some surprising ways it can make you efficient

We all do it: Texting while walking, sending emails during meetings, chatting on the phone while cooking dinner. In today’s society, doing just one thing at a time seems downright luxurious, even wasteful.

But chances are, you’re not doing yourself (or your boss, or your friends and family) any favors by multitasking your way through the day. Research shows that it’s not nearly as efficient as we like to believe, and can even be harmful to our health. Here are 12 reasons why you should stop everything you’re doing—well, all but one thing—and rethink the way you work, socialize, and live your life.

What you call multitasking is really task-switching, says Guy Winch, PhD, author of Emotional First Aid: Practical Strategies for Treating Failure, Rejection, Guilt and Other Everyday Psychological Injuries. “When it comes to attention and productivity, our brains have a finite amount,” he says.

“It’s like a pie chart, and whatever we’re working on is going to take up the majority of that pie. There’s not a lot left over for other things, with the exception of automatic behaviors like walking or chewing gum.” Moving back and forth between several tasks actually wastes productivity, he says, because your attention is expended on the act of switching gears—plus, you never get fully “in the zone” for either activity.

Contrary to popular belief, multitasking doesn’t save time. In fact, it will probably take you longer to finish two projects when you’re jumping back and forth than it would to finish each one separately. The same is true even for behaviors as seemingly automatic as driving: In a 2008 University of Utah study, drivers took longer to reach their destinations when they chatted on cell phones.

“What tends to save the most time is to do things in batches,” says Winch. “Pay your bills all at once, then send your emails all at once. Each task requires a specific mindset, and once you get in a groove you should stay there and finish.”