The eight-hour workday may be five hours too long, researcher suggests. Claro Cortes/Reuters

The average worker spends most of the eight-hour workday doing many other things beside work, including eating, socializing, or reading the news.

Psychologists have found the brain can't focus on tasks for more than a few hours at a time.

Some companies have started adjusting their schedules to help employees maximize their efficiency.

Over the course of an eight-hour workday, the average employee works for about three hours — two hours and 53 minutes, to be more precise.

The rest of the time, according to a 2016 survey of 1,989 UK office workers, people spend on a combination of reading the news, browsing social media, eating food, socializing about non-work topics, taking smoke breaks, and searching for new jobs (presumably, to pick up the same habits in a different office).

A study of UK office workers suggests the three-hour workday might be more sensible. Sean Gallup/Getty Images The research has been clear for awhile that long workdays hardly get the best from people. Some research has found people can only concentrate for about 20 minutes at a time. One study found people struggled to stay on task for more than 10 seconds.

Toward the end of the day, performance begins to flatline or even worsen, K. Anders Ericsson, an expert on the psychology of work, said.

"If you're pushing people well beyond that time they can really concentrate maximally, you're very likely to get them to acquire some bad habits," Ericsson told Business Insider in 2016.

Ericsson is the foremost expert on the topic of building expertise. He's made a career out of studying the most successful people on Earth, and figuring out what exactly helps them rise so high.

Turns out the mantra "practice makes perfect" is true, but only if people engage in a certain kind of practice known as "deliberate practice." Experts don't spend hours upon hours honing their craft, Ericsson has found. They spend a few hours at a time purposefully trying to improve, and then they stop.

People can't sustain hard work for more than a few hours, psychologists have found. Alper Çuğun/Flickr

From 40 to 32

The same psychological principle that explains why deliberate practice works also applies to ordinary tasks like writing reports and composing spreadsheets. In both cases, the brain has a finite amount of cognitive resources it can devote to substantive, creative thought.

People who are pushed past their productive limits run the risk of forming bad habits that bleed into their more productive hours, Ericsson said. After multiple hours of browsing Facebook in the afternoon, suddenly employees might not feel so bad about logging back on to the social network in the morning.

Companies have increasingly started choosing to shorten the workweek instead of the workday. Instead of asking people to work five, eight-hour days, many have switched to working four eight-hour days.

Ryan Carson, CEO of the technology education company Treehouse, has seen his employees become happier and more productive since he implemented the 32-hour work week back in 2006. Core to Carson's leadership philosophy is the belief that forcing people to work 40-hour weeks is nearly inhumane, he told the Atlantic in 2015.

"It's not about more family time, or more play time, or less work time — it's about living a more balanced total life," he said. "We basically take ridiculously good care of people because we think it's the right thing to do."



Amazon CEO Jeff Bezos. Getty/Drew Angerer Research suggests the smarter change may actually be to work five, six-hour days.

In Sweden, a government study that ran between January 2015 and January 2017 selected roughly 80 retirement-home workers in Gothenburg to work that exact schedule. At the end of the study, people said they were happier, less stressed, and enjoyed work more. The only downside: An absence of workers called on retirement homes to hire more people, increasing costs.

An ongoing experiment in productivity

Amazon is testing both shorter days and weeks. In September 2016, the retail giant began an experiment with 30-hour workweeks in which a few dozen employees began working 10 a.m. to 2 p.m., Monday to Thursday. The group would earn 75% of their normal salary but retain full benefits.

The company hasn't released any data yet on how the move has affected people's productivity or quality of life. But as a general finding for office workers around the world, psychologists say the move is likely to make people more refreshed and less stressed.

Speaking to Wisconsin Public Radio shortly after Amazon's announcement, Anders Ericsson said the move could make people more productive in the long run.

"Employers may actually be getting much more out of their employees," he said, "if they only work 50 or 75 percent of the current work hours."