Shopping with reusable bags can change your grocery buying habits in surprising ways, a recent study found.
“As concerns about climate change and resource availability become more central in public discourse, using reusable grocery bags has been strongly promoted as an environmentally and socially conscious virtue. In parallel, firms have joined policy makers in using a variety of initiatives to reduce the use of plastic bags,’’ said the report by marketing professors Uma R. Karmarkar, from Harvard Business School, and Bryan Bollinger, from New York University’s business school.
The researchers cited a recent survey by Food Shopper Insights that found about 29 percent of consumers said they had used their own reusable bags during their most recent trip to the supermarket.
“However,’’ the report said. “little is known about how adopting reusable bags might alter consumers’ in-store behavior.’’
Using transaction and cardholder data from a single “major’’ grocery chain store in California – which was not identified – the researchers uncovered several fascinating examples of reusable bags changing shoppers’ buying patterns.
Over a two-year period, the study tracked more than 2 million transactions from more than 59,000 households. For the analysis, about 935,000 of those transactions, representing about 6,000 households, were used.
“These findings have implications for decisions related to product pricing, placement and assortment, store layout, and the choice of strategies to increase the use of reusable bags,’’ the study said.
1. Buy more ‘green,’ organic goods
Feeling good about your decision to ‘go green’ with reusable bags, you make even more environmentally-friendly choices.
“For example, seeing reusable bags in their cart could evoke goals of buying environmentally friendly products, or signal to consumers that they are the type of virtuous people who takes socially or morally responsible actions,’’ the study said.
For instance, you buy more organic and green products.
The study found that buyers with reusable bags paid an average premium of about 15 percent for organic goods. According to researchers, this particular effect of reusable bag use is boosting the $550-billion industry’s profits by about $280 million.
2. Reward yourself and indulge
You also feel so proud about helping the environment, you reward yourself with treats.
“After the first virtuous action, we find that participants can increase indulgent choices regardless of, or in addition to, making other virtuous choices,’’ the report said.
For example, you indulge in more desserts, like ice cream, and snacks, like potato chips.
The study found that this particular effect of reusable bag use is increasing the supermarket industry’s profits by about $204 million.
3. Won’t indulge if you have young children
However, if you have young children, you typically – feeling responsible for the young ones’ health – won’t indulge as much or at all.
“In particular, children have distinct influences on grocery basket composition, including in the realm of health conscious choices and snack foods including indulgences,’’ the study said.
4. Spend more if reusable bag is your call
If you’re at a store where reusable bag use is optional, you’re also generally willing to spend more, particularly on organic and indulgent items.
“Policies that encourage bag use that emphasize the social and environmental benefits of the bags, but also emphasize the shopper’s agency in choosing to use them will have the strongest impact on behavior in both organic and hedonic domains,’’ said the report.
5. Spend less if forced to use reusable bags
But, at stores that only allow reusable bags or at ones that charge customers to use the traditional paper or plastic bags, you’ll likely spend less, particularly on organics and indulgences.
“If consumers are aware that they have brought grocery bags because they were told to, their desire to purchase indulgences weakens,’’ the study said.
Catch up with The Boston Globe for free.
Get The Globe's free newsletter, Today's Headlines, every morning.