文章基本信息

标题：Polychotomous traits and evolution under conformity
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作者：Kaleda K. Denton ; Uri Liberman ; Marcus W. Feldman 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：39
DOI：10.1073/pnas.2205914119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance Polychotomous traits (i.e., traits with more than two variants) are ubiquitous in nature, from phonemes to food sources. Individuals may adopt variants nonrandomly, influenced by biases including conformity and anticonformity. Mathematical models of (anti)conformity to a dichotomous trait, with two variants, are widely accepted, but fewer conformity models incorporate more than two discrete variants, and in those that do, the level of conformity is determined by a single coefficient. We generalize standard dichotomous trait conformity models—where there may be different conformity coefficients depending on the numbers of sampled variants—to include m variants. Frequency dynamics, including polymorphic equilibria, stable cycles, and chaos, can differ from what is known for a trait with only two variants. Conformist and anticonformist transmission of dichotomous cultural traits (i.e., traits with two variants) have been studied both experimentally, in many species, and theoretically, with mathematical models. Signatures of types of conformity to polychotomous traits (with more than two variants; e.g., baby names and syllables in bird song) have been inferred from population-level data, but there are few models that include individual-level biases among more than two discrete variants. We generalize the standard dichotomous trait conformity model by Boyd and Richerson to incorporate n ≥ 3 role models and m ≥ 2 variants. Our analysis shows that in the case of n=3 role models, under anticonformity, the central polymorphic equilibrium p * = ( 1 m , … , 1 m ) is globally stable, whereas under conformity, if initially the frequencies of ℓ variants are all equal to the maximum variant frequency in the population, there is global convergence to an equilibrium in which the frequencies of these variants are all 1 ℓ and all other variants are absent. With a general number n of role models, the same result holds with conformity, whereas under anticonformity, global convergence is not guaranteed, and there may be stable frequency cycles or chaos. If both conformity and anticonformity occur for different configurations of variants among the n role models, a variety of novel polymorphic equilibria may exist and be stable. Future empirical studies may use this formulation to directly quantify an individual’s level of (anti)conformist bias to a polychotomous trait.
关键词：enconformitypolychotomous traitstable equilibriapolymorphismglobal convergence