Out, Damned Spot!

Meghan Holohan

"Out, damned spot! Out, I say!" laments Lady Macbeth as she attempts to scour an invisible bloodstain in one of Shakespeare's most memorable scenes. The miserable murderess tries scrubbing her guilt—and her hands—clean. While it doesn't work for Lady Macbeth, a paper in Science suggests that hand washing reduces inner turmoil.

This paper builds on the Macbeth effect, a psychological phenomena where cleanliness lessens guilty feelings. In this latest study, Spike Lee (not the director) and Norbert Schwartz of the University of Michigan examined whether hand washing affects the feeling of loss people experience after deciding between two good options. When this occurs, people undergo overwhelming sadness because they believe they have lost one option. To cope, they justify their choices by exaggerating the greatness of the selections.

Lee and Schwartz wondered if hand washing could ease the tension created when a person chooses between two attractive offers.

They asked students to rank 10 CDs and rewarded the participants by allowing them to take a CD—either the fifth or sixth ranked albums. Following this, half of the subjects washed their hands, believing they were rating the soap, while the other half simply smelled and looked at the soap. Lee and Schwartz asked the students to rank the CDs again. Those who washed their hands ranked the CDs the same as before, whereas those who simply looked at the soap rated their take home CD higher than they did originally. The latter group behaved as people do when they decide between two good choices—they exaggerated the greatness of their selections.

The duo conducted another study, asking the participants to select a fruit jam and then clean their hands with an antiseptic wipe. Using the wipes gave the participants the same peace of mind than they would have had from washing their hands.

The researchers warn that simply washing hands to ease guilt might not be positive because it prevents people from thinking through decisions and their consequences.

[You can pick up a Lady Macbeth shirt here.]