From Swordfish to Soda

That incident started Shaw Hughner on a path of studying food nutrition labels. One of the first things she learned in her studies was how ill-informed most parents were about what’s in their food. “It’s downright scary,” she says.

Recently, Shaw Hughner, now an associate professor at ASU’s Morrison School of Agribusiness, became interested in sugar-sweetened beverages, or SSBs. It was summer, and it seemed like every convenience store and gas station had enormous ads featuring enormous photos of frosty cups of soda. “In Arizona in summer,” says Hughner, “nothing is more appealing.” It didn’t cost much more to get 64 ounces than 24 ounces — and often it cost the same — so everyone was buying the bigger cups.

Public health advocates have been trying for years to put warning labels on SSBs that point out the detrimental effects of extra sugar and empty calories. Still, the public has been resistant to what they see as Big Brother controlling their choice of beverages. Researchers refer to this consumer behavior as “reactance theory.”

Shaw Hughner and her collaborator, Claudia Dumitrescu of Central Washington University, wondered what conditions would get consumers to respond to a warning label and buy smaller quantities of SSBs without feeling resentful. They designed two experiments to find out.

Through the online platform Amazon Mechanical Turk, Shaw Hughner and Dumitrescu recruited regular consumers of SSBs. In the first test, participants were shown an image of a typical soda fountain station, like one you’d see in a convenience store or fast-food restaurant, and asked to imagine they were about to purchase a sugar-sweetened beverage. Half of them also looked at a health warning label beneath the image that read, “SAFETY WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay.” Then they were asked to choose how much soda they wanted from five cup sizes, ranging from 14 to 30 oz.

Participants were randomly assigned to one of four experimental groups: with or without a warning label and with either value or proportional pricing. Each group was shown the corresponding prices next to each cup size, reflecting two pricing strategies. One group experienced value pricing, where all drink sizes were offered at the same price. The other group encountered proportional pricing, where the cost increased directly with the beverage size, eliminating the price advantage of larger portions. After selecting a drink, participants completed a brief questionnaire on how price influences their grocery shopping decisions. The second experiment additionally measured reactance.

In both experiments, the researchers found that the subjects were more likely to choose the smaller cup size only when there was a warning label and proportional pricing. In the second experiment, the subjects with the warning label and proportional pricing had lower reactance levels than those with the warning label and value-sized pricing. Among those with no warning label, there was no difference at all.

The only thing about the results that surprised Shaw Hughner was that neither the proportional pricing nor the warning label alone was enough to limit consumption of SSBs. They were only effective together.

“At the end of the day,” Shaw Hughner says, “what it shows is that we need the help of corporations. With policymakers alone, it doesn’t work. We need companies to do their part to adjust those pricing strategies so that you’re not rewarded so heavily by choosing that much-too-large size.”

She realizes this may be an uphill battle: Cheap soda, while not quite a loss leader, is still a massive draw for restaurants and convenience stores. But she remains cautiously optimistic.

“Maybe there’s a new crop of marketers coming along that will understand this,” she says. “Looking out for the needs of the public doesn’t have to conflict with the goal of making a profit.”