Why Scientists Keep Making Test Subjects Shock Themselves (and Each Other)

​ Human beings are pretty altruistic, it turns out: When offered a monetary award in exchange for shocking someone or for shocking themselves, they're willing to say "no" to more money to avoid having to inflict harm on another person instead of themselves. They're willing to endure pain themselves to score some cash, however.

But wait, hold on: Why are scientists always shocking people or asking them to shock others? Shock-as-study is  ​perhaps most famously linked to the Milgram psychology experiments, in which Stanley Milgram studied humanity's obedience to an authority figure—by making them shock a harmless participant.

Like in Milgram's study, the altruism one published Monday by Molly Crockett of University College London in  ​Proceedings of the National Academy of Sciences is primarily a psychological study. For that reason, she says it was necessary to shock people to really figure out what was going on.

"Past studies have examined people's judgments in hypothetical scenarios, but there is evidence that hypothetical judgments cannot accurately predict actual behavior," she wrote.

In a follow up interview, Crockett says that previous studies have shown that people are willing to dick over a stranger—as long as the stranger doesn't incur any harm. If two people work on a task and one is given $20 to divide amongst the two of them (without telling the other how much the original pot was), the one who is dividing the money will often take something like $18 of it.

That would seem to suggest people aren't altruistic, but there's more going on here.

"With shocks, it's unequivocally immoral to hurt someone," she told me. "If you're failing to share money with someone else, you're not making them worse off than they were before. Refraining from harming other people is one of the sort of fundamental tenants of any moral system."

The point of all of this, of course, is to eventually figure out what the hell goes on in the brains of the lunatics that are cool with unbearably shocking another person for $30. She says that this is the first of many studies designed to "probe the neurobiology of decision making" in order to figure out why certain people are violent or lack empathy.

To do this, you gotta shock people.

There are a lot of ways to induce pain in people, many of them considered ethical by the scientific community. But for psychological studies, electric shocks are still considered the best.

For pain tolerance studies (of which there are many—for people with certain disorders, for children, for the different genders, for all sorts of things), there's all sorts of ways we induce pain.

The most common one  ​is called the cold pressor test, in which people submerge their hands in a bucket of ice water. Other ​studies have shot participants with lasers, used ​heating pads, ​applied intense pressure to them using a device known as a palpometer, and even ​required them to eat hot sauce or really spicy chili peppers. Still others have used the "​electrical stimulation of the gastrointestinal tract," a nice twist on traditional skin-attached electrodes.

None of those work all that great for psychological studies, Crockett said. Psychological studies have to be uncomfortable, to the same degree, for everyone in order to yield good results.

People are not always stoked when you shock them​.

"The shocks are nice to use, they're sort of commodifiable. They're unpleasant, but they don't cause any long lasting physical damage," she said. "And they're reasonably well outside the experience that most people have, so it's something new for them."

To set up the study, she started with a threshold test—everyone was zapped with an increasing level of voltage, up to 10 million amps. Participants gave her their pain levels, with 10 being totally unbearable. For her study, the shocks that were inflicted were at a level 8. People who could stomach 10 million amps without it hurting were thrown out of the study.

"If you use hot sauce, you'd imagine that there are large individual differences if you test someone who eats a lot of spicy food," she said. "With the shocks, we can individually set the threshold so it's equally painful for everyone."

That threshold test is incredibly important, because actually hurting someone (not permanently, of course) is a great way to give a study subject the sense that something is really at stake.  ​That's a mistake made by researchers in a study published earlier this year, in which people were left alone with their thoughts—and with a button that let them shock themselves. Most people opted to shock themselves.

"They didn't match the shocks in that study, so it's not clear whether the shocks delivered were actually painful," Crockett said. "The thing about electric shocks is that, when you're at a 5 out of 10, well, they're not actually painful, they just feel interesting. I don't think it's necessarily surprising they opted to shock themselves."

In the end, because it didn't necessarily inflict any pain at all, that earlier study about whether people would rather shock themselves or sit alone with their thoughts might not say much about us at all. Which is to say, if you're not actually hurting someone (at least a little bit), you might be selling the science short.