In 2007, a Harvard graduate student named Alia Crum walked into seven hotels in the Boston area with a clipboard and a strange question. The women who cleaned the rooms spent their shifts pushing carts, hauling vacuum cleaners up stairwells, scrubbing bathrooms, and changing linens on dozens of beds. By any reasonable measure, they were among the most physically active workers in the building.
Crum asked them whether they exercised. Two-thirds said no. A third said they got no exercise at all.
That gap between what the housekeepers did and what they believed they did became the basis for one of the most provocative experiments in health psychology, and the start of a research program that has been quietly rewriting how we understand the word “mindset.”
What one poster did to 44 women
Crum and her advisor, Ellen Langer, split the 84 housekeepers into two groups. The control group got nothing. The other group got a short presentation and a poster for the break room explaining that their work already met the Surgeon General’s recommendations for an active lifestyle. Changing linens for fifteen minutes burned about 40 calories. Vacuuming for the same time burned 50. Cleaning bathrooms, 60. Their job, in other words, was a workout.
Nothing else changed. Same shifts, same rooms, same carts. Crum confirmed afterward that the informed group hadn’t started exercising outside work, hadn’t changed their diet, hadn’t altered their workload.
Four weeks later she measured them again. The informed group had lost an average of two pounds. Their systolic blood pressure had dropped by roughly ten percent. Body fat, waist-to-hip ratio, and BMI had all moved in the right direction. The control group hadn’t budged.
The women had done the same physical work as before. The only variable was what they believed that work was doing to them.
The milkshake that lied to people’s stomachs
The hotel study drew skepticism, and reasonably so. The sample was small. The follow-up was short. Crum’s answer was to find a cleaner mechanism.
In 2011 she ran a study with a single milkshake. Every participant drank the same 380-calorie shake on two separate occasions. One time it was labeled “Indulgence,” a decadent 620-calorie treat. The other time it was labeled “Sensi-Shake,” a guilt-free 140-calorie option. Before and after each shake, Crum’s team drew blood and measured ghrelin, the hormone that signals hunger to the brain and drops after you’ve eaten.
When people believed they’d had the indulgent shake, their ghrelin fell about three times as much as when they believed they’d had the diet shake. Same shake, same calories, different hormonal response. Their bodies had metabolized the label.
This is the finding that made Crum’s career, and it’s the one she’s spent the years since at Stanford’s Mind & Body Lab trying to understand. Her framing is deliberately precise. Mindsets aren’t positive thinking. They’re the lens through which you interpret what’s happening to you, and that interpretation is a physiological input, not just a psychological one.
The study that should change how you talk about pressure
The part of Crum’s work that matters most for anyone who leads a team came in 2013, when she turned from food and exercise to stress.
Most workplaces operate on a shared belief that stress is harmful. It’s in the wellness programs, the resilience workshops, the way managers apologize for a heavy quarter. Crum wanted to know what happens when you hold the opposite belief, that stress is enhancing. Not pleasant, but useful. Sharpening. The thing that makes the work matter.
She and her collaborators, Peter Salovey and Shawn Achor, built a short questionnaire to measure which belief a person held, then tested it on employees at UBS in the middle of the 2008 financial crisis, about as stressful a workplace as it’s possible to find. Employees were shown one of two sets of three-minute videos. One set presented the case that stress is debilitating. The other presented the case that stress enhances performance, focus, and growth.
The videos shifted people’s stress mindset, and the shift showed up in their bodies and their work. Employees who moved toward a stress-is-enhancing mindset reported better health, fewer physical symptoms, and higher work performance. In a follow-up lab study, people with an enhancing mindset showed a more adaptive cortisol response under pressure, higher when a spike was useful, lower when it wasn’t, rather than the flat or runaway patterns that predict burnout.
Three minutes of video. That’s roughly the length of a manager’s opening remarks in a team meeting.
Where this lands on your team
Crum’s research reframes a question most managers get wrong. The question isn’t how to reduce your team’s stress. Some of it you can’t reduce, and some of it you shouldn’t. The question is what your team believes that stress is doing to them, and you are the single largest influence on that belief.
Think about how a demanding stretch usually gets introduced. “I know this quarter is going to be brutal.” “Sorry to pile this on.” “Just get through the next six weeks.” Every one of those sentences installs a debilitating mindset. It tells people that what they’re about to experience is damage to be endured rather than load to be grown by. It’s the equivalent of telling the housekeepers their job doesn’t count.
The alternative isn’t cheerleading, which people see through instantly. It’s the Crum framing: stress shows up when something matters, and the physical response to it, the elevated heart rate, the narrowed focus, the adrenaline, is the body preparing to perform. Naming that directly, in plain language, is the intervention. So is pointing out afterward what the pressure produced. A team that ships under load and never hears that the load was the reason they got better will learn only that load hurts.
This connects to the pattern Carol Dweck found with praise. The label you attach to an experience changes what people do with the next one. Crum’s contribution is showing that the label changes what the body does with it too.
What the research doesn’t say
It’s worth being careful here, because Crum herself is. The hotel study has been criticized for its size and its short window, and she has said the effect is best understood as a proof of concept rather than a weight-loss protocol. The milkshake study used a small sample. Mindset effects in her lab’s later work have generally been modest, real but not transformative on their own.
More importantly, Crum has been explicit that a stress-is-enhancing mindset is not a license to overload people. Her research on the 2008 bankers found the benefit in how they interpreted a crisis, not in the crisis being good for them. A manager who reads this work as permission to pile on and call it growth has misread it. Chronic, unrelenting stress with no recovery damages people regardless of what they believe about it, and no three-minute video fixes a structural problem.
What the research does support is narrower and more usable. Within the load your team actually carries, the story you tell about that load is a variable you control, and it moves outcomes you’d assume were fixed.
Forty-four women and a poster
The housekeepers in Crum’s study didn’t get healthier because they worked harder. They got healthier because someone told them the truth about what their work was already doing, and their bodies believed it.
Your team is under pressure right now. They’re either interpreting it as something that’s wearing them down or something that’s building them up, and if you haven’t said anything, they’ve defaulted to the first one, because that’s what the culture told them.
Crum’s data says you can change that interpretation in the time it takes to open a meeting. Whether you do is a choice about what you believe stress is for.