在巴布亚新几内亚高地，一个群体养猪能力的强弱直接关系到其在与其他地区群体的竞争中的经济和社会地位。猪的仪式交换使群体能够建立联盟、偿还债务、获得妻子，并通过过度慷慨的行为来获得声望。所有这些都意味着，养猪能力更强的群体能够更快地扩大其规模（通过繁殖和移民），从而有机会扩大其领地。在小规模社会中，群体规模对群体间战争非常重要，因此规模更大的群体更有可能成功地扩大其领地。然而，更成功的群体获得的声望可能会导致导致其竞争优势的制度、信仰或实践的快速传播，因为其他群体采用其策略和信仰。

🐷 **猪的仪式交换和群体竞争:** 在新几内亚高地，猪的仪式交换是群体之间建立联盟、偿还债务、获得妻子以及提升声望的重要手段。群体养猪能力的强弱直接关系到其在与其他地区的竞争中的经济和社会地位。养猪能力更强的群体能够更快地扩大其规模，从而有机会扩大其领地。

🏆 **声望传播和文化演化:** 更成功的群体获得的声望可能会导致导致其竞争优势的制度、信仰或实践的快速传播，因为其他群体采用其策略和信仰。这体现了文化演化的一个典型例子，即成功的模式被其他群体模仿，从而推动了文化的发展。

🗺️ **伊拉基亚村庄的案例:** 在1971年，人类学家大卫·博伊德在伊拉基亚村庄观察到群体之间的竞争。为了提升地位，伊拉基亚村庄的长老们决定模仿福尔族人的养猪习俗、仪式和制度，因为福尔族人以养猪能力著称，在该地区拥有强大的地位。

🎶 **福尔族的养猪习俗:** 福尔族人认为唱歌、跳舞和吹奏笛子可以促进猪的生长，并制定了一系列与猪相关的习俗，例如在宴会上优先给猪喂食。伊拉基亚村庄的长老们决定采纳这些习俗，希望能够提升自己的养猪能力，从而在竞争中获得优势。

🤝 **文化传播的意义:** 伊拉基亚村庄的案例说明了文化传播的重要性。通过模仿成功的群体，伊拉基亚村庄能够快速学习和改进，从而提升自己的竞争力。文化传播是人类社会发展的重要动力，它使人类能够不断进步和创新。

[Previously in sequence: Epistemic Learned Helplessness, Book Review: The Secret Of Our Success]

A rare example of cultural evolution in action:

Throughout the Highlands of New Guinea, a group’s ability to raise large numbers of pigs is directly related to its economic and social success in competition with other regional groups. The ceremonial exchange of pigs allows groups to forge alliances, re-pay debts, obtain wives, and generate prestige through excessive displays of generosity. All this means that groups who are better able to raise pigs can expand more rapidly in numbers—by reproduction and in-migration—and thus have the potential to expand their territory. Group size is very important in intergroup warfare in small-scale societies so larger groups are more likely to successfully expand their territory. However, the prestige more successful groups obtain may cause the rapid diffusion of the very institutions, beliefs, or practices responsible for their competitive edge as other groups adopt their strategies and beliefs.

In 1971, the anthropologist David Boyd was living in the New Guinea village of Irakia, and observed intergroup competition via prestige-biased group transmission. Concerned about their low prestige and weak pig production, the senior men of Irakia convened a series of meetings to determine how to improve their situation. Numerous suggestions were proposed for raising their pig production but after a long process of consensus building the senior men of the village decided to follow a suggestion made by a prestigious clan-leader who proposed that they “must follow the Fore’” and adopt their pig-related husbandry practices, rituals, and other institutions. The Fore’ were a large and successful ethnic group in the region, who were renowned for their pig production. The following practices, beliefs, rules, and goals were copied from the Fore’, and announced at the next general meeting of the community:

1) All villagers must sing, dance and play flutes for their pigs. This ritual causes the pigs to grow faster and bigger. At feasts, the pigs should be fed first from the oven. People are fed second.