Every week, a quarter of Americans take a painkiller that could be dampening our collective feelings of empathy. In a paper published online this week, scientists claim that acetaminophen, Tylenol’s main ingredient, makes people more likely to think that other people’s pain isn’t a big deal.
Researchers from the National Institutes of Health and Ohio State University published their findings in Social Cognitive and Affective Neuroscience after studying the effects of the drug on between 80 and about 120 college students across three different experiments.
One group of students drank a liquid with 1,000 mg of acetaminophen, while another took a placebo. An hour later, everyone read short stories about situations such as feeling emotional pain from the death of a parent, or physical pain from a knife that had cut through to the bone. The students who drank the acetaminophen assigned lower ratings for perceived pain and distress than the students who didn’t.
In the second experiment, participants socialized with other people and then, while alone, watched a game supposedly involving three of the people they had just met. The game showed two people excluding the third from an activity, and asked students to rate how hurt the excluded member was. Again, students who took the painkiller assigned lower pain ratings.
The third experiment was less conclusive: the subjects received two-second blasts of white noise and then rated how unpleasant it was for themselves, and how unpleasant it would be for an anonymous other participant. The students who took the painkiller gave lower pain ratings for others when compared to the students who didn’t—but they also gave lower pain ratings for themselves.
There are a few important things to note before blaming Tylenol for yesterday’s family fight: The sample size is quite small and the team doesn’t know why this effect happens, though they theorize that it is because there is an overlap in our ability to experience pain and our ability to empathize with others. Acetaminophen has numerous effects on the human body. Earlier studies have shown that it makes people less likely to feel joy and that it can help help treat anxiety and existential dread.
Given how common acetaminophen is (it’s present in more than 600 products) it’s worth looking into what the researchers have called its “broader social side effects” and whether other painkillers could have similar results.
Up next? They plan to study ibuprofen.