Bad Influence
If Congress approves tobacco legislation this year, it will be part of a deal that dramatically changes the way cigarette companies promote their products: no more outdoor ads, human or cartoon figures, sporting event sponsorships, trinkets or clothing embossed with brand names, or ads in magazines that teenagers like to read. Not content to wait, cities across the country are imposing their own limits on cigarette signs and billboards.
The premise behind these restrictions is that fewer ads will mean fewer smokers. Yet there is remarkably little evidence that advertising plays an important role in getting people to smoke, as opposed to getting them to smoke a particular brand. Every time a study purports to show that people smoke because of advertising and promotion, a close examination reveals that it actually shows something else.
The most recent example is a study reported in the February 18 Journal of the American Medical Association. The authors, led by University of California at San Diego researcher John P. Pierce, claimed to be presenting "the first longitudinal evidence…that tobacco promotional activities are causally related to the onset of smoking." They estimated that one-third of adolescent experimentation with cigarettes, involving 700,000 American teenagers each year, "can be attributed to tobacco promotional activities."
As usual, newspapers uncritically regurgitated the researchers' conclusions. "Advertising, Teen Smoking Found Related," said the headline in The San Diego Union-Tribune. The article quoted Pierce as saying, "Our study is the first to conclusively prove that the effect of tobacco marketing happens at the very beginning, and encourages teens to start the process of becoming a smoker."
According to The Washington Post, Pierce et al.'s findings "indicate that young people's decisions to begin smoking are influenced by advertising." The New York Times said the study "concluded that exposure to cigarette advertising was a significant factor in whether teen-agers took up smoking."
In reality, the study did not even measure "exposure to cigarette advertising." Instead, Pierce and his colleagues surveyed California teenagers and assessed their "receptivity to tobacco advertising and promotional activities" by asking them about the cigarette brand they had seen advertised most often, their favorite cigarette ad, and their use or willingness to use a cigarette promotional item (such as a jacket or flashlight). They also asked the teenagers whether they smoked and, if not, whether they might in the future.
Three years later, the researchers re-interviewed 1,752 of the respondents who had said they didn't smoke and didn't think they would. The more "receptive" ones were more likely to have "progressed toward smoking," meaning they now said they might smoke, reported experimenting with cigarettes, or had smoked a total of five packs or more.
Of the teenagers who had said they owned or might obtain a promotional item (classified as highly receptive), 62 percent had moved in the direction of smoking, compared to 38 percent of those who couldn't name the most advertised brand and said they weren't willing to own a promotional item (classified as minimally receptive). Only 22 percent of the minimally receptive teenagers had experimented with cigarettes, compared to 34 percent of the others. Based on the difference between those two rates, Pierce et al. blamed one-third of experimentation on advertising and promotion.
The problem is, the researchers never measured exposure to this evil influence, let alone showed that it was correlated with smoking. So far as we know, all of these teenagers, whether they had started smoking or not, were exposed to the same amount of advertising and promotion.
The variable that Pierce et al. did measure, "receptivity," seems to be a pretty good index of attitudes toward smoking. It stands to reason that teenagers who strongly disapprove of the habit are less likely to smoke and also less likely to admire a Camel ad or own a Marlboro tote bag. And it's hardly surprising that teenagers who express a positive attitude toward such things are more likely to try cigarettes at some point, even if they once told an interviewer they had no interest in smoking.
Pierce and his colleagues were so determined to indict advertising and promotion that they never addressed the question of what makes some teenagers more "receptive" than others. Neither did any of the press reports I saw. Which suggests another hypothesis: Perhaps receptivity to politically correct beliefs is associated with progression toward scientifically shaky conclusions.