Monday, 30 June 2014

A comment on the personality trait of Openness (and Personality in general)


Personality is supposed to be independent of intelligence - Personality is a separate explanatory variable which can be seen after Intelligence is controlled-for.

Intelligence is primary as an explanation of behaviour - primary both historically, and because intelligence (very obviously) affects personality - but personality does not affect intelligence.

In other words, as a matter of routine - when measuring personality, one should also test for intelligence - and before looking at the effect of personality on behaviour, one ought to remove the effect of intelligence (by stratified analysis, preferably - i.e. creating narrow strata of IQ and only looking a personality effects within these strata - or else by some kind of regression).


However, much personality research is done on an already-intelligence-stratified sample - such as Psychology Students at Mudsville State University - in these situations the researcher can usually get-away-with missing out IQ testing and just evaluating Personality.

However, this does not apply to the pseudo-trait of Openness - which is often so sensitive to IQ differences that it varies even within strata such as the same class of the same college.


If Intelligence is controlled-for, then the effect of Openness disappears - because Openness is merely 'the personality type of intelligent people in Western-type societies' (but rather badly conceptualized).

While the other personality traits (C, E, A and N), which derive essentially from HJ Eysenck, are robust to IQ differences (especially in college populations which provide most of the subjects): Openness is not.

Openness merely a (weak) correlate of IQ (in Western Societies)... plus noise and cross-contamination from other personality traits (e.g. a little bit of Psychoticism/ Schizotypy).


Take home message: all research on so-called Openness is either ignorant, incompetent - or (usually) both. 


This began as a comment on  the Isegoria blog


Scott McGreal said...

Dear Prof Charlton,
a number of sweeping generalisations are made in this post without supporting evidence or clarification of terms. For example: "If Intelligence is controlled-for, then the effect of Openness disappears"
This statement is not only overly-general, it does not specify what effects are referred to. Additionally, I am aware of a number of studies that contradict this assertion.
For example, a study comparing schizotypy, openness to experience, and intelligence (assessed by Raven’s matrices) found that openness to experience significantly predicted creativity even when controlling for intelligence. (Schizotypy versus openness and intelligence as predictors of creativity - see here.)
A number of other separate studies examining predictors of general knowledge have found that IQ and openness to experience independently predict this outcome variable. E.g. see here.
These studies indicate that openness does possess predictive power beyond intelligence.
You close by concluding: "Take home message: all research on so-called Openness is either ignorant, incompetent - or (usually) both."
This is a massive over-generalisation, again not supported by evidence. Unless, you have reviewed every single study on the subject, this is an unreasonable statement to make on its face. I would suggest that there is a large body of research on this personality trait that indicates that it is more than "merely 'the personality type of intelligent people in Western-type societies' (but rather badly conceptualized)."

Bruce Charlton said...

@SM - It is one of the delights of writing blog post that I can survey a wide range of work and give a pithy opinion.

Openness never should have been allowed as a personality trait - as a concept Openness is pitifully incoherent (especially when compared with the vast body of multidisciplinary work which Eysenck generated for E and N).

This happened because there is a poor understanding of what Personality is in general - a lack of theory. When theory is deficient, but empirical work continues - nonsense ensues.

The continued existence of O is an indictment of modern psychology and modern psychologists.