Does Using Reusable Grocery Bags Changes How You Shop for the Worse? A Study Says Yes

Bringing Your Own Reusable Grocery Bags Changes The Way You Shop

Do your reusable grocery bags give you a license to buy junk food?

When you bring your own reusable grocery bags to the grocery store it actually impacts purchasing patterns. That pat on the back that we give ourselves for reducing our impact has a subconscious effect on what we bring home in those bags, according to Uma Karmarkar, an assistant professor of marketing at Harvard Business School, and her research partner Bryan Bollinger, of Duke’s Fuqua School of Business.

Karmarkar and Bollinger looked at the cash register receipts of those shoppers that brought their own bags. They could easily tell who brought their own reusable grocery bags by the bag discounts on the receipts. They found that these shoppers were more likely to buy organic foods but at the same time, they were also more likely to buy high fat and calorically dense junk food.

And it wasn’t just based on the people. For example, when an individual brought their own bag one week and didn’t the next week, they were more likely to make the organic and junk food purchases on the weeks that they brought their own bags.

“You give yourself a cookie. In this case literally. In consumer psychology the word ‘licensing’ is the key. If I behave well in one situation, I give myself license to misbehave in another, unrelated situation,” said Karmarkar to the Harvard Business Review. “Similar research has also been done on health decisions. I get a Diet Coke; I treat myself to a hamburger. In this case bringing a bag makes you think you’re environmentally friendly, so you get some ice cream. You feel you’ve earned it.”

Researchers think that it’s a subconscious behavior, meaning that they don’t actively think they get a cookie for bringing a bag. When bringing your own bag becomes more common, then the pat on the back behavior will also be less common. For example, in some places, recycling bottles and cans is a requirement, so people are less likely to reward themselves for the behavior.

The effect also disappears when people have kids because the motivations are different. Parents bring their own bags to be role models and they buy healthy foods to feed their families. Karmarkar says that location may also matter, in that store behavior in California may be different than store behavior in South Carolina.

But none of this is to say that bringing your own bags doesn’t make a big difference, because it does. Consider that a plastic bag could take anywhere from 15 to 1,000 years to decompose. And when plastic bags do decompose they dissolve into toxic polymer particles and the majority of that toxic waste ends up in our oceans, maiming and killing marine species. Plus the cost of recycling plastic bags outweighs their value, so many recycling facilities won’t take them.

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Image of a reusable bag on a bike from Shuttershock