The best-known example of a nudge from Thaler and Sunstein is "Save More Tomorrow."
Most Americans say they want to put more money away in savings accounts, but few do it. If you offer employees an option to select automatic savings from their paychecks, most will say they are for it, but only about a fifth will actually get around to setting it up. However, if the default is that they are all signed up for an automatic savings deduction of, say, 2%, unless they opt out, 90% will start savings.
And what has happened two years later, when the workers have had a chance to see that 2% flow out of their paycheck and into a savings account? 98% have joined the automatic savings plan.
That is a pretty good nudge.
The further nudge of Save More Tomorrow is that every time you get a raise, a hunk of it is added to your savings deduction, before you ever see it in a paycheck. Then your savings starts to really build up - and you never miss it.