More than a feeling: physiological measures of affect index the integration of effort costs and rewards during anticipatory effort evaluation

Abstract

The notion that humans avoid effortful action is one of the oldest and most persistent in psychology. Influential theories of effort propose that effort valuations are made according to a cost-benefit trade-off: we tend to invest mental effort only when the benefits outweigh the costs. While these models provide a useful conceptual framework, the affective components of effort valuation remain poorly understood. Here, we examined whether primitive components of affective response—positive and negative valence, captured via facial electromyography (fEMG)—can be used to better understand valuations of cognitive effort. Using an effortful arithmetic task, we find that fEMG activity in the corrugator supercilii—thought to index negative valence—1) tracks the anticipation and exertion of cognitive effort and 2) is attenuated in the presence of high rewards. Together, these results suggest that activity in the corrugator reflects the integration of effort costs and rewards during effortful decision-making.