Even though Twitter is a mostly very bad website now, I still spend lots of time on it. One of the more frustrating parts about this is that I often find myself getting all riled up and anxious about things I do not (and should not) care about. When I see people I know (and sometimes even people I like) acting riled up and anxious about something, I usually start feeling that way too. Before you know it, I’m sending hot-garbage tweets about something that probably wouldn’t have bothered me if I hadn’t seen it bothering someone else.
This happens in offline life, maybe more so — I pick up on my girlfriend’s stress, and (let’s be honest, more often than not) vice versa. Sometimes, it’s because we tell each other about what’s making us anxious, but not always. Sometimes you can just feel it. But is that just empathy, or can we really transfer our stress onto others?
If we consider stress an emotion, then the answer is very likely yes — emotional contagion is a well-established psychological phenomenon, in which an individual’s affect spreads to those around her. The reason this happens, says Elaine Hatfield, a social psychologist at the University of Hawaii and a pioneer in relationship science, is because we tend to mimic those we interact with. “In conversation, people automatically and continuously mimic and synchronize their movements with the facial expressions, voices, postures, movements, and instrumental behaviors of others,” says Hatfield. “Consequently, people tend, from moment to moment, to ‘catch’ others’ emotions.”
Emotions are so catchy, in fact, that it’s hard not to contract them from the people around you. And while emotional contagion sometimes works out to our benefit (a friend’s happy mood has been found to increase your own happiness by 25 percent), it’s more often the case that we catch feelings we don’t want. “We catch happiness, but sadness, anger, and fear are a lot more contagious,” says Hatfield.
Stress seems very likely to fall in that highly contagious camp. New research, on mice, shows that stress, too, is transferrable, and the study’s principle researcher, Toni-Lee Sterley, a neuroscientist at the Hotchkiss Brain Institute in Calgary, believes these findings to be true of humans as well. “We feel that if these changes are happening even in the mouse brain, because human brains are so much more evolved and complex, they’re like to be occurring in humans too,” says Sterley.
In Sterley’s study, mice were paired off and put in cages. One of the mice was then removed from the cage, exposed to mild stress, and returned to the cage. When the stressed mouse was returned to its cage, it communicated its stress to the unstressed (or “naïve”) mouse. “The mouse that stayed in the cage, the naïve partner, will spend a lot of time sniffing the stressed mouse,” says Sterley. “The stressed mouse releases pheromones as a result of the stress, which is how we think that the stress is being communicated between the stressed and the naïve partner.” The researchers also scanned both mouses’ brains, and while the stressed mouse’s results were as expected (showing synapse changes that reflected its stressful experience), they were surprised to find that the naïve mouse’s brain scan mirrored its partner’s. Even though the naïve mouse hadn’t even witnessed the mild stress experienced by its partner, it felt as though it had.
An equivalent study has yet to be done on humans, but Sterley points to earlier research which suggests that humans are equally able to detect (and mimic) the stress response of other humans. In that study, sweaty T-shirts were collected from people who’d been skydiving (the experimental group) and people who’d just exercised (the control). By sniffing the T-shirts, subjects could essentially tell who’d been skydiving and who had exercised. “We can differentiate between a stress smell and an unstressed smell,” says Sterley. “I think we use pheromones more than we think we do, but obviously we can also communicate stress through body language and [verbal communication], too.” This, in Sterley’s mind, makes it all the more likely that human beings spread our stress to one another.
While it can be frustrating to feel stress that isn’t yours, Sterley says there are probably some evolutionary reasons we’ve adapted this way. “Only one individual in a group would have to experience the stress for the whole group to adapt to it,” she says. In some cases, this might serve as a useful preparatory tool, by which even those group members who haven’t had the stressful experience can be ready if it happens again.
This is not to say that this process can’t be maladaptive, in certain cases; obviously, it doesn’t do my girlfriend much good to get stressed over an individual experience I have that she won’t, and vice versa. It certainly isn’t useful in the context of Twitter. But it’s also, says Sterley, part of what it means to be a social animal — for better and for worse, we’re in our feelings together.