Visual Cues and Addiction

Do smoking scenes in movies make smokers want to light up?

Smokers and former smokers will understand what I mean when I say that an addiction to smoking is like a pilot light that is always lit, always ready to whoosh into full flame with the application of a few milligrams of nicotine. And they will also understand that feeling, like a bolt sliding home, of instant identification that comes from seeing someone else smoking. Especially if you are not smoking, but wish to be.

It makes sense that a smoker or former smoker who sees someone smoking might find that image to be a trigger for nicotine craving. But we have to ask whether smokers trying to quit are really endangering their newfound abstinence simply by viewing “smoking content” on TV or in the movies. It seems a bit too prudish to be true. Yet, logic would seem to suggest that some sort of behavioral effect might be expected when a smoker in withdrawal sees an image of someone smoking.  Does, say, viewing scenes of smoking in a movie produce changes in brain function robust enough to trigger relapse in the absence of any other direct cues? Are environmental cues of this nature more dangerous to newly abstinent smokers than we thought?

“Our findings support prior studies that show smokers who exit a movie that had images of smoking are more likely to crave a cigarette, compared with ones who watched a movie without them,” said Dylan Wagner of Dartmouth College, in a Society for Neuroscience Press Release. “More work is needed to show whether brain activity in response to movie smoking predicts relapse for a smoker trying to quit.”

In a small study involving 17 smokers and 17 non-smokers, scientists at Dartmouth College set out to determine what differences might show up in a functional magnetic resonance imaging (fMRI) scan of smokers and non-smokers while they watched 30 minutes of a movie with several smoking scenes. The subjects were not told that the experiment was about smoking. But when they viewed smoking scenes, the brains of smokers showed increased activity in a portion of the parietal lobe of the brain called the intraparietal sulcus. The study was published in the January 19 issue of the Journal of Neuroscience.

What does this brain region do? As it happens, the neurons in the intraparietal sulcus encode information about the position and geometrical properties of objects. This part of the brain coordinates eye movement data and reaching movements.  Using a mouse or a joystick is a good example of an activity that involves the intraparietal sulcus.

The intraparietal sulcus, or IPS, has other functions, but primarily it serves, in the words of one study, as an interface “between the perceptive and motor systems for controlling arm and eye movements in space.”  Apparently, the habitual hand gestures used in lighting and smoking a cigarette, when viewed in a movie or commercial, triggered impulses from that part charged with controlling the routine gestural aspects of smoking--if the viewer were actually smoking.

Other studies point to additional aspects of this event-related change in fMRI scans. Writing in the Journal of Neuroscience in 2006, Hamilton and Grafton offer evidence that the IPS is also “uniquely sensitive to the goals of other people’s hand actions.” The intraparietal sulcus seems to “know” what those hand gestures mean, in a sense. Macaques in the lab were used to demonstrate that “cells in macaque IPL were show to respond selectively to both the performance and observation of an action within a sequence leading to a specific goal and not to the same action when it was part of a sequence achieving a different goal.”

This was a strong suggestion that “the IPS is not just a relay but has a central role in representing and interpreting the goals of observed hand actions.”

Perhaps, then, the idea that strong cues can be produced by images and associations is not so far-fetched. It is, for that matter, the founding theory upon which the modern advertising industry has been built, and while the argument over advertising’s effectiveness is never-ending, cigarette scenes in films might have to be considered a form of indirect advertising beamed directly to the parietal lobe of smokers (and perhaps former smokers as well.)

Hamilton, A. (2006). Goal Representation in Human Anterior Intraparietal Sulcus Journal of Neuroscience, 26 (4), 1133-1137 DOI: 10.1523/JNEUROSCI.4551-05.2006

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