The Odor of Evil
My nominee for best use of fart spray in 2008:
Simone Schnall and co-authors (including the always interesting Jonathan Haidt) set up a table on the Stanford campus, asking passing Stanford students to complete a questionnaire on the immorality or not of marrying one's first cousin, having consensual sex with a first cousin, driving rather than walking 1 1/2 miles to work, and releasing a documentary over the objections of immigrants who didn't realize they were being interviewed on film. All respondents completed the questionnaire while standing near a trashbucket. For one group, the bucket was clean and empty; for another it was lightly doused with fart spray so that a mild odor emanated from it; for a third group, the bucket was liberally sprayed and emitted a strong stench. Participants in the odiferous conditions rated all four actions morally worse than in the fart-absent condition.
In other research, Haidt has found that people hypnotically induced to experience disgust are also more inclined to reach negative moral judgments then when they're not experiencing hypnotically-induced disgust; Schnall et al. found that people were more morally condemnatory when completing questionnaires in a disgustingly dirty office than in a clean one, after vividly recalling a disgusting event than after not being instructed to do so, and after watching a disgusting movie scene as opposed to a neutral or sad scene. In the last three of these experiments, they found the difference in moral judgment only among people who, in a post-test, described themselves as being highly aware of bodily states such as hunger and bodily tension. (As an aside, I'm generally mistrustful of the accuracy of people's reports about their typical daily steam of conscious experience, and I wonder if responses on the post-test might be influenced by the strength of either their reaction to the previously presented moral scenarios or their reaction to the disgusting stimulus.)
Moral condemnation and visceral disgust may be more closely related, then, than you think -- or at least than most philosophers seem inclined to think. Whether this is a good thing or a bad thing is open to dispute. In these scenarios, it seems like a bad thing, since people are being swayed in their judgments by irrelevant factors. Whether it's generally a bad thing, I suppose, will depend on whether there's generally a good relationship between the things that evoke visceral disgust and those worth morally condemning. (Unusual sexual practices? Poor hygiene? Illness? Reflecting on these sorts of cases leads me to suspect that the connection between visceral and moral disgust is overall more misleading than helpful.)
There's a practical moral to all this, too: When you're trying to get people to judge you lightly for all the crap you've done, don't fart!