Institute of Biology, University of Neuchâtel, Switzerland.
Philos Trans R Soc Lond B Biol Sci. 2011 Feb 12;366(1563):424-35. doi: 10.1098/rstb.2010.0313.
In species subject to individual and social learning, each individual is likely to express a certain number of different cultural traits acquired during its lifetime. If the process of trait innovation and transmission reaches a steady state in the population, the number of different cultural traits carried by an individual converges to some stationary distribution. We call this the trait-number distribution. In this paper, we derive the trait-number distributions for both individuals and populations when cultural traits are independent of each other. Our results suggest that as the number of cultural traits becomes large, the trait-number distributions approach Poisson distributions so that their means characterize cultural diversity in the population. We then analyse how the mean trait number varies at both the individual and population levels as a function of various demographic features, such as population size and subdivision, and social learning rules, such as conformism and anti-conformism. Diversity at the individual and population levels, as well as at the level of cultural homogeneity within groups, depends critically on the details of population demography and the individual and social learning rules.
在个体和社会学习的物种中，每个个体都可能表现出一定数量的在其一生中获得的不同文化特征。如果特征创新和传播的过程在种群中达到稳定状态，个体携带的不同文化特征的数量就会收敛到某个稳定分布。我们称这个为特征数量分布。在本文中，我们推导了当文化特征彼此独立时个体和种群的特征数量分布。我们的结果表明，随着文化特征数量的增加，特征数量分布趋近于泊松分布，因此它们的平均值可以描述种群中的文化多样性。然后，我们分析了作为个体和种群水平的各种人口特征的函数，如种群大小和细分，以及社会学习规则，如从众和反从众，特征数量平均值如何变化。个体和种群水平以及群体内文化同质性水平的多样性，极大地取决于人口统计学和个体和社会学习规则的细节。
