levels of the Science/Math trait complex were likely to have much higher-
than-average scores on physical sciences domain knowledge, and somewhat
higher scores on civics and business knowledge. Individuals with high Intel-
lectual/Cultural trait complex scores were most likely to have high humani-
ties domain knowledge levels, but also had greater than average scores on
the other knowledge domains. Those individuals who had high Social trait
complex scores, however, were likely to be less knowledgeable about all of
the knowledge domains assessed. Overall, these results are consistent with
two predictions: (a) Science/Math and Intellectual/Cultural trait complexes
that are supportive of domain knowledge and that the Social trait complex
was impeding of domain knowledge; and (b) for the two supportive trait
complexes, they differed in their respective correlations with the kinds of
domain knowledge. The results, then, support the idea that these trait com-
plexes are associated with the direction and intensity of domain knowledge
for adults across a substantial age range.
Trait Complexes, Domain Knowledge, and Gender
in a College Sample
Another study of the PPIK approach focused on individual differences in
abilities, trait complexes, and domain knowledge in a sample of college stu-
dents (Ackerman, Bowen, Beier, & Kanfer, 2001). In this study, a sample of
320 first-year college–university students was administered a battery of meas-
ures similar to that of the Ackerman (2000) study, along with additional
measures of personality, motivational traits, and background experiences. A
structural equation model of the ability determinants of domain knowledge is
shown in Fig. 5.4. The model provides a useful demonstration that for these
young adults, even though Gc is substantially determined by individual dif-
ferences in Gf, the effects of Gf on domain knowledge are largely indirect (ex-
cept for physical sciences/technology knowledge). That is, the influence of Gf
on domain knowledge is through its influence on Gc, and Gc is substantially
positively associated with all domains investigated in the study.
In this study, we largely replicated the derivation of two trait complexes
that are predicted to be supportive of domain knowledge—Science/Math/
Technology and Verbal/Intellectual. The latter trait complex was expanded
from previous studies to include achievement-oriented motivational traits of
Desire to Learn and Mastery orientation (Kanfer & Heggestad, 1997, 2000).
In addition, we effectively separated two aspects of the Social trait complex—
a Social Potency/Enterprising trait complex and a Social Closeness/Feminin-
ity trait complex. Finally, a fifth trait complex of Traditionalism/Worry/
Emotionality was derived—it included personality measures, but also avoid-
ance-related motivational traits (the Worry and Emotionality scales refer
specifically to performance contexts—Kanfer & Heggestad, 2000). Consis-
132 ACKERMAN AND KANFER