Domain Definition: Unresolved Problems with Phenotypic Structure 61(curious), fantasy (imagination), aesthetics (artistic), actions
(wide interests), feelings (excitable), and values (unconven-
tional). Others consider the domain to represent culture or
intellect (Digman, 1990; Saucier & Goldberg, 1996). John
and Srivastava (1999) maintained that the culture label
(Passini & Norman, 1966) is not supported by evidence that
traits referring to culture such as civilized, polished, digni-
fied, foresighted, and logical load more highly on the consci-
entiousness factor. This leaves the alternative interpretation
of intellect (Digman & Inouye, 1986; Goldberg, 1990). How-
ever, John and Srivastava (1999) concluded that the evidence
supports the Costa and McCrae interpretation and that intel-
lect is merely a component of a broader openness factor. This
interpretation is supported by studies of the relationship
between the domain and measures of cognitive ability. For
example, the openness-intellect factor (Understanding, Sen-
tience, Change, and Autonomy) based on the Personality
Research Form (Jackson, 1984) correlates highly with mea-
sures of crystallized intelligence (e.g., verbal subscales) but
less with measures of fluid ability (arithmetic and perfor-
mance subscales; Ashton, Lee, Vernon, & Jang, 1999).
There are other, less easily resolved confusions about the
definition and facet structure of other domains. For example,
Conscientiousness according to Costa and McCrae (1995)
consists of a single factor defined by competence, order, du-
tifulness, achievement striving, self-discipline, and deliber-
ateness. Paunonen and Jackson (1996), however, question the
unity of conscientiousness: “... The domain is best thought
of as three separate, but somewhat overlapping, dimensions
related to being (a) methodical and orderly, (b) dependable
and reliable, and (c) ambitious and driven to succeed. More-
over, the amount of overlap among these three facets may not
be high enough to justify their inclusion in an overall Consci-
entiousness measure” (p. 55).
The cluster of traits labeled impulsive–sensation seeking
poses an even greater problem. Earlier, we discussed prob-
lems with the placement of impulsiveness within the five-
factor model. The controversy, however, is deeper. For Zuck-
erman (1991, 1994), impulsivity and sensation seeking define
a separate higher-order factor within an alternative five-factor
structure. The factor resembles Eysenck’s psychoticism and
Tellegen’s (1985) constraint. There appears, therefore, to be
strong support for this domain. The five-factor model of
Costa and McCrae, however, divides this factor into impul-
sivity and sensation seeking and assigns them to different
domains. Impulsivity is considered part of neuroticism, an
interpretation that is not shared by other conceptions of neu-
roticism, whereas sensation seeking is assigned to extraver-
sion. This leads to similar problems with extraversion.
Extraversion is defined by subsets of traits that differ across
models. These subsets include such traits as sociability or af-
filiation, agency, activation, impulsive–sensation seeking,
positive emotions, and optimism (Depue & Collins, 1999;
Watson & Clark, 1997). Depue and Collins (1999) pointed
out that most accounts of extraversion postulate two central
features, an interpersonal engagement component consisting
of affiliation or sociability and agency, and an impulsivity
component that includes sensation seeking. They suggested
that impulsive–sensation seeking arises from the interaction
of extraversion and a second independent trait represented by
Tellegen’s (1985) constraint. This proposal differs, however,
from Eysenck’s model that places impulsivity in the psy-
choticism domain and Costa and McCrae’s proposal that it
belongs to neuroticism. It also differs from Gray’s (1973,
1987; Pickering & Gray, 1999) model that considers impul-
sivity as assessed by questionnaire to be a blend of Eysenck’s
higher-order dimensions of extraversion and psychoticism. It
appears, therefore, that there are major unresolved defini-
tional problems with most domains that compromise claims
that the five-factor model provides a basic assessment frame-
work (McCrae & Costa, 1986).
The existence of such basic uncertainty about the taxon-
omy of personality traits would seem to suggest that state-
ments that the structure of personality is becoming delineated
might be a little premature. Uncertainty about the relation-
ships among traits is a major obstacle to constructing a theory
of individual differences and clarification of these issues is
essential for the field to advance. The ordering of traits within
each domain forms the basis for developing theoretical ex-
planations by defining relationships that require explanation.
In effect, a descriptive taxonomy shapes subsequent research
and theory development.Approaches to Domain DefinitionIn response to these challenges, especially Paunonen and
Jackson’s (1996) critique of conscientiousness, Costa and
McCrae (1998) outlined six methodological approaches that
can be used to demonstrate the unity of any domain: (a) item
content analysis, (b) definitions of psychological opposites,
(c) examination of empirical correlates, (d) interpreting sec-
ondary and tertiary factor loadings, (e) identification of
equivalents in specialized languages and (f ) case studies.
Costa and McCrae (1998) applied these approaches to show
that the Conscientiousness domain was unitary in nature. The
limitation of these proposals is their reliance on an array of
criteria that incorporate a subjective element. The proposal
relies on a convergence of evidence across sets of traditional