FIVE REALLY GOOD REASONS NOT TO MULTITASK

Our brains are hardwired to be hooked, and our culture rewards us for doing a million things at once. Not to mention that the multitasking drive is instinctual. But here's why you need to counter that urge to pick up the phone and (fill in the blank):

Your brain will allow you to truly concentrate on only one thing at a time 
When we're doing an activity that demands some degree of focus, a network in the brain engages to zoom in on that thing, says Adam Gazzaley, M.D., Ph.D., professor of neurology, physiology and psychiatry at the University of California, San Francisco, and author of the Distracted Mind: Ancient Brains in a High-Tech World. Add another task that requires attention and focus, and another network in the brain "turns on" to manage that activity. "Try to do both tasks at the same time, and the brain has to switch between one network and the other," says Dr. Gazzaley, "and that switching leads to a loss of information."

You won't even know you've lost focus on one task
This brain bounce is subconscious, so chances are you'll feel like you're happily doing just one thing, he says.

You only think you're good at multitasking
A study published in the journal PLOS One found that those who though they were genius multitaskers turned out to be the least capable of it. Scarier: They were also the most likely to use their cell phones often when driving and the most dangerous behind the wheel.

Even when our devices are off, we may not be fully aware
Only 40 percent of the signals that hit the eye's retina for visual processing, a speed limit sign, a hole in the sidewalk, are processed by the brain. "This means that more than half of the signals that hit your eyes don't even exist as far as your brain is concerned," says Paul Atchley, Ph.D., psychologist and Dean at the University of South Florida. Try to read a text or check out Instagram while you're on the go, and your awareness of what's in front of and around you becomes even narrower.

We're too sure of ourselves
Even if you know better than to be on your device while concentrating on something else, you have what psychologists call an "optimism bias" that makes you tell yourself "I'll be fine," says Stephen O'Connor, Ph.D. psychologist at the University of Louisville. So the more we text behind the wheel without getting into an accident, the more we think distracted driving won't be an issue for us.