Correction (8/31/2019): In an earlier version, I misspelled Colin DeYoung’s name. I wrote DeYoung with a small d. I thank Colin DeYoung for pointing out this mistake.
One area of personality psychology aims to classify personality traits. I compare this activity to research in biology where organisms are classified into a large taxonomy.
In a hiearchical taxnomy, the higher levels are more abstract, less descriptive, but also comprise a larger group of items. For example, there are more mammals (class) than dogs (species).
in the 1980s, personality psychologists agreed on the Big Five. The Big Five represent a rather abstract level of description that combines many distinct traits into traits that are predominantly related to one of the Big Five dimensions. For example, talkative falls into the extraversion group.
To illustrate the level of abstraction, we can compare the Big Five to the levels in biology. After distinguishing vertebrate and invertebrate animals, there are five classes of vertebrate animals: mammals, fish, reptiles, birds, and amphibians). This suggests that the Big Five are a fairly high level of abstraction that cover a broad range of distinct traits within each dimension.
The Big Five were found using factor or pincipal component analysis (PCA). PCA is a methematical method that reduces the covariances among personality ratings to a smaller number of factors. The goal of PCA is to capture as much of the variance as possible with the smallest number of components. Evidently there is a trade-off. However, often the first components account for most of the variance while additional components add very little additional information. Using various criteria, five components seemed to account for most of the variance in personality ratings and the first five components could be identified in different datasets. So, the Big Five were born.
One important feature of PCA is that the components are independent (orthogonal). This is helpful to maximize the information that is captured with five dimensions. If the five dimensions would correlated, they would present overlapping variances and this redundancy would reduce the amount of explained variance. Thus, the Big Five are conceptually independent because they were discovered with a method that enforced independence.
Scale Scores are not Factors
While principal component analysis is useful to classify personality traits, it is not useful to do basic research on the causes and consequences of personality. For this purpose, personality psychologists create scales. Scales are usually created by summing items that belong to a common factor. For example, responses to the items “talkative,” “sociable,” and “reserved” are added up to create an extraversion score. Ratings of the item “reserved” are reversed so that higher scores reflect extraversion. Importantly, sum scores are only proxies of the components or factors that were identified in a factor analysis or a PCA. Thus, we need to distinguish between extraversion-factors and extraversion-scales. They are not the same thing. Unfortunately, personality psychologists often treat scales as if they were identical with factors.
Big Five Scales are not Independent
Now something strange happened when personalty psychologists examined the correlations among Big Five SCALES. Unlike the factors that were independent by design, Big Five Scales were not independent. Moreover, the correlations among Big Five scales were not random. Digman (1997) was the first to examine these correlations. The article has garnered over 800 citations.
Digman examined these correlations conducted another principal component analysis of the correlations. He found two factors. One factor for extraversion and openesss and the other factor for agreeableness and conscientiousness (and maybe low neuroticism). He proposed that these two factors represent an even higher level in a hierarchy of personality traits. Maybe like moving from the level of classess (mammals, fish, reptiles) to the level Phylum; a level that is so abstract that few people who are not biologists are familiar with.
Digman’s article stimulated further research on higher-order factors of personality, where higher means even higher than the Big Five, which are already at a fairly high level of abstraction. Nobody stopped to wonder how there could be higher-order factors if the Big Five are actually independent factors, and why Big Five scales show systematic correlations that were not present in factor analyses.
Instead personality psychologists speculated about the biological underpinning of the higher order factors. For example, Jordan B. Peterson (yes, them) and colleagues proposed that serotonin is related to higher stability (high agreeableness, high conscientiousness, and low neuroticism) (DeYoung, Peterson, and Higgins, 2002).
Rather than interpreting this finding as evidence that response tendencies contribute to correlations among Big Five scales, they interpreted this finding as a substantive finding about personality, society in the context of psychodynamic theories.
Only a few years later, separated from the influence of his advisor, DeYoung (2006) published a more reasonable article that used a multi-method approach to separate personality variance from method variance. This article provided strong evidence that a general evaluative bias (social desirable responding) contributes to correlations among Big Five Scales, which was formalized in Anusic et al.’s (200) model with an explicit evaluative bias (halo) factor.
However, the idea of higher-order factors was sustained by finding cross-method correlations that were consistent with the higher-order model.
After battling Colin as a reviewer, when we submitted a manuscript on halo bias in personality ratings, we finally were able to publish a compromise model that also included the higher order factors (stability/alpha; plasticity/beta), although we had problems identifying the alpha factor in some datasets.
The Big Mistake
Meanwhile, another article built on the 2002 model that did not control for rating biases and proposed that the correlation between the two higher-order factors implies that there is an even higher level in the hierarchy. The Big Trait of Personality makes people actually have more desirable personalities; They are less neurotic, more sociable, open, agreeable, and conscientious. Who wouldn’t want one of them as a spouse or friend? However, the 2006 article by DeYoung showed that the Big One only exists in the imagination of individuals and is not shared with perceptions by others. This finding was replicated in several datasets by Anusic et al. (2009).
Although claims about the Big One were already invalidated when the article was published, it appealed to some personality psychologists. In particular, white supremacist Phillip Rushton found the idea of a generally good personality very attractive and spend the rest of his life promoting it (Rushton & Irving, 2011; Rushton Bons, & Hur, 2008). He never realized the distinction between a personality factor, which is a latent construct, and a personality scale, which is the manifest sum-score of some personality items, and ignored DeYoung’s (2006) and other (Anusic et al., 2009) evidence that the evaluative portion in personality ratings is a rating bias and not substantive covariance among the Big Five traits.
Peterson and Rushton are examples of pseudo-science that mixes some empirical findings with grand ideas about human nature that are only loosely related. Fortunately, interest in the general factor of personality seems to be decreasing.
Higher Order Factors or Secondary Loadings?
Ashton, Lee, Goldberg, and deVries (2009) put some cold water on the idea of higher-order factors. They pointed out that correlations between Big Five Scales may result from secondary loadings of items on Big Five Factors. For example, the item adventurous may load on extraversion and openness. If the item is used to create an extraversion scale, the openness and extraversion scale will be positively correlated.
As it turns out, it is always possible to model the Big Five as independent factors with secondary loadings to avoid correlations among factors. After all, this is how exploratory factor analysis or PCA are able to account for correlations among personality items with independent factors or components. In an EFA, all items have secondary loadings on all factors, although some of these correlations may be small.
There are only two ways to distinguish empirically between a higher-order model and a secondary-loading model. One solution is to obtain measures of the actual causes of personality (e.g., genetic markers, shared environment factors, etc.) If there are higher order factors, some of the causes should influence more than one Big Five dimension. The problem is that it has been difficult to identify causes of personality traits.
The second approach is to examine the number of secondary loadings. If all openness items load on extraversion in the same direction (e.g., adventurous, interest in arts, interest in complex issues), it suggests that there is a real common cause. However, if secondary loadings are unique to one item (adventurous), it suggests that the general factors are independent. This is by no means a definitive test of the structure of personality, but it is instructive to examine how many items from one trait have secondary loadings on another trait. Even more informative would be the use of facet-scales rather than individual items.
I have examined this question in two datasets. One dataset is an online sample with items from the IPIP-100 (Johnson). The other dataset is an online sample with the BFI (Gosling and colleagues). The factor loading matrices have been published in separate blog posts and the syntax and complete results have been posted on OSF (Schimmack, 2019b; 2019c).
Neuroticism items show 8 out of 16 secondary loadings on agreeableness, and 4 out of 16 secondary loadings on conscientiousnes.
|not easily bothered||10||-0.58||-0.12||-0.11||0.25|
|relaxed most of the time||17||-0.61||0.19||-0.17||0.27|
|change my mood a lot||25||0.55||-0.15||-0.24|
|feel easily threatened||37||0.50||-0.25|
|get angry easily||41||0.50||-0.13|
|get caught up in my problems||42||0.56||0.13|
|get irritated easily||44||0.53||-0.13|
|get overwhelmed by emotions||45||0.62||0.30|
|stress out easily||46||0.69||0.11|
|frequent mood swings||56||0.59||-0.10|
|often feel blue||77||0.54||-0.27||-0.12|
|rarely get irritated||82||-0.52|
|seldom feel blue||83||-0.41||0.12|
|take offense easily||91||0.53|
|worry about things||100||0.57||0.21||0.09|
Agreeableness items show only one secondary loading on conscientiousness and one on neuroticism.
|indifferent to feelings of others||8||-0.58||-0.27||0.16|
|not interested in others’ problems||12||-0.58||-0.26||0.15|
|feel little concern for others||35||-0.58||-0.27||0.18|
|feel others’ emotions||36||0.60||0.22||0.17|
|have a good word for everybody||49||0.59||0.10||0.17|
|have a soft heart||51||0.42||0.29||0.17|
|inquire about others’ well-being||58||0.62||0.32||0.19|
|know how to comforte others||62||0.26||0.48||0.28||0.17|
|love to help others||69||0.14||0.64||0.33||0.19|
|sympathize with others’ feelings||89||0.74||0.30||0.18|
|take time out for others||92||0.53||0.32||0.19|
|think of others first||94||0.61||0.29||0.17|
Finally, conscientiousness items show only one secondary loading on agreeableness.
|exacting in my work||4||-0.09||0.38||0.29||0.17|
|continue until everything is perfect||26||0.14||0.49||0.13||0.16|
|do things according to a plan||28||0.65||-0.45||0.17|
|do things in a half-way manner||29||-0.49||-0.40||0.16|
|find it difficult to get down to work||39||0.09||-0.48||-0.40||0.14|
|follow a schedule||40||0.65||0.07||0.14|
|get chores done right away||43||0.54||0.24||0.14|
|leave a mess in my room||63||-0.49||-0.21||0.12|
|leave my belongings around||64||-0.50||-0.08||0.13|
|like to tidy up||66||0.19||0.52||0.12||0.14|
|love order and regularity||68||0.15||0.68||-0.19||0.15|
|make a mess of things||72||0.21||-0.50||-0.26||0.15|
|make plans and stick to them||75||0.52||0.28||0.17|
|neglect my duties||76||-0.55||-0.45||0.16|
|forget to put things back||79||-0.52||-0.22||0.13|
|shirk my duties||85||-0.45||-0.40||0.16|
|waste my time||98||-0.49||-0.46||0.14|
Of course, there could be additional relationships that are masked by fixing most secondary loadings to zero. However, it also matters how strong the secondary loadings are. Weak secondary loadings will produce weak correlations among Big Five scales. Even the secondary loadings in the model are weak. Thus, there is little evidence that neuroticism, agreeableness, and conscientiousness items are all systematically related as predicted by a higher-order model. At best, the data suggest that neuroticism has a negative influence on agreeable behaviors. That is, people differ in their altruism, but agreeable neurotic people are less agreeable when they are in a bad mood.
Results for extraversion and openness are similar. Only one extraversion item loads on openness.
|hard to get to know||7||-0.45||-0.23||0.13|
|quiet around strangers||16||-0.65||-0.24||0.14|
|skilled handling social situations||18||0.65||0.13||0.39||0.15|
|am life of the party||19||0.64||0.16||0.14|
|don’t like drawing attention to self||30||-0.54||0.13||-0.14||0.15|
|don’t mind being center of attention||31||0.56||0.23||0.13|
|don’t talk a lot||32||-0.68||0.23||0.13|
|feel at ease with people||33||-0.20||0.64||0.16||0.35||0.16|
|feel comfortable around others||34||-0.23||0.65||0.15||0.27||0.16|
|find it difficult to approach others||38||-0.60||-0.40||0.16|
|have little to say||57||-0.14||-0.52||-0.25||0.14|
|keep in the background||60||-0.69||-0.25||0.15|
|know how to captivate people||61||0.49||0.29||0.28||0.16|
|make friends easily||73||-0.10||0.66||0.14||0.25||0.15|
|feel uncomfortable around others||78||0.22||-0.64||-0.24||0.14|
|talk to different people at parties||93||0.72||0.22||0.13|
And only one extraversion item loads on openness and this loading is in the opposite direction from the prediction by the higher-order model. While open people tend to like reading challenging materials, extraverts do not.
|full of ideas||5||0.65||0.32||0.19|
|not interested in abstract ideas||11||-0.46||-0.27||0.16|
|do not have good imagination||27||-0.45||-0.19||0.16|
|have rich vocabulary||50||0.52||0.11||0.18|
|have a vivid imagination||52||0.41||-0.11||0.28||0.16|
|have difficulty imagining things||53||-0.48||-0.31||0.18|
|difficulty understanding abstract ideas||54||0.11||-0.48||-0.28||0.16|
|have excellent ideas||55||0.53||-0.09||0.37||0.22|
|love to read challenging materials||70||-0.18||0.40||0.23||0.14|
|love to think up new ways||71||0.51||0.30||0.18|
The next table shows the correlations among the Big Five SCALES.
The pattern mostly reflects the influence of the evaluative bias factor that produces negative correlations of neuroticism with the other scales and positive correlations among the other scales. There is no evidence that extraversion and openness are more strongly correlated in the IPIP-100. Overall, these results are rather disappointing for higher-order theorists.
The next table shows the correlations among the Big Five Scales.
The pattern of correlations reflects mostly the influence of the evaluative bias factor. As a result, the neuorticism scale is negatively correlated with the other scales and the other scales are positively correlated with each other. There is no evidence for a stronger correlation between extraversion and openness because there are no notable secondary loadings. There is also no evidence that agreeableness and conscientiousness are more strongly related to neuroticism. Thus, these results show that DeYoung’s (2006) higher-order model is not consistent across different Big Five questionnaires.
Big Five Inventory
DeYoung found the higher-order factors with the Big Five Inventory. Thus, it is particularly interesting to examine the secondary loadings in a measurement model with independent Big Five factors (Schimmack, 2019b).
Neuroticism items have only one secondary loading on agreeableness and one on conscientiousness and the magnitude of these loadings is small.
Four out of nine agreeableness items have secondary loadings on neuroticism, but the magnitude of these loadings is small. Four items also have loadings on conscientiousness, but one item (forgiving) has a loading opposite to the one predicted by the hgher-order model.
|find faults w. others||2||0.15||-0.42||-0.24||0.19|
|helpful / unselfish||7||0.44||0.10||0.29||0.23|
|cold and aloof||27||-0.19||0.14||-0.46||-0.35||0.17|
|considerate and kind||32||0.04||0.62||0.29||0.23|
|like to cooperate||42||0.15||-0.10||0.44||0.28||0.22|
For conscientiousness, only two items have a secondary loading on neuroticism and two items have a secondary loading on agreeableness.
|persevere until finished||28||0.56||0.26||0.20|
Overall, these results provide no support for the higher-order model that predicts correlations among all neuroticism, agreeableness, and conscientiousness items. These results are also consistent with Anusic et al.’s (2009) difficulty of identifying the alpha/stability factor in a study with the BFI-S, a shorter version of the BFI.
However, Anusic et al. (2009) did find a beta-factor with BFI-S scales. The present analysis of the BFI do not replicate this finding. Only two extraversion items have small loadings on the openness factor.
|full of energy||11||0.34||-0.11||0.58||0.20|
|shy and inhibited||31||0.18||0.64||-0.22||0.17|
And only one openness item has a small loading that is opposite to the predicted direction. Extraverts are less likely to like reflecting.
|like routine work||35||-0.28||0.10||0.13||-0.21||0.17|
|few artistic interests||41||-0.26||-0.09||0.15|
|sophisticated in art||44||0.07||0.44||-0.06||0.10||0.16|
In short, there is no support for the presence of a higher-order factor that produces overlap between extraversion and openness.
The pattern of correlations among the BFI scales, however, might suggest that there is an alpha factor because neuroticism, agreeableness and conscientiousness tend to be more strongly correlated with each other than with other dimensions. This shows the problem of using scales to study higher-order factors. However, there is no evidence for a higher-order factor that combines extraversion and openness as the correlation between these traits is an unremarkable r = .18.
So, why did DeYoung (2006) find evidence for higher-order factors? One possible explanation is that BFI scale correlations are not consistent across different samples. The next table shows the self-report correlations from DeYoung (2006) below the diagonal and discrepancies above the diagonal. Three of the four theoretically important correlations tend to be stronger in DeYoung’s (2006) data. It is therefore possible that the secondary loading pattern differs across the two datasets. It would be interesting to fit an item-level model to DeYoung’s data to explore this issue further.
In conclusion, an analysis of the BFI also does not support the higher-order model. However, results seem to be inconsistent across different samples. While this suggests that more research is needed, it is clear that this research needs to model personality at the level of items and not with scale scores that are contaminated by evaluative bias and secondary loadings.
Hindsight is 20/20 and after 20 years of research on higher-order factors a lot of this research looks silly. How could there be higher order factors for the Big Five factors if the Big Five are independent factors (or components) by default. The search for higher-order factors with Big Five scales can be attributed to methodological limitations, although higher-order models with structural equation modeling have been around since the 1980. It is rather obvious that scale scores are impure measures and that correlations among scales are influenced by secondary loadings. However, even when this fact was pointed out by Ashton et al. (2009), it was ignored. The problem is mainly due to the lack of proper training in methods. Here the problem is the use of scales as indicators of factors, when scales introduce measurement error and higher-order factors are method artifacts.
The fact that it is possible to recover independent Big Five factors from questionnaires that were designed to measure five independent dimensions says nothing about the validity of the Big Five model. To examine the validity of the Big Five as a valid model of the highest level in a taxonomy of personality trait it is important to examine the relationship of the Big Five with the diverse population of personality traits. This is an important area of research that could also benefit from proper measurement models. This post merely focused on the search for higher order factors for the Big Five and showed that searching for higher-order factors of independent factors is a futile endeavor that only leads to wild speculations that are not based on empirical evidence (Peterson, Rushton).
Even DeYoung and Peterson seems to have realized that it is more important to examine the structure of personality below rather than above the Big Five (DeYoung, Quility, & Peterson, 2007) . Whether 10 aspects, 16 factors (Cattell) or 30 facets (Costa & McCrae) represent another meaningful level in a hierarchical model of personality traits remains to be examined. Removing method variance and taking secondary loadings into account will be important to separate valid variance from noise. Also, factor analysis is superior to principle component analysis unless the goal is simply to describe personality with atheoretical components that capture as much variance as possible.
Correct me if you can
This blog post is essentially a scientific article without peer-review. I prefer this mode of communication over submitting manuscript to traditional journals where a few reviewers have the power to prevent research from being published. This happened with a manuscript that Ivana Anusic and I submitted and that was killed by Colin DeYoung as a reviewer. I prefer open reviews and I invite Colin to write an open review of this “article.” I am happy to be corrected and any constructive comments would be a welcome contribution to advancing personality science. Simply squashing critical work so that nobody gets to see it is not advancing science. The new way of conducting open science with open submissions, open reviews is the way to go. Of course, others are also invited to engage in the debate. So, let’s start a debate with the thesis “Higher-order factors of the Big Five do not exist.”