If you had to make a rat depressed, how do you think you’d go about it?

(Okay, you can’t technically make a rat “depressed” — a scientist would ask how to “create a model of depression” in rats. Actually being depressed is exclusive to humans. But the drugs used to treat depression in humans are developed and tested using rodents.)

So to test your new antidepressant, you need an efficient method of making a lot of rats exhibit anhedonia — that is, making them lose interest in things they used to enjoy, like sugar.

How do you think you’d do that?

It turns out you don’t need to traumatize them. The most reliable protocol is “chronic mild stress.” There are many methods of making the lives of experimental animals mildly but chronically miserable — a cage floor that administers random electric shocks; a deep swimming pool with no way to rest or climb out; a stronger “intruder” introduced into the same cage. One neuroscientist actually nicknamed his apparatus the Pit of Despair.

But they’re all variations on the same theme: remove all predictability and control from the animal’s life. Then take notes as they gradually lose interest in being alive.

The media mostly discusses job stress in the context of white-collar, educated professionals. We don’t put nearly as much time and energy into exploring the stress of unskilled, low-wage service work — even though the jobs most Americans actually work could be mistaken for Pits of Despair.

Perhaps it’s because as technology progresses, it tends to make life easier for the top of the labor market — those skilled, educated workers with decent salaries and benefits. Often overlooked is how those same technological advances have made it possible to control and monitor unskilled worker productivity down to the second. These technologies are also getting more powerful, and that makes a lot of people’s lives inescapably, chronically stressful.

It can be hard to understand the stress of having someone constantly looking over your shoulder if you haven’t recently — or have never — had to work a job like this. By definition, that’s most everybody with power in this country.

Even former House Speaker Paul Ryan, who has often played up the summer he spent “flipping burgers” at McDonald’s as a teenager, seems not to realize that it’s much more difficult to work fast food in 2019 than it was in 1986.

I hadn’t had a service job in a while either. But I was curious, especially after driving for Uber for a couple of months for an investigative piece fact-checking the claim that full-time drivers could expect to make $90,000 a year. When my newspaper closed a few months later, I decided to try working three jobs that serve as good examples of how technology will be used at work in the future — in an Amazon warehouse, at a call center, and at a McDonald’s — with the vague idea of writing a book about what had changed. (I used my real name and job history when applying, and was hired nonetheless.)

Even having done a lot of research, I was shocked by how much more stressful low-wage work had become in the decade I’ve been working as a journalist.

Take fast food, a sector that made up a huge chunk of the post-recession jobs recovery. It’s far from the leisurely time implied by “flipping burgers.” One of my coworkers put it best: “Fast food is intense! And it’s stressful! You’re always feeling rushed, you’re on a time crunch for literally eight hours straight, you’re never allowed to have one moment just to chill.”

The factors a scientist would remove from a rat’s life to make it depressed — predictability and control — are the exact things that have been removed from workers’ lives in the name of corporate flexibility and increased productivity. There’s little more relief for many low-wage workers than for those lab rats desperately trying to keep their heads above water.

For one thing, everything is timed and monitored digitally, second by second. If you’re not keeping up, the system will notify a manager, and you will hear about it.

When I used to do service work, we still mostly used paper time cards; you could make your case to the manager if you were late, or maybe stay a few minutes beyond your shift to make up for it. At many modern service jobs, the digital time-clock system will automatically penalize you for clocking in a minute after the start of your shift or after a break. After getting yelled at for this twice early in the month I spent working at a McDonald’s in downtown San Francisco, I started imitating my coworkers and aiming to arrive 20 minutes before my shift just in case the train was running weird that day. I came to resent how much time this ate up, particularly when comparing it to the trivial difference to McDonald’s of having me clock in at 7:31 rather than 7:30. I’ve reached out to McDonald’s for comment, and will update this story when I receive a response.

Computers and algorithms also have a much heavier hand in what a worker’s schedule looks like. The scheduling systems used to staff most major retail and fast food chains have gotten extremely good at using past sales data to extrapolate how much business to expect every hour of the coming week. Stores are then staffed around the predicted busy and slow times, which means workers’ schedules are often completely different week to week.

The more recent the data, the more accurate the prediction, which is why so many fast-food and retail workers don’t get their schedule until a day or two before it starts. It leaves workers in these industries unable to plan their lives (or their budgets) more than a few days in advance.

Algorithmic scheduling also results in bizarre things like the “clopen” — back-to-back shifts closing late and opening early the next morning with only a few hours to sleep in between — and unpaid quasi-shifts where workers are expected to be on call in case it’s busier than predicted or sent home early if it’s slower.

Technology has also made understaffing a science. At my McDonald’s, we always seemed to be staffed at a level that maximized misery for workers and customers, as exemplified by the constant line and yells of “Open up another register!” Not only did this permanently strand us in the weeds, it meant that customers were often in a bad mood by the time they got to us.

Understaffing is a widespread tactic to cut down on labor costs. For what it looks like in fast food, check out the dozens of Occupational Safety and Health Administration complaints filed by McDonald’s workers in 2015 about deliberate understaffing at stores in several cities. The workers claim the corporate-supplied scheduling system understaffs stores, then pressures the skeleton crew to work faster to make up for it, which leads to hazardous conditions and injuries like these:

“My managers kept pushing me to work faster, and while trying to meet their demands, I slipped on a wet floor, catching my arm on a hot grill,” one worker, Brittney Berry, said in a statement when the complaints were filed. “The managers told me to put mustard on it.”

Responding to the OSHA filings, the company wrote that “McDonald’s and its independent franchisees are committed to providing safe working conditions for employees in the 14,000 McDonald’s Brand U.S. restaurants. We will review these allegations.”

The statement also made a reference to Fight for $15, the Service Employees International Union-funded campaign that had been involved in coordinating and publicizing the complaints: “It is important to note that these complaints are part of a larger strategy orchestrated by activists targeting our brand and designed to generate media coverage.” (The cases have not been resolved.)

According to a 2015 survey of thousands of US fast-food employees by the National Council for Occupational Safety and Health, 79 percent of industry workers had been burned on the job in the previous year — most more than once.

This would now include me. I worked on the now-notorious Szechuan Sauce Day, which was miserable for McDonald’s workers across the country. We were more slammed than I’d ever seen, and as I hurriedly checked the coffee levels between orders, one pot’s handle broke, slicing open my finger and dumping scalding coffee all over my pants.

The thing I found the most stressful at my three jobs was the small percentage of customers who will, for whatever reason, just scream stuff you wouldn’t believe at you. This was mostly at the call center; at McDonald’s, customers tended to be in a better mood. But in person, screamers can also do things like splatter you with honey mustard, which is a thing that actually happened in my third week on the job.

The woman I now refer to as Mustard Lady had already been screaming at me for a few minutes, but I was so surprised when she nailed me in the chest with a container of honey mustard dipping sauce that I instinctively screamed back, “Hey, fuck you, lady! What the fuck?” before removing myself from the situation.

I got written up for that.

If you haven’t had to do it for a while, it may seem like having to be completely submissive to customers shouldn’t be that big of a deal. But believe me, there’s a cost associated with continually swallowing your pride and apologizing to unreasonable jerks. “The customer is always right” policies may be good for business, but they’re bad for humans, physically and mentally.

When Paul Ryan worked at McDonald’s in the ’80s, he might have been representative of a largely teenage sea of fast-food workers, a perception that persists today. But last time the National Employment Law Project checked, the average age of fast-food workers was 29, and more than a quarter of workers were supporting a child. These jobs are not just a source of teenage pocket money; they’re something adults are trying to survive on.

The average pay for someone with the job I had is around $8 an hour — about half of what’s needed to keep a family with two working parents and two kids afloat. (That is, each parent would need to work two fast-food jobs.)

American culture is full of lingering afterimages of Midwestern guys making cars and mining coal, but, to quote an excellent headline from the Chicago Tribune, The Entire Coal Industry Employs Fewer People Than Arby’s. This is the modern working class — fast food, retail, warehousing, delivery, call centers. Service workers.

Everybody I talked to at my McDonald’s — along with the many other fast-food workers I interviewed — had had food items thrown at them. I got the impression that I was the weird one for Mustard Lady being my first. They’d been hit by nearly everything in the store: wrapped burgers, unwrapped burgers, burger patties, McNuggets, smoothies, sodas, napkins, straws, sauces, fries, apple pies, ice cream cones, even a full cup of hot coffee.

Why do so many people choose to put up with this? Because some choices aren’t really choices.

In my experience, most people are willing to make immense sacrifices to keep their children safe and happy. In a country with a moth-eaten social safety net, health care tied to employment, and few job quality differences between working at McDonald’s, Burger King, or Walmart, corporations have long since figured out that workers will put up with nearly anything if it means keeping their jobs. This fulcrum is being used to leverage more and more out of workers — even, ironically, the ability to spend time with their families. Many of my coworkers were in the O’Henry-like position of providing for families they barely got to see because of their work schedule.

Free market capitalism doesn’t assign a negative value to “how much stress workers are under.” It just assumes that unhappy workers will leave their job for a better one, and things will find a natural balance. But when the technologies that make life miserable spread everywhere at the speed of globalization, finding something better isn’t really an option anymore. And a system that runs by marinating a third or more of the workforce in chronic stress isn’t sustainable.

Chronic stress will destroy your body like doing burnouts will destroy a rental car that someone else is paying for. It’s a huge factor behind the epidemics of heart disease, obesity, autoimmune disorders, depression, anxiety, and drug misuse that afflict developed countries — the “diseases of civilization.”

And right now, corporations kind of are treating the low-wage workforce like a rental car someone else is paying for. Because while American jobs have gotten safer in terms of limbs caught in machinery, individual companies are extremely unlikely to be held accountable for workers’ long-term stress-related health problems. They’re doing burnouts with the bodies and minds of millions of American workers, because either workers or taxpayers will pick up the bill.

Why? Because “hard work” as an undisputed moral good is a deep part of the American psyche. The idea of penalizing a company for making its employees work too hard can seem ridiculous if the work environment is safe. Plus, “flipping burgers” has been shorthand for an easy job for decades, so it can be hard to associate that with the constant monitoring, understaffing, and sub-living wage of modern service work. Chronically stressful work is different from hard work. And it’s dangerous.

Should people be asked to sacrifice their physical and mental health — and their experience of life as something other than an exhausting, hopeless slog — for the survival of their families? Would a moral society ask them to make this choice?

A lot of people blithely advise the poor to work their way toward dignity and self-respect. I’d wager that none of them has been written up for having a natural reaction to being splattered with mustard, or had their schedule cut to 15 hours a week because they took a sick day, or been bawled out for being one minute late. Their mental image of work comes from the pre-internet era, and we need to stop taking them seriously and start listening to the people on the brutal front lines of the modern low-wage workforce. They’re very easy to find.

At McDonald’s, I asked the manager who wrote me up for losing my temper at Mustard Lady if anyone had ever thrown food at her, and, if so, how she’d kept it together. Was there ... a trick to it?

My manager looked at me as if I were oblivious, and responded that of course people had thrown food at her. “You have a family to support. You think about your family, and you walk away.”

Emily Guendelsberger is the author of On the Clock: What Low-Wage Work Did to Me and How It Drives America Insane.