Why can we hurt ourselves? Human agency and embodied action in the attenuation of self-induced pain.

Abstract

Abstract: Self-initiated actions often generate sensory signals perceived to be less intense than identical signals generated externally. This phenomenon, known as sensory attenuation, is particularly robust for nonpainful tactile sensations. For pain, however, even if the stimulation is self-generated and predictable, it remains painful, albeit sometimes slightly less intense. This difference may reflect the functional divergence between pain and nonpainful sensations, with the sense of agency playing a central role in this distinction. Across 2 experiments involving 61 pain-free adults, we investigated the attenuation of self-induced pain and nonpainful sensations across different stimulation modalities, contexts, and agency levels. We found that self-induced attenuation depended on stimulation modality rather than intensity, with significant reductions for modalities involving strong motoric components and high spatiotemporal alignment (eg, mechanical pressure), in line with the internal forward model. Individuals' trait agency played a pivotal role, with stronger agency associated with enhanced attenuation of nonpainful sensations and mild pain, but reduced attenuation of intense pain. Sex differences also emerged with stronger attenuation effects in men, who also reported higher levels of agency. This study is the first to show that trait-level agency differentially modulates attenuation for painful and nonpainful sensations and the first to explore sex differences. By comparing pain with nonpainful touch, we proposed that self-induced sensations are not attenuated uniformly but shaped by evolutionary priorities such that socially or playfully mediated sensations are more readily suppressed, while high-threat sensations like pain resist qualitative suppression to preserve their protective function.