Man is distinctively different from the lower species of animals because of his ability in controlling the environment he lives in. The distinction between man and other animals also springs from his successful adaptation to his environmental demands. The animals can at best escape to safety, protect their lives, may build nests as their shelter, can migrate to a distant land, but cannot conquer nature. The animals hardly can ingeniously adapt to any unfavorable chaotic environment.
On the contrary, man can recreate the world, create comforts for him with the help of scientific gadgets, climb the high ranges of mountains, invade the depth of the seas and air, travel with enormous speed, and can extend the life-span of its species by inventing remedies for several fatal diseases. His intellectual skills place him as the most superior species in the animal kingdom. Thus, underlying all human abilities lie the essential attributes of intelligence.
Intelligence is a popular term referring to all forms of man's complex mental abilities. Intelligence as a term refers to the ability to understand, act, interpret, and predict the future, and to achieve and handle relationships, information, concepts, and abstract symbols. Intelligence is thus a commonly used word to express universal capacity required for survival and progress beyond the present.
Intelligence is a process of cognition. "Cognition refers to how we acquire, store, retrieve, and use knowledge" (Matlin, 1996). All the basic psychological processes such as learning, perception, memory, concept formation, thinking, reasoning, problem solving, decision-making, and creativity are related to intelligence.
Therefore, intelligent behavior includes all forms of cognitive behavior such as attending, perceiving, learning, memorizing, thinking and predicting. Intelligence is an abstract concept. It cannot be observed direction it can be estimated only through individual's performance on tests and re life situations. Recently, the concept of intelligence has been broadened include such terms as "emotional intelligence", "spiritual intelligence "practical intelligence", "social intelligence", "vocational intelligence" and "musical intelligence".