Experimentally induced innovations lead to persistent culture via conformity in wild birds

摘要

In human societies, cultural norms arise when behaviours are transmitted through social networks via high-fidelity social learning. However, a paucity of experimental studies has meant that there is no comparable understanding of the process by which socially transmitted behaviours might spread and persist in animal populations. Here we show experimental evidence of the establishment of foraging traditions in a wild bird population. We introduced alternative novel foraging techniques into replicated wild sub-populations of great tits (Parus major) and used automated tracking to map the diffusion, establishment and long-term persistence of the seeded innovations. Furthermore, we used social network analysis to examine the social factors that influenced diffusion dynamics. From only two trained birds in each sub-population, the information spread rapidly through social network ties, to reach an average of 75% of individuals, with a total of 414 knowledgeable individuals performing 57,909 solutions over all replicates. The sub-populations were heavily biased towards using the technique that was originally introduced, resulting in established local traditions that were stable over two generations, despite a high population turnover. Finally, we demonstrate a strong effect of social conformity, with individuals disproportionately adopting the most frequent local variant when first acquiring an innovation, and continuing to favour social information over personal information. Cultural conformity is thought to be a key factor in the evolution of complex culture in humans. In providing the first experimental demonstration of conformity in a wild non-primate, and of cultural norms in foraging techniques in any wild animal, our results suggest a much broader taxonomic occurrence of such an apparently complex cultural behaviour.%虽然通过社会方式传播的行为已在几种不同的鸟类和哺乳动物中被观察到,但我们对这样的行为怎样传播和持久存在却知之甚少。这篇论文演示了野生鸟的社会从众性的非常强的效应,也说明了它在维持持久觅食传统中所起作用。Lucy Aplin等人教两小组大山雀一种不同的新颖觅食策略,然后当这些受训过的鸟儿被释放回它们各自群组时对该策略在野生种群中的传播进行跟踪。该策略仅从两只受训过的鸟儿就传播给了种群中75%的鸟儿,其中两个子种群(sub-population)至少两代都在它们的群体内严重偏向于采用经过训练掌握的该策略。同时接触到两个策略的鸟儿采用了一个适合自身情况的变通策略。