Sympathetic Magic in the Grocery Aisles

Tam emailed me this article and said she would like to read more about it. Since I happened to have at that very moment a copy of the most recent issue of the Journal of Market Research, which contains the write-up of the study discussed in the article, sitting on the desk in my office, this was too good an opportunity to pass up, so I brought the journal home to blog about for your reading pleasure.

This work involves applying the "law of contagion" to consumer attitudes and choices. The law of contagion states that objects can transfer aspects of their essence through physical contact and that the contamination of the previously neutral/desirable object by a disgusting item continues after the objects are no longer touching. There is an obvious basis here in the possibility of microbial contamination of food through contact with bodily products, vermin, etc., but the law holds even in situations where actual physical contamination is impossible.

The study covers 6 related experiments that included the use of a disgusting object* (a package of menstrual pads or a tub of lard), a desirable target object that comes into contact with the disgusting one (a package of cookies or rice cakes), and 2 other neutral grocery store items. The researchers varied conditions such as whether the disgusting item touched the desirable item and whether the desirable item was in an opaque or transparent container. Subjects looked at the tableau of items and then rated the target object on a 10 point scale for how much they would like to try/use the target object.

* They were able to identify "disgusting" objects in a separate study by asking people to rate a number of grocery store items on a disgust scale. Items such as trash bags, kitty litter, and diapers were also commonly found to be disgusting.

Experiment 1 showed that subjects reported a higher interest in trying cookies and notebook paper when the item was not touching a (new, sealed) box of menstrual pads. Contrary to their hypothesis, the effect was the same for both the consumable and nonconsumable target objects.

In experiment 2, they found a contaminating effect of physical contact with a disgusting item even when subjects rated the cookies an hour after seeing the tableau (the subjects spent the intervening time in an interactive classroom session to distract them from what they had seen).

In experiment 3, the researchers investigated whether contagion effects would be found for products that had a negative association but were not deemed disgusting* by comparing the effect of contact with menstrual pads and income tax software. Subjects were less interested in trying cookies after being in contact with menstrual pads, but were not affected by the cookies being in contact with the software. This suggested that the decreased interest in the cookies was driven not by an overall negative association with the item that it touched, but rather more specifically by the disgusting nature of the pads (even though the cookies did not come into real contact with the pads themselves).

* Again, they did pre-testing on items to ensure that the disgusting and merely negative items yielded the same overall level of negativity in subjects, so that the difference was in the particular emotions they inspired.

Experiment 4 demonstrated that subjects were less interested in trying cookies that had been in contact with menstrual pads when the cookies were in a clear container but not when they were in an opaque (and labeled) container. They found the same effect for rice cakes in a clear vs. opaque container touching a box of lard, showing that contagion effects can occur even when the item is not seen as generally disgusting, but disgusting in some particular way (by being extremely fattening).

In experiment 5, subjects who saw a clear container of rice cakes in contact with the container of lard reported them as having more fat than did subjects who saw the two items not touching. (There was no difference for the opaque container of rice cakes.) However, the groups did not differ in their ratings of the calorie content of the rice cakes across the two conditions. In this case, the lard appeared to transfer its primary quality (fattiness) specifically to the rice cakes rather than simply making the rice cakes appear different (worse) along multiple dimensions.

In experiment 6, the researchers performed a mediation analysis to determine how the variables of "disgust" (measured by asking subjects to rate their level of disgust with the menstrual pads) and "contact with the pads" influence reduced interest in trying the cookies. They found that contact leads to disgust and disgust leads to a lower interest in eat the cookies.

So overall, the study finds that people are less interested in an item when it has been in contact with a disgusting object due to a contamination effect. Further, this effect is strong when the item is in a clear, rather than opaque, package, due to the role of visualization.

The clear implication of this line of research is that if you want to make the cookies you keep in your house (and that you claim to yourself have to be there to keep your spouse/kids happy) less desirable to you, you should place them in a clear container (precisely the opposite of the usual dieting advice) with some disgusting item in physical contact with it. I'm thinking that a line of clear plastic containers with extremely realistically rendered cockroaches on it would do wonders. The devil of it is in figuring out how to get the cookies into the cockroach container, since, ick!, who would want to touch it? The containers would have to be sold with special gloves for handling the container.

I found the Time article a bit misleading in its treatment of the positive effect a desirable object can have on other objects. Although this kind of effect has been found, it isn't quite the same to my mind as the contagion effect. There is no situation in which, for instance, a bowl of pure spring water with a piece of dogshit floating in it will be seen as purifying the shit rather than contaminating the water. The "holy icon"/"my beloved's sweater" effect seems to stem from positive associations with an individual - interpersonal factors - rather than from strictly physical contamination.

Source: Morales, A.C., and Fitzsimons, G. J. (2007). Product contagion: changing consumer evaluations through physical contact with "disgusting" products. Journal of Market Research, 44, 272-283.