Do clean hands signal pure heart?

It's taken more than 300 years but researchers in Canada and Illinois have some data to back up the Shakespearean link between guilt and hand washing.

Known as the "Macbeth effect" after Shakespeare's famous tragedy, the study on cleanliness and conscience found that people who recall acting unethically are more drawn to cleansing products than those who behave ethically, WebMd reports.

Chen-Bo Zhong of the University of Toronto and graduate student Katie Liljenquist of Northwestern University's Kellogg School of Management compiled the results, published in the journal Science.

The two did four short studies that included private conversations with undergraduates asking them to describe an ethical or unethical deed.

After that the students were asked to complete unfinished words.

Those who recalled past unethical deeds were most likely to come up with words that had to do with cleansing, the researchers reported.

"It remains to be seen whether clean hands really do make a pure heart, but our studies indicate that they at least provide a clean conscience after moral trespasses," write Zhong and Liljenquist.

Copyright 2006 by United Press International