The Two Arrows of Pain: Mechanisms of Pain Related to Meditation and Mental States of Aversion and Identification · Valentina Nicolardi et al.

2026-06-24 · A faithful, transcript-grounded reading by PodLens

Source paper:https://doi.org/10.1007/s12671-021-01797-0

What This Paper Is About

Buddhist psychology has a metaphor known as the "two arrows": the first arrow is physical pain itself, the second arrow is one's mental reaction to that pain (resisting it, identifying with it, feeling "this is my pain"). This is the first paper to test this ancient framework with experimental data — are aversion and identification truly independent psychological states that predict the pain experience, separate from the painful stimulus itself? Researchers recruited long-term Theravada Buddhist meditators (monks) and short-term meditators, administered controlled nociceptive electrical stimulation during focused attention meditation (FAM), open monitoring meditation (OMM), loving kindness meditation (LKM), and a non-meditative rest condition, and used Granger causality analysis to test the temporal causal relationships among these two psychological variables and pain.

Paper Skeleton

• Introduction: cites the original "two arrows" parable from the Sallatha Sutta — an untrained person struck by the arrow of pain is then struck by a second arrow, their own mental reaction; a trained person experiences only the first arrow. Reviews background research on the neural correlates of mindfulness meditation and pain (insular cortex, anterior cingulate cortex).
• Methods: subjects were long-term Theravada Buddhist meditators (monks, roughly 2 hours of formal daily meditation, at least one 3-month retreat) matched against a short-term meditator control group; nociceptive electrical stimulation was administered during FAM, OMM, LKM, and a non-meditative rest condition; after each trial, subjects rated pain, aversion, and identification separately.
• Results — Descriptive findings: pain thresholds were significantly higher in long-term meditators than short-term meditators; in short-term meditators, pain was significantly lower than rest during FAM and OMM, and aversion and identification dropped across all meditation conditions; in long-term meditators, pain was significantly lower only during LKM, identification dropped across all three meditation forms, but aversion was not modulated by meditation.
• Results — Granger causality analysis: tests the pairwise temporal causal relationships among pain, aversion, and identification, finding that in long-term meditators, "identification" Granger-causes "pain" in one direction only (the reverse was not significant), while "aversion" showed bidirectional causal relationships with both pain and identification.
• Relationships with the Models / Discussion: connects the experimental results to the Buddhist psychology models of "two arrows" and "co-dependent origination," arguing that the experience of pain is the result of a "co-production" of sensory and mental factors, rather than a simple chain where pain occurs first and mental reaction follows.

Core Arguments List

1. Pain thresholds were significantly higher in long-term meditators than short-term meditators, yet meditation expertise (years of practice) itself predicted higher, not lower, pain ratings. The paper explains this seemingly contradictory result: expert meditators aren't "numbed" — their refined introspective ability lets them report pain experience more precisely, without it being amplified by the second arrow. - Anchor: Results · "Pain thresholds were higher in long-term meditators than in short-term meditators" / Expertise section · "Pain significantly increased with Expertise" - Type: Experimental finding (partly counterintuitive)
2. Both aversion and identification statistically predict the pain experience in a positive direction, and this predictive power is independent of the painful stimulus itself. The more aversion or identification, the stronger the pain — these two psychological states aren't byproducts of pain, but variables that participate in constituting the pain experience. - Anchor: Aversion / Identification regression results · "Aversion positively predicting Pain" / "Identification positively predicting Pain" - Type: Regression analysis
3. Granger causality analysis shows that in long-term meditators, identification precedes pain intensification in time, in one direction only — pain cannot predict identification in reverse. This is the paper's most critical finding: it positions "identification" as an upstream factor in the pain experience, not merely an accompanying feeling triggered by pain. - Anchor: Granger Causality Analysis · "identification Granger-caused pain, i.e., the identification state in the previous trial predicted the pain experience at the next trial... [but] the reverse test, i.e., Pain caused Identification, was not significant" - Type: Causal analysis
4. Aversion shows a bidirectional causal relationship with both pain and identification, structurally contrasting with identification's one-directional causal relationship with pain. This suggests the different psychological components within the "two arrows" model may play structurally distinct roles, rather than all uniformly acting as "amplifiers." - Anchor: Granger Causality Analysis · "aversion showed mutual influence with both pain and identification, whereas identification Granger-caused pain" - Type: Causal analysis
5. Different meditation types produced different pain-modulation patterns in long-term versus short-term meditators — short-term meditators relied on focused-attention/open-monitoring meditation (FAM, OMM) to reduce pain, while long-term meditators showed reduced pain only during loving kindness meditation (LKM). This suggests the mature stage of meditation training may involve a shift in the underlying mechanism itself, not just a strengthening of the same mechanism. - Anchor: Results · "In the short-term meditators, as compared to rest, pain was reduced in FAM and OMM... In the long-term meditators, pain was reduced only in LKM" - Type: Experimental finding

Plain English Explanation

An ancient Buddhist text says: if you're struck by an arrow, that's the first arrow — physical pain. But if you start thinking "why me," "this is so unfair," "I can't bear this," that's a second arrow you fire at yourself — and it's often more painful than the first.

The scientists behind this study took that metaphor into the lab and measured it.

They recruited two groups: Buddhist monks who meditate two hours a day and take at least three months of retreat per year, and ordinary people with some meditation experience. They applied moderate electrical stimulation to participants' hands during different meditation states, and had them rate three things simultaneously:

1. How intense is the pain?
2. How strong is the urge to escape it? (Aversion)
3. How much does this feel like "my" pain? (Identification)

The result was clear: regardless of group, the more aversion and the more identification, the stronger the pain felt. These two psychological states aren't byproducts of pain — they're fuel that amplifies it.

More critically, a time-series analysis found that, in long-term meditators, the "identification" rating from the previous trial predicted "pain" intensity in the next trial — but not the reverse; pain did not predict identification. This means "identification" precedes pain intensification in time, supporting the claim that it's an upstream factor in pain amplification. "Aversion" showed a different pattern — it influenced, and was influenced by, both pain and identification, without such a clean one-way arrow.

There was also an unexpected finding: the more years of meditation experience, the higher the pain ratings. The researchers' explanation: long-term meditators aren't "not feeling" the pain — they're feeling it more precisely, but without it being amplified by the second arrow.

Short-term and long-term meditators also differed on which meditation type reduced pain: short-term meditators could lower pain through focused attention (FAM) and open monitoring (OMM) meditation; long-term meditators only showed reduced pain during loving kindness (LKM) meditation — suggesting that as practice deepens, the mechanism doing the work may itself shift, not just grow stronger along the same lines.

Glossary

The Two Arrows: from the Pali Sallatha Sutta. The first arrow is physical pain; the second arrow is the mental reaction to pain (aversion, fear, self-identification as a sufferer). A trained person experiences only the first arrow.

Focused Attention Meditation (FAM): meditation focused on a single object (typically the breath). The goal is sustaining stable attention.

Open Monitoring Meditation (OMM): observing all present-moment experiential content (thoughts, feelings, sensations) with open, non-judgmental awareness — neither grasping nor rejecting.

Loving Kindness Meditation (LKM): cultivating goodwill, acceptance, and warmth toward oneself and others.

Granger Causality Analysis: a time-series statistical method (Granger, 1969) testing whether past values of variable x predict future values of variable y (controlling for y's own history). Used to infer temporal causal relationships, not physiological mechanism causation.

Before and After This Paper

Preceding Works

Research on meditation reducing pain had mostly measured overall pain-score differences between meditation and non-meditation states, with mechanistic explanations stopping at "distraction" or "reduced anxiety." The Buddhist psychology frameworks of "two arrows" and "co-dependent origination" remained literary, doctrinal descriptions, never operationalized into measurable independent variables in an experiment. Neuroscience research on the insular cortex and anterior cingulate cortex's role in mindfulness and emotional pain modulation had already accumulated, but lacked an experimental design treating "aversion" and "identification" as independent report dimensions.

Succeeding Lines

"Aversion" and "identification" were experimentally confirmed as measurable psychological variables independent of the painful stimulus itself, and Granger causality analysis revealed distinct causal structures between each of them and pain (identification influences pain one-directionally; aversion is mutually causal with both pain and identification). This provides a more fine-grained mechanistic target for future research, and empirical support for the theoretical framework of meditation in pain intervention — the paper proposes that the pain experience is the result of a "co-production" of sensory and mental factors, rather than a simple chain in which sensory factors alone determine the outcome and mental factors are merely added on top.

Sections Most Worth Reading in the Original

• Introduction (the original Sallatha Sutta passage):

  "When an untaught worldling is touched by a painful (bodily) feeling, he worries and grieves, he laments, beats his breast, weeps and is distraught. He thus experiences two kinds of feelings, a bodily and a mental feeling. It is as if a man were pierced by a dart and, following the first piercing, he is hit by a second dart."

• Why it matters: This is the source parable for the paper's entire argument — a 2,600-year-old text uses an extremely concrete bodily image (being struck by two consecutive arrows) to precisely anticipate the causal structure this paper proves with modern statistics.
• Discussion (the co-production mechanism):

  "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."

• Why it matters: This sentence names the paper's real theoretical contribution — not merely showing "mental factors also influence pain," but providing a concrete, multi-stage "co-production" mechanism that fills a long-standing epistemological gap between sensory and mental causation.
• Granger Causality Analysis (the core finding):

  "identification Granger-caused pain, i.e., the identification state in the previous trial predicted the pain experience at the next trial... the reverse test, i.e., Pain caused Identification, was not significant."

• Why it matters: The paper's most concrete, most citable statistical finding — it converts a Buddhist teaching that could previously only be expressed through metaphor into a directional, falsifiable temporal-causal claim.

Resonances with past episodes

• The two papers describe the same mechanism in two completely different traditions — cognitive-behavioral science and Buddhist psychology. The 'rumination' and 'helplessness' in the Pain Catastrophizing review point to the same psychological process as the 'second arrow' (the aversive mental reaction to pain) in the Two Arrows of Pain's Buddhist framework — the pain itself (the first arrow, the physiological injury) is relatively fixed, while the additional suffering layered on by the mental reaction is exactly the part that can be intervened on, measured, and changed. One paper offers neuroscience and psychometric evidence via fMRI and the PCS scale; the other uses Granger causality analysis to prove how meditation acts on the causal upstream of that exact same process.← Pain Catastrophizing: A Critical Review · Phillip Quartana et al.
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• Both papers build on the Buddhist 'two arrows' framework, describing the same mechanism at two different timescales. The Two Arrows of Pain uses Granger causality analysis to prove that 'identification' (this is my pain) appears before pain intensifies in time — identification is an upstream variable for pain, not a downstream result. Letting Go of the Unwell Self describes what that same identification process looks like stretched out over months or years: as 'this is my pain' repeats, it gradually hardens into the identity narrative 'I am a sick person' — and that identity fusion, in turn, makes pain catastrophizing and functional impairment worse. One paper measures the instantaneous causal chain in a lab; the other observes the long-term identity outcome clinically — they're describing two ends of the same causal line.← Letting Go of the "Unwell Self" in Chronic and Life-Challenging Conditions · Chloe Wells et al.
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This is one source-grounded reading, not a replacement for the original. Every point is anchored to its source, so you can check it yourself — and corrections are welcome.