The intelligence quotient or IQ is a score which attempts to describe someone’s intellectual or cognitive ability. G-factor analysis is the psychometric evaluation of cognitive abilities. More specifically, General Intelligence or Spearman’s G (G), is believed to be a leading indicator which explains 40-50% of the variability of test takers’ performance on individual cognitive tasks. In other words, the level of your general intelligence (usually represented by a global IQ score) will correlate strongly to your performance on individual cognitive tasks. Thurstone (1938) was an opponent of G and expanded the narrow definition of intelligence to encompass 7 primary types of mental abilities, which could be measure in multiple intelligence tests:
- Verbal comprehension
- Word fluency
- Number
- Spatial ability
- Associative memory
- Perceptual speed
- Reasoning or Induction