(Submitted by Skepticality listener Jim Fitzsimons)

Ok, here’s an excellent coincidence! This past Monday (Feb. 9) while at my day job, an old book of (mostly) urban legends came to my mind. The book was called ‘Strangely Enough’. I had blogged about it five years ago. I looked up the blog and reread it and in it I mentioned a favorite story in the book about the Devil’s Footprints which appeared overnight in England in 1855. It was claimed that the prints went in an unwaveringly straight line across several miles, over houses and haystacks, across rivers and lakes; all in one night.

Later that same Monday (Feb. 9), while at my night job, I was listening to the February 3rd episode of Skepticality. During the contributors’ segment at the beginning of the show, Tim Farley talked about those same Devil’s Footprints as part of his Skepticism, Past and Future.

Cool, no? Well, it gets even more coincidental!

Tim mentioned the date of the event. People woke up and discovered the uncanny prints in 1855 on the morning of February 9th.

That means I had thought of the book, looked up my blog piece on it, read about the Devil’s Footprints, and then, later, heard Tim talk about them all on the 160th anniversary of the event!

How crazy are those odds?

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 262.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog ICBS Everywhere, and Insight at Skeptics Society.

I can actually do a little bit of calculation with this.

At first glance it might seem that some of the odds in this case can be calculated. After all, we know how many days of the year there are. If the likelihood of the events occurring on a given day was the same as the likelihood that it would occur on any other day, then the odds of thinking about the Devil’s Footprints on its anniversary are approximately 1 in 365, or .0027. And the odds of hearing about it on that same day (given it’s the same year) are .0027 x .0027, or .000007.

However, there is a lot here that is nonrandom. For example, Tim Farley talked about the Devil’s Footprints as part of his Skeptical History segment precisely because the anniversary was that week. The probability that any given person would listen to the episode on February 9th is quite high–not easily calculated, but definitely much higher than 1 in 365. Furthermore, the probability that the Devil’s Footprints would come to mind is not the same for all days. Memories are activated by cues and cues come in all manner of form. Integral to the story of the Devil’s Footprints is snow and even if it is not snowing, cold weather may easily trigger a thought or two about the incident, especially to someone who has studied it. The date itself may have triggered the memory without the author’s awareness.

For these reasons, what appears to be a crazy coincidence probably isn’t all that crazy.