So we introduced a token system.9 The children were given ten tokens at the beginning of the week. These could each be traded in for either thirty minutes of screen time or fifty cents at the end of the week, adding up to $5 or five hours of screen time a week. If a child read a book for thirty minutes, he or she would earn an additional token, which could also be traded in for screen time or for money. The results were incredible: overnight, screen time went down 90 per cent, reading went up by the same amount, and the overall effort we had to put into policing the system went way, way down. In other words, non-essential activity dramatically decreased and essential activity dramatically increased. Once a small amount of initial effort was invested to set up the system, it worked without friction.