Ego Depletion and Multiple Rewards: Implicit and explicit measures of the impact of self-control of one reward in other rewards

Abstract

Ego depletion, referring to the phenomenon that exertion of self-control in one domain leads to depleted self-control in another domain, is a controversial concept regarding its interpretations and replicability. The current study explores ego depletion from a reward perspective. In Study 1, which used a lab-based experimental paradigm, all the participants were exposed to monetary and sexual rewards, while being asked to regulate snacking behaviour/food reward responses (experimental group) or not (control group). Participants’ responses to the rewards were implicitly measured using measures of cheating behaviours (monetary reward) and picture viewing times (sexual reward). Participants were not asked to exert their self-control in the first phase of both tasks but subsequently asked to regulate their responses to the rewards in the second phase. In the monetary reward task, participants in the experimental group displayed stronger reward responses (more cheating behaviours) than those in the control group in the first phase, while this pattern disappeared in the second phase. The findings supported the process model (Inzlicht & Schmeichel, 2012) which explains ego depletion as a result of a motivational shift from ‘have-to’ to ‘want-to’ by displaying the shift in the first phase. Considering the participants in the experimental group were able to regulate their reward responses in the second phase, the findings disputed the interpretation of self-control as a limited resource. This evidence for a motivational shift was confined to the monetary reward. Hence, as a follow-up study, Study 2 used a vignette-based online experiment aimed to disentangle potential reasons of the different impacts of food rewards in sexual and monetary rewards, in which rewards can be categorised as materialistic or non-materialistic, and that such a shift can occur only within the same category. However, the findings showed that such a categorisation did not seem to explain the different impacts. Rather, Study 2 showed a different pattern from Study 1, showing that behaviours do not always correspond to attitudes and beliefs in self-control.