Saturday, December 01, 2007

chicken sexing

OK, this is my favorite example of fractionation. Thanks to Jared Spool who talks about it in his webcast The Dawning of the Age of Experience. Basically, chicken farms profit by identifying the gender of their baby chicks as early as possible. Unfortunately, there are no physical differences between the male and female babies for several months. With no expertise, that gives them a 50/50 chance of guessing correctly. There are experts who can get up to 80/20, but they can't articulate how they know. They have fractionated their male/female schema so that they can recognize the differences, but there are no connections to any labels. They "just know."

So the training process simply repeats the learning process. A new hire categorizes the baby chicks by gender (at an accuracy of just 50/50 because they don't have any clue), and the expert hits them on the shoulder when they are wrong (feedback). After a few weeks (and hundreds of chicks), the new hires can get up to 70/30 accuracy rates, even though they also can't say quite how they know.

It is a great example of how much cognition goes on in areas of the brain that are simply not accessible to conscious examination.