March 13, 2007

The Prisoner's Dilemma

You and your partner in crime are put in separate jail cells. The choice is whether to rat out your partner or not. If neithier of you says a thing, each gets 6 months. If you defect and your partner doesn't, you go free and he gets 10 years (and vice versa). If you both defect, both serve two years.

I like this game's Groundhog Day, No Exit sensibility-- it captures a central element of human behavior: trust.

Computer scientists have tournaments where they let their programs play the game over and over again with the prize going to the best algorithm. The first time around a four-line BASIC program called 'tit for tat' won the tournament: if your partner defected last turn, you defect this turn, and if he or she didn't turn you in last time, then you do the same. However later programs were able to beat tit for tat. The problem is that the partners can get stuck in defect mode-- once trust is lost it can never be regained. A better strategy, shown by computer simulations, is 'hard love': usually tit for tat, but occassionally you forgive your opponent. Hard love starts by trusting your opponent, but it is also willing to punish defection in later rounds, and it uses a 1 to 5% chance of forgiveness.

The prisoner's dilemma comes up in Kim Stanley Robinson's book Forty Signs of Rain. The main character is from California and is stuck working in Washington DC. He hates east coast drivers, defectors, every last one. They cut you off in trafic and punish infringements. Everyone ends up doing time. On the left coast on the other hand drivers are enlightened and have faith in their fellow drivers-- they let people merge and make space if you signal a lane change. I drove in LA for years and its true-- there's a lot of traffic, sure, but everyone does a pretty good job of getting along, an easy sentence.

I am reading Richard Dawkins' The God Delusion. I can recommend it-- Dawkins doesn't pull his punches and he knows the terrain. The discussion is ratcheted upwards on every page. Dawkins argues convincingly that there is no need for God the Creator, and a God of the Gaps is on a slippery slope. A double blind prayer experiment showed no difference in the recovery rate of heart patients who were prayed for and didn't know it compared to those who weren't prayed for and didn't know it. Amazingly those who were prayed for and knew it showed a worse rate of recovery; the authors of the study say this might have been from 'performance anxiety': the added stress of not wanting to let the prayers down. The book forces you to be honest about what you believe. And so I wonder if there is room left for a personal God, and the one God I haven't seen Dawkins discuss is the God of the Human Spirit, working psychological miracles through faith, hope and charity, allowing us to trust, grow, forgive, love, overcome.


At March 14, 2007 2:16 AM , Anonymous Tim said...

Is 40 signs of rain any good?

At March 14, 2007 12:15 PM , Blogger Matt_J said...

I liked it-- good character development. I liked the view inside the workings of the NSF and biotech startups. I wished that the book had had a classic plot trajectory: Robinson does a lot of work laying the foundation for the trilogy, and I just had to trust that there would be payoffs down the line. I am reading fifty degrees below zero now now and yes, things are paying off. The climate discussion has moved so quickly that some things he would have written in 2003 or 2004 that were cutting edge have now lost a little of their edge (e.g. due to The Day After Tomorrow and Inconvenient Truth), but that's not a big problem.

At March 15, 2007 2:48 PM , Blogger rigtenzin said...

I want to read Dawkins' book.

At March 16, 2007 7:14 AM , Blogger this verdant country said...

It seems like Dawkins' book is the flying spaghetti monster argument constructed repeatedly, but in different forms. I haven't read it, but I did hear him speak and read various excerpts and reviews, and this is the impression I got. It's probably good reinforcement for the already atheist-ish, but not likely to win many converts.

At March 16, 2007 9:00 PM , Blogger Matt_J said...

I think it's a good book for everyone, not least adult Christians looking to strengthen their faith. If you believe God gave us brains so we could use them to think, or that our brains evolved with a great capacity for thought, or that God allowed our brains to evolve with a great capacity for thought, then this kind of a challenging book is just the thing for you. The unexamined faith is not worth having. The flying spaghetti monster appears (along with His Noodly Appendage) to be sure, but there's a lot more to the book than that.


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