Stochasticity

I was catching up on podcasts at the gym this morning and listened to the most recent episisode of Radio Lab on stochasticity. Stochasticity is fifty cent word for randomness. Most people think they know random when they see it, but frequently find patterns where there is really randomness.

The show starts off with a very interesting story about a young girl letting go a balloon with a note tied to it. It is found and, at first, the commonalities she shares with the girl who found it seem extraordinary...but only if you look at the things they have in common of course. A quick examination of their differences makes you wonder a bit more.

They discuss one of my favorite games I did with students occasionally. They do it with two groups but I would do it with 5-7 depending on class size. The game is you give one group a coin. You tell them to flip it 10o times and write down the series of heads and tails (using h and t). The other groups are just to write down (what they think) is a random series of h's and t's without flipping the coin. I leave the room so I don't know which group has the coin. I then come back a few minutes later when they are done and tell them which group was flipping a real coin based on their sequences. What they think is a random sequence has easily recognizable differences from a real random sequence. I am going to make you listen to the episode to hear one way of doing this (they don't reveal all the tricks, but the others are similar to the one they use).

We are programmed to see patterns. That served us well when we were dodging tigers, but now we can see patterns where there are none. From an evolutionary standpoint, we not recognizing a tiger attack results in death and a false positive results in a change of underwear at worst. Therefore, we tend to have a lot of false positives when it comes to recognizing patterns.

We see everything from the face of Jesus on a tortilla to Elvis in the Eagle Nebula (recognizing faces has its whole own subcategory). Gamblers think they recognize patterns (reinforced by bells and flashing lights) that keep them gaming. They have an interesting statistical analysis of athletes who get the hot hand and find it usually isn't as hot as you think it is.

People base their lives on patterns that don't exist. Everything from who they date and marry to their stock market picks and the lottery tickets they buy. We all could use a little better understanding of statistics and how to pick out meaningful patterns.

Reprinted with permission from the Half-Astrophysicist Blog.