<p class="first" id="P2">Delay discounting, the tendency to choose smaller immediate
rewards over larger delayed
rewards, is theorized to promote consumption of immediately rewarding but unhealthy
foods at the expense of long-term weight maintenance and nutritional health. An untested
implication of delay discounting models of decision-making is that selectively delaying
access to less healthy foods may promote selection of healthier (immediately available)
alternatives, even if they may be less desirable. The current study tested this hypothesis
by measuring healthy versus regular vending machine snack purchasing before and during
the implementation of a 25-second time delay on the delivery of regular snacks. Purchasing
was also examined under a $0.25 discount on healthy snacks, a $0.25 tax on regular
snacks, and the combination of both pricing interventions with the 25-second time
delay. Across 32,019 vending sales from three separate vending locations, the 25-second
time delay increased healthy snack purchasing from 40.1% to 42.5%, which was comparable
to the impact of a $0.25 discount (43.0%). Combining the delay and the discount had
a roughly additive effect (46.0%). However, the strongest effects were seen under
the $0.25 tax on regular snacks (53.7%) and the combination of the delay and the tax
(50.2%). Intervention effects varied substantially between vending locations. Importantly,
time delays did not harm overall vending sales or revenue, which is relevant to the
real-world feasibility of this intervention. More investigation is needed to better
understand how the impact of time delays on food choice varies across populations,
evaluate the effects of time delays on beverage vending choices, and extend this approach
to food choices in contexts other than vending machines.
</p>