Endless options can be exhausting. We need to know when choice matters. Cass Sunstein, March 28, 2015, Opinion. "All over the world, taxis have installed credit card touchscreens, which makes three possible tips visible and simple for customers to select with a quick “touch”. In New York City, the suggested amounts are usually 20%, 25% or 30%. People are free to give a larger tip, a smaller tip or no tip at all, but it is easiest just to touch one of the three conspicuous options. What are the effects of the suggested numbers? The economists Kareem Haggag and Giovanni Paci compiled data on more than 13m New York taxi rides. They found that the touchscreen has led to a significant increase in tips – by an average of more than 10%..." Link