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Public Domain · 1938

Thurstone Primary Mental Abilities: First multi-factor IQ battery

Louis Thurstone's empirically-derived 7-factor model of intelligence: Verbal, Number, Spatial, Memory, Word Fluency, Perceptual Speed, Reasoning. The 1938 PMA battery and accompanying monograph are the foundational documents of modern multi-factor cognitive ability theory.

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About the Thurstone Primary Mental Abilities

By the 1930s the major question in intelligence research was whether there was one general intelligence factor (Charles Spearman's g) or multiple independent abilities. Spearman's view dominated in the UK; American psychologists were more skeptical. Louis Thurstone, at the University of Chicago, set out to settle the question empirically.

Thurstone administered 57 cognitive tests to a large sample of students and applied his new multiple-factor analysis method (a major statistical innovation he had developed). The result was 7 distinct, weakly-correlated factors: Verbal Comprehension (V), Word Fluency (W), Number (N), Spatial Visualization (S), Associative Memory (M), Perceptual Speed (P), and Reasoning (R). He called these the Primary Mental Abilities.

Thurstone's 7-factor model directly competed with Spearman's general-factor view through the 1940s and 1950s. The eventual synthesis (Cattell-Horn-Carroll model, 1990s-2000s) accepted both: there IS a general factor at the top, AND there are distinct broad abilities below it. But Thurstone's empirical demonstration that intelligence is multi-dimensional shaped every modern cognitive battery, including the WAIS-IV, WISC-V, and Stanford-Binet 5.

The 7 subtests

#V
Verbal Comprehension Vocabulary, reading comprehension, verbal analogies. The factor most closely related to general intelligence.
Interactive
#W
Word Fluency Generate as many words as possible meeting some criterion (start with letter K, etc.) in a time limit.
Timed Production
#N
Number Speed and accuracy of arithmetic computation.
Interactive
#S
Spatial Visualization Mental rotation of 2D and 3D shapes; identifying the same shape in a different orientation.
Interactive
#M
Associative Memory Memorize paired associates (word-word, picture-word).
Memory Task
#P
Perceptual Speed Speed of visual scanning; matching items in a row, finding differences.
Interactive
#R
Reasoning Letter series, number series, abstract pattern recognition.
Interactive

Take the interactive subset

Sample items from each of Thurstone's 7 factors. The original PMA battery had several specific tests per factor.

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About these items: These Thurstone Primary Mental Abilities items are originally-written reconstructions in the tradition of the original 1938 test, NOT verbatim copies of the historical items. Where the original is a 1-on-1 oral or physical-apparatus test (e.g., examiner shows a card, child draws a shape), we have adapted the format to self-administered multiple choice. See the original source for the authentic 1938-era items in their original administration format.

Source

All test materials and historical content on this page are transcribed from:

Thurstone, L. L. (1938). Primary Mental Abilities. Psychometric Monographs No. 1. Chicago: University of Chicago Press.

Louis Thurstone (1887-1955) was the most influential American psychometrician of the 20th century. The PMA monograph is one of the most-cited papers in the history of psychology. Read it on Internet Archive: https://archive.org/details/primarymentalabi0000llth.

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This page is part of the Historical IQ Tests Archive. Editorial content, transcription notes, and curation are released under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). Public-domain primary sources retain their public-domain status. BibTeX · RIS · CSL JSON

Historical test materials are obsolete and are not valid modern IQ assessments. This page is preserved for educational, research, and historiographic purposes.

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