Meaning of Intelligence
Intelligence is the ability to acquire and apply knowledge. Intelligence is defined as mental capability that involves the ability to reason, to plan, to solve problems, to think abstractly, to comprehend complex ideas, to learn quickly and to learn from experience. More generally, it can be described as the ability to perceive or infer information, and to retain it as knowledge to be applied towards adaptive behaviors within an environment or context.
Spearman's Two Factor Theory of Intelligence
Two factor theory was propounded by Charles Spearman in 1904. fle concluded that intelligence is comprised by two factors, viz. "General ability" known as 'g' factor and Specific ability known as 'S' factor. This theory states that every cognitive task involves a general factor 'g' which it shares with all other cognitive tasks and a specific factor 'S' which it shares with none.
To state in simple terms, Intelligence is composed of two factors. One is general factor 'g' which is involved in all walks of life and ether is specific factor or 'S' which is reflected in a specific or particular ability e.g. musical ability, artistic ability etc.
The performance on any cognitive task is predicted by the formula-
P = g + S
Performance = General factor + Specific factor
However, this formula suggests that both 'g' and 'S' factors participate equally in affecting the performance (P). Actually they vary in different activities. Vocabularly is very closely related to 'g. So the performance on vocabularly should be written as
Pe = g + S
Whereas, performance on the test of aesthetic judgement may depend on training of art and some specific ability. Here we would write the formula
Pa = g + S
The exact nature of 'g' is unknown. Figure showing the relationship between 'g' and 'S' abilities.
Characteristics of 'g'
- 'g' is universal and inborn ability.
- 'g' varies from person to person but in a person it is constant.
- 'g' is common in all life activities.
- 'g' is responsible for success in life.
- Whenever we talk of testing intelligence, we actually mean to measure 'g' with the help of intelligence test.
Characteristics of 'S'
- 'S' is learnt and acquired in the environment.
- 'S' is closely associated with the aptitude of person.
- 'S' varies from person to person.
Spearman tried to find the ratio between 'g' and 'S' factor on the basis of his longitudinal studies. According to him, for a creative musician the ratio between 'g' and 'S' should be 1:4.
Later on Spearman propagated Three Factor Theory. After the indoctrination of Two Factor Theory he introduced another factor of intelligence in his previous theory and that is Group Factor denoted by 'G which is superior to general ability but inferior to Specific Factor i.e., 'S'. Now his formula was
P = 'g' + 'G' + 'S'