Moseley’s Red/Blue Light Study: Why It’s Time to Move On

Moseley’s Red/Blue Light Study: Why It’s Time to Move On

Let’s talk about Moseley’s infamous red/blue light study—a research piece from nearly 20 years ago that somehow still gets rolled out as a cornerstone of pain science education.

It’s a clever experiment, sure, but it’s wildly overused to justify his unwavering commitment to the neuromatrix model.

Here’s the thing - it’s an extremely superficial look at pain that doesn’t hold up when you dig deeper.

Worse, its oversimplified conclusions have caused real-world harm to patients and clinicians alike.

I think it’s to time we moved on.

What Does the Study Actually Show?

In the study, a noxious cold probe was paired with either a red light (associated with danger, tissue damage) or a blue light (associated with cold, less dangerous).

Participants rated the pain unpleasantness as higher with the red light, but pain intensity—how physically strong the pain felt—didn’t change.

This means that context (the visual cue) affected the emotional evaluation of pain (unpleasantness) but not the raw sensory experience (intensity).

This is an interesting finding—but very narrow.

It’s about exteroception (external cues like vision) influencing pain perception.

That’s fine for a lab-controlled experiment on acute pain, but it tells us nothing about interoception, chronic pain, or the real-world complexity of pain.

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In a recent 2023 podcast, Moseley doubled down on his study with this quote:

“There were some people for whom, with the blue light they reported no pain and with the red light they reported pain eight out of ten. And that’s a very severe pain. There are other people who reported the same level of pain in each situation. And in scientific terms we describe those people as idiots (laugh) because their brains are not picking up on these cues that everyone else is picking up on.”

This is deeply problematic for several reasons:

• Dismissive attitude: Referring to participants as "idiots" because they didn’t conform to the expected pattern is disrespectful and ignores the complexity of individual pain responses and the fact that they can trust their bodies experience without being contaminated with external distractions (a rare and amazing skill to be honest)

• Moseley uses phrases like "pain eight out of ten" without distinguishing whether he means intensity (strength) or unpleasantness (emotional impact). However, based on the study results, the only dimension that showed such variability in response to the cues was pain unpleasantness, not intensity. This lack of clarity can be misleading

• Pain intensity and pain unpleasantness are distinct dimensions, and conflating them obscures the actual findings of the study. It risks overstating the impact of visual cues, as they DIDN’T alter the sensory intensity of the pain but only its EMOTIONAL interpretation.

• Failure to update his model: Instead of recognizing that his study barely scratches the surface of pain complexity, Moseley doubles down on his original findings, refusing to appreciate their limited scope.

• Ignores interoception and chronic pain: His study is about acute nociceptive pain modulated by visual cues. Chronic pain, which involves interoceptive processes (e.g., inflammation, fatigue, homeostatic dysregulation), isn’t even in the same ballpark.

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Moseley’s study isn’t a bad experiment—it’s just wildly overgeneralized. Here’s why:

• It only applies to exteroceptive pain: The study is about surface-level pain influenced by external cues (red/blue light). It says nothing about deeper, interoceptive pain (e.g., from muscles or organs), which involves different brain regions like the insular cortex.

• It separates pain intensity from unpleasantness: The findings show that context changes unpleasantness (salience), NOT intensity.

• But in real-world chronic pain, those dimensions are deeply intertwined and modulated by systemic factors like inflammation and central sensitization.

• It ignores chronic pain altogether: Chronic pain is a much messier phenomenon involving altered interoception, disrupted homeostasis, and central sensitization. This study doesn’t even begin to address that complexity.

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Unintended Harmful Consequences

By clinging to this superficial study, Moseley’s work has contributed to serious downstream problems:

• Gaslighting patients: Patients with chronic pain are often told their pain is just a "brain output," implying it’s all in their head. This dismisses the real interoceptive and structural factors driving their pain, leaving them feeling invalidated and alienated.

• Oversimplified treatments: The idea that context alone can “rewire” pain has spawned treatments that focus on changing the brain’s interpretation of pain while ignoring physical contributors like mitochondrial dysfunction, inflammation, and recovery deficits.

• Therapist confusion: Clinicians trying to reconcile this brain-centric model with their patients’ real-world experiences often find it doesn’t work. Chronic pain doesn’t behave like the tidy pain in Moseley’s lab study, and therapists are left frustrated and unsure how to help.

Bud Craig’s Interoceptive Model: A Better Framework

Bud Craig’s work on interoception offers a much more realistic and applicable model for understanding pain:

• Pain as a homeostatic emotion: Pain reflects disruptions in the body’s internal state, integrating interoceptive signals with emotional and cognitive processes.

• Role of the insular cortex: Unlike the neuromatrix model, Craig’s framework emphasizes the insular cortex as a hub for processing interoceptive inputs (e.g., inflammation, fatigue) and driving adaptive responses.

• Chronic pain as a prediction mismatch: Craig’s model explains chronic pain as a mismatch between the brain’s predictions and the body’s actual internal signals, a more accurate representation of what patients experience.

This framework doesn’t just make more sense scientifically—it aligns better with what patients and therapists see in the real world.

The unpleasantness of tonic pain is encoded by the insular cortex

While Moseley’s red/blue light study has been widely cited, its focus on acute skin-based sensations (exteroception) offers little relevance to the kind of pain most patients bring to a physiotherapist.

In stark contrast, Schreckenberger’s study, The unpleasantness of tonic pain is encoded by the insular cortex, dives into the mechanisms of interoceptive pain, the deep, internal discomfort often experienced in muscles and other tissues.

Schreckenberger’s research highlights how muscle pain—the type of pain patients commonly report—activates the insular cortex, which encodes the unpleasantness of pain tied to homeostatic dysregulation and internal states.

Unlike superficial findings from Moseley’s study, which rely on external cues like light, Schreckenberger’s work reflects real-world pain mechanisms and offers a far more valid framework for understanding and treating the persistent pain that drives patients to seek care.

This critical distinction underlines why Moseley’s study, despite its fame lacks practical relevance.

Time to Retire the Red/Blue Light Study

Moseley needs to stop using this study as the cornerstone of his arguments.

It’s outdated, oversimplified, and irrelevant to the complexity of chronic pain.

Pain science has moved on, and so should Moseley. His refusal to update his model—despite the clear limitations of this study—shows a troubling lack of humility.

The future of pain science lies in embracing complexity, not reducing pain to a “brain output” but understanding it as a dynamic interplay of interoception, homeostasis, and real-world biology.

Bud Craig’s interoceptive model offers a path forward.

Let’s stop relying on superficial lab studies and start focusing on what truly helps patients.

If Lorimer Mosely was open to question - this is what I would love to know…

"How do you see your red/blue light study, which focuses on external skin pain, applying to the deeper, internal pain that most patients experience in muscles or joints? And do you think its widespread interpretation might have unintentionally led to oversimplified treatments or left some patients feeling dismissed?"

Is It Time for a New Pain Model?

Is It Time for a New Pain Model?

In the early 2000s, pain neuroscience education (PNE) emerged as a revolutionary approach to understanding pain, spearheaded by prominent figures like Lorimer Mosley and David Butler.

Their work shifted the conversation away from a purely structural perspective and introduced the world to the concept that pain is not solely a result of tissue damage, but also a brain-driven phenomenon.

For some in the rehab profession, this helped us move beyond simplistic reductionist narratives (some other practitioners continued the narrative - see below).

How many overly simplistic nocebic inducing narratives could you fit in one physiotherapy session?

This was an exciting revelation at the time, and it gave clinicians and patients alike a new way to explain chronic pain.

However, as the years have passed, it’s become increasingly clear that PNE, while groundbreaking, may not have fully lived up to its promise.

Many have “drunk the Kool-Aid,” so to speak, fully subscribing to the PNE narrative without recognizing its limitations.

As a result, it may be time for a new explanatory model—one that embraces both the brain and the body in a more profound and grounded way.

Enter Bud Craig’s homeostatic model.

The Cognitive Focus of PNE: A Double-Edged Sword

Butler and Mosley’s PNE revolution gave us the gift of understanding the brain's role in pain perception.

It showed that pain is a complex experience that involves more than just signals from the body—our thoughts, beliefs, and prior experiences shape how we experience pain.

This has led to cognitive-based interventions aimed at reshaping our understanding of pain, helping patients reframe their pain experience and reduce fear.

But this approach has its downsides.

The heavy focus on cognition—the idea that it’s all in the brain—can stigmatize patients, making them feel like their brain is "broken" or diseased.

Just today I heard on the Curable podcast (link here - 38 min mark) Sophie Hawley-Weld discuss her negative experience with PNE as a stand alone approach - “It made me feel crazy, because I did ALL the things!”

Lisa Feldman Barrett points out in her book How Emotions Are Made:

“Scientists now consider chronic pain to be a brain disease with its roots in inflammation.”

Therapists, too, can get stuck in this model, sometimes doubling down when their approach doesn’t yield results, leading to frustration and cognitive dissonance on both sides.

While PNE has helped many, its reductionist trap—the idea that pain is purely a cognitive or brain-based experience—can leave patients feeling confused, alienated, and in some cases, harmed.

The Quiet Work of Bud Craig: A Model Ready for Its Time

While PNE experts have been front and center, promoting their work as being of the highest evidence-based standard, Bud Craig has worked quietly and diligently in his lab for over two decades.

Without any fanfare or jumping to premature conclusions, Craig has steadily built his homeostatic model of pain, focusing on understanding how the brain and body interact to maintain balance. His approach has been one of careful observation and deep research, avoiding the sensationalism that often accompanies new theories.

Unlike the self-promotion that has often characterized the PNE movement, Craig’s work has been humble yet profound.

While PNE experts have confidently marketed their approach and, at times, looked down on therapists who use what they consider to be outdated modalities, Craig has taken a more measured, thoughtful path.

This divide between the PNE camp and other healthcare professionals has created divisions within the profession that threaten to tear it apart. As the PNE model gained traction, those who embraced different methods, even those rooted in manual therapy or movement-based approaches, have often been labeled as being behind the times or lacking evidence.

This division is unhealthy.

When experts adopt a fixed stance, particularly when that stance dominates the conversation, it can prevent the evolution of new ideas.

The rigid adherence to the neuromatrix theory has made it difficult for PNE proponents to integrate other valuable insights, particularly those that focus on the body’s physiological processes.

Bud Craig’s Homeostatic Model: A More Balanced Approach

This is where Bud Craig’s homeostatic model offers a refreshing alternative.

Craig’s model doesn’t disregard the brain’s role, but it brings the body back into the equation in a more meaningful way. His model focuses on interoception—the way the brain perceives signals from inside the body—and homeostasis, or the body's ability to maintain internal balance.

Craig suggests that pain emerges from the brain's interpretation of signals related to disruptions in homeostasis.

In other words, pain is a result of the body trying to maintain balance, involving not just cognitive processes but also metabolic health, the immune system, and the autonomic nervous system.

This multi-dimensional approach goes beyond the brain to include a broader understanding of the body's physiological state.

Why PNE Has Reached Its Limits

The current PNE model, with its strong focus on the brain, misses out on these broader dimensions. While it’s been helpful for some, it has also led to iatrogenic harm—the unintended negative consequences of treatment.

Patients who don’t respond to PNE can feel as though their brain is at fault, or that they’re failing to think positively enough to overcome their pain. This can lead to a sense of disempowerment, where patients feel like they’re not in control of their own healing.

On the flip side, therapists who are deeply invested in the neuromatrix theory of pain, popularized by PNE, can become stuck in their thinking.

They may struggle to embrace newer models like Craig’s, falling into expert bias and resisting change due to their commitment to a theory that no longer fully explains the complexity of pain.

Big organizations or thought leaders who have built their careers on the neuromatrix theory may find it difficult to pivot, even when emerging evidence suggests a new direction is needed.

The Risk of Reductionism

When we boil down pain to a purely cognitive process, we risk oversimplifying a very complex experience.

Pain is not just in the mind, and it’s not just in the body—it’s an emergent experience that arises from the brain’s interpretation of the body’s internal state.

PNE’s reductionist approach may have been a necessary stepping stone, but it’s clear now that it’s not enough.

We need a model that honors the complexity of pain—one that integrates the brain, body, and emotions.

A New Paradigm for Pain: Bud Craig’s Homeostatic Model

Bud Craig’s homeostatic model offers the kind of paradigm shift that the pain world desperately needs.

His model moves beyond the brain-centric view of pain and looks at how pain is a signal of the body’s struggle to maintain balance.

It integrates brain and body, cognition and physiology, offering a more multi-dimensional and empowering view of pain.

This model suggests that pain is not just about faulty neural circuits or maladaptive thoughts but is a multi-dimensional signal that can arise from metabolic imbalance, poor immune function, or disruptions in the autonomic nervous system.

In this way, it respects the body's role in pain, and it offers patients a more empowering framework for understanding their pain and healing.

Instead of being told that their brain is “the problem,” patients can see how their body and brain work together to maintain balance.

Time for a New Direction

As with any scientific revolution, there comes a time when we must move forward. Karl Popper’s philosophy reminds us that science should be open to change, that we must always be ready to discard old theories when new evidence challenges them.

The PNE revolution, while groundbreaking, may now need to give way to a more nuanced, integrative approach. The homeostatic model offers a new direction—one that respects the brain’s role but also fully embraces the body’s physiological contributions to pain.

It’s time for a new pain model—one that’s more grounded in science, one that empowers patients rather than stigmatizing them, and one that helps therapists and patients alike see the bigger picture.

The time for Bud Craig’s homeostatic model has come.

Final Thoughts:

We owe a debt of gratitude to Butler, Mosley, and the pioneers of PNE for opening the door to a new understanding of pain.

But now, we have the opportunity to take the next step. By embracing the homeostatic model, we can help patients reclaim their power, and in doing so, move away from the reductionist trap that has limited our approach to pain for too long.

Let's bridge the divisions in the profession and build a new, unified path forward—one that honors both the brain and the body.