“Out, damned spot! Out, I say!”

in Article
March 1st, 2011

Lady Macbeth

Lady Macbeth



If you are not a humanities major, you may ask yourself why you should care about Shakespeare, and even if you are, you might be asking yourself what place this topic has in a blog dedicated to mind and brain sciences…aside from the obvious madness thing.

To answer the first question exclusively, Shakespeare is awesome. So there’s that.  To more appropriately answer the first question and the second question as well, I submit that you might have more in common with Lady M than you think.

A paper titled “Washing Away Your Sins: Threatened Morality and Physical Cleansing” published in 2006 in the journal Science examined the connection between physical cleanliness and morality in presumably non-homicidal normal subjects.  Researchers found a strong link between feelings of guilt and various physical cleansing desires/behaviors and it has a name–The Lady Macbeth Effect.

Subjects in the study performed tasks such as recalling memories from their pasts in which they performed either a good or a bad deed.  They were subsequently told to fill in the missing letters in a list of incomplete words including “W_ _H,” “SH_ _ER” and   “S_ _P.”  Those who had been primed for guilt were 60% more likely to complete the list as “WASH,” “SHOWER,” and “SOAP” rather than more neutral possibilities such as “WISH” “SHAKER” and “SLIP.”

The researchers then decided to take the experiment a step further and examine any perceived efficacy of such behaviors.  The researchers again asked the participants to recall stories of past immoral or selfish behavior, and were offered various small, inexpensive items as a reward.  Unsurprisingly, amongst those offered the choice between a hand wipe and a pencil, the participants who recalled an unethical deed were more likely to choose hand wipes.

washing hands

After presumably using the wipes to wash the metaphorical blood from their hands, these subjects were asked to perform a selfless deed such as donating money, the type of behavior established as increasing with feelings of guilt.  While the subjects who had not been offered cleanliness products volunteered  74% of the time, only 41% of those with clean hands, and thereby apparently clean consciences, donated.

These results, from an anthropological viewpoint, are not that surprising.  Many cultures make some association between evil and uncleanliness, and many religions advocate some form of ritual purification for both the body and the soul.  While it is somewhat counterintuitive that such complex, useful human capacities as guilt and remorse can be allayed by such trivial things, and disturbing that feelings of physical cleanliness can decrease potential charitable acts, these are by no means complete negating effects–for the mentally stable, a bar of soap isn’t going to magically erase from your mind whatever it is you have done.

Still, one wonders if Macbeth might have turned out differently if only Purell had existed in medieval Scotland.

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2 Comments on “Out, damned spot! Out, I say!”

  • Had Purell existed in medieval Scotland, Lady MacScottishPlay would have had non-metaphorical blood on her hands, but it would have been hers; her hands would have gotten super chapped.

    PS. You are awesome, both generally and for tying Shakespeare and neuroscience together.

  • Ablution is a fun and relevant word.

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