Correlations between performance on different intellectual tasks fail to reach 1.00, indicating specialization of intelligence¶
Claim · All claims
Evidence · 1 study · theoreticalr2·q2
Currency · newest study 1921 · checked against its sources 2026-10-24 (automated, 1 of 1 entry) · not reviewed by a person
Subclaims¶
Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
the rigour judged within that kind: what each code means.
This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.
q2 i? As the task changes across data domains or across operations with the same data, correlations between performances never reach 1.00. → E. L. Thorndike and L. M. Terman 1921
Evidence¶
E. L. Thorndike and L. M. Terman 1921¶
E. L. Thorndike and L. M. Terman. (1921). Intelligence and Its Measurement. The Journal of Educational Psychology. https://archive.org/search?query=Journal+of+Educational+Psychology+1921
q2 · i? · theoretical · r2
Thorndike's analytical argument in the symposium essay states that across data domains and across operations "the correlation never holds up to 1.00", treating this as evidence that intellect is specialized rather than a single general power. No empirical correlations are printed in the text.
"As we change the task from space relations to animals, to plants, to machines, to moral issues, to numbers, the correlation never holds up to 1.00. As we change from accuracy in perception, to accuracy in memory, to accuracy in inference, all with the same data, the correlation again fails to hold at 1.00."
Discussion¶
Related Claims¶
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- The association between musical training and school performance appears general and non-specific across subjects, with no evidence for special links to single domains — related
- Embedded figures test performance differed by sex and correlated relatively highly with intelligence — related
- Digit span running loaded on the focus of attention factor rather than the phonological factor, supporting Cowan's claim that running span performance reflects attentional capacity — related
- A common attentional component is needed for feature binding, running digit span, and visual short-term memory tasks, while phonological storage is separate — related
- A 12-year-old's intelligence test score prophesies book-learning outcomes more accurately than practical or social-intellectual performance — a narrower finding that bears on this claim
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
intellectual-task-correlations-below-unity-specialization |
title |
Correlations between performance on different intellectual tasks fail to reach 1.00, indicating specialization of intelligence |
description |
Correlations between performance on different intellectual tasks fail to reach 1.00, indicating specialization of intelligence |
status |
review |
evidence_strength |
weak |
newest_evidence |
1921 |
source_checked |
2026-10-24 |
generated |
by process:wiki-ingest on 2026-10-24 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — e-l-thorndike-and-l-m-terman-1921 |
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