Thursday, May 10, 2012

Feeling lucky?

Here are a couple of fallacies that more or less drive two whole industries (gambling and religion). They represent examples of where human intuition, which has been sculpted over millions of years by natural selection, completely fails us in the face of a basic grasp of the mathematics of probability.

Our evolutionary heritage has pre-wired us (homo-sapiens) to look for causality in things, it's a really handy behaviour to have, for example associating a rustle in the bush with a hiding predator or dark clouds on the horizon with an approaching storm are useful survival rules of thumb. However we don't live on the plains of Africa any more and yet we still all feel this desire to find causation, who hasn't had something bad happen to them and thought "why me, what have I done?" or something good and felt there was some benevolent force looking after them, we're causality addicts!

THE GAMBLERS FALLACY - Believing that ‘runs’ occur to statistically independent phenomena such as roulette wheel spins.

This commonly believed fallacy can be fairly said to have created an entire city in the desert of Nevada USA. Though the overall odds of a ‘big run’ happening may be low, each spin of the wheel is itself entirely independent from the last. Red had come up six times in a row on the roulette wheel, so Greg knew that it was close to certain that black would be next up. Suffering a kind of economic form of natural selection with this thinking, he soon lost all of his savings.

FALSE CAUSE - Presuming that a real or perceived relationship between things means that one is the cause of the other.

Many people confuse correlation (things happening together or in sequence) for causation (that one thing actually causes the other to happen). Sometimes correlation is coincidental, or it may be attributable to a common cause. Pointing to a fancy chart, Roger shows how temperatures have been rising over the past few centuries, whilst at the same time the numbers of pirates have been decreasing; thus pirates cool the world and global warming is a hoax.


Chairman Bill said...

We'd better get those bloody pirates then! What is the government doing about it, that what I want to know?

Is that the Daily Mail headline for tomorrow?

Steve Borthwick said...

CB, ayyy