An email with the subject line "OMG" recently came from one of our mothers, and it contained chilling information about the HPV vaccine. "200 people have died from it," Mom claimed, "and it does not even last long enough to prevent cervical cancer."
Her source was not her doctor, a new study or the Food and Drug Administration. Her information came from a recent episode of Katie Couric's ABC talk show about "all sides" of the "HPV controversy." Since then, most of the alarmist vaccine claims made in the episode have been debunked. But Mom remains a victim of celebrity medicine: She heard a warning from someone famous, believed it and spread the misinformation.
Unfortunately, Mom is not alone. Celebrities have crept into our medicine cabinets and kitchens, influencing what pills we pop, tests we order and foods we fear. More often than not, their advice and products are dubious. "Then why do so many people believe them?" Mom asked.
This time, we have an answer. One of us -- Hoffman -- just published a review of research on celebrity in the Dec. 18 issue of the British Medical Journal. It addresses this question.
The review draws on studies from a range of disciplines and synthesizes key narratives on celebrity followership. The conclusion? Our brains, psyches and societies appear to be hardwired to trust celebrities, whether on anti-vaccine antics or miracle medicines.
Economics tells us that we use celebrity endorsements as signals or shortcuts for judging qualities such as validity or relevance. So when Bill Clinton recommends veganism, his approval elevates animal-free eating even though his expertise lies more with foreign policy than nutrition.
The halo theory from marketing studies explains how celebrities' success in one area -- say, acting -- makes people presume they are competent in unrelated areas -- say, medicine. This influences how we interpret their health messages no matter how nonsensical, and may explain why Gwyneth Paltrow has become a credible advisor on vitamin D deficiency, even though she didn't go to medical school nor is she a health expert.
Classical conditioning suggests that we learn to psychologically associate unrelated stimuli in a way that exposure to them achieves similar responses. This means warm feelings toward celebrities are stirred up in us by the things they pitch. It's no surprise, then, that PepsiCo paid Beyonce $50 million to promote its products.
Neuroscience studies also help explain why these endorsements work on us. Brain scans have demonstrated that images of celebrities increase activity in our medial orbitofrontal cortices, the region responsible for forming positive associations. So if you're an Angelina Jolie fan, seeing her image lights up this part of the brain, making you more likely to think highly about whatever she is promoting, even when it's something extreme like a double mastectomy to prevent breast cancer.
Reason should help us overcome an illogical addiction to celebrity health advice. Questioning prescriptions from prominent people and asking about the evidence behind them could save us time, money and harm. But, as the science shows, celebrity influence is not rational.
The first step to addressing celebrity medicine is recognizing that it is a human vulnerability and a serious public health challenge. Doing that can empower us to think twice before we take advice from the stars.
We should also use these new insights to rethink how we promote healthy living and evidence-based decision-making. Actress and anti-vaccine activist Jenny McCarthy may be their arch-nemesis, but doctors and public health practitioners can learn from her. Making vaccines, exercise and oral hygiene as attractive as celebrities would be more valuable than any million-dollar endorsement deal and more effective than any detox diet. It might also save Mom from putting her most sacred asset -- her health -- into the well-manicured hands of famous people.