process), wemight obtain an estimate of overall adult intellect that more heavily
weights Gc and domain knowledge in comparison to Gf. Such a weighting
would certainly indicate that, according to this definition, middle-aged adults are
more intelligent than younger adults. With an equal weighting of Gf, Gc, and
overall domain knowledge, the correlation between age and overall intellect is
essentially zero (rcomposite,age= –.02), which indicates that middle-aged adults are,
on average, equally intelligent, compared to younger adults.
In this study, three of the four trait complexes identified by Ackerman
and Heggestad (1997)—Science/Math, Intellectual/Cultural, and Social
were assessed. The complexes were derived from a joint factor analysis of
ability, personality, interest, and self-concept measures. A simple structure
solution was obtained with an orthogonal rotation—which means that the
trait complex scores were essentially uncorrelated with one another. That is,
individuals can have widely different patterns of trait complex profiles (e.g.,
high on one, low on others, high on all, low on all, etc.). Thus, an individual
could have high Intellectual/Cultural trait complex and would be just as
likely to have high, medium, or low scores on the Social trait complex. Cor-
relations between derived trait complex scores (after the ability components
of the trait complexes were removed) and composite domain knowledge
scores are shown in Fig. 5.3. As the figure indicates, individuals with high
- TYPICAL AND MAXIMAL PERFORMANCE 131
FIG. 5.3. Correlations between trait complex scores (after ability measures
were removed) and domain knowledge for Physical Sciences, Civics, Human-
ities, and Business composites. Shown are correlations with Social, Science/
Math, and Intellectual/Cultural trait complexes. Data from Ackerman (2000).