Spearman, Thurstone & Guilford
Before Gardner, psychologists argued over how many factors make up intelligence, and CTET likes to test who held which view. Charles Spearman proposed the two-factor theory: every intellectual task draws on a single general intelligence, the 'g' factor, that runs through all abilities, plus a 's' factor specific to that particular task. So 'g' explains why a child good at one thing tends to be good at others, while 's' explains the differences between tasks. Louis Thurstone disagreed with a single overarching 'g' and argued intelligence is made of several independent Primary Mental Abilities — typically listed as verbal comprehension, word fluency, number, spatial visualisation, memory, perceptual speed and reasoning — each relatively distinct. J. P. Guilford pushed this multi-factor view furthest with his Structure of Intellect (SOI) model, picturing intelligence as a large three-dimensional cube formed by combining three categories: operations (the mental process, e.g. cognition, memory, evaluation), contents (the kind of material, e.g. figural, symbolic, semantic) and products (the result, e.g. units, classes, relations). Crossing these dimensions yields a very large number of distinct abilities. The simple memory line CTET rewards: Spearman = one general 'g' plus specifics; Thurstone = several primary abilities, no single 'g'; Guilford = many abilities from a three-dimensional model.
✅ Solved examples
✏️ Practice — try these, take hints as needed
📝 Topic test — 8 questions
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Key Concepts — Quick Reference
The IQ idea and the multi-ability theories
| IQ formula (Stern/Terman) | IQ = (Mental Age / Chronological Age) x 100 |
|---|---|
| Gardner | Multiple Intelligences - 8 distinct, independent intelligences |
| Spearman | Two-factor: one general "g" + specific "s" abilities |
| Sternberg | Triarchic: analytical + creative + practical |
Quick attributions (who said what)
| Binet | First practical intelligence test + the idea of mental age |
|---|---|
| Thurstone | Primary Mental Abilities - intelligence is several factors, not one g |
| Guilford | Structure of Intellect - a 3-dimensional model of many abilities |
| Gardner key list | Linguistic, Logical-Math, Spatial, Bodily, Musical, Inter-, Intra-, Naturalistic |