8 Surprising Psychological Benefits of Hand Washing
But hand washing does much more than cleanse us physically; sometimes it can wipe our mental slate clean. Here are some examples of what a bit of soap can do for our psyches.
1. It can remove our
guilt
Washing our hands can rid us of remorse, according to a now-classic 2006 study[1] in which psychologists Chen-Bo Zhong and Katie Liljenquist asked volunteers to recall something bad that they had done before giving half of them an antiseptic wipe to use as “part of the hygiene protocol for using public computers.”
The
researchers then asked the participants to report their emotions and found that
those who cleansed their hands after recalling their unethical deeds felt less
remorseful and ashamed. Then, knowing that people who feel guilty about past
transgressions normally try to make made amends by doing something good, the
scientists asked everyone whether they would help with another experiment.
Three-quarters of those who had not wiped their hands offered their time
whereas only four in 10 of those who had been given the chance to wipe their
hands did.
The researchers concluded that a threat to our
moral purity makes us want to get clean and called it “the Macbeth effect,”
after the Shakespearean character Lady Macbeth who, after assisting her husband
in a murder, feels so guilty that she starts compulsively washing her hands in
an effort to cleanse them of imaginary blood. Watching someone else wash their
hands produces a similar,[2] if
slightly weaker, effect.
2. It can affect our moral judgments
We are more likely to judge other people’s
“dirty” behaviors harshly when we are feeling squeaky clean. In a 2010 study,[3] participants who were instructed to clean
their hands before judging vignettes depicting social issues like using drugs
and committing adultery were less forgiving than those who had not cleaned
their hands. Cleaning their hands had given them an inflated sense of
self-righteousness, and the resulting moral high ground made them more
judgmental.
3. It can help us
justify our decisions
Hand washing has been shown to help us justify our purchase decisions. In one study,[4] participants were asked to rank 10 CDs and were then allowed to choose either their fifth- or sixth-ranked CD as a gift to take home with them. Then they took part in a bogus product test of hand soap.
Half of them just got to examine the bottle of hand soap, and the other half were asked to test it by washing their hands. Then they were asked to provide a final evaluation of the CDs. Those who had merely examined the soap bottle showed the usual post-decision justification: their preference for the CD they had chosen was stronger after they made their choice than it was before.
However, this was not the case for people who had
washed their hands after making their choice. A second study, in which a new
set of participants were asked to choose between fruit jams before judging an
antiseptic wipe, replicated these results. Simply cleaning our hands seems to
eliminate our need to justify our choices to ourselves.
4. It can help us
recover our optimism
People who wash their hands after failure tend
to feel more optimistic. This was demonstrated in a study[5] in which people who washed their hands after
failing an anagram task showed more optimistic expectations about their future
performance on a second anagram task than those who did not wash their hands.
That said, their actual performance was even worse on the second task, possibly
because they didn’t try as hard.
5. It can encourage
risk-taking
Cleanliness encourages us to take risks, according to a study[6] in which business students were either asked to recall an incident in which they had been lucky financially or one in which they had had bad financial luck. Those who had recalled a good financial outcome tended to take more risk on a subsequent financial decision task than people who had recalled a bad financial outcome.
However, cleaning their hands with an antiseptic wipe as part of a bogus
product test seemed to effectively remove the influence of either good or bad
luck in the past. After wiping, those who had thought about a good outcome took
less risk, whereas those who had recalled a bad outcome took more risk.
6. It can strengthen
cognitive control
Hand washing can help us to strengthen our executive function — the set of cognitive skills we need for self-control and goal-directed behavior, often described as “the management system of the brain” — by freeing our minds from ruminating about moral failures. In this study,[7] participants were asked to write a detailed description of an unethical deed they had done before being asked to complete a computer questionnaire.
Half were told that the “Research Protection Board
recommended that everyone should wipe their hands before using public
computers,” and half were not. They then went on to take several cognitive
tests. Those who had used an antiseptic wipe performed much better than those
who had not and whose performance was described as approximating a level
“commonly found only in young children.”
7. It can remove the
endowment effect
The endowment effect is a bias that makes us
assign more value to an object that we own simply because we own it, and often
results in sellers asking for more money for a product than buyers are prepared
to offer. Hand washing can lessen or eliminate the effect, as shown by a study[8] in which participants who washed their hands
were more likely to exchange a previously endowed chocolate bar or drink for a
different one than participants who merely evaluated a liquid soap or had their
height measured.
8. It can reduce
prejudice
The world was a dangerous place for our ancient
ancestors, with parasites, pathogens, and other disease-causing organisms
constantly challenging their survival. So they evolved mechanisms — a behavioral
immune system — to help them minimize their exposure to disease-related
threats, which included strangers and people who were not kin. To this day, a
fear of germs underlines prejudice toward social groups that are associated
with unfamiliar cultural practices.
As it happens, we may be able to clear the prejudice away with an antiseptic wipe. In one study,[9] undergraduates were split into two groups, seated in front of a computer, and asked to rate a hand wipe. The experimental group was asked to use it to wipe the keyboard and their hands, whereas the control group just examined it.
Then they were asked to read a passage about
the seasonal flu that emphasized the use of antibacterial hand wipes as a
protective measure against contamination, before being asked to rate their
impressions of certain social groups — such as crack addicts, illegal
immigrants, Muslims, and the homeless. Those who had been given an opportunity
to clean their hands had less negative attitudes toward those groups than those
who had not.
References:
- “Washing
Away Your Sins: Threatened Morality and Physical Cleansing” by Chen-Bo
Zhong and Katie Liljenquist, 8 September 2006, Science.
DOI: 10.1126/science.1130726 - “Washing
the guilt away: effects of personal versus vicarious cleansing on guilty
feelings and prosocial behavior” by Hanyi Xu, Laurent Bègue and Brad J.
Bushman, 28 February 2014, Frontiers in Human
Neuroscience.
DOI: 10.3389/fnhum.2014.00097 - “A
clean self can render harsh moral judgment” by Chen-BoZhong, Brendan
Strejcek and Niro Sivanathan, 27 April 2010, Journal of Experimental Social Psychology.
DOI: 10.1016/j.jesp.2010.04.003 - “Washing
Away Postdecisional Dissonance” by Spike W. S. Lee and Norbert Schwarz, 7
May 2010, Science.
DOI: 10.1126/science.1186799 - “Washing
One’s Hands After Failure Enhances Optimism but Hampers Future
Performance” by Kai Kaspar, 10 April 2012, Social
Psychological and Personality Science.
DOI: 10.1177%2F1948550612443267 - “Washing
away your (good or bad) luck: Physical cleansing affects risk-taking
behavior” by A. J. Xu, R. Zwick and N. Schwarz, Journal of Experimental Psychology.
DOI: 10.1037/a0023997 - “Washing
away your sins will set your mind free: physical cleansing modulates the
effect of threatened morality on executive control” by Eyal Kalanthroff,
Chen Aslan and Reuven Dar, 21 September 2015, Cognition and Emotion.
DOI: 10.1080/02699931.2015.1086313 - “Detaching
the ties of ownership: the effects of hand washing on the exchange of
endowed products” by Arnd Florack, Janet Kleber, Romy Busch and David
Stöhr, 5 October 2013, Journal of Consumer
Psychology.
DOI: 10.1016/j.jcps.2013.09.010 - “Immunizing
Against Prejudice: Effects of Disease Protection on Attitudes Toward
Out-Groups” by Julie Y. Huang, Alexandra Sedlovskaya, Joshua M. Ackerman
and John A. Bargh, 4 November 2011, Psychological Science.
DOI: 10.1177/0956797611417261