Everyone knows they should wash their hands after using the bathroom, but that doesn’t mean everyone does it – particularly men.

According to a 2010 study, 93 percent of women scrub up after using a public restroom, while only 77 percent of men do the same.

NEWS: Why Skin Wrinkles When Wet

To see if public-health messages could get men to clean up their acts, researchers infiltrated undergraduate men’s bathrooms at Michigan State University. On the walls, the scientists put up posters that showed various combinations of students from MSU or other schools with variations on information about hand-washing.

A poster with one of the strongest messages, for example, showed the backs of five college-age males facing urinals. Four wore backward-facing MSU baseball caps, while one whore a cap from a rival university. At the bottom of the poster were the words: ‘‘Four out of five college students wash their hands EVERY time they use the bathroom.’’

In a series of experiments, researchers entered the poster-decorated bathroom behind randomly chosen men. Then, they pretended to scrub a stain on their shirts, while observing how many men washed their hands and how thoroughly they scrubbed. They also interviewed men after bathroom use.

BLOG: Skin Traps Harmful Pollutants

Regardless of which poster they saw, the researchers reported Thursday in the journal Human Communication Research, men became more likely to wash their hands and to wash them well with the water running for a longer time.

In surveys, participants in the study estimated that they normally wash their hands 73 percent of the time after using the bathroom, though they thought that just over half of other men did. When reinforced by posters, though, hand-washing rates went up to 86 percent.

The findings could lead to better compliance with hand-washing recommendations, which would be a welcome development, particularly during cold and flu season.

“It is important from a public health standpoint,” said MSU’s Maria Lapinski, “because quality hand washing can prevent transmission of many diseases and we have good evidence that people typically don’t do it as often or as well as they should.”

Image: iStockPhoto