UFOs vs Bigfoot

It seems the dismal science has something to contribute to scientific skepticism! Peter Leeson, an economist at George Mason University, is guest blogging this week on Freakonomics and has an interesting post on UFOs and Bigfoot. Leeson, who's other interests include piracy (as in, argghhh not as in file-sharing), reports the initial finding of a project he's collaborating on with Claudia Williamson to use the tools of economics to get to the bottom of the belief in alien visitation. Their intriguing preliminary result is that there seems to be a strong positive correlation between UFO and Bigfoot sightings per state. That is, US states where there are lots of purported Bigfoot sightings tend also to have lots of UFO sightings. Check out the graph below; it charts the total UFO sightings for each US state (per 10,000 people) between 1997 and 2007 against the total Bigfoot sightings in each state (again per 10,000 people):


This correlation is somewhat suggestive (but certainly far from conclusive) evidence that neither UFOs nor Bigfoots are real. Why? Because evidence for the existence of Bigfoots and evidence for alien visitation are clearly statistically independent, that is, sightings of the former do not increase or decrease the probability of sightings of the latter. Therefore, speaking very roughly, were there a real signal among the noise for either (or both) Bigfoots or UFOs, we'd wouldn't expect to find a correlation between them. (There are clearly a whole bunch of other ways in which a correlation could arise so there are numerous possible confounds. See Leeson's post for his response to some of these). The finding that there is a strong positive correlation between these sightings thus somewhat strengthens the skeptical argument that there is a common socio-cultural factor which produces both the purported Bigfoot and UFO sightings. It is important to keep in mind, however, that this research is (1) correlational and thus not compelling and (2) in its early stages. That said, it's certainly very interesting and seemingly quite a promising avenue of research.

By the way, I thought the second comment on Leeson's post was just awesome: "It strongly suggests to me that the aliens are Wookies." Indeed and LOL.

(HT: John McCoy).