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.
