Rush's 'time tax': a 25-second wait steers vending users to healthier snacks

Brad Appelhans, an associate professor of preventive medicine at Rush University Medical Center, built DISC — 'Delays to Influence Snack Choice' — a platform fitted inside ordinary vending machines. Operators stock processed snacks in the top half, where every drop lands on DISC and starts a 25-second countdown; healthier fare that meets at least 5 of 7 criteria (under 250 calories, 350mg sodium or 10mg added sugars per serving, no trans fats, under 35% of calories from fat) sits in the bottom half and falls instantly.

Over several months with DISC in machines around Rush University, trying a different price condition each month, healthy choices rose roughly 5% whenever the delay ran — about the same lift as cutting healthy snacks' price by 25 cents, but unlike the discount it did not hurt the machine's overall revenue. The results were presented at the Society of Behavioral Medicine's annual meeting in San Diego, and Rush has a patent pending on the device.

Economist David Just of Cornell and psychologist Marlene Schwartz of the University of Connecticut, neither involved in the study, read it as a way around the politics of food taxes: small amounts of time are something pretty much everybody has. Schwartz called it 'a brilliant idea' and floated stealth variants; Appelhans suggested extensions like fast-lane checkout for smart carts full of healthy food.

A roughly 5% shift in healthy-share matched what a 25-cent discount achieved — without giving up any revenue, unlike price subsidies.

Soda taxes show price levers provoke pushback and hit food-insecure households hardest; a minor delay dodges both problems.

The hardware is cheap and retrofit: one platform plus a decal turns an existing machine into a nudge device.

Independent researchers at Cornell and UConn endorsed the mechanism, calling it 'promising' and 'brilliant'.

Time can be taxed where money can't: a small visible delay shifts choices as a price subsidy would, but the operator keeps full margin and nobody's pocket is touched.

Appelhans presented the findings at the Society of Behavioral Medicine's 2017 meeting in San Diego and noted the small effect could add up across a million US vending machines. He proposed taking the idea beyond vending — for example, smart shopping carts loaded with healthy food earning a fast checkout lane, 'something' he said didn't yet exist. Rush University held a patent pending on DISC.