El. Rolfhus et Pl. Ackerman, Assessing individual differences in knowledge: Knowledge, intelligence, and related traits, J EDUC PSYC, 91(3), 1999, pp. 511-526
Twenty academic knowledge tests were developed to locate domain knowledge w
ithin a nomological network of traits. Spatial, numerical, and verbal aptit
ude measures and personality and interest measures were administered to 141
undergraduates. Domain knowledge factored along curricular lines; a genera
l knowledge factor accounted for about half of knowledge variance. Domain k
nowledge exhibited positive relations with general intelligence (g), verbal
abilities after g was removed, Openness, Typical Intellectual engagement,
and specific vocational interests. Spatial and numerical abilities were unr
elated to knowledge beyond g. Extraversion related negatively to all knowle
dge domains. Results provide broad support for R. B. Cattell's (1971/1987)
crystallized intelligence as something more than verbal abilities and speci
fic support for P. L. Ackerman's (1996) intelligence-as-process, personalit
y, interests, and intelligence-as-knowledge theory of adult intelligence.