Validation of the Mini‐<scp>IPIP6</scp> Short‐Form Personality Inventory: Honesty‐Humility Predicts Cooperation in Economic Games

ABSTRACT This study validated the Mini‐IPIP6 short‐form measure of Honesty‐Humility to predict cooperative behaviour in online economic games. A subsample of participants from the New Zealand Attitudes and Values Study completed four online economic games for money, in addition to the Mini‐IPIP6 six‐factor personality inventory ( N = 979). Cooperative behaviour was modelled as a latent variable reflecting behaviour across the four games. Honesty‐Humility was the sole personality dimension associated with cooperative behaviour, even after adjusting for relevant demographics (including gender, age, ethnicity, socio‐economic status, education and religiosity). Consistent with the hypothesised adaptive benefits of Honesty‐Humility (i.e., gains from cooperation, mutual help and non‐aggression), people higher in Honesty‐Humility cooperated more with anonymous others in online economic exchanges for money when there was a risk of exploitation. Given the nature of the games, people higher in Honesty‐Humility tended to earn more money if their partner cooperated, but less if their partner defected. These results validate the Mini‐IPIP6 measure of Honesty‐Humility and support its convergent and discriminant validity. These results highlight the predictive validity of the Mini‐IPIP6 measure of Honesty‐Humility and show it is reliably associated with cooperative behaviour.