How grocery bags manipulate your mind…

Be careful while taking your own bags for shopping. There is a probability that you will either binge on extra calories via ice-cream/chocolates etc.

HBSWK has this superb summary of research by Uma R. Karmarkar and Bryan Bollinger on the topic.

There’s a classic cartoon plot device that represents a struggle with temptation. A tiny angel pops up on the conflicted character’s left shoulder, urging him to follow the path of righteousness. A tiny devil sits on his right shoulder, pressing him to give into his desires.

In real life, it turns out that an everyday item has the power to act as both angel and devil every time we go to the grocery store. It lurks in car trunks and pantries all over the world, waiting to guide us simultaneously down paths of virtue and vice. What is this surprising Svengali?

It’s a reusable shopping bag.


First they track shopping behavior of customers.

Looking at loyalty card data from a large grocery chain in California, Karmarkar and Bollinger tracked and analyzed 936,232 purchases by 5,987 households across two years. To assess organic purchases, they looked for transactions in which the consumer could choose either an organic or a nonorganic option—a carton of milk, for example. In monitoring what they called “indulgent” purchases, the researchers looked at sugary items like ice cream and candy bars, as well as salty treats like potato chips.

The data showed a definite correlation: Shoppers who had brought their own bags bought decidedly more indulgences and chose more organic products than those who didn’t. But this wasn’t necessarily enough information to establish causality—that is, that both effects were specifically due to bringing their own bags. “There are a lot of things going on in a store and a lot of inputs,” Karmarkar says.

They dug further:

In the first experiment, the researchers assigned participants to one of two conditions. The “with bags” participants were asked to imagine approaching a supermarket to do their grocery shopping with their own bags. The “without bags” group received nearly identical instructions, but nothing about bags was mentioned. All the participants looked at a floor map of the grocery store and listed 10 items they would most likely purchase on their hypothetical outing.

Regarding indulgent items, the results depended on whether the participants had children in their households. For those with dependents, there was no significant difference between the with-bags and the without-bags condition. For those without children, the with-bags participants were more likely to imagine buying ice cream and potato chips than the -without-bags- participants.

But the results couldn’t speak to organic items; while participants listed items such as milk and vegetables, they generally didn’t list whether their hypothetical choices were organic milk and vegetables.

Then there are other experiments trying to look at the issue from different angles. The Prof says:

“A simple way I think about those results is that if you do something good, you reward yourself,” Karmarkar says. “You did something good for the environment, so you can have a cookie.”

This opens opportunities for stores:

For retailers, the results suggest that store managers should reconsider where they display their organic items. In short, it may make sense to locate the kale near the Kit Kats.

“The research implies that the area near the checkout counter is a good place to display organic or environmentally positive items,” Karmarkar says. “That’s the place where shoppers’ attention is probably going to be most focused on this element, the bag, which seems to encourage them to buy these things.”

For consumers, she recommends that they just think about the findings as they stroll down the grocery store aisles.

“I’m of the mindset that it’s useful to know the kinds of things that influence your own behavior,” Karmarkar says. “If you’re trying to maintain a strict diet, maybe you can recognize the bag’s influence, and consciously fill the desire to treat yourself in another way that doesn’t interfere with your goals. Maybe you can treat yourself to an extra half hour of sleep.” 

Useful stuff.

Though I have a different kind of issue  in mind as well. Most cities in India have banned usage of plastic bags and ask the stores to charge customers if they demand a plastic bag. Now I am sure it has desisted some shoppers as one does see shoppers carrying their own bags

But at the same time it has become a source of earning for the stores as some shoppers continue to use bags. And this typically happens in case of a heavy bill or large number of items. The shopper thinks if I am spending so much how does a cost of bag matter?

So for smaller and daily need items people still carry bags or there is a shift in thinking as the cost of the bag becomes a larger % of budget. But not really for large number of items and heavy bills. Atleast that is the hypothesis which needs to be tested. The other hypothesis is to see whether this decision has lowered plastic bag litter in the places where it has been banned..

I think the onus should also be on stores to move to reusable bags. Some stores have but others just don’t care. By simply selling bags for a price has become easy money. People still do forget bags and end up paying for a plastic bag. If the stores are also pushed into being more responsible may be the effort would be lot better.


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