Brief Vending Machine Delay Helps People Make Better Snack Choices

When a vending machine withheld junky snacks for 25 seconds, people were slightly more likely to choose a healthier option

Vending machine
Your vending machine is judging you. RubberBall / Alamy Stock Photo

When buying treats from a vending machine, we often have the opportunity to choose between unhealthy and (relatively) healthy snacks. Doritos or popcorn? Snickers or a granola bar? Peanuts or so-bad-yet-so-good cheese crackers?  According to an inventive new study, a short delay may help people make better choices when confronted by a tantalizing selection of snacks, Angus Chen reports for NPR.

Brad Appelhans, associate professor of preventative medicine at Rush University Medical Center, designed a special vending machine system that forced people to wait 25 seconds for unhealthy nosh. He called his invention DISC, or “Delays to Influence Snack Choices,” and outfitted Rush University with the new technology across campus.

Appelhans and his team of researchers categorized snacks as healthy if they met five out of seven criteria, like containing less than 250 calories, less than 350 mg of sodium, and no trans fats. They then placed these less salubrious snacks in the top half of a vending machine. Once ordered, they were caught on a platform for the waiting duration. Healthier choices were sorted at the bottom, allowing them to evade the platform.

The scheme was advertised clearly in a decal on the machine’s display window, letting customers know that they would be in for a short wait if they opted for unhealthy treats.  The DISC vending machines also came equipped with a “delivery countdown,” which allowed people to change their snack choices during the delay, according to a Rush University press release.

The team’s findings, which were presented at the Society of Behavioral Medicine's Annual Meeting & Scientific Sessions in San Diego, state that the 25-second delay resulted in two-to-five percent increase in the proportion of healthy items that were purchased from the vending machine. It’s a small change, but as James Hamblin writes for The Atlantic, that number might represent a significant increase if it is extrapolated across the 1.3 million vending machines in the U.S. These machines have become “the most prevalent source of high-calorie snacks in the U.S.,” according to the press release.

The researchers did not observe a decrease in total sales volume or revenue of the DISC vending machines—a point that is “important to vending machine operators," Appelhans says in a statement. Hungry patrons, in other words, were not buying significantly fewer snacks from the judgmental vending machines. They were simply opting for healthier ones.

Why did the scheme work? One reason might be that the DISC vending machines tapped into human preference for instant gratification. "It could be that people don't like waiting and will pick a quicker choice,” psychologist Marlene Schwartz tells Chen.

“And also you're giving them time to think about it," Schwartz added. "It's clear in these machines which are healthier options. Building this in probably increases the amount of attention to the healthier options."

Throughout 14 months of experimentation, researchers also tested the effects of a 25-cent tax on unhealthy vending machine snacks and a 25-cent discount on healthier ones, according to Amanda MacMillan of Health. Those scenarios also boosted the number of healthy snacks purchased, but toying with food taxes can be a tricky business. Local and state governments have recently been trying to curb sugar intake by placing taxes on sugary drinks, for instance, but such measures have prompted outcries from consumers and companies. Making junky snacks a little harder to access, however, may be a gentler, more palatable way to nudge people towards healthier food options.

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