New Scientist reports: Long a metaphor for the desire to distance oneself from immoral acts, hand washing doesn’t just wipe the conscience clean – it also changes how an individual regards a decision they have just made.

Lady Macbeth notwithstanding, the physical act of washing one’s hands is known to ease the guilt we feel about past unethical deeds. Now it seems that the act also removes our natural inclination to validate even trivial past decisions.

To find out more check out New Scientist.