(1) Uni-factor theory considered one similar set of abilities in all.
(2) Two-factor theory consisted of two factors:G factor (abilities common to all) and S factor (special abilities)
(3) Theory of Primary Mental abilities consists of 7 primary mental abilities: Verbal comprehension, Numerical abilities, Spatial relations, Perceptual speed, Word fluency, Memory, and Inductive Reasoning.
(4) Hierarchical Model has two levels. Level 1 is associative learning, and the output is similar to input. Level 2 is cognitive competence, and the output is more than input.
(5) Structure of Intellect Model comprises 3 components: operations, contents, and products. The model has 180 (5 ×6×5) cells.