Reusable Grocery Bags: How Green Customers Help the Environment-and Your Business - Ideas for Leaders
Idea #542

Reusable Grocery Bags: How Green Customers Help the Environment-and Your Business

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Shoppers bringing their own bags help reduce the adverse environmental impact of plastic bags. New research shows, however, that the environment is not the only winner. Environmentally conscious shoppers are inspired to buy more expensive organic products, and reward themselves with unplanned indulgent purchases — a boon to grocery stores.


When people do good things, they reward themselves. This is the conclusion of a number of previous studies into the psychology of doing good deeds. Two researchers from Harvard Business School and Duke University’s Fuqua School of Business explored through their own series of studies the business implications of this previous psychological research.

The researchers looked specifically at the case of reusable grocery bags, an effort to avoid the negative environmental impact of the proliferation of plastic and paper grocery bags. They wondered: How does bringing or purchasing a reusable grocery bag, instead of using disposable plastic or paper bags, influence the purchases of a shopper?

To answer these questions, the researchers used nearly two years’ worth of loyalty card data from the transactions of a single grocery chain. The data, which covered 884 household making 143,000 shopping trips, included information on whether the shoppers brought or purchased a reusable bag. Only households who brought or bought reusable bags some of the time were used in the study. This allowed the researchers to compare the actions of the same shoppers on trips during which they brought or bought reusable bags and other trips they didn’t.

The deep analysis of the real-world data was complemented by a series of laboratory experiments in which participants were given different scenarios (e.g. you brought you own reusable grocery bag, you used the plastic bags of the store, you are required by the store to use reusable bags) and then asked to choose follow-up actions (e.g. pick 10 items to buy, decide whether to buy rather expensive chocolates at the check-out counter, etc.).

The results from the data analysis and the follow-up experiments revealed the varied psychological impact on shoppers who brought or purchased reusable bags.

The research showed that when consumers bring their own bags, they are primed to choose more environmentally friendly products, which in the grocery store translates into organic products. Priming occurs when external influences prepare or ‘prime’ a mind to think in certain ways or of certain things.

Second, the research showed that when consumers bring their own bags, they feel licensed to purchase more indulgent products. Licensing is generated internally: when someone feels he or she has done something that should be rewarded, the action permits or ‘licenses’ some kind of subsequent rewarding action.

The research also showed that customers who purchased bags didn’t feel as virtuous as customers who brought their bag, and thus purchased less indulgent products. They did not, however, purchase less organic products, proving that the psychological mechanisms leading to organic and indulgent purchases are different, as described above.

Looking at the purchasing data to identify households with children, the researchers concluded that parents are less likely to be impacted by the action of bringing reusable bags — i.e. they did not buy more organic or indulgent products.

Finally, the research showed that if price becomes an issue — that is, if customers pay more attention to the price of organic or indulgent products — they are less inclined to buy these products even when they brought reusable bags. The researchers found, in short, that premium pricing mitigated the effect of bringing reusable bags.


These results have managerial implications for retailers offering or encouraging environmentally friendly actions. The first implication is that encouraging a green action such as bringing your own reusable bag is good for the store. Customers will be in the mood to buy organic, and they’ll reward themselves with some indulgent purchases.

The research on attribution — customers giving the store credit for the green action instead of giving themselves credit, which happens when customers purchase the bags instead of bringing them — shows that it’s better to encourage customers to take action than to force them. If a store requires customers to use reusable bags or strongly pushes them (through free bags, for example) to use them, customers do not feel the same satisfaction in making the decision, and thus are less inclined to reward themselves with indulgent products.

Another business implication of the research — remembering that customers who bring reusable bags are more likely to buy organic and indulgent products — is to promote environmentally friendly products such as organic or farm-raised foods as indulgent. This psychologically one-two punch will undoubtedly increase purchase rates for these foods.

And still another implication of the research relates to the old retailing motto of location, location, location. First, stores should place organic offerings near the door. Remember that customers with reusable bags are primed to shop in an environmentally friendly way. Take advantage of this priming as soon as they enter the store.

As these customers wander through the store, give them little reminders through in-store messages about how virtuous they were to bring their own bags. The idea is to keep the flame of indulgent rewards alive. As they reach the checkout counters, emphasize the indulgent characteristic of the checkout counter products to give them the final push.

Of course, at the checkout counter and throughout the store, the prices of organic and indulgent products should be as discreet as possible. Premium prices dampen the effect of reusable bags.



BYOB: How Bringing Your Own Shopping Bags Leads to Treating Yourself, and the Environment. Uma R. Karmarkar & Bryan Bollinger. Journal of Marketing (July 2015). 

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Idea conceived

July 1, 2015

Idea posted

Aug 2015
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