We have known for a long time that repeated interruptions affect concentration. In 2005, research carried out by Dr Glenn Wilson at London’s Institute of Psychiatry found that persistent interruptions and distractions at work had a profound effect. Those distracted by emails and phone calls saw a 10-point fall in their IQ, twice that found in studies on the impact of smoking marijuana. More than half of the 1,100 participants said they always responded to an email immediately or as soon as possible, while 21% admitted they would interrupt a meeting to do so. Constant interruptions can have the same effect as the loss of a night’s sleep.
Nicholas Carr picked up on this again in an article in the Atlantic in 2008, before going on to publish his book The Shallows two years later. “Immersing myself in a book or a lengthy article used to be easy,” he wrote. “My mind would get caught up in the narrative or the turns of the argument, and I’d spend hours strolling through long stretches of prose. That’s rarely the case any more. Now my concentration often starts to drift after two or three pages. I get fidgety, lose the thread, begin looking for something else to do. I feel as if I’m always dragging my wayward brain back to the text. The deep reading that used to come naturally has become a struggle.”
The impact of interruptions on individual productivity can also be catastrophic. In 2002, it was reported that, on average, we experience an interruption every eight minutes or about seven or eight per hour. In an eight-hour day, that is about 60 interruptions. The average interruption takes about five minutes, so that is about five hours out of eight. And if it takes around 15 minutes to resume the interrupted activity at a good level of concentration, this means that we are never concentrating very well.