THE REAL ERROR OF CYRIL BURT 341
Epilogue: Arthur Jensen and the resurrection
of Spearman's g
When I researched this chapter in 1979, I knew that the ghost
of Spearman's g still haunted modern theories of intelligence. But
I thought that its image was veiled, and its influence largely unrec-
ognized. I hoped that a historical analysis of conceptual errors in
its formulation and use might expose the hidden fallacies in some
contemporary views of intelligence and IQ. I never expected to
find a modern defense of IQ from an explicitly Spearmanian per-
spective.
But then America's best-known hereditarian, Arthur Jensen
('979) revealed himself as an unreconstructed Spearmanian, and
centered an eight-hundred-page defense of IQ on the reality of g.
More recently, Richard Herrnstein and Charles Murray also base
their equally long Bell Curve (1994) on the same fallacy. I shall ana-
lyze Jensen's error here and The Bell Curve's version in the first two
essays at the end of the book. History often cycles its errors.
Jensen performs most of his factor analyses in Spearman and
Burt's preferred principal components orientation (though he is
also willing to accept g in the form of Thurstone's correlation
between oblique simple structure axes). Throughout the book, he
names and reifies factors by the usual invalid appeal to mathemat-
ical pattern alone. We have g's for general intelligence as well as g's
for general athletic ability (with subsidiary group factors for hand
and arm strength, hand-eye coordination, and body balance).
Jensen explicitly defines intelligence as "the g factor of an
indefinitely large and varied battery of mental tests" (p. 249). "We
identify intelligence with g," he states. "To the extent that a test
orders individuals on g, it can be said to be a test of intelligence"
(p. 224). IQ is our most effective test of intelligence because it proj-
ects so strongly upon the first principal component (g) in factor
analyses of mental tests. Jensen reports (p. 219) that Full Scale IQ
of the Wechsler adult scale correlates about 0.9 with g, while the
•937 Stanford-Binet projects about 0.8 upon a g that remains
"highly stable over successive age levels" (while the few small group
factors are not always present and tend to be unstable in any case).
Jensen proclaims the "ubiquity" of g, extending its scope into
realms that might even have embarrassed Spearman himself. Jen-
sen would not only rank people; he believes that all God's creatures