협력 비율의 특징

찰스 다윈은 이타적 행동, 상호 협력, 그리고 성 선택은 자연 선택, 적자생존 등의 개념만으로는 설명이 쉽지 않아 한동안 골머리를 앓았습니다. 이후 윌리엄 해밀턴이라는 진화생물학자가 ‘근연도’라는 개념을 바탕으로 한 해밀턴 법칙을 제시하면서 이타성을 깔끔하게 설명했습니다. 이후 상호 협력은 진화론적 게임이론으로 충분히 설명할 수 있다는 것을 많은 수학자가 밝혀냈습니다.

그런데 캐나다 브리티시컬럼비아대(UBC) 수학과, 동물학과, 헝가리 부다페스트 기술물리·재료과학 연구소, 진화연구소 공동 연구팀은 두 집단에서 협력 행위는 계속 증가하지 않고 일정 비율로 유지된다는 사실을 수학적으로 확인했다고 밝혔습니다. 

협력은 비용이 낮거나 이익이 클 때 나타납니다. 협력을 하는 데 비용이 너무 많이 들면 협력할 이유가 없는 것은 너무도 당연합니다. 이를 근거로 진화수학자들은 게임이론으로 자기 이익만 추구하려는 개체가 있을 때도 상호 협력이 유지되는 이유에 관해 설명했습니다. 이는 꿀벌, 나비와 같은 꽃가루 수분 곤충과 식물 간의 공생 관계로도 확인됐습니다.

이번 연구팀은 상호 협력이 언제 증가하고 감소하는지 알아보기 위해 ‘계산공간모형’(CSM)이라는 일종의 컴퓨터 모의실험을 했습니다. 두 종의 개체를 바둑판처럼 생긴 격자에서 서로 마주 보도록 한 뒤 협력 행동을 실험한 것입니다. 연구팀은 각 개체가 군집을 형성해 자기 이익만 챙기려는 사기꾼 개체를 쫓아내는 방식으로 협력을 확대하도록 컴퓨터 모델을 설계했습니다.

그 결과 협력 조건이 개선될 때마다 두 종 사이에서 상호 이익이 되는 방향으로 협력 행위가 증가하는 것이 확인됐습니다. 그런데 협력의 비율이 50%에 가까워지면 갑자기 분열이 발생하는 것이 관찰됐습니다. 공간적으로 한쪽에는 협력자들이, 다른 쪽으로는 비협조자나 배신자들이 모이면서 나타난 현상입니다. 연구팀에 따르면 협력과 비협력의 비율이 일정하게 유지된다는 것입니다.

 

 

 

Charles Darwin struggled for a while because it was not easy to explain altruistic behavior, mutual cooperation, and gender selection only with the concepts of natural selection and survival of the fittest. Later, an evolutionary biologist named William Hamilton presented Hamilton's law based on the concept of 'neighborhood' and neatly explained altruism. Since then, many mathematicians have found that mutual cooperation can be fully explained by evolutionary game theory.

However, a joint research team at the University of British Columbia (UBC) mathematics department, zoology department, Budapest Institute of Technology and Materials Science in Hungary, and evolutionary research team have mathematically confirmed that cooperative behavior in the two groups does not continue to increase but remains at a certain rate.

Cooperation occurs when the cost is low or the profit is high. If cooperation is too expensive, it is only natural that there is no reason to cooperate. Evolution mathematicians explained why mutual cooperation is maintained even when there are individuals who only pursue self-interest through game theory. This was also confirmed by the symbiotic relationship between plants and pollen insects such as honeybees and butterflies.

The research team conducted a computer simulation called the Computational Space Model (CSM) to find out when mutual cooperation increases and decreases. They experimented with cooperative behavior after making two types of objects face each other on a grid shaped like a checkerboard. The research team designed a computer model so that each individual could form a cluster to expand cooperation in a way that drives out fraudulent individuals who try to take care of their own interests.

As a result, it was confirmed that cooperative behavior increased in a mutually beneficial direction between the two species whenever the conditions for cooperation improved. However, it was observed that when the proportion of cooperation approached 50%, division suddenly occurred. Spatially, this phenomenon occurred when collaborators gathered on one side and non-cooperative or traitors on the other. According to the research team, the ratio of cooperation and non-cooperation remains constant.