A Family Model of Trait Structure 249the trait pedigree is the first principal component, named the
pfactor of personality by Hofstee et al. (1998), in analogy to
thegfactor of intelligence, and in distinction to Eysenck’s
(1992) psychoticism or P factor, which is intended as a lower
level construct. A family of models may be constructed by
adding one principal component at a time. Thus at the second
level we have a circumplex or semi-circumplex; at the third a
three-dimensional generalized one, and so on.
The Primordial One
In search of superlatives over the Big Five and the giant three
(Eysenck, 1992), primordial appears as a good label for the p
factor. That factor derives a mythical quality from its close
association with desirability. It presents a fundamental para-
dox to students of personality, whose ultimate challenge is to
manage the potent values that nourish its roots: Not until we
are capable of giving an overall evaluation of an individual’s
personality in a perfectly respectful manner will we have
mastered that challenge.
In principle, there is nothing broad or vague about the p
factor. Quite to the contrary, it is by definition the most inter-
nally consistent linear combination of all traits, explaining
some 10% to 15% of the total variance in unselected item sets
(see, e.g., Brokken, 1978; Hendriks, 1997; Ostendorf, 1990),
just like the gfactor does in the intelligence domain. In other
words, no scale based on any subset of the items, however
optimally weighted, is as internally consistent as p. Its
location in the personality sphere is almost completely fixed
in any large data set.
Fixing the interpretation ofpacross studies is another
matter. In Hendriks’s (1997) unselected set of 914 items,pis
best labeled as competence (Hofstee, 2001). In Saucier’s
(2002a) study of representative sets of trait adjectives, it ap-
pears as a character factor taking in altruism, self-discipline,
and success. The first principal component of the FFPI,
whose 100 items were selected to cover the five factors
equally, is an optimism factor (Hofstee et al., 1998). In view
of the psychometric accuracy and the statistical reliability
that was attained in these large-scale studies, the differences
in interpretation cannot be attributed to chance. Differences
in composition of the item pools must be responsible.
Saucier (2002a) interprets his first principal component as
SD, for socially desirable qualities. On the one hand, this in-
terpretation cannot be far off because the first principal com-
ponent in any mixed set of positive and negative trait
descriptors will be close to the desirability axis. On the other,
it masks the fact that the first principal component bends to-
ward whatever content is best represented in the item pool.
For an extreme example, if that pool were overloaded with
fairly neutral extraversion and introversion items, the first
principal component would appear as extraverted desirabil-
ity. Therefore, active steps have to be taken to justify the
desirability interpretation.
I propose to define thepfactor of personality as the indi-
viduals’ Desirability. The most obvious operational definition
of that variable consists of obtaining a score by weighting the
items proportional to their desirability values. Both these val-
ues and the item scores are best expressed as positive and
negative deviations from the neutral midpoint of the scale. In
the absence of desirability values, the first principal compo-
nent of a heterogeneous and representative set of traits will
closely approximate the desirability variable. The desirability
score reflects the extent to which an individual is assessed to
have desirable versus undesirable qualities. The result will be
that most people are found to be desirable, although some are
more desirable than others. A few people would be assessed
to be undesirable.
The implied conception of personality is literally perpen-
dicular to the neutral view according to which, for example,
there are no right or wrong answers to the items of a ques-
tionnaire, and by which all people are equally desirable, just
different. One could of course use the desirability variable
just to partial it out, and retain a value-free, neutrally descrip-
tive account of personality, as in Saucier’s (1994) model.
Here, on the contrary, it functions as the pivot around which
the personality hypersphere revolves. The present approach
is comparable to emphasizing the gfactor of intelligence,
rather than its multidimensional conception according to
which people are just differently intelligent (even though no
one, to my knowledge, has gone as far as to partial out g).
There can hardly be any doubt that capitalizing onpprovides
the most realistic account of personality.
In the present context, the social part of social desirability
is terminologically dubious. It could be used in opposition to
personal desirability, but then the proper specification would
be intersubjective versus subjective. In its actual use, SD
refers primarily to impression management in self-report.
This socially desirable responding (SDR) may be an interest-
ing topic of study in its own right, but it is not at issue here.
People have desirable and undesirable traits; they show over-
all differences in the extent to which that is the case; there is
substantial agreement among third persons, and even be-
tween self and other, about someone’s desirability score; its
heredity coefficient is undoubtedly in the same order of mag-
nitude as with other traits, as it is a linear combination of
them. Socially desirable responding is orthogonal to these
individual differences: In a Persons AssessorsSituations
design with Desirability as the dependent variable, SDR is
an Assessors main effect (e.g., a self-assessment may be