Although we think we're doing several things at once, multitasking, this has been shown to be a powerful and diabolical illusion. Earl Miller, a neuroscientist at MIT and one of the world experts on divided attention, says that our brains are "not wired to multi-task well. ... When people think they're multi-tasking, they're actually just switching from one task to another very rapidly. And every time they do, there's a cognitive cost in doing so."