I knew it! Multitasking makes you stupider

Excerpts from "The Autumn of the Multitaskers," by Walter Kim, The Atlantic Monthly, November 2007, 66-80.

"Multitasking messes with the brian in several ways. At the most basic level, the mental balancing act that it requires- the constant switiching and pivoting- energize regions of the brain that specialize in visual processing and physical coordination and simultaneously appear to shortchange some of the higher areas related to memory and learning. We concentrate on the act of concentration at the expense of whatever it is that we're supposed to be concentrating on. "
"What does this mean in practice? Consider a recent experiment at UCLA, where researchers asked a group of 20-somethings to sort index cards in two trials, once in silence and once while simultaneously listening for specific tones in a series of randomly presented sounds. The subjects' brains coped with the additional task by shifting responsibility from the hippocampus- which stores and recalls information- to the striatum, which takes care of rote, repetitive activities. Thanks to this switch, the subjects managed to sort the cards just as well with the musical distraction- but they had a much harder time remembering what, exactly, they'd been sorting once the experiment was over." (I thought I had been having blonde moments)

"Even worse, certain studies find that multitasking boosts the level of stress-related hormones such as cortosol and adrenaline and wears down our systems through biochemical friction, prematurely aging us. In the short term, the confusion, fatigue, and chaos merely hamper our ability to focus and analyze, but in the long term, they may cause it to atrophy." (Graduate school, anyone?)

"Multitasking slows our thinking. It forces us to chop competing tasks into pieces, set them in different piles, then hunt for the pile we're interested in, pick up its pieces, review the rules for putting the pieces back together, and then attempt to do so, often quite awkardly. Fact, and one more reason the bubble will pop: A brain attempting to perform two tasks simultaneously will, because of all the back-and-forth stress, exhibit a substantial lag in information processing."

"It begins by giving us more tasks to do, making each task harder to do, and dimming the mental powers required to do them. It finishes by making us forget exactly how on earth we did them (assuming we didn't give up or "multi-quit"), which makes them harder to do again."

I guess that Pubilius Syrus (Roman slave, first century BCE) got it right: "To do two things at once is to do neither."