  We consider an open-ended set of cultural features in the Axelrod's model of
cultural dissemination. By replacing the features in which a high degree of
consensus is achieved by new ones, we address here an essential ingredient of
societies: the evolution of topics as a result of social dynamics and debate.
Our results show that, once cultural clusters have been formed, the
introduction of new topics into the social debate has little effect on them,
but it does have a significant influence on the cultural overlap. Along with
the Monte-Carlo simulations, we derive and numerically solve an equation for
the stationary cultural overlap based on a mean-field approach. Although the
mean-field analysis reproduces qualitatively the characteristic phase
transition of the Axelrod's model, it underestimates the cultural overlap,
highlighting the role of the local interactions in the Axelrod's dynamics, as
well as the correlations between the different cultural features.
