A theoretical model of coevolution of culture and gene and the effects of mating and learning biases on cultural evolution

Abstract

Gene-culture coevolutionary theory examines the effects of cultural traits, in addition to passing on of genetic traits from one generation to the next differentially. I construct a theoretical model that studies, in addition to the contribution of the phenotype of the organism, its interaction with the extended phenotype while determining the fitness of an individual in the population. I study both negative and positive interactions between the organismal phenotype and the extended phenotype. Positive interaction is when the extended phenotype enhances the fecundity of the individual, whereas negative interaction is when the extended phenotype adversely affects the fecundity of the individual. In both cases, the fitness increases as the population evolves with time. Interestingly, however, this increase is faster in the case of negative interaction than in positive interaction. In the second part of my thesis, I extend my model to study the evolution of cultural learning in a sexual system of reproduction. I combine frequency- dependent learning biases namely, conformation bias and novelty bias, and assortative mating (in addition to the usual case of random mating) to examine the evolutionary dynamics of cultural traits. Since the biases modelled are frequency-dependent, I also investigate the cyclical fluctuations in cultural trait values for the two mating systems. My results agree with several results present in literature and also add a few insights to the existing knowledge of cultural evolution.