Pontius Pilate may have been on to something when he decided to wash his hands before allowing Jesus Christ to be crucified.
Scientists have found that washing your hands frees you of taking the blame for any unhappy outcome of a difficult decision.
Spike Lee, a researcher at the University of Michigan in Ann Arbor, found that people who wash their hands before making a hard decision become more free in their choice.
"It's not just that washing your hands contributes to moral cleanliness as well as physical cleanliness... our studies show that washing also reduces the influence of past behaviours and decisions that have no moral implications whatsoever," Dr Lee said.
Previous research has shown that once people make a choice, they are psychologically driven to stand by it.
An item already selected is seen as more attractive than it was before the choice was taken, and a rejected one less attractive, but the effect is wiped out by washing hands, showed the study published in Science.
Dr Norbert Schwarz, also from the University of Michigan, said that hundreds of earlier studies had shown that people's earlier choices influenced later decisions, but hand-washing eliminated this classic observation.