Ironically, warning labels on cigarettes and over-the-counter drugs may actually increase the sales of the product. Psychological scientists have found that under certain conditions, a clear warning may be interpreted by consumers as an admirable attempt at honesty, thus boosting the demand of the item it is intended to control. In a market where such labels abound, the findings may urge health officials to rethink current warning strategies.

Published in the journal Psychological Science, the new study investigated consumer decision making in a world where potentially harmful products are subject to increasingly strict regulations. Today, virtually all products must feature information regarding possible side effects and health risks. These labels range from subtle warnings to graphic photos.

“We were struck by just how detailed, clear, and scary many warnings had become with regard to potential negative side effects of products,” said study author Ziv Carmon, a psychological scientist at the Institut Européen d'Administration des Affaires (INSEAD) in Singapore. "It then occurred to us that such warnings might perversely boost rather than detract from the appeal of the risky product."

To test their hypothesis, Carmon and his colleagues designed four experiments. In one experiment, a number of smokers were shown one of two versions of the same cigarette ad: one with a clear warning that smoking causes cardiovascular disease and cancer, and one with the warning removed. Later on, subjects were then given the opportunity to purchase the advertised cigarette.

When subjects were offered the opportunity to buy cigarettes soon after the experiment, those who had seen the ad that included the warning were less likely to make the purchase. However, a few days later, subject appeared to buy more if they had seen the same warning. Intriguingly, identical experiments with artificial sweeteners in place of cigarettes yielded the same results.

The curious findings led the researchers to believe that the intervening time between advertisement exposure and consumer decision making caused the warning labels to backfire. They theorized that as the initial visceral reaction wore off, subjects began to abstract intent from the warnings. At this point, the labels took on a new meaning: rather than a potentially harmful product, they suddenly signified an honest and caring manufacturer. As a result, sales increased.

"This effect may fly under the radar since people who try to protect the public — regulatory agencies, for example — tend to test the impact of a warning shortly after consumers are exposed to it," Carmon told reporters. "By doing so, they miss out on this worrisome delayed outcome."

The effects of warning labels on smokers was probed in a similar capacity earlier this year, when researchers at the Hebrew University of Jerusalem and the Technion-Israel Institute of Technology sought to answer the question why so many smokers still smoke. The study offered similar advice to regulatory agencies, and urged health officials to reexamine the processes whereby prospective warning labels are evaluated. 

Source: Y. Steinhart, Z. Carmon, Y. Trope. Warnings of Adverse Side Effects Can Backfire Over Time. Psychological Science, 2013; 24 (9)