## New Year Coincidence, 2015

(Submitted by Skepticality listener  Mark Gouch relayed to The Odds Must Be Crazy by Barbara Drescher.)

Here is the article (includes video) by Barry Wolf, WKYC.

But how can we say this is unbelievable as they do in the article? Sorry, but I can’t help myself here…

The odds would be one out of 365 * 365 * 365, or about one out of 48.6 million births. With 7 billion people on the planet, odds are that this has probably happened about 143 times ( to living persons. many more to those in the past). So rare, fun, and interesting, but not unbelievable.

I believe it happened based on the evidence (their claim that it did, which is good enough).

Actually since everyone has to have a birthday, we can ignore the first birthday, that of the man or the woman. So the odds someone marries someone with the same birthday (date of the year) as them is 1/365.

Then the odds their baby has that same birthday would be 1/(365 * 365) or 1/133,225. So with ~7 billion people this probably happened 52,543 times to persons living on the planet now.

The error in the first calculation is that the date was selected first. That calculation is correct for any specific date, whether it is January 1st or July 4th, or March 15th, or July 22nd. Anyone with better knowlege of probability please correct me if any of the above is incorrect.

As often happens, things that seem unbelievable are quite believable and things that are believed without evidence are not believable.

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 246.  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.

Good job!

You are correct with both calculations. It depends on how you frame it. If you’re wondering the odds of two people with the birthday of January 1st marrying and having a baby on January 1st, then the first is correct, but as you pointed out, that’s not really what’s interesting.

The only thing I would add is that these calculations also assume some things that we know are not true, such as that births are uniformly distributed across the days of the year. Even if natural births were (they aren’t), we’d see fewer births on days like January 1st simply because the number of scheduled C-sections and inductions is lower because it’s a holiday. However, figuring those few things in requires data that probably isn’t available.

## A triple play birthday!

Today is my birthday, so here’s a birthday-related anecdote for you.

About a dozen years ago, I went to a lecture at a nearby school.  As we waited for the lecture to start, the lady in the seat to my left started talking with me.  After a little while, she mentioned her birthday is August 11th.  The lady in the seat to my right overheard, and she told us that HER birthday is also August 11th.  At that point, I revealed that my own birthday is August 11th, too!

None of us had ever met or even seen each other before, but we’d all just happened to sit side by side by side!  Since then, the lady on my left has become a good friend, and every year we celebrate our birthdays together.

## The Coincidental CD

(Submitted by blog reader Chuck Colht)

A few years (2009?) ago, one of my daughters gave me a mix cd for my birthday. I had just bought a(nother) sports car and she found a bunch of driving songs from the ’60s to current.  It stayed in my cd player but I didn’t listen too often because I generally had the top down and preferred the sound of the wind.

Anyway, this cd moved from car to car as I changed up but got little play. In 2012, I went to the theater to meet my kids and grand kids to see Wreck-It Ralph. On the way, because I left my iPod at home, I fired up the cd and found track 6: Rhianna’s “Shut up and Drive.” I’m more into grunge but I love this song and couldn’t believe I hadn’t noticed it before.

Now for the coincidence. At one point in the movie Vanellope starts racing around a track to what song? “Shut up and Drive.” So the first time I notice a song that’s been at my disposal for 3 years is the day I hear it on the big screen.

Pretty cool no?

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 226.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own sarcastic and hilarious commentary. Also, visit Barbara’s blog.

At least a third of the stories submitted to TOMBC involve incidents which are not statistically interesting, but demonstrate the human brain’s amazing ability to make connections. Humans begin making associations the day we are born, connecting dots wherever we can. This process allows us to predict the world around us. Prediction, in turn, allows us to avoid dangers and plan for the future. It is also the first step in understanding cause and effect, which may allow us to control things in the world. So, it shouldn’t be surprising that we often ascribe deeper meaning to the connections we’ve made.

The author of this story demonstrates the power of attention. The fact that he rarely played the CD before is not relevant, but because he was surprised to enjoy the song, he noticed when he heard it again a short time later. In psychology, we call this effect “priming”. Priming refers to the tendency for something we see or hear to increase the probability that we will respond to that same thing, or something similar or related to it, when we are exposed to it again.

However, there is no real coincidence here. The song is quite popular, so it shouldn’t be surprising to hear it in a movie such as “Wreck-It Ralph”. The CD was appropriate to the outing, so it also shouldn’t be surprising that a song (or even two) on the CD would overlap with the soundtrack of the movie.

## My Grandmother & the Wizardly Birthday Coincidence

(Submitted by reader, Kyle Delaney)

Before it was popular, on my 11th birthday I received the first Harry Potter book from my now-dead grandmother who had not read it.

It is on Harry Potter’s 11th birthday that Hagrid bursts his door down to tell him he’s a wizard. My birthday, July 31st, is the same as Harry Potter’s.

[EDITOR:  Sometimes it’s just as much fun to enjoy the coincidence as a fun story. By the way, the contributor sent us this coincidence story on his birthday. In case you don’t know who Harry Potter is, look here.  – Wendy]

## Fly like a beagle

(Submitted by reader David Buck)

I work in an office tower that’s connected to a shopping mall. Yesterday I was taking a break from work by going to the grocery store and buying a tray of vegetables for a healthy snack. When I arrived at that section of the store, I saw a friend of mine there who I’d known for about 30 years.

“Hi” I said.
“Hey,” he replies, “you have a birthday coming up soon.”
“Yea,” I answer, “but I’ll be out of town that day.”
“I have a scary birthday coming up” he says. “I’m turning 50”.
“Been there, done that,” I say. “It’s not such a big deal. It’s just another day”.
“Well,” he answers. “You know what they say… ‘Time keeps on slippin’ slippin’ slippin’ into the future’. Then it’s something like ‘I want to fly like a beagle to the sea’ – you know bark, bark, splash.”
“I didn’t know beagles could fly” I said.

We both chuckled and I went to the cash to pay for my vegetable tray.  I left the store and walked outside to enter the mall near my office tower and all the time I had that song running through my head.  When I entered the mall again, the music that plays constantly in the mall had just started playing “Time keeps on slippin’ slippin’ slippin’ into the future.” I just shook my head and thought “the odds must be crazy”.

Below are the extended notes provided by Ed Clint for use in Skepticality Episode 216.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own sarcastic and hilarious commentary.

The odds might be crazy, or maybe they’re simply stressed and in need of a holiday. Judging by the letters we get, song coincidences are common, or at least more so than other sorts. Consideration of the “raw-ish” odds sheds some light on this. If you picked a song at random, what are the odds of hearing it played by an independent music-player such as a mall? The company Gracenote catalogs music, and lists over 100 million songs. However, that number includes duplicates, international, and independent music. Perhaps more relevant are the libraries of streaming music services because they will only pay to stock music people are likely to want: LastFM houses 12 million, Rdio 18 million, Spotify 20 million, and Pandora offers about a million unique songs. Conservatively, we might say there are 20 million pop songs “in the ether” that people regularly wish to listen to. This number is still far too high for our story. A shopping mall won’t play hits from the ’40s or Gangsta Rap, as much as we might want to hum “Cop Killer” to ourselves when perusing khaki slacks. Those genres are included in every streaming music service, but really a store manager is going to confine musical choices to playlists including only the relatively recent (’90s and forward), songs that charted, and those which are G-rated and inoffensive. Not so coincidentally, these are also the sorts of songs an acquaintance is most likely to cite in public conversation.

That cuts down the number substantially. There are no more than 20,000 songs that could fit that description. What about the other half of the problem, how likely is it an acquaintance would mention *any* song to you on a given day? Unless you’re on the cast of Glee, hard to say. Surely somewhere south of a percentage point make our best-case odds less than 1 in two million, and probably much less than that.

However, it is possible there was very little real coincidence at all. Commercial music services that provide tunage to stores, and even radio stations have a much smaller and more rigid weekly playlist than you might think: 150-200 songs replayed throughout the week. Many (like myself) who have worked in retail can confirm hearing the same songs repeatedly. Since we know the grocer works very close to the mall, it’s not unlikely he had been there recently. Since his own birthday was near, hearing the song would have stuck in his head, consciously or subconscious.

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Edward Clint produces the Skeptic Ink Network and writes about Evolutionary Psychology, critical thinking and more at his blog Incredulous. He is presently an intern at the JREF and a bioanthropology graduate student at UCLA studying evolutionary psychology.

## Shirley You Can’t Be Serious

(Submitted by friend of the blog, Ross Blocher of Oh No, Ross and Carrie!)

My extended family was enjoying its annual trip to Disneyland in late November of 2008. While we typically go to celebrate my mom’s birthday, this particular Saturday happened to fall on my niece Shirley’s third birthday. She was the delightful recipient of many gifts and happy birthday wishes. You could be forgiven for thinking that Shirley is something of an older-fashioned name; she was named after my grandmother.

We’d made dinner reservations at the Big Thunder Mountain BBQ. As we arrived there we heard a guitar-playing cowboy on the stage announce, “Come on up here, Shirley. Let’s all sing Happy Birthday to Shirley!”

Everyone in our party started looking at each other. “Who told him? How do they know it’s Shirley’s birthday?” As my brother-in-law walked Shirley toward the stage, we saw that another little girl was being escorted up in front of the crowd. Before my brother-in-law could say anything, another man yelled out from the crowd, “Our daughter is Shirley, too, and it’s HER birthday!”

Now we felt like we had to prove that OUR Shirley was really named Shirley and was also having her birthday, because the coincidence was simply too amazing! Here we had three girls, aged three, four, and five, each with a traditional name that is apparently all the rage, sharing the same birthday!

All three Shirleys were serenaded by the crowd. It took a long time for my family to stop laughing.

Below are the extended notes provided by Barbara Drescher for use in Skepticality Episode 184. Take a look and leave your comments below. Please note that in the original version Ross sent us, the month and year were not included. Ross updated the story with more details after Barbara’s analysis and our recording.

When we are in the midst of these experiences, they seem astonishing, but there are a great many factors to consider when calculating the odds of such a thing. Although I cannot estimate those odds without some basic information such as the year in which this occurred, I think the list of factors will make it clear that the odds are greater than they appear.

• How unusual was the name “Shirley” at the time? Although I concede that it sounds old fashioned, the popularity of baby names is an interesting animal with somewhat cyclical patterns. Sometimes a name is popular simply because it is widely assumed that it will be unpopular and people tend to seek uncommon names for their children. ‘Shirley’ is considered uncommon according to several databases that I consulted, including Babypedia, but it peaked at #2 in 1935. Naming children after great grandparents is a common practice; my own youngest’s middle name is Patrick, after my grandmother (Patricia).
• How many girls born in the last decade or two had great grandmothers born during the name’s heyday?
• How many people visited Disneyland that day?
• How many young visitors to Disneyland that day were celebrating a birthday?
• How many of the visitors were within earshot of the stage on which this occurred? Keep in mind that it was a popular park restaurant at dinnertime.

I imagine the park performers who do such things have many stories like this one. Still, it’s fun and memorable when it happens to you because, although the odds are not shockingly low, it is uncommon.

## Busy Day for Toledo Family

(Link submitted by friend of the blog, Nancy Matson)

Families sometimes have strangely scheduled and often inconvenient birthdays. Sometimes people are born too close to a major gift-giving holiday, increasing the financial strain and reducing the flow of gifts. Others end up with family members closely clustered together, with the same result. But in one much happier reversal of Bleak Winters, a Toledo-area family experienced something much more precise:

FOUR birthdays all on January 4th, across four generations.

That’s right, Richard Stiff’s family started off the tradition with his (now-passed) father Marshall being born on January 4th, 1924. Richard, himself was then born on the same day in 1947, his daughter Julia following the pattern in 1978, and her daughter Kourtney following up the rear (for now) in 2011.

The family claims this was entirely unplanned timing and seems to enjoy the family connection, with various family traditions each year to celebrate the connection. Their biggest challenge appears to be simply the difficulty in finding appropriate birthday activities in the chilly month of January.

[SOURCE: Toledo Blade via Yahoo! News]