So, what's a nudge? A nudge is some small feature of the environment that attracts our attention and alters our behavior.

In a typical 401k plan, when you first become eligible you get a big pile of forms and you're told, fill out these forms if you want to join. Tell us how much amount you've saved and how you want to invest the money. In, under automatic enrollment you get that same pile of forms but the top page says, if you don't fill out these forms, we're going to enroll you anyway and we're going to enroll you at this saving rate and in these investments.

Most people start claiming benefits within a year of when they become eligible, although benefits increase substantially if they wait.

If rather than setting the minimum balance as the lowest possible amount, so we keep people in debt for as long as possible, we raise the minimum payment and encourage people to pay off their credit cards, we're going to make less money, but we're going to have costumers that are more solvent.

I think we also have learned the lesson that we have to have better incentive structures.

The reason is they failed to learned the primary lesson we should have learned from when Long Term Capital Management went belly up ten years ago. That is, investments that seem uncorrelated can be correlated simply because we're interested in it.

A good rule of thumb is to assume that everything matters.