It pays to pay - Big Five personality influences on co-operative behaviour in an incentivized and hypothetical prisoner's dilemma game

The authors investigated how the presence or absence of monetary incentives in a prisoner's dilemma game may influence research outcomes. Specifically, the predictive power of the Big Five personality traits on decisions in an incentivized (N = 60) or hypothetical (N = 60) prisoner's dilemma game was investigated. Participants were less generous in the incentivized game. More importantly, personality predicted decisions only in the incentivized game, with low Neuroticism and high Openness to Experience predicting more cooperative transfers. The influence of Neuroticism on behaviour in the incentivized game was mediated by risk attitude. The results are consistent with other results suggesting that the Big Five are relevant predictors of moral behaviour, and with results suggesting that the determinants of hypothetical decisions are different from the determinants of real decisions, with the latter being more revealing of one's true preferences. The authors argue that psychologists, contrary to prevailing praxis, should consider making their participants' decisions more real. This could allow psychologists to more convincingly generalize laboratory findings into contexts outside of the laboratory.