46 I. THEORETICAL  PERSPECTI vES AND  CONCEPT uAL uNITS
on. This literature has grown far beyond 
the scope of this chapter, and we thus refer 
the reader to several in-  depths reviews (e.g., 
Ashton et al., 2004; de Raad & Perugini, 
2002; Saucier et al., 2000). Most generally, 
our reading of this literature is that factors 
similar to the Big Five were found in many 
other languages but sometimes more than 
five factors needed to be rotated and some -
times two indigenous factors corresponded 
to one of the Big Five. The Big Five have 
been well-  replicated in Germanic languages, 
but the evidence for non-  Western languag -
es and cultures tends to be more complex. 
Overall, the evidence is least compelling for 
the fifth factor, which appears in various 
guises, ranging from pure Intellect (in Ger -
man) to Unconventionality and Rebellious -
ness (in Dutch and Italian). Moreover, when 
we only consider which factors are the most  
replicable, then structures with fewer factors 
(e.g., two or three) can be even more robust 
than the more differentiated Big Five (e.g., 
Saucier, Georgiades, Tsouasis, & Goldberg, 
2005).
Finally, a number of researchers have 
suggested more than five factors. For ex -
ample, the seven-  factor solutions in Spanish 
and English (see Benet-  Martinez & Waller, 
1997) suggested additional separate positive 
and negative self-  evaluation factors (but see 
Simms, 2006). The more recent six-  factor so -
lutions, obtained in reanalyses of data from 
several different languages (Ashton et al., 
2004; Ashton & Lee, 2020; but see Crowe, 
Lynam, & Miller, 2018), failed to replicate 
the seven-  factor solution and instead sug -
gested that an additional honesty–  humility 
factor may be important. Three general con -
clusions seem to hold. First, note that these 
factors are indeed “additional”; that is, they 
provide evidence for the generalizability of 
the Big Five plus  one or two further factors. 
Second, when more factors than the Big Five 
have been identified, the analysis may have 
broken one of the broad Big Five domains 
into two parts; for example, Crowe, Lynam, 
and Miller (2018) and Soto (2020b) have 
argued that measures of honesty–  humility 
tend to be positively correlated with Agree -
ableness, rather than representing a truly 
independent sixth dimension. Third, the ad -
ditional factors, such as positive and nega -
tive self-  evaluation, rarely replicate across 
multiple studies conducted by independent investigators. Thus, we agree with de Raad, 
Perugini, and colleagues (1998), who con -
cluded that the findings show “the general 
contours of the Big Five model as the best 
working hypothesis of an omnipresent trait 
structure” (p. 214). While this cautious 
conclusion falls short of an unequivocal en -
dorsement of the universality of the Big Five, 
it nonetheless offers a disconfirmation of the 
strong linguistic relativism hypothesis that 
many of personality researchers (including 
ourselves) had expected to hold true before 
the lexical data became available: There are 
no data to suggest that each culture and lan -
guage has its own unique set of personality 
dimensions; at least at the level of broad trait 
dimensions, most cultures are more alike 
than we had expected.
The Big Five in Personality Questionnaires
While researchers in the lexical tradition 
were accumulating evidence for the Big 
Five, the need for an integrative framework 
became more pressing among researchers 
who studied personality with questionnaire 
scales. Joint factor analyses of question -
naires developed by different investigators 
had shown that two broad dimensions: Ex -
traversion and Neuroticism appear in one 
form or another in most personality inven -
tories. Beyond these “Big Two” (Wiggins, 
1968), however, the various questionnaire- 
based models had shown few signs of con -
vergence. For example, Eysenck (1991) 
observed that “where we have literally hun -
dreds of inventories incorporating thou -
sands of traits, largely overlapping but also 
containing specific variance, each empirical 
finding is strictly speaking only relevant to a 
specific trait. . . . This is not the way to build 
a unified scientific discipline” (p. 786).
Costa and  McCrae’s  Research
The situation began to change in the early 
1980s, when Costa and McCrae were devel -
oping the NEO Personality Inventory (even -
tually published in 1985), labeled N-E-O 
because it was designed to measure the three 
dimensions of Neuroticism, Extraversion, 
and Openness to Experience. Costa and Mc -
Crae (1976) had begun their work with clus -
ter analyses of the 16PF (Cattell et al., 1970) 