Mirrors in Grocery Carts

One of my colleagues forwarded me this article in the New York Times on some research published in an agricultural economics journal on the effects of "nudges" on consumer purchases of vegetables and produce.  

One part of the authors' research program is looking at how placing a mirror in the cart affects sales (I suppose it is supposed to encourage you to think more about the effects of your purchases on your long term self).  They don't yet know what effects the mirrors will have, but what they have found is the following: 

the scientists tinkered again with the cart, creating a glossy placard that hung inside the baskets like the mirrors. In English and Spanish, the signs told shoppers how much produce the average customer was buying (five items a visit), and which fruits and vegetables were the biggest sellers (bananas, limes and avocados) — information that, in scientific parlance, conveys social norms, or acceptable behavior.
By the second week, produce sales had jumped 10 percent, with a whopping 91 percent rise for those participating in the government nutrition program called Women, Infants and Children. 

This research is being facilitated by a grocery chain, which is interesting.  I find it interesting because this research and the author's article (Michael Moss) position this as research into the "Nudge" phenomenon advocated by many behavioral economists:

Mr. Payne and Mr. Niculescu are pursuing a strategy that behavioral scientists call nudge marketing, an idea popularized by the 2008 book “Nudge,” by the former Obama administration regulatory affairs administrator Cass R. Sunstein and the University of Chicago professor Richard H. Thaler.
Nudge marketing calls for applying just the right amount of pressure to persuade: not too little, not too much.

Here's my beef.  The Sunstein and Thaler book is primarily about government "nudges".  This research is about a grocery store's "nudge".  Retailers try to nudge us all the time - it's called advertising.  And I suspect this store will not continue with the mirrors and special carts if it ultimately hurts sales in the long run. The difference between a store nudge and a government nudge is important: if we don't like what a store is doing, we can leave and shop elsewhere.  Stores have an incentive to only adopt those nudges that consumers actually want, as revealed in their purchase behavior.  Governments, by contrast, have no such accountability or rapid feedback mechanisms.  For these reasons, I think it is important to draw a distinction between marketing and advertising on the one hand and nudging on the other.