You have probably guessed it – you have a gut instinct for numbers. Sometimes the exact number of things up to 7-9. But also large collections of things such that distinguishing quickly which are most numerous is of survival import – are there more women then men at a party or more black pieces than white on a chess board. The latter is called feel or gut approximation for numbers. And the NYTimes has a nifty article and quick test of your gut number approximation skills.
There is a whole world of number and judgment approximations covered in a classic book, Judgment under Uncertainty, by Kahneman and Tversky, which details how we generally decide and how from time to time we can slip from rational to irrational in a blink. Two other recent books have recently taken up this work and others contributions have brought the ideas of slipping from rational to popular attention:
The Logic of Life: The Rational Economics of an Irrational World by Tim Hardford
Predictably Irrational by Dan Ariely
If you have ever been wondering why the Heck that Lehman Brothers could be touted as “one of the strongest of Investment banks” a mere 3 months before its bankruptcy, these books will go beyond greed and show the games we play in our own minds in making and then justifying our decisions. Revealing and fascinating reading. I could take at least a5th more of these numeric lessons.