 2. History, Measurement, and Conceptual Elaboration of the Big‑Five Trait Taxonomy  71
a comprehensive theoretical account of the 
Big Five.
Conclusions and  Implications
At the beginning of this chapter, we argued 
that a personality taxonomy should provide 
a systematic framework for distinguishing, 
ordering, and naming the behavioral, emo -
tional, and experiential characteristics of 
individuals.
Ideally, that taxonomy would be built 
around principles that are causal and dy -
namic, exist at multiple levels of abstraction 
or hierarchy, and offer a standard nomen -
clature for scientists working in the field of 
personality. The Big Five taxonomy does not 
yet meet all of these high standards. It pro -
vides descriptive concepts that still need to 
be explicated theoretically, and a nomencla -
ture that is still rooted in the “vernacular” 
English but has accumulated considerable 
technical knowledge and increasing preci -
sion.
The Big Five structure has the advantage 
that everybody can understand the words 
that define the factors. Moreover, the nat -
ural language is not biased in favor of any 
existing scientific conceptions; although the 
atheoretical nature of the Big Five dimen -
sions makes them less appealing to some 
psychologists, it also makes them more pal -
atable to researchers who reject dimensions 
cast in a theoretical mold different from their 
own. Whatever the inadequacies of the natu -
ral language for scientific systematics, broad 
dimensions inferred from folk usage are not  
a bad place to start a taxonomy. Even in the 
biological taxonomy of animals, “the tech -
nical system evolved from the vernacular” 
(Simpson, 1961, pp. 12–13).
Obviously, a system that initially derives 
from the natural language does not need to 
reify such terms indefinitely. Indeed, several 
of the dimensions included among the Big 
Five, most notably Extraversion and Neuro -
ticism, have been the target of various physi -
ological and mechanistic explanations (e.g., 
Canli et al., 2001; see also Clark, 2005; De -
Young et al., Chapter 8, this volume). In their 
research on emotion regulatory processes, 
John and Gross (2007) have begun to ar -
ticulate the links between broad personality 
dimensions such as the Big Five, the chronic use of particular regulatory strategies, and 
their emotional and social consequences. 
Similarly, the conceptual explication of Ex -
traversion and Neuroticism as persistent dis -
positions toward thinking and behaving in 
ways that foster, respectively, positive and 
negative affective experiences (e.g., Tellegen, 
1985; see also Clark & Watson, Chapter 6, 
this volume) promises to connect the Big 
Five with individual differences in affective 
functioning, which, in turn, may be studied 
in more tightly controlled laboratory settings 
(see English, Eldesouky, & Gross, Chapter 
24, this volume). At this point, the Big Five 
differentiate domains of individual differenc -
es that have similar surface manifestations, 
just like the early animal taxonomy that was 
transformed by better accounts of evolution -
ary processes and by the advent of new tools, 
such as molecular genetics. Likewise, the 
structures and processes underlying these 
personality trait domains are now beginning 
to be explicated. Explication in explanatory 
and mechanistic terms will likely change the 
definition and assessment of the Big Five di -
mensions as we know them today.
Remember Robert? We met him in the be -
ginning of this chapter. Given what we have 
learned about the Big Five taxonomy, what 
can we say about his personality structure? 
Next, we have reprinted the sketch from the 
Introduction but we’ve classified his behav -
ior and experience in terms of two core Big 
Five dimensions, one in bold and the other 
in italics.
Thirty-  one-year-old Robert often feels rest -
less. He has problems sitting at a desk for 
more than a few minutes, cannot get orga -
nized, loses his keys and wallet, and forgets 
about his plans for the evening. He fails to 
achieve  up to his potential at work. Dur -
ing conversations, his mind wanders  and 
he interrupts others , blurting out  what he 
is thinking without considering the conse -
quences . He gets into arguments . His mood 
swings and periodic outbursts make life dif -
ficult for those around him. Now his mar -
riage is in trouble .
How should we summarize Robert’s be -
havior, experience, and cognitions? Clearly, 
his lack of organization and deliberation, his 
failure to focus on work and to achieve (in 
italics) are all hallmarks of low Conscien -