A study done at the University of London found that constant emailing and text-messaging reduces mental capability by an average of ten points on an IQ test. It was five points for women, and fifteen points for men. This effect is similar to missing a night of sleep. For men, it’s around three times more than the effect of smoking cannabis. While this fact might make an interesting dinner party topic, it’s really not that amusing that one of the most common ‘productivity tools’ can make one as dumb as a stoner. (Apologies to technology manufacturers: there are good ways to use this technology, specifically being able to ‘switch off’ for hours at a time.) ‘Always on’ may not be the most productive way to work. One of the reasons for this will become clearer in the chapter on staying cool under pressure; however, in summary, the brain is being forced to be on ‘alert’ far too much. This increases what is known as your allostatic load, which is a reading of stress hormones and other factors relating to a sense of threat. The wear and tear from this has an impact. As Stone says, ‘This always on, anywhere, anytime, anyplace era has created an artificial sense of constant crisis. What happens to mammals in a state of constant crisis is the adrenalized fight-or-flight mechanism kicks in. It’s great when tigers are chasing us. How many of those five hundred emails a day is a tiger?
– David Rock
from Your Brain at Work