Why Does Medicine Taste So Gross?

Source: Flickr/rult57

Imagine you are a member of a preliterate tribe on the way to invade an enemy camp. Then someone says, “Oh, man. I have a thorn in my foot. I have to turn back. Sorry guys; I can’t join the fight.” You might be skeptical. But if you both know that when he turns back, a doctor is likely to amputate his foot, you’ll have more reason to believe him.

A fascinating paper in Evolutionary Human Sciences led by Mícheál de Barra uses evolutionary game theory and mathematical modeling to describe why aversive and harmful medical treatments have been so pervasive throughout history.

The idea is that unpleasant or aversive treatments (e.g., drilling holes into skulls, amputating limbs, ingesting noxious substances, bloodletting, leeches) have been ways of making sure people are actually sick or injured. They are social technologies to make faking it more costly.

Among large-bodied mammals, humans are especially pathetic, weak, and vulnerable. We’ve had to rely on one another to survive. We are by far the most social among mammals, as well as the most physically vulnerable. Caregiving has been important for humans.

But caregiving can be exploited by deception. The range of conditions for which recipients should request care is much larger than the range of conditions for which donors should be willing to grant care.

Plainly, I might want you to care for me when I’m feeling a bit under the weather. But you might only be willing to help me if you believe I’m truly incapacitated. This gives me an incentive to exaggerate my symptoms. It allows me to save my energy while getting you to spend yours.

“There is good evidence,” the authors of the paper write, “that people harness this ambiguity in order to access caregiving which the donor would not be willing to offer had they complete information about the recipient’s disease state.”

Furthermore, it’s not uncommon for people to pretend to have illnesses or injuries.

In one survey, 30 percent of personal injury cases and 33 percent of disability and worker’s compensation cases were judged to involve deception or exaggeration. Every year, billions of dollars are lost from fraudulent claims made to insurance companies, governmental aid agencies, or charities by people who pretend to be victims.

People lie about many things. Some lie about being a victim if they can obtain an advantage by doing so.

Imagine that every time someone claimed to be ill, others unfailingly and unquestionably provided care to them. The person receives care, sympathy, kindness, food, etc., as well as an excuse to forgo their usual duties to contribute to their community. Others would reasonably respond to this state of affairs by claiming to be ill. They receive benefits while not having to pay any cost. Very quickly, there would be a community of layabouts — unless it is widely known that the treatment for being ill is unpleasant. Then people would only claim illness if they were truly unwell.

Relatedly, research has found that people who score high on the "dark triad" (narcissism, psychopathy, and Machiavellianism) are especially likely to engage in victim signaling. In other words, people with “dark” personalities are more likely to feign victimhood to extract rewards. Aversive medical treatments may have arisen to prevent such people from exploiting the kindness of others.

Interestingly, parents have been known to use a version of “aversive treatment.” Sometimes kids pretend to be sick to get out of going to school. Skeptical parents react by calling the kid’s bluff: “Oh, you’re sick, then I’ll schedule a doctor’s appointment.” Kids, who often hate visiting doctors, relent.

Juvenile animals also fake pain to obtain rewards. In his book on Machiavellianism, the psychology professor Tamás Bereczkei tells the story of a young male baboon who repeatedly duped adult group members. For example, the little male would see an older female digging up some nutritious roots. Then he would suddenly cry out, as if in pain. The young male's mother would then appear and think the older female was harassing her son. The mother would chase the older female away and then return to her own business. The little male would then scurry over and enjoy the roots the older female had been digging up.

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Given that humans have been known to fake pain to receive benefits, aversive treatments arose to introduce a cost that keeps signals honest. It allows caregivers to distinguish the truly ill from the pretenders. And it allows those with symptoms that can be easily faked to credibly request care.

If you can’t see my injuries, but I tell you that I am in pain, you might be skeptical. But if we both know that the treatment for my pain is unpleasant, then you will have little reason to doubt my claims. And, thus, you will be more likely to help me.