Demand and Experimenter Bias and the Ego-Depletion Effect

Possible reasons for these variations in the ego-depletion effect may be participant expectations of the demand of the upcoming task and experimenter expectations or demand bias. In three experiments we tested the hypothesis that the ego-depletion effect is partly or exclusively attributable to (i) participants’ expectations of the task (Studies 1a and b) and (ii) experimental demand bias (Study 2). In both studies we did not observe a robust ego-depletion effect, and only participants informed that the task was tiring exhibited the effect. Taken together, findings suggest that the ego-depletion effect may be an experimental artifact related participant or experimenter expectations.