Smoking continues to rank as the foremost preventable cause of premature death. In a paper published this week in the Proceedings of the National Academy of Science, Harvard researchers report findings that evoking feelings of gratitude in people who smoke helps reduce their urge to smoke, and increases their likelihood of enrollment in a smoking cessation program. They note that these findings could inform newer approaches to public health messaging campaigns that aim to reduce so-called "appetitive" risk behaviours like smoking, drinking, and drug use.

The research team built on the Appraisal Tendency Framework, a theoretical model of emotional and decision-making, and earlier experimental studies on the connection between emotions and risk behaviours to hypothesize that sparking the specific positive emotion of gratitude could drive reductions in smoking. Previous meta-analyses have concluded that positive emotion has no effect on these types of behaviours.

"The conventional wisdom in the field was to induce negative emotions in anti-smoking campaigns," said lead researcher Ke Wang, Harvard Kennedy School Ph.D. 2024. "Our work suggests that such campaigns should consider inducing gratitude, a positive emotion that triggers cascading positive effects."

Through a series of multi-method studies, the researchers found consistent evidence that inducing feelings of gratitude was associated with lower rates of smoking behaviour. Nationally representative surveys in the U.S. and a global sample found that higher levels of gratitude correlated with a lower likelihood of smoking, even after accounting for other known drivers of smoking.

Experimental studies further demonstrated causality. Inducing feelings of gratitude in adults who smoke significantly reduced their self-reported craving to smoke, whereas inducing compassion or sadness did not have these beneficial effects. Critically, inducing gratitude also increased participants' enrollment in an online smoking cessation program, showing effects on actual quit-smoking behaviours.

These findings create opportunities to re-think the scientific foundations of anti-smoking campaigns. The investigators examined the largest federally funded anti-smoking public service campaign, Tips from Former Smokers, by the Centers for Disease Control and Prevention. Unfortunately, this landmark campaign has seldom induced gratitude.

Instead, it has most often induced emotions of sympathy, sadness, and compassion—three emotions that may not produce intended effects on smoking cessation behaviours. In the case of sadness, earlier research by the research team found that evoking sadness actually increased the desire to smoke, as well as the intensity with which smokers inhale immediately after the emotion is triggered.

"Compared to how much money tobacco companies spend on advertising, public health campaigns have paltry budgets; they need to make the most of every dollar," said Professor Jennifer Lerner.

"The theoretically-grounded and empirically-tested framework presented here will hopefully help public health officials design more effective public media campaigns across a broad spectrum of appetitive risk behaviours that have underlying emotional components."

Unlike other positive emotions (e.g., happiness, compassion, and hope), gratitude has the unique quality of making people less inclined toward immediate gratification and more focused on long-term relationships and health. The research team posits that this unique effect is related to the emotion's influence on smoking behaviours and desires to quit.

The researchers believe designing public health messaging campaigns to more effectively induce gratitude could help them have a greater impact on reducing smoking rates and other risky health behaviours.