Bags of Junk Food

The Type of Grocery Bag You Use Could Influence What You Buy
July 13, 2015

Those giant reusable grocery bags hold a lot of food, and marketing researchers say the feeling you get when you use them could be causing you to pack those bags with junk food.

Duke University marketing professor Bryan Bollinger and Harvard University business professor Uma Karmarkar studied the buying habits of almost 900 families who would sometimes use reusable bags over a two-year span.

The receipts from these shopping trips showed more ice cream, chips and candy in the cart when the shoppers brought their reusable bags.

The researchers also conducted a lab test in which they asked 111 people to pretend they were shopping with either reusable or disposable bags and list what they would buy. The reusable bag group listed twice as many junk food items as the store bag group.

Bollinger and Karmarkar say this is due to a psychological phenomenon called self-licensing. The basic idea is that when you do something good like protect the environment with your reusable bags, you are more likely to overlook doing something bad like buying an unhealthy snack.

Their research supports this conclusion. In the lab test, half of the reusable bag participants were told that the store required reusable bags, while the other half were told they brought them themselves. Only the participants who “brought” the bags of their own volition said they would buy extra junk food.

Those who were “required to bring bags” were not making that good choice and therefore did not feel entitled to the snacks.

You can learn more about this research here. The study was published in the Journal of Marketing.

— Daniel Lane

Daniel Lane covers science, engineering, medicine and the environment in North Carolina.