Is IQ related to "dark triad" traits, like machiavellianism, narcissism, and sadism?

Note: This is a section of a longer article. To go to the start, click here.

Yes, to some of them. Specifically, the dark triad consists of personality traits that are often viewed as being socially harmful: machiavellianism, narcissism, and sadism. 

• Machiavellianism is a personality trait characterized by manipulativeness, a strategic, calculating approach to social interactions, and a focus on self-interest and deception. 

• Narcissism is marked by grandiosity, an inflated sense of self-importance, a need for admiration, attention-seeking, and favoring the self over the needs of others. 

• Sadism is characterized by enjoyment of inflicting pain or humiliation, as well as a lack of empathy.

What we uncovered on a subsample of n = 701 was that IQ was negatively related to narcissism (r = -0.20) and sadism (r = -0.24), but had no relationship with machiavellianism (r = -0.02). Thus, higher IQ people in our sample exhibited lower levels of socially aversive traits, except for machiavellianism. Here are the scatterplots that illustrate these correlations.

What do the other studies say?

We found two meta-analyses that investigated the relationship between cognitive ability and dark triad traits. Interestingly, in both meta-analyses the correlations between cognitive ability and dark triad traits were practically non-existent. Specifically, in O’Boyle et al. (2013) meta-analysis, the correlations between the three traits and IQ ranged from -0.05 to 0.03, while in Michels (2022) meta-analysis they ranged from -0.06 to 0.08.

We are unsure why our findings differ from these meta-analyses. However, there was a substantial heterogeneity of effects in both meta-analyses, meaning that some effects were strong and some were weak. It is still not clear what accounts for these differences in effect sizes, and the effects we obtained seem to be similar to some of the bigger effects reported in these meta-analyses. However, the existence of weaker effects drove the overall effect in the meta-analyses down, and studies still have to explain what drives these differences in effect sizes across studies.

Takeaways

• We found higher IQ people to be lower on two out of three dark triad traits, narcissism and sadism, but not on machiavellianism (with which there was no correlation)

• However, meta-analyses appear to find no relationship between IQ and these traits.

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