The @#$% 2010 Ig Nobel Peace Prize: Pain files 1

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The 2010 Ig Nobel Prizes were awarded recently by the Annals of Improbable Science, and a paper I read a while ago and wanted to comment on won the Ig Nobel for Peace! (By the way, comment on, not because I thought it was Ig Nobel-esque, but because it was actually relevant to my work — what does that say about my research!?)! Congratulations to Richard Stephens, John Atkins, and Andrew Kingston for the prize, awarded for their paper, ‘Swearing as a Response to Pain,’ in Neuroreport. I’ll blog specifically about their article below the fold.

Apparently, recipients didn’t get to try on bra-gas masks this year like at last year’s Ig Nobels 2009, but I’m sure much fun was had. Paper plane throwing, operatic songs about tooth bacteria, bat porn (well, they didn’t actually get to show the bat porn…), a little girl telling award winners she was bored to stop them from giving overly-long acceptance speeches… sounds like something for the whole family.

There are a number of great-looking winners, including a brilliant engineering team who used remote-controlled toy helicopters to breathalyze whales to better sample their snot (yeah, ‘why didn’t *I* think of that?!,’ you’re saying…), a game-theory demonstration that hierarchical firms were better off simply promoting people randomly, a demonstration that oil and water in fact do mix together (the award was shared with BP for demonstrating the same effect on a much larger scale), and a too-long-ignored, forty-year-old contribution to epidemiology which pointed out the dangers of beards on microbiologists.

For more on all the papers that won, check out Christie Wilcox’s prize-by-prize rundown with links or a great discussion by Jeff Hecht at New Scientist. If you wanted to watch the ceremony, it was streamed, but I haven’t found it archived yet; I’m sure it will eventually be available at the Annals of Improbable Research YouTube channel.


Pain and swearing

In their paper in Neuroreport, Richard Stephens, John Atkins, and Andrew Kingston discuss research in which they tested whether swearing really helped pain resistance. They hypothesized, like good emotionally repressive scientists, that swearing was a maladaptive response to pain, exacerbating the pain by generating additional ‘negative thoughts.’ They first asked experimental subjects to list five words that people might say if they struck their thumb with a hammer (controls were asked for five descriptors for a table). Subjects then did a cold pressor test, in which they held an open hand in iced water; both groups were instructed to repeat a word from their list, seeing how long they could keep their hands immersed.

The test subjects who swore kept their hands in the water longer than the folks who muttered about tables, and reported less perceived pain from the cold pressor than did the control subjects, with some variation: ‘Although both sexes experienced a reduction in perceived pain in the swearing condition, females did so to a greater extent’ (1057). The table below shows some of the key results: not only did the swearing subjects hold their hands in longer, they experienced less pain according to their reports, and their heart rates spiked higher.

The data not only disproved the researchers’ hypothesis (that swearing was maladaptive), it also revealed interesting sex differences between men and women, and the link to increased heart rate, which I think is especially interesting. Stephens and co-authors suggest that the increased heart rate while swearing may indicate a heightened emotional response like fear or aggression that downward regulates experiences of pain through ‘classic fight or flight mechanisms’ (1060).

As the researchers conclude:

This study has shown that, under certain conditions, swearing produces a hypoalgesic effect. Swearing may have induced a fight or flight response and we speculate on a role for aggression in this. In addition swearing nullified the link between fear of pain and pain perception. (1060)

Minor issues

Of course, the research did confront the occasional outlier. After they asked all the experimental subjects to list the words a person would say when hit on the thumb with a hammer, ‘One participant was excluded because none of their suggested words were swear words’ (1057). Unfortunately, no footnote reveals what precisely this outlier thought a person would say if hit on the thumb with a hammer. (‘Rats’? ‘Fudge’? ‘Sugar’? ‘Fiddlesticks’?)

Trying to create a careful control for the swearing/non-swearing conditions also created some issues, forcing a control that meant that some of the cathartic value of swearing had to be sacrificed: ‘Participants were asked to maintain a similar pace and volume of word recital across conditions’ (1056). Subjects were also required to repeat the same word over and over again — anyone who swears like a stuck sailor knows that part of the relief comes from the stream of changing epithets shouted at the top of one’s lungs, the profane creativity of the novel compound vulgarity, ‘@#$%! *&^%-*&^%! $@*^^&^$#@! &^%$#@@!’ (although sometimes you just can’t manage anything more interesting than repeating the same choice epithet).

Vocal volume especially would seem to be an issue if the researchers are postulating that the analgesic mechanism was an effect of aggression downward mediating perceptions of pain. I’m not sure that swearing relatively quietly and at a measured pace would actually provoke a strong emotional dynamic, no matter what sort of dynamic you’re expecting.

Thinking through the dynamic of vulgar analgesia

The research is fun, of course, but I find it particularly intriguing because the experiment, in its own way, illuminates some of the neurological complexity underlying pain, including the possibility that top-down mechanisms— like coping techniques, conscious thought, or learned emotional responses—might modulate our experience. As a number of neuropsychologists have argued (and demonstrated empirically), pain involves a constellation of interacting neural mechanisms, some of them more conscious than others, rather than a single ‘pain centre’ (see Apkarian et al., 2005). Donald Price (2000), for example, reviews the relations among pain, feelings of ‘unpleasantness’, and ‘secondary pain affect,’ such as the emotional feelings of long-term worry or ‘suffering’ that may accompany the unpleasantness. As Price writes (2000: 1769):

Psychophysical studies demonstrate that pain sensation and pain unpleasantness represent two distinct dimensions of pain that demonstrate reliably different relations to nociceptive stimulus intensity and are separately influenced by various psychological factors.

One of the clearest examples of the way that pain stimulus can be, to a limited degree, decoupled from sensations of unpleasantness is that subjects reliably report diminished sensations of pain if told that a pain is transitory and will produce no lasting effect and enhance reports of suffering if they believe that a pain will be long-lasting.

In some cases, the decoupling can produce a quite profound gulf between pain sensation and pain unpleasantness; in a study at a Forward Hospital in World War II, military surgeon Dr. Henry Beecher found that three-quarters of severely wounded men did not experience such pain that they asked for pain relief, even when they were reminded that it was available (1946: 99). Beecher was surprised by the result, pointing out that even patients suffering severe wounds to the chest and head and broken bones, caused a minority of sufferers to report significant subjective pain.

In addition, the relation between unpleasantness and secondary pain affect – suffering or distress – also varies. A study of ethnic differences in pain perception, for example, conducted by Zborowski (1952), found that different ethnic groups felt varying levels of distress in relation to similar reports of pain, some groups worrying extensively about the future implications of pain and others curtailing expression of suffering. Price (2000: 1769) summarizes this research:

Pain is often experienced not only as a threat to the present state of one’s body, comfort, or activity but also to one’s future well-being and life in general. The perceived implications that present distress holds for future well- being and functioning support the link between pain unpleasantness and secondary pain affect.

Price (2000: 1770) points specifically to studies of relationships between personality traits like neuroticism and different relations between unpleasantness and secondary pain affects. (The short version is that neurotics don’t feel much more pain, but they report much greater suffering or distress, secondary affects.)

Price (2000: 1770) discusses how the complex sequential chain of pain sensation-unpleasantness-secondary affect can be at least partially related to the fact that there are several ascending spinal pathways for pain perception that project to a number of brainstem, subcortical and even cortical brain areas. Apkarian and colleagues (2005) also review how neuroimaging research has over-turned the idea that pain was largely subcortical; their meta-analysis revealed that, across a wide range of imaging studies, a handful of somatosensory, limbic and associative brain regions were reliably involved in pain, with some variation but overlap, even between chronic and acute pain.

Some pathways are quite direct, running directly from the top of the spine in the dorsal cord to the limbic and brainstem areas responsible for registering pain like the anterior cingulate and the insular cortex. Other, less direct chains of upward-bound sensation route instead through a number of brain regions including the somatosensory cortex and the insular cortex, amygdala, perirhinal cortex, and hippocampus (see Apkarian et al. 2005, for a discussion of the temporal pattern of pain reactions).

Price suggests that there might be several pain-related structures, including a fast, direct route from the spine’s dorsal horn to such structures as the ‘medullary and midbrain reticular formation nuclei, deep layers of the superior colliculus, central gray, amygdala, hypothalamus, and specific medial thalamic nuclei’ (2000: 1771). These structures could cue rudimentary reactions such as the activation of the autonomic system, heightened arousal, attention orientation, and even the first stages of fear.

A second mechanism, longer and slower, would bring into play the somatosensory cortex and other higher regions of the brain, especially in the posterior parietal and insular regions, placing the pain into context and evaluating its intensity and significance significance for injury to the body. Studies that explore the unfolding of pain suggest that this secondary mechanism might be responsible for the unpleasantness of pain. Damage to this second pain mechanism might render pain sensations emotionally ambivalent, such as when patients with lesions to the insular cortex develop ‘pain asymbolia,’ or an indifference to painful sensations. Although they ‘feel’ pain, they fail to demonstrate the withdrawal response from painful sensation and don’t seem to appreciate the potential damage to their own tissue (see Price for a much fuller review and references to the original sources, if you’re especially interested).

In particular, Price (2000: 1771) highlights the variety in responses of the anterior cingulate cortex (ACC), hypothesizing that it might have a ‘complex pivotal role in interrelating attentional and evaluative functions with that of establishing emotional valence and response priorities.’ The ACC would continue to be involved as pain lasted, as more information, affect, anticipation of future consequences, and other input from brain regions continued to cycle into the ongoing pain perception, creating different trajectories depending on issues like whether a patient ‘catastrophizes’ or how the consequences of the pain were evaluated. As Price writes:

Pain unpleasantness endured over time engages prefrontal cortical areas involved in reflection and rumination over the future implications of a persistent pain condition. The ACC may serve this function by coordinating somato-sensory features of pain with prefrontal cerebral mechanisms involved in attaching significance and long-term implications to pain, a function associated with secondary pain affect. Thus, ACC may be a region that coordinates inputs from parietal areas involved in perception of bodily threat with frontal cortical areas involved in plans and response priorities for pain-related behavior.

In other words, although the pathways eventually converge, they get to their destination through different routes, some of which take in cortical areas that can be affected by context, learning, and other factors. And different types of pains provoke some differences in various parts of the pain-related network of regions, such as different locations in the somatosensory cortex.

Pain is especially important for neuroanthropology because the sensation brings together what are arguably some of the most evolutionarily simple functions of a nervous system (recoil from noxious stimuli or protect damaged tissue) with layers of perceptual and interpretive complexity, overlaid and interlocked in the nervous system. As Price reviews, the pain ‘system’ runs both serially and parallel, producing by an accumulation of automatic, sensory and evaluative inputs that shift over time. Pain is not just a sensation, but a trajectory through sensations, and not everyone takes precisely the same trajectory through these sensations, just as you don’t feel the same pain in every circumstance.

Because pain is arguably such a neurologically ‘primitive’ sensation, one that even the simplest nervous systems would have on some basic level (although not necessarily in any phenomenological sense), the complicated unfolding of pain in humans is a great way to show that even the most ‘basic’ human neurological processes get complicated by evolutionarily-younger processes, such as evaluation and rumination.

Alright, but what about the @#$% swearing?

I know what you’re thinking at this point: okay, but what does this have to do with swearing and pain? One interesting wrinkle in the data provided by Stephens and collaborators was the interaction between ‘fear of pain’ and swearing:

Fear of pain predicted perceived pain in the nonswearing condition, consistent with previous research…. However, fear of pain did not predict perceived pain in the swearing condition. This interesting finding suggests that a part of the hypoalgesic effect of swearing may be because of the amelioration of that part of increased pain perception that is brought about by fear of pain, although further research would be required to investigate this further. (2009: 1059)

Part of this is hardly surprising; fear is likely to be part of the tangle of emotions around pain, so greater fear of pain would likely correlate with greater perceived pain, under normal conditions. Let’s say that feeling fear is part of an experiential package that we call ‘pain’ that has to do with the system Price describes; if you’re more likely to be afraid, and are especially afraid of pain, this turns up that ‘portion’ of the whole pain experience for you.

However, ‘fear of pain’ is a precondition of experiencing pain. In other words, it’s not just a different reaction in the neural system triggered by pain; ‘fear of pain’ is an anticipatory neural state or ‘pre-primary affect,’ you might call it, something that the sufferer brings to the pain experience, to contrast it with the idea of ‘secondary affects’ that Price discusses as the third stage in a pain sequence. Before the pain sensation, the person might have a prior, longer stage of pain pre-perception that helps to set up how the three stages Price describes will unfold.

Those who read Neuroanthropology frequently know that I’m interested in this kind of ‘enculturation’ of perception a lot, that I think affective, physiological and perceptual conditioning are under-discussed in anthropological reflection on the nature of ‘culture’ itself. (By the way, I think Price would not be adverse to this suggestion, as he’s clearly allowing for learning in the relation between stages two and three, between ‘unpleasantness’ and ‘suffering,’ but I just want to highlight that factors that come into play in stage three of ‘secondary affect’ are actually in place prior to the experience.)

But the interesting part of Stephens and colleagues research is that swearing specifically seems to confound the anticipatory part of the ‘pain’ experience; the analgesic effect of pain is greatest where the prior pain conditioning would otherwise add the most to the suffering of the subject. Something about swearing can neutralize (or at least diminish) part of the experience of being in pain by disproportionately affecting the sufferer’s pre-experiential conditioning. If you’re not as afraid, swearing doesn’t do as much for you (in addition, if you don’t swear much, you also get a bigger analgesic jolt, as we’ll get to).

Stephens, Atkins, and Kingston seek to explain the analgesic effect by referring to Steven Pinker’s (2007:334) suggestion that ‘swearing aloud… taps the deeper and older parts of the brain,’ based in parts on the resilience of swearing in cases where brain damage leads to otherwise-devastating aphasia (see, for example, Van Lancker and Cummings 1999). That is, Pinker cites cases where severe damage to the cortex of the brain’s left hemisphere wipes out other language abilities but leaves swearing and other forms of formulaic speech or interjection intact.

But just knowing that swearing is a form of formulaic speech, and that formulaic speech is less vulnerable to aphasia in cortical injury, doesn’t really explain why swearing diminishes fear specifically. There’s lots of behaviours that ‘tap the deeper and older parts of the brain’ that don’t cause analgesia (in fact, arguably, virtually every brain function probably taps some ‘deeper and older parts of the brain,’ but I don’t want to get into that here). The authors instead turn to work on ‘negative affect’ to try to understand the analgesia of swearing:

The influence of negative affect on pain has been well researched although with inconsistent results: negative emotions produce hypoalgesia in some studies, but the opposite effect of hyperalgesia in others…. Rhudy and Meagher [2000, 2003] suggest that hypoalgesia occurs only if the negative emotion experienced in the context of a painful stimulus is sufficiently strongly felt to cause fear rather than anxiety. For instance, they observed a stress-induced hypoalgesic response to radiant heat pain after fear-eliciting electric shocks [2000, 2003]. It was suggested that fear, being an immediate alarm reaction to present threat, leads to a fight or flight response including heart rate acceleration, whereas anxiety, being a future-oriented emotion, is characterized by a less-activated state of hypervigilance and somatic tension. Neurobiologically, fear may cause amygdala activation of descending pain inhibitory systems that regulate the flow of incoming nociceptive signals [2000, 2003].

For me, part of the confusion is the concept of ‘negative affect’ itself, which seems to draw together into a single category what are neurodynamically quite different phenomena. Although Stephens and his collaborators try to distinguish fear from anxiety, hoping that this can isolate differences, this explanation doesn’t seem wholly satisfying to me. Possibly, there’s greater variety even than this (no guarantee, for example, that the English-language distinctions in emotion capture all the possible variations in the neurological dynamics that we might call ‘fear’ and related experiences). In addition, there are likely individual differences, threshold effects (too much fear, and the neurological dynamics might suddenly shift, causing shock or withdrawal, for example, or panic).

I’m also not convinced that the recourse to a ‘fight or flight’ response is terribly helpful, although certainly arousal is involved, because the neurodynamics of profanity analgesia might be precisely the division of ‘flight’ from ‘fight.’ That is, swearing in response to pain might be diverting arousal, at least partially, into an aggressive response that either confounds part of the ongoing pain dynamic or draws off some of the stimulus into a separate dynamic. Aggression and fear are often closely linked, and one can fluctuate suddenly between them, but they also produce quite different behaviour patterns in some respect, so firing up one’s aggression might be a good way to inhibit some of the secondary affects connected to the pain experience or reroute arousal through a different chain of neurological events. Evolutionarily, anger or rage in the face of pain might be an excellent way to, at least temporarily, keep a person from succumbing to pain with inactivity.

Perhaps the simplest explanation for vulgar analgesia, though, is a mechanism like distracted attention. Distraction can decrease pain perception (see Apkarian et al. 2005: 472-473). Distracted attention may actively inhibit upward transmission of noxious stimulation from the spinal cord or it may simply cause a modification in the cortical pattern of pain perception. (For example, hypnosis seems to leave the inbound stimulation normal even though hypnotized subjects can report much less pain sensation from hypnotic suggestion.)

Because pain itself is a complex sensation, involving more than just the actual physical sensation, such as additional sensations and secondary emotions provoked by the sensation, the overall sense of ‘pain’ might be reduced by confounding some part of the overall sensory dynamic. If fear is part of the ‘pain’ constellation, and swearing somehow undermines the compounding of fear (the whole discussion in the article of ‘catastrophizing,’ for example, is relevant), then it’s not so much that swearing diminishes total pain, but that it specifically undermines one facet of what is experienced as pain.

Swearing as a cultural technique

The final interesting wrinkle to this research for today is that swearing itself is not wholly an innate or instinctual behaviour; if it were, we’d be able to better understand swearing in foreign languages (although we can sometimes get a basic sense of what someone is carrying on about, even if we don’t understand the words). We all know that swearing varies tremendously between individuals, some of them doing it a lot more than others and some cultural contexts encourage the development of one’s profane capacities more than others. The variation occurs alongside the (almost) universal use of profanity, even the suggestion that expletives may constitute, linguistically and neurologically, a special class of words (see Van Lancker and Cummings 1999: 86).

Asserting this variation is not to deny the point that Pinker makes, that swearing engages evolutionarily old parts of the brain. In fact, most neural phenomena likely do. But the ways in which we habitually engage these parts of the brain affects how they can perform (as studies of Buddhist monks and compassion suggest – yes, I’m saying that swearing is a self-making technique, like mindfulness meditation…). The enculturation doesn’t simply affect the cortex as most neural functions bring together cortical and subcortical resources. Working these circuits affect how they perform.

Often, with neurological systems, however, they respond to increased use by becoming better refined and able to produce their outcome. This is not the case with vulgar analgesia. According to Jeff Hecht (New Scientist): ‘Stephens revealed groundbreaking new findings at the ceremony: people who don’t normally swear much benefit more than habitual potty-mouths. “Swearing is useful, but don’t overdo it,” he advised.’

Unlike other practices which become more expert with repeated use, swearing becomes less powerful, proving less and less able to mitigate pain or demanding that the individual up the ante, I suppose. And could we conclude with any better advice than this? Don’t swear too much because, when you need it, it’ll be a lot more effective if you save it for special occasions.

Also makes me wonder about that excluded subject who didn’t list a swear word – what kind of analgesic boost would that person have gotten in the cold pressor test!

For more on the 2010 Ignobels:

Jeff Hecht has a great rundown, Best of the Ig Nobel prizes 2010, at New Scientist. Some really nice discussion of the ceremonies as well as the winners.

The Ig Nobels have been announced! by Christie Wilcox at Observations of a Nerd. With lots of links to the papers.

The 2010 Ig Nobel Award Winners Announced by Maggie Koerth-Baker at BoingBoing.

Ig Nobel awards go to slime mould and fruity bats at the Guardian, written by Ian Sample.

More on swearing and pain tolerance:

Swearing can reduce your pain, by Jacob Aron of Just a Theory.

http://scientopia.org/blogs/scicurious/2010/10/15/friday-weird-science-that-motherfking-hurts/

Friday Weird Science: That MotherF**king HURTS!!! by Scicurious at Neurotic Physiology.

Swearing increases pain tolerance, by the mighty Mo at Neurophilosophy (a serial offender here at Neuroanthropology).

References:

Apkarian, A., Bushnell, M., Treede, R., & Zubieta, J. (2005). Human brain mechanisms of pain perception and regulation in health and disease European Journal of Pain, 9 (4), 463-484 DOI: 10.1016/j.ejpain.2004.11.001

BEECHER, H. (1946). PAIN IN MEN WOUNDED IN BATTLE Annals of Surgery, 123 (1), 96-105 DOI: 10.1097/00000658-194601000-00008

Pinker, Steven. 2007. The Stuff of Thought: Language as a Window into Human Nature. New York: Viking.

Price, D. (2000). Psychological and Neural Mechanisms of the Affective Dimension of Pain Science, 288 (5472), 1769-1772 DOI: 10.1126/science.288.5472.1769

Rhudy, Jamie L., and Mary W. Meagher. 2003. ‘Negative affect: effects on an evaluative measure of human pain.’ Pain 104: 617–626.

Rhudy, Jamie L., and Mary W. Meagher. 2000. ‘Fear and anxiety: divergent effects on human pain thresholds.’ Pain 84: 65–75.

Stephens, R., Atkins, J., & Kingston, A. (2009). Swearing as a response to pain NeuroReport DOI: 10.1097/WNR.0b013e32832e64b1

Van Lancker, D. (1999). Expletives: neurolinguistic and neurobehavioral perspectives on swearing Brain Research Reviews, 31 (1), 83-104 DOI: 10.1016/S0165-0173(99)00060-0

Zborowski, M. 1952. Cultural components in response to pain. Journal of Social Issues 8: 15-35.

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