Effort shapes empathy: Distinct aftereffects of cognitive and physical exertion on pain empathy.

Empathy is fundamental for social functioning yet incurs significant mental costs. While contemporary theories emphasize that empathy is not automatic but regulated by resource availability, this cognitive cost hypothesis relies largely on indirect evidence. Few studies have causally manipulated effort to test its impact on neural empathetic processing. Addressing this gap, Study 1 examined the impact of prior cognitive effort exertion on event-related potential elicited by others' pain. Study 2 extended this investigation to the physical domain (Study 2a) and examined the specificity of these effects using nonpain negative stimuli (Study 2b). Across the three studies, participants consistently showed heightened neural responses for painful compared to neutral stimuli and successful machine classification between the two categories. Crucially, this neural pain empathic response was attenuated following cognitive effort exertion but amplified following physical effort exertion. Furthermore, this modulation was not observed for nonpainful negative stimuli. Collectively, these findings provide direct empirical support for the cognitive cost hypothesis of empathy while revealing that cognitive and physical effort do not simply deplete a shared pool of resources. Instead, they appear to engage distinct mechanisms that differentially shape the regulation of pain empathy. This work advances understanding of empathy as a dynamic process shaped by effort, with implications for theories of self-regulation and social behavior. (PsycInfo Database Record (c) 2026 APA, all rights reserved).