MIT neuroscientist Earl Miller explains that humans can only consciously think about one or two things at a time. What we call multitasking is actually rapid switching between tasks, not parallel thinking. This limitation is hardwired by evolution, though many people, especially teenagers, overestimate their ability to do multiple things at once.
One of the real bombshells for me was when I went to interview an amazing neuroscientist, one of the leading neuroscientists in the world, a man named Professor Earl Miller. He's at mit, where I interviewed him. Professor Miller said to me, look, there's one thing you need to understand about the human brain more than anything else. You can only consciously think about one or two things at a time. That's it. This is a fundamental limitation of the human brain. The human brain has not changed significantly in 40,000 years. It's not going to change on any time scale we're going to see. But what's happened is we've fallen from mass delusion. The average teenager now believes they can follow seven forms of media at the same time. And the rest of us are not far behind them. So what happens is scientists like Professor Miller, scientists all over the world get people into labs and they get them to think they're doing more than one thing at a time, and they monitor them. And what they discover is always the same. You can't do more than one thing at a time. What you do is you juggle very rapidly between tasks.
