Intelligence
The first widely used measure of intelligence was created by Alfred Binet. Then, Lewis Terman modified Binet's test, and turned it into a numerical measure for IQ. The test rated 100 as average intelligence, 130 or higher as gifted, and 70 and below as an intellectual disability. Defining intelligence has proven difficult for psychologists, so various theories have arisen to define the concept. For example, Spearman incorporated a general intelligence, or g factor into his definition. In contrast, Sternberg identified three factors of intelligence: analytical, creative, and practical. Gardner contended that intelligence can be defined in several different areas, with everyone exhibiting at least one form of intelligence. Finally, Goleman argued that emotional intelligence predicts future success.