Are you a regular BYO bagger at the supermarket or greengrocer? Well done! But what is ‘intrinsic  reward’ for bringing your own bags? Have you contributed to reducing your carbon footprint and saved a plastic bag or few from entering the downcycle-sphere, leaving you with a happy ‘gold star’ feeling inside. Or do you need a congratulatory doughnut instead of a pat on the head.

Research reported in the Harvard Business Review  found that bringing your own bags wasn’t enough of a reward for shoppers.

The study, lead by Harvard Business School assistant professor Uma Karmarkar , analysed grocery receipts from Californian shoppers and found that people brought their own bags to the supermarket were more likely to a) buy organic products and b) reward themselves for their green behaviour by buying junk food.

From the interview conducted with Harvard Business Review:

“So this is the classic indulgence: You do good and—

Karmarkar: 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. 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.”

However, shoppers bringing their own bags were also more likely to ‘green up’ their purchases.

“Karmarkar: It was clear that shoppers who brought their own bags were more likely to replace nonorganic versions of goods like milk with organic versions. So one green action led to another.”

This type of behaviour is indicative of linking habit theory – where changing one portion of your habit or life can create a snowball effect, leading to other changes in the same area. So one green step can lead to another.  Recycling can lead to composting and other sustainability measures. The green bags lead to organic produce purchases and potentially awareness of food waste, buying local, food miles and changing consumer habits.

If only that doughnut were organic too…