(Submitted by Skepticality listener Vandy Beth Glenn)

Last Saturday afternoon, I was watching the TV show Fringe on Netflix streaming. In the guest-cast credits of the third-season episode, “Do Shapeshifters Dream of Electric Sheep?,” I saw the name “Marcus Giamatti.” I’d never heard of him or seen the name, and wondered if he was related to Paul Giamatti, one of my favorite actors. So I looked him up on the IMDb and saw that they’re brothers. “Cool,” I thought, and that was that.

Later that same day I got on my treadmill for my daily run. I watch TV while I run, and this time I had a DVD from CSI Season 10, also provided by Netflix.

The next episode on this disc was “Lover’s Lanes.” The guest cast for this episode included, you guessed it: Marcus Giamatti.

What are the odds?

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 256.  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.

Once again it’s not a reasonable task to calculate these odds, but it is an opportunity to discuss what questions we should ask ourselves before getting too excited about the coincidence.

A look at IMDB tells us that Marcus Giamatti has a pretty long resume, but since many of the entries are guest spots on episodes of short-lived TV shows, we shouldn’t expect to see him when choosing something at random.

However, once we have paid attention to something, we are much more likely to notice the same thing or something similar or related afterward. This concept is called “priming”.

How many times has the author seen this actor in something and did not take note? Would she have noticed him in the episode of CSI if she had not looked him up earlier in the day? Had she seen this episode before and was not interested enough in who the actor was to look him up?

Also, how many times has the author seen an actor in two roles on the same day without noticing?

Another interesting question to consider: how much time would need to be between these two sightings to make the coincidence uninteresting (not a coincidence)? A day? A week?

Attention is really important when it comes noticing crazy odds.