identifications, values, and so on. This literature is now voluminous,
numbering in the hundreds of studies. Recently, however, Leong,
Hartung, Goh, and Gaylor (2001) found birth order to correlate
with Holland type and occupational interests in a sample of med-
ical students. First-born students were lower in Realistic and Artis-
tic than their second-born counterparts, and “only” children were
higher on Investigative. Later-born children scored higher on music,
athletics, and nature. This study sheds some light on the develop-
mental origins of the types.
Parallel or Commensurate Work Environments.Holland postu-
lates a parallel set of six work environments and combinations or
subtypes of those six environments with the same names and defi-
nitions as the person types (Realistic, Investigative, Artistic, Social,
Enterprising, Conventional). Work on the environments has been
slower but even more interesting than that conducted on persons.
The early work on environments, led by Alexander Astin, was rig-
orous, complex, and longitudinal (Astin, 1999; Spokane, 1985).
Although there have been few studies recently, and the person
studies have eclipsed the environment studies, the importance of
the environmental studies to the ecological base of Holland’s the-
ory is paramount (Chartrand, Strong, & Weitzman, 1997; Char-
trand & Walsh, 1999; Hesketh, 2000).
Three studies (Smart, 1997; Smart & Feldman, 1998; Thompson
& Smart, 1999) illustrate the complex manner in which academic
environments exert their influence on students with regard to self-
perceived growth and student competencies. Faculty, according to
Smart and his colleagues, actively create environments consistent
with Holland’s theory and then require, reinforce, and reward stu-
dents differentially according to their patterns of behavior.
Two novel studies redirect our attention to the complex social
processes and interactions that transpire in work environments
(Wampold et al., 1995; Wampold, Mondin, & Ahn, 1999). The
first of these studies (Wampold et al., 1995) tested chemistry labo-
ratory groups and found that Holland Social types demonstrated
HOLLAND’S THEORY 395