Thurstone | Louis

Thurstone moved beyond Charles Spearman’s single-factor model. He developed , a computationally simpler method (pre-computer era) for extracting multiple common factors from a correlation matrix.

) : The speed of spotting visual details, similarities, and differences. Induction (

Thurstone married Hazel Stagner in 1915, and they had two children together. He was known for his love of music and was an accomplished violinist. Thurstone was also a passionate advocate for social justice and civil rights, and was actively involved in various community organizations throughout his life. louis thurstone

He introduced the idea that everyone has a

: Developed the method of equal-appearing intervals to measure social attitudes quantified via specific questionnaires. Induction ( Thurstone married Hazel Stagner in 1915,

-factor. Instead of a single, overarching intelligence, Thurstone argued that human intellect consists of seven independent components. He called these the . The Seven Primary Mental Abilities Verbal Comprehension (

Later work found these abilities are not completely independent, suggesting a hierarchical model (general + group factors). However, PMA influenced modern intelligence tests (e.g., Woodcock-Johnson, WJ-IV). He introduced the idea that everyone has a

Here is the breakdown of why this feature of his work is so fascinating:

| 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. |

Thurstone didn't just change how we measure intelligence; he changed how we view human competence. He proved that intelligence has geometry , not just magnitude. He validated the idea that being "smart" isn't a single destination—it's a unique configuration of strengths and weaknesses.