is presented, without previous opportunity for learning. Although such behavior is sometimes found in the lower animals, it is very rare in man. His behavior patterns fall on a continuum between pure instinct and pure learning, depending upon the degree to which learning has interacted with maturation in their development.