Worth the ‘EEfRT’? The Effort Expenditure for Rewards Task as an Objective Measure of Motivation and Anhedonia

TLDR

Anhedonia, a well‑supported subtype of major depressive disorder, is thought to reflect abnormal motivation and reward responsiveness, yet objective measures of reward motivation are lacking. The study introduces the Effort‑Expenditure for Rewards Task (EEfRT) to examine effort‑based decision‑making and tests whether it is linked to trait anhedonia. Sixty‑one undergraduate participants completed mood and trait anhedonia questionnaires followed by the EEfRT. Results show a significant inverse relationship between trait anhedonia and willingness to expend effort for rewards, indicating that anhedonia is linked to reduced reward motivation and supporting the EEfRT as a valid laboratory measure.

Abstract

Background Of the putative psychopathological endophenotypes in major depressive disorder (MDD), the anhedonic subtype is particularly well supported. Anhedonia is generally assumed to reflect aberrant motivation and reward responsivity. However, research has been limited by a lack of objective measures of reward motivation. We present the Effort-Expenditure for Rewards Task (EEfRT or “effort”), a novel behavioral paradigm as a means of exploring effort-based decision-making in humans. Using the EEfRT, we test the hypothesis that effort-based decision-making is related to trait anhedonia. Methods/Results 61 undergraduate students participated in the experiment. Subjects completed self-report measures of mood and trait anhedonia, and completed the EEfRT. Across multiple analyses, we found a significant inverse relationship between anhedonia and willingness to expend effort for rewards. Conclusions These findings suggest that anhedonia is specifically associated with decreased motivation for rewards, and provide initial validation for the EEfRT as a laboratory-based behavioral measure of reward motivation and effort-based decision-making in humans.