Sometimes it may be necessary to learn how to distinguish real pain expressions from deceptive ones. Not only does this aid in deception detection, but it can also help further our understanding of the pain expression, itself!

In order to address this question, a team of researchers from the University of California, San Diego, and the University of Toronto ran two experiments trying to see if observers could reliably distinguish faked pain from real pain, including one that implemented this analysis with computer learning software.

Initially, the treatment conditions had to be determined. This involved recruiting an admittedly small number of 26 participants who were asked to be recorded under three conditions. In addition to a baseline where no pain expression was solicited, they were also induced to present a genuine or faked pain expression.

This was stimulated by having each participant submerge their arm in water, either at a lukewarm or freezing cold temperature. When the water was lukewarm, they were asked to act as though it was cold and painful, while the freezing cold water reliably generated the desired expression of genuine pain. These images were evaluated first by a new set of 170 volunteers but also by an automated system which tried to analyze facial expressions without human interference.

In the first of these, the new volunteers were exposed to video clips of the genuine and fake pain expressions and asked to distinguish them. Interestingly, their success was almost entirely random, at about 52 percent accuracy. Notably, they had no prior experience making these distinctions.

While this first study indicates that people without training can’t seem to distinguish real pain from deception, they also cite previous research finding that even clinicians do not perform much better.

However, machine algorithms may make up for our human failures in this regard. Each clip was broken down into a set of discrete frames, allowing a computer to look at individual stills extracted from the videos. These were then paired with the previously discussed FACS software which codes images based on a preexisting series of templates representing typical facial expressions, in order to see if the software could also distinguish between faked and genuine pain expressions.

While the software was able to reliably distinguish with an accuracy of over 70 percent, what is more interesting is exactly what components of the facial expression were most useful in doing so. For instance, faked expressions relied on a lowered brow which was not present in genuine instances of pain. Similarly, raised cheeks and fearful brows were also reliable indicators of deception.

This study shows us a couple of pretty interesting things. First, human efforts alone in distinguishing real and fake expressions were prohibitively inaccurate, at least for untrained participants. Second, computer methods were much more accurate. This is perhaps the most interesting finding, given the potential to feed any videotaped facial expression into this software to determine whether the subject is lying.

Importantly, this blog is written as part of Pain Awareness Month. While many people, especially those with chronic illnesses, are frequently accused of faking their pain, this is not an effort to exacerbate that. Instead, it shows how unreliably doctors determine whether patients are telling the truth, often to the patients’ detriment, and it helps show the way forward to a more reliable approach.

Moreover, we have much to learn in how to accurately detect deception. There is no reason that similar approaches cannot be applied to fear or sadness, and while you might be inaccurate untrained, there is a reason we offer a robust training program in deception detection!

It seems like a pretty straightforward question, but recognizing signs of pain in other people can be tricky.

Not only is this an interesting intellectual question, but the ability to recognize pain can literally have life or death consequences. Many doctors are tasked with diagnosing a problem based only on the expression of pain by the patient, and sometimes the failure to accurately recognize pain leads to misdiagnosis, with severe implications. This is especially relevant with young infants, cognitively impaired patients, or those in post-surgery recovery.

It is by reminding us of those stakes that Drs. Prkachin and Craig ground their landmark 1995 study on the communication and interpretation of pain in facial expressions. While they develop a framework of expression reading for health-care workers, it can also be incredibly useful for anyone who wants to better recognize pain in other people.

Pain can be understood as occurring in “episodes” where a painful stimulus is created in one section of body tissue. This is often acute but can also be chronic, such as with a compressed nerve. The nervous system then “encodes” the episode, automatically leading to subtle changes in facial expressions.

Once encoded, the pain can then be broadcast through more overt expressions, but this is not always the case as people often attempt to conceal their pain from others. Researchers have tried to systematize the many  aspects of the pain expression into the Facial Action Coding System or FACS, consisting of 46 unique configurations.

The most reliable of these indicators is the tightening of muscles around the eye, leading to a squint and rise in the cheek. This is accompanied by wrinkling in the bridge of the nose, the rise of the upper lip, and even the outright closure of the eyes. If readers attempt to simulate these indicators, the resulting grimace should feel quite familiar.

The FACS model has even been adapted to infants, though they often present pain in distinctive ways. However, by adapting the model to newborns and other babies, medical professionals have also been able to extend their insights to recognizing subtle signs of pain in those who can’t verbally express it.

As we discussed last week, the pain expression is a unique one.  This may seem to conflict with the notion that FACS identified so many configurations, but Drs. Prkachin and Craig emphasize the notion of a “prototypical” expression. There is something in common to various instances of the expression, despite variations in the pain or in the individual.

Finally, all of this must confront the sociocultural factors that encourage us to hide or modulate our experience of pain. While practitioners can attempt to situate the individual within their culture, this approach can often be misleading.

It is up to us when attempting to recognize pain to look closely for these FACS indicators while also keeping in mind the extent to which an individual could be moderating their expression. It is important to note, however, that overall we tend to underestimate other people’s pain.

While there are a lot of ways to get better at reading people, reading pain is especially tricky. Please keep following our blog this month as we delve even further into the subject in recognition of Pain Awareness Month.

We have written a great deal about recognizing basic emotions, but what about pain?

Certainly, pain has many similarities with other basic emotions, given its deep evolutionary basis and the universal nature of the pain experience. However, further attention must be paid to how we recognize expressions of pain as opposed to those of other emotions. The ability to recognize when people are in pain is incredibly important in many contexts, and Humintell would like to focus attention on this field as part of September’s Pain Awareness Month.

In a 2017 study, Dr. Daniela Simon of Humboldt University of Berlin and a team of Canadian and British researchers sought to better understand pain recognition by exposing participants to a series of film clips of faces demonstrating either pain or basic emotions. Participants were asked to evaluate these clips and report what emotion was being displayed, in an effort to see if pain is consistently distinguished from other emotions.

Theoretically, Dr. Simon and her team’s research was grounded in the evolutionary history of facial expressions, seeing painful expressions as an effort to communicate pain to onlookers, either to warn them or to ask for help. This fits with our previous blogs on research connecting basic emotions and their related expressions to evolutionary purposes.

Moreover, research in neurobiology has found that pain and its expression is a distinctive and specific neurological event. They contend that both the evolutionary and neurological background of pain fail to give a full picture without exploring how pain is recognized by onlookers.

In order to assess this experimentally, actors were hired to simulate basic emotions and pain expressions, with the resulting videos compared by the researchers to accepted images of the expressions in question. This helped ensure accuracy while also using a dynamic video as opposed to a static photograph.

Participants were asked not only to identify the expression displayed but also to rate the intensity of the emotion and how relaxed or comfortable the displayed person was. This helped delve further than just identifying emotions but also explored interplay between them, such as whether fear and pain tend to coincide, for instance.

Overall, participants regularly distinguished between basic emotions and pain. There was some overlap, such as between fear and pain and between fear and surprise. Moreover, many pain expressions showed disgust, or even surprise, to varying extents. Finally, participants tended to accurately identify pleasant emotions, such as happiness, and unpleasant expressions, such as pain, anger, or fear.

Not only was this study able to make strides in better understanding the recognition of pain, as contrasted to basic emotions, but it helped further develop a prototypical measurement of the pain expression, which is invaluable for further research on recognizing pain.

While understanding how to read people’s emotions is critical, understanding when people are in pain is also a helpful way of communicating with them, both in professional and perhaps especially in personal contexts.