Prospective emotion enables episodic prospection to shift time preference.

The episodic effect suggests that episodic prospection (imagining future events) can effectively reduce time discounting, the propensity to discount the value of delayed rewards relative to immediate ones. However, less clear is how episodic prospection modulates time preference. As engagement in episodic prospection usually evokes prospective emotions, it was proposed that episodic prospection might work by inducing prospective emotions. Although one previous study has attempted to provide evidence to the emotional account of the episodic effect, shortcomings in its experimental design make its conclusion questionable. In this study, we replicated previous experimental design with improvements to further test the effects of prospective emotion on time preference. By manipulating the emotional valency associated with episodic prospection in a delay discounting task, we found that positive episodic prospection attenuated time discounting; negative episodic prospection exacerbated time discounting; and episodic prospection did not shift time preference when prospective emotion is removed. These results were essentially identical to the result of the previous study. Together, these studies suggested that the effects of episodic prospection depended on prospective emotion. Thus, one cannot ignore prospective emotion if counting on episodic prospection to combat humans' impulsive behaviours.