Take one step out the front door, and an individual brain cell fires. Pass by your rose bush on the way to the car, another specific neuron fires. And so it goes. Ultimately, the brain constructs its own pinpoint geographical chart that is far more precise than anything you’d find on Google Maps. But just how neurons make these maps of space has fascinated scientists for decades. It is known that several types of stimuli influence the creation of neuronal maps, including visual cues in the physical environment—that rose bush, for instance—the body’s innate knowledge of how fast it is moving, and other inputs, like smell. Yet the mechanisms by which groups of neurons combine these various stimuli to make precise maps are unknown. To solve this puzzle, UCLA neurophysicists built a virtual reality environment that allowed them to manipulate these cues while measuring the activity of map-making neurons in rats.

Researchers have found that one part of the brain in rats responds differently to virtual reality than to the real world. They found that “place” cells in the rats’ hippocampus didn’t light up as much when immersed in a virtual reality experiment as they did when the rats were engaging with the real world.

The researchers found that the level of place cell activity that occurred was dramatically different between the two environments. For the real world runs, approximately 45 percent of the rats’ place cells fired, compared to just 22 percent for the virtual reality runs.

These results weren’t a surprise to the team as previous research has suggested that place cell activity is incited by at least three types of cues: visual, self-motion and proximal. Virtual reality in its current state isn’t capable of generating the sensation of a breeze kicking up, the smell of bacon frying or the way the ground responds beneath the feet—all of these are part of proximal awareness. In order for virtual reality to become truly immersive, the research suggests, proximal cues must be added to the virtual reality experience.”

In fact, multitasking is a misnomer. In most situations, the person juggling e-mail, text messaging, Facebook and a meeting is really doing something called “rapid toggling between tasks,” and is engaged in constant context switching. As economics students know, switching involves costs. But how much?

We expected the Interrupted group to make some mistakes, but the results were truly dismal, especially for those who think of themselves as multitaskers: during this first test, both interrupted groups answered correctly 20 percent less often than members of the control group.

In other words, the distraction of an interruption, combined with the brain drain of preparing for that interruption, made our test takers 20 percent dumber.

But in Part 2 of the experiment, the results were not as bleak. This time, part of the group was told they would be interrupted again, but they were actually left alone to focus on the questions.

Again, the Interrupted group underperformed the control group, but this time they closed the gap significantly, to a respectable 14 percent. Dr. Peer said this suggested that people who experience an interruption, and expect another, can learn to improve how they deal with it.

But among the On High Alert group, there was a twist. Those who were warned of an interruption that never came improved by a whopping 43 percent, and even outperformed the control test takers who were left alone. This unexpected, counterintuitive finding requires further research, but Dr. Peer thinks there’s a simple explanation: participants learned from their experience, and their brains adapted.

Clifford Nass, a Stanford sociologist who conducted some of the first tests on multitasking, has said that those who can’t resist the lure of doing two things at once are “suckers for irrelevancy.” There is some evidence that we’re not just suckers for that new text message, or addicted to it; it’s actually robbing us of brain power, too.

What the Carnegie Mellon study shows, however, is that it is possible to train yourself for distractions, even if you don’t know when they’ll hit.