Reply: Todd Hargrove’s post “Is Pain a Sensation or a Perception?”

Todd argues for these claims:

  1. The debate is not substantive or of practical import. It does not involve disagreements about pain physiology, what causes pain, or how pain should be treated. Instead, the debate is semantic.
  2. The debate is easily resolved by simply looking at textbooks that describe how the terms sensation and perception are conventionally defined and used.
  3. These textbooks make clear that it is completely appropriate to refer to pain as a perception, and it doesn’t make much sense to say that pain is a sensation but not a perception.
  4. In any event, it doesn’t matter that much how we use these words in practice, because they are inherently fuzzy and often used interchangeably.

I think Todd’s post is a decent contribution to the question, and will make a positive difference to some patients and HCPs.

Below, some thoughts from me; Todd, if you read this, your response is very welcome.

Todd: “…the terms sensation and perception are inherently nebulous and there’s no bright line between them. Why not? Because they encompass a vast number of different physiological processes happening at every level of the nervous system…”

Me: The terms ‘sensation’ and ‘perception’ are ordinary language terms, and do not capture neurophysiological or genetic differences, but differences in the kinds of behavioural and perceptual capacities human beings are interested in. We are social by nature. Human languages include psychological terms because of our need to describe, explain, predict, and otherwise understand the behaviour of other human (and non-human) animals, and because of the need to provide such information to other humans.

Of course, psychological terms can be defined or characterised scientifically, but the original ‘home’ of our psychological vocabulary is the ordinary language we use every day.

Todd highlighted the indeterminacy of our psychological terms, such as ‘sensation’ and ‘perception’; e.g., ‘…there’s no bright line between them’; ‘…are inherently fuzzy, and are often used interchangeably’.

Me: I think the possibility of disagreement or uncertainty about pain in others reflects this indeterminacy. In our ordinary pain language, that indeterminacy is not due to neurophysiological or genetic factors, but to social patterns of behaviour: our concept of pain is flexible because pain behaviour, and our complex reactions to it, is diverse and unpredictable. Care-giving in pain settings can involve a threat to the caregiver, and is conditional on the authenticity of manifest pain behaviour. As observers of pain behaviour, we are sensitive to signs of exaggeration, suppression, or malingering, in behavioural displays of pain. Accordingly, our concept of pain does not always connect behaviour, situation, and personal experience, in a rigid way.

What could follow if we always connected behaviour, situation, and personal experience, in a rigid – necessary – way? To propose a simple, but rather extreme, illustration: suppose a group of people defined pain in terms of a particular neurophysiological biomarker, and used a sophisticated scanner to test for this marker. In their practice, the scanner’s verdict, and not the individual’s utterances or behaviour, is treated as definitive.

Would we want to call this practice a concept of pain? Would this practice be desirable or even possible for us? Would we, for example, accept that an apparent malingerer was in pain, if the scanner said so? Or, that a friend wasn’t, despite her facial grimaces? Would the absence of an abnormal scanner finding be held against a person applying for health benefits?

The new practice with its unanimity and clarity would be a far cry from our current, indeterminant, one. Although some people might engage in this practice, the fact that they do so perhaps makes them a different type of people from us?

What the face reveals: the experience of pain

Presented at: De/Constructing the Body: Ancient and Modern Dynamics, Workshop 3:Trans-Formation, April 9, 2021.

Abstract here.

Slide transcript

Slide 2
Human beings are describable in two distinct, but complementary ways: in terms of the way the world is, through scientific descriptions of the causal mechanisms and laws that explain physical things, or, in terms of the way the world seems, through descriptions of personal experiences and meanings.

As a person, I can recognise within myself a perspective or point of view on the world and identify it as belonging to me. Every person has such a unique perspective; this is partly what it means to be a person rather than a physical thing. In contrast, a scientific description of the world does not presuppose any personal point of view. Physical or biological science does not use words like “I”, “here”, or “now”.

Slide 3
The features of personal experience—thought, feeling, speech and action—are amenable to standard scientific explanation as specific changes in the body.

A philosophical assumption held by some neurophysiologists is that a person is identical with his or her body. Person and body are one and the same thing. This assumption is behind the slogan in pain science, “pain is in the brain”.

In terms of personal experience, however, the identity between person and body escapes understanding. For example, when I feel a pain, there is no information or evidence, or nothing that I could discover about my body subsequent to the experience of pain, that could demonstrate it to be false. When I feel a pain, I simply I am in pain.

Slide 4
In person-to-person interactions, we commonly respond to each other as though we are not identical with the human body, but in a compelling sense operating “through” the body, which seems to be a vehicle of thought, emotion, pain or suffering.

We feel that each person we encounter in the world is a unique perspective that is not the body, but the “self”, which is lodged in the face.

Slide 5
Pain is not an action, but a personal experience. Yet, pain reveals itself in those gestures, or expressions, which cannot fail to reveal the person in pain.

People in pain communicate their experience through a range of actions, ranging from self-report, to nonverbal actions, which include paralinguistic vocalisations, bodily activity and facial expressions.

Verbal self-report is mostly voluntary, and relies on reflection and deliberation, whereas nonverbal expression is involuntary and reflexive.

Slide 6
But the involuntary transformations revealed in the face are more meaningful than in other body-parts. This is because body-parts do not have the individuating meaning of the face: the meaning of revealing me, here, now. When I observe another’s pain facial expression, I am not perceiving a physical part of him, as I am when I notice his injured arm or leg. I am meeting him, a real person, who reveals himself in the face.

A person may be perceived by his arm, but not in his arm.

Involuntary facial changes show the person with pain “as he really is”, because he does not fully control them.

We express preference for non-verbal behaviour over verbal behaviour when judging or interpreting the credibility of pain displays.

Slide 7
Pain expressed through the face acquires, for us, an individuality, a personality, that readies us for the human encounter.

Not understanding a face means not seeing where it fits into our gallery of portraits, and therefore not knowing how to properly relate to the person whom it prefigures. One study showed that physicians tended to attribute lower levels of pain to physically attractive patients than physically unattractive patients. Another study found that physically attractive and male patients were perceived as experiencing less pain and disability than physically unattractive and female patients. Finally, in another study, observers judging patient facial pain expressions on video perceived older and less physically attractive patients to be of lower overall functioning.

I can decide to enter into another’s pain expression; or I can decide to remain outside it, as it were, and to see it as a thing apart; perhaps more darkly, as something foreign, or subordinate to my will. How we judge a face may affect the outcomes the patient can achieve.

Slide 8
Pain imposes a significant vulnerability on persons: the vulnerability of a free person who is overwhelmed in his or her body by the presence of pain. This can make the person with pain feel answerable for what he or she experiences. Men who adopt a stoical attitude to their pain are less likely to express pain in the presence of others.

The expression on a face is an offering in the world of mutual responsibilities: it projects into our interpersonal relations a particular person’s “being there”. As soon as I notice pain in another person’s face, my responsibilities are engaged. Facial expressions of pain call on you to respond to me.

The face has this meaning for us because it is the boundary at which the other appears, offering “this person” as one in need of help.

Slide 9
However, expressing pain does not always lead to compassionate reactions, and people are careful about when and with whom they express pain.

Voluntary control of pain through facial actions is normally judged to be an insincere expression of pain, and open to doubt. The controlled pain face is perceived as a mask, which conceals the person lying “behind” it. The expressions on the human face are not always transparent effects of the personal experiences that elicit them, as perhaps they are in non-human mammals. Human beings can deceive through their faces, and children and adults can use the face to fake, and amplify, or suppress, pain.

The capacity to modulate pain expressed through the face has led to difficulty in interpreting the meaning of facially expressed pain. The fidelity with which facial signs mean “pain” is limited to a narrow range of involuntary facial expressions of pain. It is often uncertain whether the presence or absence of information means “pain” or, if they are exaggerated or suppressed consistent with perceived situational demands.

Slide 10
If there is a configuration of facial actions that signals pain, then assessing its presence is amenable to pattern recognition technologies. Substantial progress has been made toward the development of IT-based analysis of pain facial expression.

These systems raise ethical questions about control of patient information.
As these IT systems are used in health care settings, informed consent will need to be obtained for collecting and storing patients’ images, but also for the specific purposes for which those images might be analyzed by these systems.

IT systems can store data as a complete facial image or as a facial template. Facial templates are considered biometric data and thus personally identifiable information. The notion that a photo can reveal private health information is relatively new, and privacy regulations and practices are still catching up. Clinicians should advise patients that there may be limited protections for storing and sharing data when using an facial recognition tool.

Meanings of Pain, Volume I (2016, Springer)

161214_Meanings of Pain_Cover

van Rysewyk S (2016). Meanings of Pain. Springer International Publishing AG: Switzerland.

  • First book devoted to study of the meanings of pain
  • Explains why meaning is important in the way that pain is felt
  • Promotes integration of qualitative and quantitative research methods to study meanings of pain
  • Includes insights that can aid in the clinical management of patients with pain

About Meanings of Pain, Volume I

Although pain is widely recognized by clinicians and researchers as an experience, pain is always felt in a patient-specific way rather than experienced for what it objectively is. This fact makes perceived meaning important in the study of pain. The book contributors explain why meaning is important in the way that pain is felt and promote the integration of quantitative and qualitative methods to study meanings of pain. For the first time in a book, the study of the meanings of pain is given the attention it deserves.

All pain research and medicine inevitably have to negotiate how pain is perceived, how meanings of pain can be described within the fabric of a person’s life and neurophysiology, what factors mediate them, how they interact and change over time, and how the relationship between patient, researcher, and clinician might be understood in terms of meaning.

Though meanings of pain are not intensively studied in contemporary pain research or thoroughly described as part of clinical assessment, no pain researcher or clinician can avoid asking questions about how pain is perceived or the types of data and scientific methods relevant in discovering the answers.

Reviews of Meanings of Pain

“Meanings of Pain offers an intriguing investigation into the implications of the psychological, sociological, and personal lived meanings of pain for the overall management of patients struggling with this chronic condition. … it may prove invaluable to the physician struggling to understand the intricacies of the patient pain experience, facilitating improved comprehensive pain therapy.” (Emily E. Smith-Straesser and Amanda M. Kleiman, Anestesia & Analgesia, Vol. 125 (5), November, 2017)

Pain Science and Sensibility Episode 29: Discussion of the book “Meanings of Pain”

Meanings of Pain – Book Review by Josie Billington (University of Liverpool), Andrew Jones, and James Ledson (The Royal Liverpool and Broadgreen University Hospitals NHS Trust)

Meanings of Pain – Book Review by Christin Bird

The Science and Philosophy of the Meaning of Pain – Review of Chapter 7, “A Scientific and Philosophical Analysis of Meanings of Pain in Studies of Pain and Suffering” in Meanings of Pain by Smadar Bustan – by Tim Cocks

Meanings of Pain – Book Review by Asaf Weisman

N=1 as a reference for general concepts of experiencing pain by Morten Høgh

New Developments

Springer is considering publishing Meanings of Pain in a multiple volume series. Watch this space for an update on this development.