Discover your intellectual strengths
Charles Spearman introduced the notion of a general factor underlying all tests of intelligence. He called this the g factor. It is important to note that 'g' does not represent intelligence in any way, it simply represents the fact that many different tests of cognitive abilities are positively correlated with each other. This concept of 'g' has been highly controversial especially due to the fact that some researchers have attempted to correlate it with biological differences among groups of people.
Raymond Cattell proposed that intelligence was comprised of two broad factors representing fluid and crystallized abilities. Some examples of crystallized abilities are vocabulary and verbal fluency skills, while fluid abilities emphasize processing speed, and abstract thinking.
Modern theories by Robert Sternberg and Howard Gardner highlight the existence of many intelligences. Robert Sternberg proposed the existence of practical and creative intelligence, in addition to analytical intelligence which most modern day IQ tests measure. Howard Gardner's theory of multiple intelligences include linguistic, logical/mathematical, spatial, bodily/kinesthetic, musical/rhythmic, interpersonal, intrapersonal and naturalistic intelligences.