This could help explain why some of us (think coffee shop worker bees, and fans of the open-office floor plan) are more productive around other people—at least other people who aren't slacking off.

"Our findings might also suggest that we will copy low effort too, so it's not as simple as 'studying together is better,'" lead author Kobe Desender, a doctoral researcher in the cognitive psychology group of the Faculty of Psychology and Educational Sciences at Vrije Universiteit Brussel in Belgium, told Health in an e-mail. "But working in the vicinity of highly motivated people might be wise."

Research had already shown that having another person nearby can affect how well you perform. But does what the other person is doing have any influence? To find out, Desender and his co-authors conducted two experiments.

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In the first, 38 volunteers sat side by side in pairs, each duo sharing a computer and a keyboard. They were asked to respond to certain colors appearing on the screen by hitting pre-specified buttons on the keyboard. The task became more difficult for participant A but stayed the same for participant B. Regardless, participant B tended to match his or her effort to participant A even though B's task remained the same.

The second experiment was the same as the first, except this time a cardboard wall divided the computer screen in half. That way participants could not see what their matched pair was doing, and the researchers could determine that Participant B's improved performance was due to mental effort, and not just seeing the partner's tasks.

Either way, the result was the same—and not too different from the findings of other "social contagion" studies which have suggested, for instance, that obesity may be contagious.

When one person in a group gains or loses weight, friends tend to follow suit. "How your partner, friend, or Weight Watchers [buddy] is engaging with the world, the task that they're doing is going to have some impact on you and your behavior," Aaron Heller, PhD, assistant professor of psychology at the University of Miami Miller School of Medicine, told Health. (Heller wasn't involved in the current study.)

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There's no good explanation for why mental effort may be contagious, at least not yet. It's possible that we pick up on scent cues emanating from our neighbors, or even their body posture. "Some postures are indicative of increased effort," says Desender. "But [this is] very speculative." 

Who knows—there may even be an evolutionary perk to matching the level of exertion of the person in the next cave, er, cube…

Thing is, there's no scientific evidence this condition actually exists.

An alternative medicine specialist named James L. Wilson first introduced the concept of adrenal fatigue with his 1998 book, Adrenal Fatigue: The 21st Century Stress Syndrome. The condition, as he explained it, is a group of non-specific symptoms associated with "below optimal adrenal function resulting from stress." When the adrenals (small glands that sit on top of the kidneys and produce vital hormones and help the body to regulate metabolism and respond to stress) are overtaxed, he argued, we can suffer from everything from "'gray' feelings" to the inability to leave bed for more than a few hours. Wilson offered "unique dietary supplements" as the remedy.

Nearly two decades later, there's still no way to test for the condition. What's more, researchers have uncovered no concrete evidence that stress actually does drain the adrenal glands. The Endocrine Society, a group representing more than 18,000 physicians and scientists around the world, doesn't mince words in its fact sheet: "'Adrenal fatigue' is not a real medical condition. There are no scientific facts to support the theory that long-term mental, emotional, or physical stress drains the adrenal glands and causes many common symptoms."

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"The symptoms people experience [when they believe they have adrenal fatigue] are very real, and sometimes it's difficult to have symptoms and not have a diagnosis, so that could be where the persistent myth of 'adrenal fatigue' syndrome comes from," says Salila Kurra, MD, co-director of the Columbia Adrenal Center and assistant professor of medicine at Columbia University Medical Center in New York City.

There really is harm in believing that myth and "waiting for the research to catch up," as some people put it, says Marilyn Tan, MD, an endocrinologist with Stanford Health Care and clinical assistant professor of medicine at Stanford School of Medicine in California. "Symptoms of fatigue, body aches, trouble sleeping, indigestion, and nervousness are non-specific and could be due to a variety of other diseases, including sleep disorders, depression, irritable bowel syndrome, and thyroid disease," she explains. "To attribute all symptoms to a single diagnosis of 'adrenal fatigue' risks missing the detection of other treatable underlying diseases."

Confusing matters, there is a similarly-named condition that's widely accepted in the medical community, with research supporting its existence: adrenal insufficiency…