as semantic-rich or knowledge-rich rather than knowledge-lean (Simon,
1979; see Alexander, chap. 10, for an illustration of the distinction).
Based on Geary’s (1995) distinction between biologically primary and sec-
ondary abilities, and Greenough’s distinction experience-expectant and expe-
rience-dependent learning in terms of differing brain mechanisms (see Green-
ough, Black, & Wallace, 1987), it is likely that various biologically primary
abilities and dispositions are co-opted to learn specific skills valued in a cul-
ture. The question becomes what constellation of cognitive and affective
traits would support the development of expertise in a specific domain, an is-
sue addressed by Ackerman (1999; Ackerman & Kanfer, chap. 5).
Aptitude Versus Deep Engagement. While traditional psychometric per-
spectives tend to emphasize high IQ, among other factors, as a necessary apti-
tude factor for the development of expertise (see Ackerman & Kanfer, chap.
5), some researchers suggests that IQ and expertise are unrelated; rather, ex-
pertise reflects dedicated mechanisms specific to domains (Ceci & Liker,
1986; Hirshfeld & Gelman, 1994). Ceci and Ruiz (1993) questioned a typical
conception of intelligence (presumably under the influences of Spearman and
Piaget) as the general mental power for abstract thinking, which would show
through in any domain-specific learning. Ceci and Liker (1986) found that
people who gave mediocre performance on adult intelligence tests can per-
form marvelous intellectual feats when it comes to their domain of expertise
(e.g., highly sophisticated reasoning on the racetrack gambling). The implica-
tion is that deep engagement in a domain counts much more than some gen-
eral mental power for the development of expertise, a position consistent with
ecological theories of intelligence (e.g., Pea, 1993) and expertise (Vicente &
Wang, 1998). More recently, talent accounts of expertise have also been chal-
lenged (Howe, Davidson, & Sloboda, 1998).
Similarly, according to Ericsson (Ericsson, Krampe, & Tesch-Romer,
1993), a key mechanism for the development of expertise is deliberate prac-
tice, a form of practice that is highly focused and intensive. The logic is as fol-
lows: if the achievement of expertise takes thousands of hours of deliberate
practice, and the pay-off of these efforts is often remote, then, what may ulti-
mately distinguishes those who became experts from those who did not is not
their initial abilities, but their motivational characteristics, such as determi-
nation and commitment (see also Charness, Tuffiash, & Jastrzembski, chap.
11). However, the variables of aptitude^5 and deep engagement or deliberate
22 DAI AND STERNBERG
5 5 It is important to distinguish between psychometrically defined aptitudes such as IQ or mu-
sic aptitude tests, and aptitude as a theoretical construct. Snow’s (1992) definition of aptitude as
the inclination or readiness to respond to a certain class of situations already implies a selective
tendency for deep engagement in certain activities.