The Lady Macbeth Effect: Can Guilt Really Be Washed Away?

By Kimberly Shen
Editor Bryce Harlan

“Out, damned spot! Out, I say!”

These were the words Lady Macbeth uttered as she tried to wash away imagined bloodstains. Famous for the pangs of conscience she experiences after acting as an accomplice in King Duncan’s murder, Lady Macbeth draws attention to the perceived connection between physical cleansing and moral purification by attempting to cleanse her hands to free herself from guilt. Indeed, this link is found in many cultures around the world, for the act of cleansing is a coping mechanism that is believed to bring about the purity of the soul. This concept is manifest in a number of religions, including Christianity, Islam, and Hinduism. Certainly, research on the link between physical and moral purity suggests that people are predisposed to connect categories based on bodily experience (clean versus dirty) with social categories (moral versus immoral).

Two researchers named Chen-bo Zhong and Katie Liljenquist worked to explore this connection in order to better understand the Lady Macbeth effect–a priming effect characterized by an increased response to cleaning triggered by feelings of shame. In each set of tests, researchers asked participants to recall an ethical or unethical act they committed in the past. The researchers then asked some of the participants to fill in the missing letters in a number of incomplete words, such as W__ __ H and SH__ __ ER, and some of the participants to choose between a pencil and an anti-septic wipe. Participants who recalled ethical acts returned words like WISH and SHAKER, and largely chose the pencil (three-quarters of the time). In contrast, the subjects who were asked to think of unethical acts mostly returned WASH and SHOWER, and chose the anti-septic wipe three-quarters of the time.

To further test whether the act of physical cleansing had any effect on feelings of guilt, Zhong and Liljenquist asked every participant to recall an unethical act and type a description of it into a computer. They then told half of the participants that the keyboard was dirty and gave the participants a chance to wash their hands. Afterwards, the researchers asked each of the subjects if they would be willing to work as unpaid volunteers for a study. Interestingly, the participants who washed their hands were far less likely to volunteer than the subjects who did not wash their hands.
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This result suggests that feelings of guilt can, to some extent, be “washed away.” After all, the relationship between bodily and moral purity is not only rooted in cognition, but also in emotion. A gustatory emotion that has developed through evolution as a safeguard against unsafe food, disgust, is now culturally associated with aversion towards social and moral wrongdoing. Certainly, the experience of “amoral” or “gustatory” disgust and the experience of “moral” disgust have some biological overlaps–pure disgust and moral disgust bring about similar facial expressions and stimulate overlapping areas of the brain, including the frontal and temporal lobes. Given this, physical cleansing is implied to reduce self-feelings of moral condemnation due to the overlapping physiological and neurological relationships between physical and moral disgust.