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Macbeth Effect

October 5, 2006

Washing your hands really can relieve a guilty conscience, according to new research.


Washing away your sins. I’m Bob Hirshon and this is Science Update.

Lady Macbeth might disagree, but new evidence suggests that washing your hands really does relieve guilt. University of Toronto behavioral scientist Chen-bo Zhong and his colleagues found that after contemplating something unethical, people were more likely to express interest in soaps and cleansers. From a selection of small gifts, they were more likely to choose an antiseptic wipe. What’s more, people who washed their hands after unethical thoughts were then less likely to help a stranger. Zhong says the results pose a challenge.

CHEN-BO ZHONG (University of Toronto):
Do you really want your past sins to be easily washed away, which discourages you from engaging in ethical behaviors to help others?

The findings also help explain why cleanliness and godliness are intertwined in culture, religion, and literature.

I’m Bob Hirshon, for AAAS, the science society.