Daniel J Levitan: ‘When trying to concentrate on a task, an unread email in your inbox can reduce your effective IQ by 10 points.’Our brains are busier than ever before. We’re assaulted with facts, pseudo facts, jibber-jabber, and rumour, all posing as information. Trying to figure out what you need to know and what you can ignore is exhausting. At the same time, we are all doing more. Thirty year