從囚犯困境看瀰的演化

Abstract

在真實社會中，我們隨時有和別人合作的需要，因為合作會為我們帶來利益，但合作常伴隨著背叛，當你遭到背叛時，不但得不到預期的利益，反而會受到意想不到的傷害，囚犯困境充分描述了這樣的情境；在一對一的情境下，囚犯困境已被充分探討過，在本研究中，將用來探討個體和群體間的合作關係。 理察道金斯（Richard Dawkins）曾在“自私的基因”這本書中提出瀰（meme）的觀念，他認為瀰是文化演化的基本單位，一如基因（gene）是生物演化的基本單位；我很認同人類文化是一個演化的產品，那麼策略的使用也是文化的一環，所以在這個研究中，我們試圖以基因演算法（genetic algorithm）來模擬策略的演化現象。 結合這兩個元素，我採用代理人式的電腦輔助模擬（Agent-Based Computer-Assisted Simulation）來進行這個研究，以一個策略代理人（Agent）來代表一個瀰，而這個策略代理人則是以囚犯困境為設計的藍本；再以基因演算法來模擬演化的過程。利用這樣的模擬來觀察在什麼情況下，會浮現出合作的行為，並探討出現合作現象的原因，並和真實社會的情形相互比較和印證。

In this world, we need to cooperate with others. Why? Because cooperation can usually create more benefit. But cooperation always also interweave with defection. When defection happens, not only there is no more benefit, but also more damage. A game theory is to describe such situation, The Prisoner’s Dilemma. Prisoner’s Dilemma had been well discussed in two players. In this study, I try to model the relationship between individual and society with Prisoner’s Dilemma. Richard Dawkins created a word “Meme” in his book “The Selfish Gene”. He presented that meme is a unit of the culture evolution, just like gene is a unit of the creature evolution. I agree with his opinion about the culture evolution. So in this study, I try to model the evolution of strategy with genetic algorithm. To combine the two features, I adapt Agent-Based Computer-Assisted Simulation. The strategy agent is a meme, which is projected from The Prisoner’s Dilemma. Then I model the evolution with genetic algorithm. So we can see when the cooperation will happen, and we discuss why it happens. Then think about if it happens in the real world.