In a recent study on multitasking, researcher Zhen Wang mentions that if we study with our books open, watch TV at the same time and text friends every so often, we get a great feeling of fulfillment. We are getting all these things done at once, and we feel incredibly efficient. Unfortunately, exactly the opposite is the case. Wang found that students who engaged heavily in multitasking activities felt great, but their results were much worse than that of people who didn't multitask.
As it turns out, our brains can't multitask at all. If we have lunch, 5 Facebook chat windows open and also try to send off an email, it isn't that our brain focuses on all these activities at the same time.
Instead, multitasking splits the brain. It creates something researchers have called "spotlights". So all your brain is doing is to frantically switch between the activity of eating, to writing an email, to answering chat conversations.
What's more is that Clifford Nass, a researcher at Stanford assumed that those who multitask heavily will nonetheless develop some other outstanding skills. He thought that they will be amazing at 1. filtering information, 2. being very fast at switching between the tasks and 3. keeping a high working memory.
He found that none of these 3 points are true: "We were absolutely shocked. We all lost our bets. It turns out multitaskers are terrible at every aspect of multitasking."
People who multitask a lot are in fact a lot worse at filtering irrelevant information and also perform significantly worse at switching between task, compared to singletaskers.