The two arrows of pain: mechanisms of pain related to meditation and mental states of aversion and identification

Objectives: According to the core Buddhist psychology models of the “two arrows of pain” and “co-dependent origination,” pain is the resultant of bodily and mental factors, which can be regulated by meditation states and traits. Here we investigated how pain and the related aversion and identification (self-involvement) experiences are modulated by focused attention meditation (FAM), open monitoring meditation (OMM), and loving kindness meditation (LKM), as well as by meditation expertise. Methods: Theravada Buddhist long-term meditators were matched with a group of short-term meditators. Nociceptive electrical stimulation was administered during FAM, OMM, and LKM, and in a non-meditative rest condition. Experience reports of pain, aversion, and identification were collected in each trial. Results: Pain thresholds were higher in long-term meditators than in short-term meditators. In the short-term meditators, as compared to rest, pain was reduced in FAM and OMM, and aversion and identification in all meditation conditions. In the long-term meditators, pain was reduced only in LKM. Identification was reduced in the three forms of meditation, while aversion was not affected by meditation. Further analyses with a particular focus on long-term meditators showed that pain was predicted to increase with meditation expertise, aversion, and identification. Granger causality analysis revealed that aversion and pain, as well as aversion and identification, causally influenced each other; identification causally influenced pain. This pattern of results about the relationships between pain, aversion, and identification was largely overlapping in the group of short-term meditators. Conclusions: The findings reveal mechanisms of pain in interaction with aversive and identification mental states, as well as their modulation by meditation states and traits. They also suggest that pain feeling is the resultant of coupling of sensory and mental factors, thus highlighting the relevance of the second arrow of pain and providing a clarification of the epistemological gap between sensory causation and mental state causation of pain, in terms of a co-production mechanism with multiple stages. In particular, the evidence about the causal influences of identification on pain highlights a self-related factor of relevance in pain experiences that can be modulated by mindfulness. The study also inspires new testable neuroscientific hypotheses, and sheds new light on core Buddhist psychology models, based on evidence from a controlled experimental setting and experience dimension reports by long-term meditators with enhanced mindfulness skills.