Pain is Contagious
Nearly all that happens in your body is a result of chemicals interacting. From your heartbeat powered by sodium, to the sense of touch from our nerves, or even feeling uneasy on a creepy night, it all happens because simple and complex chemicals make it so. Chemistry is more than compounds in our food that we can’t pronounce – chemicals make us and change us.
We also share them with those around us in everyday interactions, thereby changing other people as well. When you come across a person with a strong odor, not only do you detect it, you may have a reaction, and whether it’s pity, disgust, puzzlement, or anything else, your body responds to the experience by altering your own chemical balance. This might in turn cause you to treat the person accordingly. If instead you met someone with a pleasant scent about them, your body would tune to produce chemicals associated with joy, arousal, or other positive feelings. Simply looking at someone also evokes lots of chemical responses inside your body, and the same is true when people see you.
Whether they are fair or not, these interactions are easy to understand. Now think, what if our bodies release chemicals that don’t have a particular odor so we can’t easily detect them, but they affect us anyway? Spoiling the suspense: they do, and you don’t really have a say in how it changes your behavior. Humanity is essentially a gigantic web of interactions fueled largely through decisions made by our subconscious long before we start thinking active thoughts. You feel the vibe with your date because your body made that decision, and now your mind will think thoughts accordingly.
Experiments with people show that we are affected by other people’s stress. Experiments with rodents show convincingly that being around someone in pain decreases the tolerance for pain in healthy animals. Speaking beyond emotion and empathy, the suffering of others around you may well increase your own discomfort in a real and practical sense.
One of several experiments done went like this: first there was a little pilot test where a healthy mouse was placed with a cage mate that was experiencing discomfort, and the two got to interact for one hour. Afterwards, the healthy mouse was tested for its response to stimulation which showed it had become sensitive. This lasted a couple of hours.
We already knew from other experiments done by different teams that simply seeing or hearing from cage mates in pain during an interaction can make healthy mice more sensitive, so our test went as expected. Now we wanted to know if animals could “smell” to feel the pain from each other. A good place to start was the bedding material where mice in discomfort rest. Anywhere a mouse sleeps will contain a bit of pee, poop, and all sorts of secretions from glands – a buffet of chemicals from their body with or without scent. We let a healthy mouse sniff this bedding from a distance for an hour, and it also began to show sensitivity that lasted a couple of hours.
Longer exposure over weeks caused an ongoing and worsening sensitivity in mice that were completely healthy otherwise. We even used an advanced chemical sniffer to test the beds of both mice to see which chemicals were different and maybe responsible for the effect, but there were simply too many strong candidates for the scope of our work. You hear lots about famous behavior chemicals like dopamine, when in reality there are thousands of different ones that interact to make you do stuff.
Humans don’t have noses that are as good as mice, but we still receive chemicals through them. If we speculate that pain, like stress, is also directly contagious between us, consider the cascading effect. You feel more miserable, which makes those around you feel more miserable, and on it goes. Dealing with work and life is more daunting when you’re not well, and you don’t have to be sick with fever, coughing, or sneezing, even mild discomfort has a negative impact on your life.
Perhaps the reason why Denmark and other countries are so often found to have happy citizens is because they fight against this cycle of misery by offering good healthcare to all their people. First they don’t stress over doctors or tests to the same degree as someone struggling to pay, and secondly there are many fewer who go without treatment. For each person improving their health, the experience of those around them also improves in a real, physical sense, and they may not even realize it. There isn’t a big neon sign announcing our level of comfort, there are just chemicals doing the work nature ordained, mostly without our knowledge.
Should we throw all those who suffer into a volcano and leave only the healthy ones alive so they won’t be affected? Well, no, because it’s morally wrong, but it also creates a stressed and miserable society where everyone is afraid of being thrown into a volcano, and people will hide their pain which means the problem will still affect you anyway. The easier solution is to make sure people have useful healthcare and the support to overcome their problems.
That we are sharing molecules with each other is old knowledge, yet we continue to gain data about what this means. We can use it improve our happiness in a natural way by helping each other.
Behind the Article
For this article I worked with Mick René Hansen, a New York writer. We first met in Portland where I read an early manuscript of his first book, realizing we both examine the human condition from each of our avenues. For my research on empathy pain, it made sense to get his perspective on what this discovery might mean for human society, and use his writer’s touch to connect with a wider audience.
Citations
Mice feel more pain after smelling others in pain
European Journal of Pain (2023), 28, 578 – 598
Yangmiao Zhang, Wentai Luo, Mary Heinricher, and Andrey Ryabinin
Social transfer of pain in mice
Science Advances (2016), 2, 10, e1600855
Monique Smith, Caroline Hostetler, Mary Heinricher, and Andrey Ryabinin
Stress can transfer between humans
Psychoneuroendocrinology (2019), 105, 138 – 146
Veronika Engert, Roman Linz, and Joshua Grant
Mice feel more pain after seeing others in pain
Science (2006), 312 (5782), 1967 – 1970
Dale Langford, Sara Crager, Zarrar Shehzad, Shad Smith, Susana Sotocinal, Jeremy Levenstadt, Mona Chanda, Daniel Levitin, and others