While watching a TED video about algorithms, mention was made of an unrealistic price on Amazon. Apparently two retailers had an out-of-control computer feedback loop.

One company, with lots of good customer points, is in the habit of selling products a little higher than the competition. Anyone’s guess why, but facts are facts – they routinely price merchandise about 25% higher than the competition (and rely on the customer experience points to pull customers away?).

Well, the competition routinely prices merchandise a little lower than the highest priced competitor: about 1% less.

So these computer programs began a game of one-upmanship. A $10.00 product was listed for $12.70 by the first company. Later in the day, the second company’s computer listed the same product for 1% less – $12.57. So the process repeated:  $15.96 and $15.80. Then $20.07 and $1987. The process continued until the book was listed for $23,698,655.93, plus shipping. (all numbers illustrative)

This story illustrates one of the challenges to automated feedback loops. An engineering instructor once explained it – if the gain feedback is a positive value greater than 1, the feedback will either oscillate, or latch-up.

More on feedback controls for real systems another day.

Read more here: https://www.google.com/#q=making+of+a+fly