In search of the Big One

Nice, nasty, charming, chatty, vulpine, vulgar…when we get down to it, just how many personality traits are there? It's a question psychologists and philosophers have been wrestling with for centuries.

In recent years, researchers have tended to agree that personality is pretty much summed up by the Big Five factors of Extraversion, Neuroticism, Conscientiousness, Agreeableness, and Openness. Now Janek Musek at the University of Ljubljana in Slovenia has waded into the debate with the suggestion that there exists an overriding personality characteristic – he calls it the 'Big One' – with which all other personality traits are correlated.

Musek tested hundreds of participants using numerous personality measures, including the Big Five Inventory, the Big Five Observer and the Positive Affect and Negative Affect Schedule (PANAS).

Using a statistical technique called factor analysis, Musek found that a single factor explained much of the variance in people's scores on the Big Five Dimensions of personality. This means that someone who scores highly on one of the five factors (in the case of neuroticism, scores are reversed so that a 'high score' reflects emotional stability) is also more likely to score high on the others. In other words, there seems to be some critical trait that captures the essence of all these dimensions.

What does this mean in psychological terms? The Big One seems to reflect a contrast between the socially desirable and undesirable components of the Big Five. "The Big One unifies positive aspects of conformity (stability) and non-conformity (plasticity) within a single superordinated dimension," Musek wrote.

And according to Musek there could even be a physiological basis for the person who scores high on the Big One – "combining low levels of the functioning of the central serotonergic system and higher levels of the functioning of the ascending rostral dopaminergic system."

Further reading

Musek Janek (2007). A general factor of personality: Evidence for the Big One in the five-factor model. Journal of Research in Personality, 41, 1213-1233.