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”.
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.
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.
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.
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.
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.
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.
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.
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.