) : The speed of spotting visual details, similarities, and differences. Induction (
Compare Thurstone's PMAs directly against . louis thurstone
Before Thurstone, intelligence was largely viewed through the lens of Charles Spearman’s (general intelligence). Spearman believed that intelligence was a single, general energy or power. If you were good at math, you were likely also good at verbal reasoning and spatial tasks. In this view, intelligence was a vertical ladder—some people were simply "higher" up than others. ) : The speed of spotting visual details,
| Criticism | Explanation | |-----------|-------------| | | Factor solutions require subjective rotation to achieve simple structure; different rotations can yield different interpretations. | | Overfactoring | Early centroid method could extract too many factors, some not replicable. | | Neglect of hierarchical structure | Later research (e.g., Carroll’s three-stratum model) showed PMAs correlate positively, suggesting a higher-order general factor (g) – which Thurstone initially denied. | | Computational burden | Before computers, centroid factor analysis was tedious; modern methods (principal axis, maximum likelihood) are now standard. | Spearman believed that intelligence was a single, general
: Directly influenced the development of the SAT, ACT, and modern intelligence batteries like the Wechsler scales, which now measure sub-indices rather than just one IQ score. ✅ Summary of Key Concepts