“Consult your physician immediately if . . .”

It’s difficult to turn on the TV today without seeing an advertisement for one drug or another. That’s not surprising, since drug makers spend billions of dollars each year to promote their treatments for depression, low testosterone, osteoporosis, incontinence, erectile dysfunction, and more. The ad spots are aimed not at physicians but at patients themselves.

These ads are required to list the most serious side effects for the prescription drugs they promote, and some are indeed serious—nausea and bleeding and blindness and suicidal thoughts, even death. The warnings are so dire that they must scare some consumers away, yet drug marketers continue to flood the airways.

Are they smart to do so? Do consumers take these warnings seriously, and do these frightening catalogs of symptoms change their attitudes toward the drugs? Psychological scientist Ziv Carmon, of INSEAD in Singapore, has been studying the way TV viewers process product warnings—not just for drugs but for cigarettes and artificial sweeteners as well. Working with Yael Steinhart of Tel Aviv University and Yaacov Trope at NYU, Carmon has been exploring how warnings stack up against the seductive benefits that marketers hope for.

Carmon and colleagues ran four simple experiments, all basically the same, though with different products and slightly different measures of their impact. In one, for example, they recruited a group of men to watch an advertisement for an erectile dysfunction drug, which listed heart disease as one of the potential side effects. Half of the men were told that the drug was about to come on the market, while the others were told that it would not hit the pharmacy until the following year. Then they all rated the attractiveness of the drug. They also said if the warnings concerned them, or if they boosted their trust in the drug.

I know. Why would dire warnings boost anyone’s trust in a product? Well, the scientists theorize that the warnings can have an ironic effect of boosting trust under certain circumstances. Specifically, time can create psychological distance, and this distance can make us interpret messages in an abstract way. Accordingly, the scientists expected that those men who heard warnings about a future product would react to the ad as an honest “conversation” between themselves and the drug maker—actually boosting trust. By contrast, those who heard the same scary warning about a readily available drug would focus on the here-and-now, including the risk of heart disease.

And that’s precisely what they found in the study. As described in the journal Psychological Science, men who saw an ad for an immediately available drug were very concerned about the risks. But the men who were thinking of the ED drug as a future possibility—they viewed it more favorably, and they also viewed the ad as more trustworthy. Psychological distance had the ironic effect of diminishing worry about side effects.

This experiment simulates real life, in the sense that most our important decisions involve some contemplation over time. As time passes, our immediate fear of side effects gives way to general feelings of trust. Carmon and his team ran similar experiments with ads for cigarettes, artificial sweeteners and hair loss medications, and got basically the same results. In each case, the product was immediately available—or a more distant option. In some cases, only some saw a warning of side effects, while others saw no warning. In every case, psychological distance boosted trustworthiness, which led to more favorable views of products with warnings. The consumers didn’t focus on the actual bleeding and nausea, but rather on the marketers’ good intentions in describing those symptoms.

Cigarette makers have long been prohibited from hawking their product on American TV, but the drugs now being promoted directly to consumers are not benign. The presumption is that the explicit warnings about dangerous side effect will make people think twice before taking medical risks. This research shows why this presumption may be naïve. The more time that elapses after the warning message, the more likely it is that the warning will backfire—with the ironic and worrisome effect of boosting trust in the drug makers.

Wray Herbert’s blogs—“We’re Only Human” and “Full Frontal Psychology”—appear regularly in The Huffington Post and elsewhere.