"A lot", say researchers from Plymouth University.
We always wash our hands in a bid to ward off infection, but now it appears there is one more solid reason to do so.
Washing hands may affect judgement, researchers in Britain said. The hygiene conscious could be less judgemental, causing them to gauge actions leniently.
To understand the link between washing hands and judgement, Dr Schnall and colleagues conducted a study with 22 people who had cleaned their hands and 22 who had not. As part of the study, the two groups were made to watch revolting scenes from the film 'Trainspotting'.
After watching revolting scenes from this film about heroin addicts, they were asked to make personal assessment of morality about a series of actions in the movie. Rating had to be done on a scale of one to nine, with one being okay and seven being incorrect.
The actions judged involved abusing a kitten, stealing, putting up a false job application, and killing a family dog and eating it.
Though most participants rated these actions as 'wrong', yet those who had washed their hands were less severe in their judgement compared to those who had not.
Lead researcher Dr Simone Schnall said, "We like to think we arrive at decisions because we deliberate, but incidental things can influence us. This could have implications when voting and when juries make up their minds."