Beth Camasar colors an adult coloring book in her New London, Conn. home Thursday, Jan. 7, 2016. Camasar lost feeling in her hands a year ago and is trying adult coloring as a therapy. (Shelly Yang/The Day via AP) MANDATORY CREDIT (REV-SHARE) (The Minnesota Star Tribune)

A colleague's recent Facebook post made me laugh, and attempt to explain.

What in the world, she wondered, was the appeal of coloring books for adults?

True as it may be that grown-up titles were among the hottest trends of 2015 — many making bestseller lists — she'd rather sit in the corner than draw inside the lines of a bursting bouquet or placid winter scene with a box of crayons.

I laughed mostly because I thought the same thing, until a tempting example landed on my desk at work. The little book arrived just as another study popped up in my e-mail about how bad multi-tasking is for us.

Us, as in adults.

We can bemoan our kids' insistence on doing homework while wearing earbuds, and watching television, and Snapchatting. But we're worse.

I've heard party-planning conversations going on in bathroom stalls. iPhones are standard operating procedure at fine restaurants. Many early risers I pass on my morning runs miss the majestic winter (spring/summer/autumn) beauty because they're conducting business via Bluetooth.

We prize multitaskers for their capacity to juggle. We strive to be more like them.

The truth is that most of us have no idea anymore how to uni-task, which is a fancy way of saying focus on Just. One. Thing.

This loss is hurting us. Our brains simply aren't designed to take in so much disparate information at once.

Earl K. Miller, a professor of neuroscience at MIT, recently explained to today.com that our brains, in fact, have "very limited bandwidth to process new information," and can only handle a small number of thoughts at once.

Multi-tasking, it turns out, is actually not multi-tasking at all. It is doing many singular things, switching back and forth between them.

In the process, we're taxing our overworked brains to realign again and again. Miller calls this a "switch cost," and it's expensive. Nothing gets our complete attention, so the quality of our work, or conversations, is compromised. Our well-being, or somebody else's, is compromised, too, if we multi-task behind the wheel.

The best antidote is to practice the art of singular concentration. Start small. Devote a few minutes to stepping away from your computer or smartphone. Sit in a sunny spot and read a few pages in a book. You remember books, right?

Or channel your childhood self. Remember recess? There wasn't a moment of multi-tasking going on then. Just running, climbing or swinging with the simple mission of having fun. So bundle up, go find a hill and sled down it. (Just don't steal a little kid's sled to do it.)

The best idea I've found, though, is to treat yourself to one of the multitude of gorgeous coloring books designed for brain-weary adults. Add a box of perfectly sharpened colored pencils if you want to really go wild.

Prepare to find the coloring exercise weird or silly or time-wasting at first, until you become giddy when you realize that the only choice you need to make for the next many minutes is whether to use the coral or the lime-green pencil.

With titles such as "Kaleidoscope Mandalas," "Dream Doodles," even the "Official 'A Game of Thrones' Coloring Book," you will quickly decide that it's time to put the kids to bed.

Who cares if they're 17?

gail.rosenblum@startribune.com

612-673-7350 • Twitter: @grosenblum