Smokers recall visual health warnings better

“Graphic warning labels on cigarette packs work better” than written warnings, the BBC reported. The broadcaster said researchers have found that graphic images of health problems are more effective than written warnings when placed on cigarette packets.

This US trial enrolled 200 current smokers and randomly showed them a static cigarette advertisement that had either a standard text warning or a photographic warning label. The study used eye-tracking technology to monitor how the participants viewed the images, and then later assessed their recall of the health warning. The authors found that 83% of participants could recall the graphic health warning compared with only 50% who could recall the text-only health warning. The researchers noted that longer time spent observing the health warning was associated with better recall.

This study provides evidence that graphic images on cigarette packages can make the health warning stick better in a person’s mind, and improve their recall of the health warning. However, the study did not go on to see whether it changed people’s attitudes to smoking or made them want to quit. Therefore, the most important limitation of this study is that we don’t know whether viewing graphic or text-only adverts translates into people quitting smoking.

Where did the story come from?

This study was carried out by researchers from Interdisciplinary Research on Nicotine Addiction, Perelman School of Medicine, Abramson Cancer Center, Annenberg Public Policy Center and School for Communication, and University of Pennsylvania, Philadelphia. The study was funded by the Robert Wood Johnson Foundation, the US National Cancer Institute, the US National Cancer Institute Center of Excellence in Cancer Communication Research, and the US National Institute of Health.

The study was published in the peer-reviewed American Journal of Preventative Medicine.

The BBC’s headlines need to be interpreted in context. The study only provides evidence that graphic warning labels on cigarettes help people recall health warnings better, not that they influence people’s decisions to quit or help them to quit. The news story said that images of patients on ventilators on cigarette packets help smokers “heed the health warnings”, but this study does not show whether increased awareness translates into improved health outcomes.

What kind of research was this?

Recent US legislation has given the Food and Drug Administration (FDA) the legal power to place compulsory graphic warning labels on cigarette advertising and packaging. The legislation stipulates that graphic warning labels must be embedded into cigarette advertising and packaging by September 2012. For cigarette advertisements, the warning label must occupy a minimum of 20% of the advertisement and include graphic images and text. The authors say that previous observational studies from the US and Canada have demonstrated that graphic warning labels can elicit negative responses to smoking, and increase reported intention-to-quit rates.

The authors say that an important first step in evaluating whether a warning label is effective is to demonstrate whether smokers can correctly recall its content or message, and this is what their study investigated. The authors hypothesised that recall would be greater for the image-based warning labels compared with the text-only warning labels. They expected that this would be the case because people view graphic images for longer and so this improves their recall.

To examine this hypothesis, the researchers conducted a randomised controlled trial, which is the best way of seeing whether recall is better after viewing a graphic image than a written message. However, the study’s results cannot tell us whether graphic images are effective in making people quit smoking.

What did the research involve?

The 200 participants in this study were current smokers, aged 21–65 years old, who reported smoking a minimum of ten cigarettes a day for at least five years. Participants could not be attempting to quit at the time of the study. The participants had responded to local advertisements in the Philadelphia area, received financial compensation for their participation in the study, and being a self-selected sample “were not intended to be representative of the smoking population”.

The study was conducted in 75-minute sessions at a media research laboratory within a nicotine addiction research clinic at a university medical school. The participants had study procedures explained, smoked a cigarette to standardise the time since their last smoke, provided demographic details and smoking history, and had their eye-tracking calibrated on a computer monitor. This was to help the researchers later track how participants’ gaze moved around mock-up cigarette packaging.

The researchers produced two versions of a cigarette advertisement featuring a cowboy:

one with a text-only warning label (the “Surgeon General’s warning” about the pregnancy risks of smoking, which has appeared on cigarette advertisements since 1985)
one with a graphic warning label featuring an image of a person on a ventilator, with the caption that cigarettes cause lung cancer, which is one version of a graphic used by Health Canada (the photo occupied 22% of the cigarette advertisement space)

Participants viewed the images for 30 seconds. Computer software was used to track the person’s gaze and eye movement while viewing the cigarette advertisement. After viewing the advertisement, participants were first asked a “distracter” question (“What thoughts [opinions] did you have about the image?”), followed by the recall question: “Based on the ad you just viewed, please type what the warning label read.”

Three trained raters, unaware of the exact study hypothesis, scored each participant as answering correctly or incorrectly. Correct answers were defined as “those containing the words quitting, smoking, reduces, risk, and health, or the root words (e.g. reduce), for the text warning label; and warning, lung, cancer, smoke, increases, or the root words, for the graphic warning”. Incorrect answers were defined as any response that contained fewer than five of the target words in each set.

What were the basic results?

The participant sample had an average age of 30, reported smoking for 12.8 years, and smoked an average of 16.6 cigarettes a day.

There was a significant difference in the percentage of participants who correctly recalled the warning, with 83% of those who saw the graphic image correctly recalling the warning, compared with 50% of those who viewed the text-only advert.

When researchers looked at eye-tracking data, those who viewed the advert with the graphic looked at the warning for the first time significantly quicker and spent longer dwelling on the warning than those who saw the text warning. When the researchers carried out further analyses, they found that these factors were associated with improved recall.

How did the researchers interpret the results?

The authors concluded that graphic warning labels grab and hold a person’s attention and so improve smokers’ recall of the warning and health risks.

Conclusion

This study provides evidence that graphic images on cigarette packages can help health warnings stick in people’s minds better, and improve their recall of the health warning. However, at the current stage of this research, we still don’t know whether this has any meaningful impact on people’s smoking habits. The study did not test whether remembering health warnings more accurately translated into the desired effect of making a person quit smoking. Therefore, we don’t know from this study alone whether graphic warning labels on cigarette packs really “work better” than written warnings when it comes to quit rates.

The study has other important limitations:

The participants selected themselves to take part in this study by responding to adverts which offered a financial incentive. They were also only representative of the Philadelphia area. Therefore, as the researchers rightly acknowledge, this relatively small sample of 200 people can’t be considered to represent the general smoking population.
The text-only and graphic warnings weren’t comparable health warnings. The text-only warning was about the risks of smoking in pregnancy, while the graphic warning showing the person on a ventilator was about the risks of lung cancer (which is significant considering that 65% of study participants were male). Male smokers might, for example, take less notice of warnings about pregnancy than women would.
It may have been a better comparison if both warnings examined the same health risk, which applied to both men and women, for example both highlighting the risk of lung cancer.
The study only assessed immediate recall. The study reports only asked one “distracter” question about the advertisement picture, followed by the recall question. The authors do not state how soon after viewing the warnings their recall was questioned, but presumably it was only a short time after, rather than hours or days later, which may be of more interest.
Lastly, the researchers attempted to use valid measures to assess whether a person recalled the health warning, noting whether they said or did not say a selection of key words. However, this may not necessarily give an accurate picture of a person’s memory.