One week in 1995,176 the psychologist Kipling Williams and his colleagues at the University of Toledo, in Ohio, decided to experiment on themselves. He and four of the other researchers in his department would ostracize a different person among them every day for a week. Each day, a randomly selected colleague would have a scarlet letter “O,” for “ostracized,” taped above his or her office door. That day, the others would ignore and otherwise subtly reject that colleague. They would avoid eye contact and conversation with that person. The ostracized colleague would not get so much as a hello or goodbye.

Some of the scientists thought the project would surely be a bust, since they all knew about it to start with. One of the researchers even worried she would start giggling while attempting to faux-ostracize her coworkers. Others thought the treatment wouldn’t be so different from what they already experienced in their everyday lives. One researcher, a young immigrant, wrote that she thought it would be easier for her to tolerate the ostracism; since “this is not my country, people don’t acknowledge my existence all the time.”

Even though the researchers knew the experiment was fake, the diaries they kept during the week revealed a surprising amount of angst. “I feel like I am a ghost on the floor that everyone hears, but no one can talk to,” one of the participants wrote on his “O” ostracism day. They felt stupid when people didn’t laugh at their jokes. Even a few seconds of accidental eye contact felt “wonderful.” One of the ostracized researchers, on his O day, would annoy his colleagues just to get any kind of attention. Some of them grew a little paranoid. “No matter how much I know why they’re [ostracizing me], there’s a part of me that wonders if it isn’t something else,” one of the participants wrote in his journal.

“Despite knowing the reasons behind the ostracism, and knowing that a predetermined end was in sight,” the ostracism felt unpleasant, they wrote in a journal article about the experience after the fact. “We questioned each other’s motives, had difficulties carrying out our day-to-day duties, and felt disengaged from our friends and colleagues. As targets we felt disconnected to the group, frustrated by our lack of control, uncertain of the value of our contributions, and unrecognized.” Even though the ostracism was temporary and experimental, it nevertheless made its painful mark on the ostracized.

The “Scarlet O” study and others like it underscore just how distressing social isolation can be. There are, of course, some people who feel untroubled by their societal exclusion. In my reporting, I’ve found, for instance, that polyamorous people tend to recognize that their lifestyle is considered strange by society, but they will nevertheless defend it vociferously. They seem certain that monogamous normals are the ones who are really missing out.