Charles Spearman
1863-1945 · British · Psychometrics
Every normal man, woman, and child is, then, a genius at something, as well as an idiot at something.
Charles Spearman came late to psychology, after fifteen years as an army officer, and brought to it the conviction that the study of mind must become exact, measured and mathematical. In two papers of 1904 he changed the field twice: one introduced rank correlation and the correction for attenuation, the other announced the general factor of intelligence, g.
Questions to put to Charles Spearman
The General Factor and the Positive Manifold
- What do you mean by g, the general factor of intelligence?
- Why do you think all cognitive test scores correlate with each other?
- How is g different from just being good at taking tests?
- What convinced you that g is a real thing and not just a statistical artifact?
- Can someone have high g but still fail at specific tasks?
Factor Analysis and the Two-Factor Theory
- How does factor analysis let you discover g from a table of correlations?
- What's the difference between the general factor g and the specific factors s?
- How do you respond to the criticism that factor analysis just summarizes data rather than discovering real mental entities?
- Why did you later add group factors between g and s to your original theory?
- What are tetrad differences and why do they matter for proving g exists?
The Noegenetic Laws and the Nature of Intelligence
- What are the three noegenetic laws of cognition?
- What do you mean by the eduction of relations?
- How does educing correlates work in practice?
- Why do analogies reveal the fundamental operations of intelligence?
- How do your three laws explain why some people are more intelligent than others?
Mental Energy and the Heritability of Intelligence
- What do you mean when you call g a quantity of mental energy?
- How much of intelligence do you think is inborn versus learned?
- Can education or training significantly increase someone's g?
- How do you defend the view that intelligence is largely hereditary?
- What's your response to critics who say your hereditarian view has been misused to justify inequality?
Monarchic, Oligarchic, and Anarchic Doctrines
- What's the difference between the monarchic, oligarchic, and anarchic doctrines of mind?
- How do you respond to Thurstone's claim that there are multiple primary mental abilities instead of one g?
- What's your answer to Godfrey Thomson's argument that the positive manifold could arise from many overlapping bonds without any single g?
- Why do you think the monarchic doctrine is right and the others are wrong?
- Can the oligarchic and monarchic views both be partly true?
Mental Testing and the Measurement of Abilities
- How should we design tests to measure g accurately?
- What makes a good intelligence test versus a bad one?
- How do you correct for the fact that all tests have measurement error?
- What did you discover about the abilities of men across different occupations and fields?
- Should intelligence tests be used to select people for education or jobs?
Converse with Charles Spearman on Simposeum. Replies are grounded in Charles Spearman's own writing, cited to the page.