“Every time you shift your attention from one thing to another, the brain has to engage a neurochemical switch that uses up nutrients in the brain to accomplish that. So if you’re attempting to multitask, you know, doing four or five things at once, you’re not actually doing four or five things at once, because the brain doesn’t work that way. Instead, you’re rapidly shifting from one thing to the next, depleting neural resources as you go.”
Dr. Daniel Levitin