Key Points
- Friday the 13th refers to when the 13th day of the month in the Gregorian calendar falls on a Friday.
- Western cultures are more likely to consider the day to be unlucky, but its origins are contested.
- A researcher says evidence demonstrates it is no unluckier than any other day, but can influence behaviour.
It's one of the most well known superstitions in western culture that can leave us with a feeling of foreboding misfortune.
Friday the 13th - when the 13th day of the month in the Gregorian calendar falls on a Friday - is considered by some to be an unlucky day.
A psychotherapist specialising in phobias has even coined the term, paraskevidekatriaphobia, one which refers to an irrational fear of the day.
Dr Kylie Sturgess, a researcher from Murdoch University, said it's also one of the most debated superstitions in terms of its origins, why it's associated with bad luck, and whether we should be scared at all.
The origins of Friday the 13th
Based on the way the Gregorian calendar is structured, there is always at least one Friday the 13th every year and sometimes up to three, Dr Sturgess explained. This year, that falls in January and October.
She said western cultures are more likely to consider the day to be unlucky. The origins of that are contested and have evolved over time.
"If there's one thing we know about Friday the 13th, it's that lots of people have lots of different opinions as to why it's unlucky," she told SBS News.
In Teutonic legend - a body of myths based on the religion of ancient Teutons or mostly northern European peoples - the god Loki attends a dinner party seated for 12 gods, making him the 13th seated at the table. Deceived by Loki, another god is killed.
In the Christian tradition, the Last Supper was attended by 13 guests - Jesus Christ and his disciples, which is said to have taken place before his crucifixion on Good Friday.
But Friday the 13th isn't considered unlucky across all cultures or religions.
Based on the Hindu calendar, the thirteenth day is called 'Trayodashi,' on which people worship Shiva, the third god in the Hindu triumvirate.
In Greece and Spanish-speaking countries, Tuesday the 13th is considered unlucky, while that date in Italy is Friday the 17th.
These days, Dr Sturgess said popular culture is a key driver, helped along by it becoming an American horror franchise.
What does the evidence say?
In recent years, researchers in the United Kingdom and Europe have looked into links between health, behaviour and superstition surrounding Friday the 13th.
One study looked at the on Friday the 13th and the preceding Friday. It found there were significantly increased hospital admissions on the 13th despite there being fewer drivers on the road.
But it noted work was needed on a larger sample size, and that an "unrecognised factor" may be related to both driving patterns and accident rates.
Separate explored whether there was a difference between working on-call as a surgeon on Friday the 13th compared to the preceding Friday at a large hospital. It found no significant difference, inferring that "Friday the 13th didn't appear any busier than any other Friday," Dr Sturgess said.
Based on the Gregorian calendar, there is always at least one Friday the 13th every year and sometimes up to three. Source: Getty / Stockbyte
Dr Sturgess said the evidence "certainly demonstrates that it's [Friday the 13th] no unluckier than any other day".
"Overall, what we can say [is] about how people might behave on this particular day, and whether or not they let it get to them," she said.
What’s the verdict?
Dr Sturgess said it's not unusual to feel anxious on such a day.
"One thing we do know is that superstitions are popular, superstitions are common - and anxiety is not unusual, but it shouldn't be allowed to control your life," she said.
"So if you are feeling a little anxious this Friday, just try to remember there's nothing different about it than any other day out there."
