Washing your hands after you have failed at something can make you optimistic, a new study has found.
Washing our hands influences how we think, judge and decide, according to researchers who examined how physical cleansing affects people after failure.

They found that test subjects who washed their hands after a task were more optimistic than those who did not wash their hands, but it hampered their future performance in the same task domain.
For the experiment, Dr Kai Kaspar from the University of Cologne in Germany, took 98 subjects in three groups.
In the first part of the experiment, participants from two groups had to solve an impossible task. Both the group who after failing washed their hands as well as the one that did not wash their hands were optimistic that they would do better the second time.
The optimism of the group who washed their hands was, however, much greater.
In contrast to the usual finding that higher optimism results in better performance, the opposite was the case here: the subjects who did not wash their hands did considerably better than the group who washed their hands.
Instead, the performance of those who had washed their hands was on the level if the third group who had not experienced failure and only taken part in the second test run.
According to Kaspar, it can be concluded from the results that while physical cleansing after failure may eliminate negative feelings, it reduces the motivation to try harder in a new test situation to restore one's own perception of competence.
The findings of the study were published in the journal Social Psychological and Personality Science.