vestigation of various sources of aptitude–treatment interactions in learning
contexts. Ackerman and Heggestad (1997) adapted and expanded this con-
cept into trait complexes—which are considered to be constellations of traits
across cognitive, affective, and conative trait families. The conceptualization
of trait complexes does not imply the existence of interactions with learning
treatments, but instead does suggest that there is a value added (over and above
consideration of single traits or single trait families) in predicting and under-
standing adult intellectual development and express. In a meta-analysis and re-
view of the personality, ability, and interest literature, Ackerman and Heggestad
(1997) determined the existence of four broad trait complexes, called Social,
Clerical/Conventional, Science/Math, and Intellectual/Cultural.
The Clerical/Conventional and Intellectual/Cultural trait complexes have
components of all three trait families. The Social trait complex has only inter-
est and personality traits, probably because there is little extant literature on
valid social or interpersonal intelligence measures. The Science/Math trait
complex has only ability and interest components, perhaps because there is
an insufficient literature on the specific personality characteristics that are
uniquely associated with spatial and math abilities, along with realistic voca-
tional interests. The literature, however, supports that notion that the Intel-
lectual/Cultural trait complex will be positively associated with adult intellect
along the lines of Gc, the Science/Math trait complex will be associated with
Gf, and the Clerical/Conventional trait complex might only be associated
with perceptual speed and psychomotor abilities. The Social trait complex is
not associated with traditional measures of intellectual abilities—suggesting
that individuals with high levels of this complex, might not be oriented to-
ward academically oriented intellectual activities.
It should be noted that the Ackerman and Heggestad (1997) meta-analysis
and review found significant, but not large associations among many of these
variables. This finding was not particularly surprising, given the divergence
between typical behavior assessments (for personality and interests) and
maximal performance assessments (for abilities). As such, these findings pro-
vide an important starting point for evaluating the overlap among different
trait families under similar conditions (either typical or maximal), but obvi-
ously do not yield a final answer to the question of the degree of overlap
among the underlying traits.
AN INVESTMENT THEORY OF ADULT
INTELLECTUAL DEVELOPMENT
A theory that integrates the concepts of typical behavior and maximal per-
formance, trait complexes, and domain knowledge has been offered by Acker-
man (1996). The four component theoretical framework has been referred to as
126 ACKERMAN AND KANFER