Actual behaviour is influenced in important ways by moral emotions, for instance guilt or shame (see, among others, Tangney et al., 2007). Belief-dependant models of social preferences using the framework of psychological games aim to consider such emotions to explain other-regarding behaviour. Our experimental study links recent advances in psychological theory on moral emotions to belief-dependant models in economics. We find that – in addition to second-order beliefs and promises – individuals’ disposition to guilt (their proneness to respond in an evaluative way to personal transgressions) is an important determinant of pro-social behaviour.