Power of lucky charms 'all in mind'.
The first comprehensive test of charms' effectiveness found they do not increase luck in events of pure chance, but users often felt luckier and more successful.
The study, by Professor Richard Wiseman of the Psychology Department of the University of Hertfordshire, found that carrying a charm had no effect on the chances of choosing winning lottery numbers.
However, 30% of those tested felt their luck had improved.
Although they were sceptical of any magical effects, these subjects felt more confident, secure and optimistic about the future.
Professor Wiseman said, 'When it comes to totally chance events like the lottery, it made no difference, but when it comes to luck in life, it made a difference in terms of opportunities and confidence.'
One hundred people from across the UK were asked to carry a Victorian penny as a charm for a month.
Participants kept a diary recording how their luck had changed in areas such as health and finance.
Those who reported an increase on average felt they had become 50% luckier.
Nearly all those who did report increased luck had said prior to the study that they expected the charm to work, suggesting the charm's efficacy was based on expectation.
At the end of the study, 70% of participants said that they would continue to carry the lucky coin with them once the experiment had finished.
Professor Wiseman said women were more likely to report an increase in luck, probably because it was culturally more acceptable for them to believe in intuition and luck.
He added that the study explained the popularity of charms and talismans in civilisations throughout history.
He said, 'It shows why it's been around for such a long time.
'It would be easy to dismiss lucky charms as irrational, but the study shows that they have an impact so it's useful to be irrational once in a while.'
Four-leaf clovers have been seen as good luck charms since the time that Druids believed they could impart special powers, such as the ability to detect the presence of bad spirits.