This result offers pretty convincing evidence in itself that the connection between black and bad is not just a metaphor we all have learned over the years, but rather it is deeply associated with our ancient fear of filth and contagion. But Sherman and Clore wanted to look at the question yet another way. If the association between sin and blackness really does reflect a concern about dirt and impurity, then this association should be stronger for people who are preoccupied with purity and pollution. Such fastidiousness often manifests as personal cleanliness, and a proxy for personal cleansing might be the desire for cleaning products. The researchers tested this string of psychological connections in a final study, again ending with the Stroop test.
The results were unambiguous. As reported in the August issue of Psychological Science, those who expressed the strongest desire for an array of cleaning products were also those most likely to link morality with white and immorality with black. But here is the really interesting part: The only products to show such an association were Dove soap and Crest toothpaste, products for personal cleanliness. Items such as Lysol and Windex did not activate the sin-blackness connection. In short, concerns about filth and personal hygiene appear central to seeing the moral universe in black and white.
These findings have obvious implications for our understanding of racial prejudice. Although scientists have not yet investigated whether people of different races perform the same way on the moral Stroop test, research on other types of unconscious associations has shown racial differences [see “Buried Prejudice,” by Siri Carpenter; Scientific American Mind, April/May 2008]. As Sherman and Clore note, this country once had a “one drop of blood” rule, which meant that even a trace of African lineage “tainted” an otherwise white lineage. These official practices may be gone, but this new study may help explain why black is linked to immorality and impurity on a fundamental level in many people’s minds.