There's a book called Nudge: Improving Decisions About Health, Wealth, and Happiness, and it basically explains behavioural economics. The example that starts out this book is a high school cafeteria, and what we're asked to imagine is how the diet of the kids would change depending on how you arrange the food choices. If you think about that for a minute, I think we would all agree that by arranging the order that people go through the choices in food, you could create healthy diets or poor diets.
The analogy is actually a very powerful one because it explains how people make decisions, and, by the way, a lot of the stuff the Obama administration is doing is based on these notions of behaviour. The point of the Nudge book is that we could do the same thing with retirement savings, in that how we design the mechanism impacts how people behave. If we can do a really good assessment of what makes the most sense, then we can design that.