Page last updated: November 27, 2012
'Just say no' campaign could have the oppostie affect

Researchers from Oxford University and American colleagues found that smokers showed more interest in cigarettes after being shown a series of images that contained ‘no smoking’ signs in the background. The results suggest that campaigns against smoking and other undesirable behaviour could ironically “trigger the very behaviours they are meant to discourage”.

Previous studies have shown that cues in the environment can ‘prime’ the brain for particular behaviour.  But in a paper to be published in the Journal of Applied Social Psychology, Brian Earp and colleagues explained that we tend to disregard negations, such as the word “don’t” in the phrase “don’t drink and drive”, when we are not paying full attention.

They state: “For unconscious or automatic processing, “not good” is often taken as ‘good’, and ‘not bad’ as ‘bad’. Negation of concepts does not occur automatically but requires cognitive effort… Our model suggests that public health campaigns which explicitly discourage the consumption of unhealthy substances could in fact trigger that very consumption.”

The researchers tested their theory by asking a group of 32 volunteers, all of whom were smokers, to look at a series of photographs, some of which featured ‘no smoking’ signs in the background. Their motivation to smoke was then estimated by a test in which the participants were shown several images of objects including cigarettes, and told to ‘approach’ or ‘avoid’ them as quickly as possible by pushing or pulling a lever.

Their findings showed that volunteers who had seen photographs containing ‘no smoking’ signs were quicker to approach smoking-related images than neutral ones. In contrast, a control group who initially saw a neutral set of photographs without ‘no smoking’ signs showed no preference for smoking-related images. There was also no difference between participants who spotted the ‘no smoking’ signs in the photographs and those who saw the same pictures but did not consciously notice the signs.

“This finding indicates that the ironic effect of incidental exposure to no-smoking signs can occur regardless of whether the smoker consciously notices the signs, and that conscious awareness may not be sufficient to override the automatic motivation to attain the negated item,” the researchers wrote.

Brian Earp, who led the study,  the same effects may apply to public health campaigns which urge people to “just say no”.

Source: Earp, B. D., Dill, B., Harris, J., Ackerman, J. M., & Bargh, J. A. (in press). No sign of quitting: Incidental exposure to no-smoking signs ironically boosts cigarette-approach tendencies in smokers. Journal of Applied Social Psychology. Pre-publication draft.

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