Do people avoid mental effort after facing a highly demanding task?

Abstract

Ego depletion effects are usually examined in a sequential task paradigm in which exerting mental effort in a first task is thought to affect performance on a subsequent self-control task. A so-called ego depletion effect is observed if performance on the second task is impaired for the high demand relative to the low demand group. The present studies take a different approach. Instead of measuring performance in the second task that is equally difficult for all participants, the present studies investigated effects of effortful exertion on the choice to willingly exert effort on a subsequent task. Three pre-registered studies investigated if participants select less effort demanding math problems for upcoming tasks compared to a control group after exerting mental effort in an initial task. Results were mixed. Study 1 (N = 86) revealed no significant effect of mental effort exertion on mean choice difficulty. In Study 2 (N = 269), the expected effect emerged in an exploratory analysis when controlling for math self-assessment, which was robustly associated with the choice measure. Study 3 (N = 330) descriptively, albeit non-significantly replicated this result. An internal random-effects meta-analysis revealed a small overall effect of g = 0.18 when accounting for math self-assessment, albeit with large heterogeneity. Exploratory analyses point to the importance of the subjective experience of mental effort in effort-selection paradigms. We discuss the implications of the small overall effect size for future research and the possibility to examine effort choice in everyday life.