Wash away your doubts when you wash your hands

May 6, 2010, University of Michigan

Washing your hands "wipes the slate clean," removing doubts about recent choices. That's the key finding of a University of Michigan study published in the current (May 7) issue of Science.

The study, conducted by U-M Spike W. S. Lee and Norbert Schwarz, expands on past research by showing that does more than remove the guilt of past misdeeds.

"It's not just that washing your hands contributes to moral cleanliness as well as physical cleanliness, as seen in earlier research" said Lee, a doctoral candidate in . "Our studies show that washing also reduces the influence of past behaviors and decisions that have no moral implications whatsoever."

For the study, Lee and Schwarz, who is affiliated with the U-M Institute for Social Research (ISR) and the Ross School of Business in addition to the Department of Psychology, asked undergraduate students to browse through 30 CD covers as part of an alleged consumer survey. Participants picked 10 CDs they would like to own, ranking them by preference. Later, the experimenter offered them a choice between their 5th and 6th ranked CDs as a token of appreciation. Following that choice, participants completed an ostensibly unrelated product survey---of liquid soap. Half merely examined the bottle before answering while the others tested the soap by washing their hands. After completing a filler task, participants were asked to rank the 10 CDs again.

"People who merely examined the soap bottle dealt with their doubts about their decision by changing how they saw the CDs: As in hundreds of earlier studies, once they had made a choice, they saw the chosen CD as much more attractive than before and the rejected CD as much less attractive. But hand-washing eliminated this classic effect. Once participants had washed their hands, they no longer needed to justify their choice when they ranked the CDs the second time around," Schwarz said.

The researchers replicated the findings in a study using a different task---taste expectations of jars of fruit jams and ostensibly unrelated surveys of antiseptic wipes. "Participants who merely examined an antiseptic wipe after choosing a jar of fruit jam expected the taste of the chosen jam to far exceed the taste of the rejected one. This difference was eliminated when participants tested the antiseptic wipe by cleaning their hands," said Lee.

According to the authors, the results show that as much as washing can cleanse us from traces of past immoral behavior, it can also cleanse us from traces of past decisions, reducing the need to justify them.

This "clean slate" effect may be relevant to many choices in life. Does washing away the urge to justify one's choice of one car over another, or even one partner over another, result in less rosy evaluations of them in the long run? If so, does this increase buyer's remorse because buyers are less likely to convince themselves that they made the best choice possible?

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May 06, 2010
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4 / 5 (8) May 06, 2010
@Alizee, because the research had nothing to do with the Bible. The bible connection is something that readers such as yourself can make all on their own, or can find on a website devoted to that subject.
May 06, 2010
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5 / 5 (3) May 06, 2010
@Alizee There are similar instances within several holy books, which are easily explained from the above. It is like talking about QED and saying "Of course, the bible talked about the existence of light" Learning about the cause after the subtle observation doesn't mean it happens in such order.
1 / 5 (3) May 06, 2010
There's no need to piss on Alizee. This study, like many others, is simply "reinventing the wheel" as the researchers attempt to resculpt the data in their own image. Look up "releasing negative energies," methods for "Awakening the 3rd Eye" according to ancient traditions by Samuel Sagan. Here's an interesting sample: "a significant proportion of the population is 'etherically constipated, unable to release negative energies... the accumulation of negative energies in the etheric body of the majority of (peoples) contributes greatly to the general 'malaise' and the level of neurosis in the modern world..." Yeah, that explains alot.
1 / 5 (2) May 07, 2010
do i wash away my regrets when i wash my butt?
May 07, 2010
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not rated yet May 07, 2010
Cognitive propensity. As I understand the article, participants decided themselves whether or not to wash their hands. So one confounding factor is whether the propensity to wash one's hands correlates with the propensity to resolve one's choice making doubts. There may be no actual cause and effect unless the handwashers are randomly chosen rather than self selecting.
May 07, 2010
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not rated yet May 08, 2010

The participants didn't get to decide whether to wash their hands or not. Half were randomly assigned to looking at the bottle, the other half randomly assigned to washing their hands. It's standard design for a social psychology study, and the results are therefore causal.
not rated yet May 09, 2010
Why didn't they mention the bible?

"Your Highness, I have no need of this hypothesis."
(Pierre Laplace / 1749-1827)
to Napoleon on why his works on celestial mechanics make no mention of God

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