Some time ago, I heard a story. Coming to work high on marijuana allegedly takes the equivalent of 10 points off your IQ. You’re stupider when you’re stoned. No argument there.

But sitting at work with the constant distractions of voicemail and e-mail is worse. Listening to your e-mail ping in every few secondsĀ takes the equivalent of 20 points off your IQ. Meaning that you’d actually be smarter and more productive if you came to work high than if you just…you just…

You know. Just do what you do every day.

Most of us who work at a desk for a living have, in one way or another, fallen for the idea that multitasking is a good thing–that we can be more productive if we do two or three or four things at once. We try to monitor our e-mail and listen to music and keep an eye on Twitter and Facebook–and write that report–all at the same time, all day long.

First note: it can’t be done. “Multitasking” is an illusion. You can’t actually look at Facebook and write your report at the same time. You can’t actually listen to music and read. You have to stop one–if only for a few seconds–to do the other. According to this story in the New York Times, research shows that people who use computers at work change windows and/or check e-mail an average of 37 times an hour.

“Yes,” you may say, “but that’s the way it is. And I’m a good multitasker. I can get a lot done because I can switch quickly from task to task.”

Apparently, that’s not true, either.

The Times hasĀ a couple of interactive quizzes that test your ability to focus and switch tasks. “High multitaskers” actually score worse on these tests than “low multitaskers.” It seems that if you’re less distractible, you’re also better and faster at switching tasks.

Technology overload is real, and it’s pernicious, and we all have to be on guard. And–guess what?–we really don’t have to look at our e-mail every minute-and-a-half. Turn off Facebook, minimize your e-mail window, mute your sound, and work. You may be amazed at how much you’ll get done.