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 Cancer-Related Pain”

Sculpture by Fabio Viale

Australian Pain Society Annual Scientific Meeting 2020
Hobart Tasmania

Topical Session
Tuesday, April 7, 2020, 3.30-5.00pm

Session Description: Cognitive factors are important determinants of cancer-related pain experience. Simon van Rysewyk describes some common meanings and beliefs that people have about cancer, illness, and pain, and the consequences these meanings have in relation to common help-seeking behaviours or coping strategies people choose to adopt. Suffering is a cognitive and emotional response to recurrent perceived losses experienced in some people with cancer. Megan Best presents on the challenges in assessing people with cancer-related suffering and the relationship of suffering to cancer-related pain. Melanie Lovell compares levels of suffering in people with cancer-related pain versus non-cancer chronic pain, highlighting differential meanings of existential or spiritual distress and mood dysfunction. Best and Lovell outline management approaches to cancer pain and suffering that are not responsive to analgesia, such as meaning- or peace-centred therapies.

Session Objectives
At the end of the session, attendees will know:
– Common meanings of cancer-related pain and how people apply these meanings to cope with their pain
– Common meanings of suffering in cancer-related pain and the relationship between these meanings and non-cancer chronic pain experience and mood dysfunction
– Effective approaches to diagnosis and management of cancer-related pain symptoms, including interventions based on meaning

Presenter Duties
Chair: Professor Jane Phillips, University of Technology, Sydney
Organiser/Presenter 1: Dr Simon van Rysewyk, University of Tasmania
Presenter 2: Dr Megan Best, University of Sydney
Presenter 3: Associate Professor Melanie Lovell, University of Sydney

A neurobehavioral-polyvagal theory of pain facial expression

The personal experience of pain produces a reliable effect on facial behavior in humans and in nonhuman mammals. Why should pain have a face? What is it for? I will attempt to head towards answering this question by invoking a theoretical framework: polyvagal theory (Porges, 2001, 2006).

1 Polyvagal Theory

According to polyvagal theory (Porges, 2001, 2006), evolution of neural control within the autonomic nervous system (ANS) has tracked three stages, each revealing a specific behavior, and a specific function:

In the first stage, the ancient unmyelinated visceral vagus nerve that enables digestion could respond to danger and pain only by reducing metabolic output and producing immobilization behaviors.

In the second stage, the sympathetic nervous system (SNS) made it possible to increase metabolic activity and inhibit the visceral vagus nerve, thus allowing fight/flight behaviors following perceived threat or pain.

The third stage, which is uniquely mammalian, involves a myelinated vagus that can rapidly control cardiac and bronchi output to enable spontaneous interaction (i.e., engagement or disengagement) with the environment. The interaction of the autonomic nervous system (ANS) with the hypothalamo-pituitary-adrenal (HPA) axis, nervous and immune systems change to maximize response to stressors such as nociception. During nociception, the ANS operates together with nervous, endocrine and immune systems to produce stress (Chapman et al. 2008; Porges, 2001, 2006). In terms of polyvagal theory, pain facial expression is a dynamic autonomic response caused by noxious signaling. In terms of polyvagal-type identity mechanistic theory pain facial expression is a type of behavior that is identical to a type of neurophysiological mechanism; namely, the phylogenetically recent brain-heart-face mechanism.

The expansion of cortex in the third stage increased innervation and neural control of the mammalian face: upper face innervation is bilateral and arises from the supplementary motor area (M2) and the rostral cingulate motor area (M3). Lower face innervation is contralateral and arises from primary motor cortex (M1), ventral lateral premotor cortex, and the caudal cingulate motor cortex (M4) (Morecraft et al. 2004). Human pain facial movements of the eyebrows and upper lip are type identical with negative emotional aspects of pain and activation of M1, M2, M3, whereas facial movements around the eyes are type identical with somatosensory aspects of pain, and activation of M2 and M3 (Kunz et al. 2011). Thus, evolution of cranial anatomy enabled a highly integrated facial representation of the multidimensional experience of pain.

2 Why Pain Should Have a Face

In clinical and experimental settings, the pain face is observed to rapidly appear following noxious stimulation, and diminish concurrent with cessation of the noxious stimulus, or when analgesics are administered (e.g., Craig & Patrick, 1985). The brain-heart-face mechanism is an integrated system with both a somatomotor part controlling the striated facial muscles and a visceromotor part controlling the heart through a myelinated vagus nerve (Porges, 2001, 2006). When the vagal tone to the cardiac pacemaker is high, the myelinated vagus acts as a brake or restraint limiting heart rate. Rapid inhibition and disinhibition of vagal tone to the heart supports the rapid mobilization of facial muscles and formation of the pain face concurrent with pain onset. In humans and nonhuman mammals, the main vagal inhibitory pathways in the myelinated vagus originate in the nucleus ambiguus.

The vagal brake supports the low-metabolic requirements involved in the rapidly appearing and disappearing pain face. Withdrawal of the vagal brake is strongly correlated with the rapid appearance of the pain face; reinstatement of the vagal brake is strongly correlated with the rapid diminishing of the pain face. These correlations are not unique to pain facial expression; similar relationships hold with regard to the vagal brake and the timing and duration of aversive, but non-noxious emotional facial expressions (e.g., Pu et al. 2010), and positive emotional facial expressions (e.g., Kok & Fredrickson, 2010).

In terms of the function of rapid pain face onset and offset, the vagal brake makes it possible for the individual in pain to quickly disengage from source of wounding and pain, concurrent with the rapid appearance or diminishing of pain facial expression, which may offer temporary access to additional metabolic resources to aid healing, recovery and self-soothing behaviors, with likely involvement from care givers.

Concerning aid from others, the vagal brake reliably maps onto specific interaction types observed in mammalian pain events. In pain events comprising the individual in pain and care givers, mammalian behavior is typed according to interpersonal communication through facial expressions, vocalizations, head and hand gestures (Hadjistavropoulos et al. 2011; Porges, 2001, 2006; Williams, 2002). A relevant feature is the rapid ‘switching’ of temporary engagement to temporary disengagement behaviors between the individual in pain and care givers. This interaction type may involve care givers speaking to the one in pain, and then quickly switching to listening; for the one in pain, looking into the face of the care giver, and then quickly switching to vocalizing (Craig et al. 2011; Hadjistavropoulos et al. 2011; Porges, 2001, 2006; Williams, 2002). The brain-heart-face mechanism thus allows the one in pain and the care giver to get the timing right. Some philosophers and neuroscientists claim that evolutionary neurobehavioral solutions to timing problems such as these are implicated in the origin of empathy and ultimately consciousness itself (Churchland, 2002; Cole, 1998; Engen & Singer, 2012; van Rysewyk, 2011).

However, if pain is severe or chronic and the vagal brake is withdrawn (or dysfunctional), the concurrency of increased pain facial expression, cardiac output, and other mobilization behaviors (i.e., increased SNS and HPA output), means that, if care giving is to succeed in promoting healing and recovery, the care giver’s vagal brake must be dynamically reinstated. By applying their own vagal brake, care givers may regulate their own visceral distress and thereby succeed in allocating valuable metabolic resources to communicate safety to the one in pain (and themselves) through calming facial and head behaviors, eye gaze, and prosodic vocalizations (i.e., increasing the vagal brake decreases SNS and HPA output). Since the vagal brake of the person in pain has been provisionally withdrawn, the care giver is effectively an integrated external brain-heart-face mechanism (cf. Tantam, 2009, the ‘interbrain’).

Thus, the pain facial muscles function as neural timekeepers detecting and expressing features of safety and danger that cue the one in pain to quickly disengage from the source of wounding and pain, simultaneous with the rapid appearance or attenuation of pain facial activity, and also cue others who can help.

References

Chapman, C. R., Tuckett, R. P., & Song, C. W. (2008). Pain and stress in a systems perspective: reciprocal neural, endocrine, and immune interactions. Journal of Pain, 9(2), 122-145.

Churchland, P. S. (1989). Neurophilosophy: Toward a Unified Science of the Mind-Brain. Cambridge, Mass.: MIT Press.

Cole, J. (1998) About face. Cambridge, Mass.: The MIT Press.

Craig, K. D., & Patrick, C. J. (1985). Facial expression during induced pain. Journal of Personality and Social Psychology, 48(4), 1080-1091.

Craig, K. D., Prkachin, K. M., & Grunau, R. E. (2011). .The facial expression of pain. In D. C. Turk, & R. Melzack, Handbook of Pain Assessment, 2nd Edition (pp. 117-133). New York: The Guilford Press.

Engen, H. G., & Singer, T. (2012). Empathy circuits. Current Opinion in Neurobiology, 23, 1-8.

Hadjistavropoulos, T., Craig, K. D., Duck, S., Cano, A., Goubert, L., Jackson, P. L., Mogil, J. S., Rainville, P., Sullivan, M. J. L., de C. Williams, Amanda C., Vervoort, T., & Fitzgerald, T. D. (2011). A biopsychosocial formulation of pain communication. Psychological Bulletin, 137(6), 910-939.

Kok, B. E., & Fredrickson, B. L. (2010). Upward spirals of the heart: Autonomic flexibility, as indexed by vagal tone, reciprocally and prospectively predicts positive emotions and social connectedness. Biological Psychology, 85(3), 432-436.

Kunz, M., Lautenbacher, S., LeBlanc, N., & Rainville, P. (2011). Are both the sensory and the affective dimensions of pain encoded in the face? Pain, 153(2), 350-358.

Morecraft, R. J., Stilwell-Morecraft, K. S., & Rossing, W. R. (2004). The Motor Cortex and Facial Expression: New Insights From Neuroscience. The Neurologist, 10(5), 235-249.

Porges, S. W. (2001). The polyvagal theory: phylogenetic substrates of a social nervous system. International Journal of Psychophysiology, 42(2), 123-146.

Porges, S. W. (2006). Emotion: An Evolutionary By‐Product of the Neural Regulation of the Autonomic Nervous System. Annals of the New York Academy of Sciences, 807(1), 62-77.

Pu, J., Schmeichel, B. J., & Demaree, H. A. (2010). Cardiac vagal control predicts spontaneous regulation of negative emotional expression and subsequent cognitive performance. Biological Psychology, 84(3), 531-540.

van Rysewyk, S. (2011). Beyond faces: The relevance of Moebius Syndrome to emotion recognition and empathy. In: A. Freitas-Magalhães (Ed.), ‘Emotional Expression: The Brain and the Face’ (V. III, Second Series), University of Fernando Pessoa Press, Oporto: pp. 75-97.

Williams, A. C. D. C. (2002). Facial expression of pain: an evolutionary account. Behavioral and Brain Sciences, 25(4), 439-455.

First-Person Neuroscience of Pain: Puzzles, Methods and Data

Music and human imitation

Apparently, human beings who wish to be only happy in life, are the same people who the next moment willingly listen to sad music and make themselves become sad. Why?

Does such a person think to himself: ‘This music is sad; I want to be sad; therefore, I listen to this music to be sad’? No, of course not. A person in this situation does not need to inform himself why he acts as he does. In addition, there is typically no such thought process preceeding a musical experience, during it, or following it. It is not characteristic of listening to or performing music to bethink to oneself such motivating factors as if the experience must be accompanied by a spoken soliloquy to make sense. Isn’t this true of routine human behaviours generally? Second, such a thought process cannot inform me in the same way as it informs you. For you, it is information. For me, a point of emphasis? Let me develop this last idea.

A human being may talk to himself inwardly while the music is on, but not to give himself information. Then, what is the meaning of this internal monologue, and how should it be described? The words used may convey the the level of interest in the music (a melody, a recurring theme, how the trombones sound, etc), and may function more like an exclamation than a descriptive statement. Certainly, one can imagine this occurring in upbeat or joyful music. In sad or melancholic music, self-talk is expressive of the sad quality perceived in the music. Again, it stresses what is noteworthy in the music. The music merits attention. It really did amaze me.

We want to be sad for a time; at least, sad for as long as the music lasts. The listener follows the sad music as he follows the sad face which changes expression. Music is like a familiar face, and we resonate with it in understanding as long as we are interested. The music plays on, the face moves predictably. On occasion, the music is too predictable. So, we stop it in mid-flight, like an uncomfortable human conversation, and move to something else. Typically, however, the sad piece of music I know completely by heart is a rewarding experience as though I listen to it for the very first time. It really is like empathy for a fellow human being, or parity in facial expressions exchanged between close friends during conversation. Now – is your closest friend entirely predictable? No. Even deep rapport between human beings harbours dark regions. I do not even wish to say that we aim in music listening to recreate sadness, happiness, or any such fleeting emotional response. What human beings do, I believe, is empathize with what is perceived in the music as expressive of our shared human interests, wants, desires, hopes, etc. We find it there in music, and return to it habitually, just as we find it in the faces of other people.