Louis L. Thurstone's Primary Mental Abilities theory argues intelligence isn't one general capacity but seven separate abilities (verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, and reasoning), each identified through factor analysis.
Thurstone's Primary Mental Abilities theory is a multiple-intelligences answer to Spearman's single g factor. Using factor analysis (the same statistical tool Spearman used), Thurstone analyzed people's scores on dozens of mental tests and concluded that intelligence breaks into seven distinct, independent abilities: verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, and reasoning. In his view, you don't have one overall smartness level. You have a profile, so someone can be strong in spatial visualization but average in word fluency.
Here's the twist the AP exam loves. When researchers re-analyzed Thurstone's data, people who scored high on one ability tended to score high on the others too. The seven abilities weren't as independent as Thurstone claimed, which actually lent support back to Spearman's g. So Thurstone's theory matters both as a model of intelligence and as a case study in how the same data can be read two ways.
This term lives in Topic 5.9, Introduction to Intelligence, in Unit 5 of AP Psych Revised. The CED frames intelligence around a central debate, whether intelligence is one general ability or many specific ones, and Thurstone is the classic 'many abilities' side of that debate. Knowing his seven primary mental abilities lets you contrast theorists (Spearman vs. Thurstone vs. Cattell vs. Gardner vs. Sternberg), which is exactly the comparison move multiple-choice questions set up. It also reinforces a bigger AP Psych skill, evaluating how a research method (factor analysis here) shapes the conclusions psychologists draw.
G factor / Spearman's general intelligence (Unit 5)
Thurstone built his theory as a direct rebuttal to Spearman. Spearman saw one general intelligence underlying all tasks; Thurstone saw seven separate abilities. Exam questions almost always frame these two as opposites, so know them as a pair.
Factor analysis (Unit 5)
Both Spearman and Thurstone used factor analysis, a statistical method that finds clusters of related test items. The fun part is that the same tool produced opposite conclusions, which shows that how you interpret statistical clusters matters as much as the math itself.
Fluid intelligence (Unit 5)
Cattell later split intelligence into fluid and crystallized types, a middle path between Spearman's one factor and Thurstone's seven. Thurstone's reasoning and perceptual speed abilities map roughly onto what Cattell would call fluid intelligence.
Flynn Effect (Unit 5)
The Flynn Effect (rising IQ scores across generations) raises the same question Thurstone did, namely what intelligence tests actually measure. If scores can rise over decades, are tests capturing one stable g or a shifting mix of specific abilities?
Expect Thurstone in multiple-choice questions that ask you to match a theorist to a theory or to identify which view of intelligence a scenario describes. A classic stem describes a student who excels at spatial puzzles but struggles with vocabulary, then asks which theory best explains the pattern. Thurstone's is the answer when the question stresses separate, independent abilities. You may also see critique-style questions, like one Fiveable practice question asking how the practical application of Thurstone's theory could be challenged. The strongest answer points to the re-analysis showing his seven abilities correlate with each other, which undercuts the claim that they're truly independent. No released FRQ has used this term verbatim, but it works well as evidence in any free-response prompt about competing theories of intelligence or the limits of factor analysis.
Both theorists used factor analysis on intelligence test data, which is why they blur together. The difference is the conclusion. Spearman found one general factor (g) underlying all mental tasks, while Thurstone argued for seven independent primary mental abilities with no single g behind them. Quick check for MCQs: 'one general ability' means Spearman, 'seven separate abilities' means Thurstone.
Thurstone proposed that intelligence consists of seven primary mental abilities: verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, and reasoning.
His theory directly challenges Spearman's g factor by claiming these abilities are independent rather than reflections of one general intelligence.
Thurstone reached his conclusion using factor analysis, the same statistical method Spearman used to argue the opposite.
Later re-analysis showed people strong in one ability tend to be strong in the others, so the abilities aren't fully independent, which partly supports g after all.
On the AP exam, pick Thurstone when a question describes someone with an uneven profile of strengths and weaknesses explained by separate abilities.
It's the theory that intelligence is made of seven independent abilities (verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, and reasoning) rather than one general intelligence. It appears in Topic 5.9, Introduction to Intelligence.
No. Thurstone challenged g, but when his own data was re-analyzed, scores on the seven abilities correlated with each other. That overlap actually provided evidence that some general factor exists, so the debate stayed alive rather than being settled.
Spearman argued one general intelligence (g) underlies performance on all mental tasks, while Thurstone argued for seven separate primary mental abilities with no single underlying factor. Both used factor analysis but interpreted the clusters differently.
Verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, and reasoning. You don't usually need to recite all seven on the exam, but recognizing them in a question stem signals Thurstone is the answer.
No. Both reject a single intelligence, but Thurstone's seven abilities all came from factor analysis of traditional mental tests, while Gardner's intelligences (like musical and bodily-kinesthetic) go beyond what standard tests measure. Thurstone is the statistical version of the 'many intelligences' argument.
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