Archaeological analyses often detect abrupt changes over time in the hierarchy of settlement sizes and the spatial distribution of residential units. These transformations have been explained looking at a variety of possible causes, from climatic changes to the sudden release of slowly cumulating political tensions. While many of these models offer plausible explanations for specific historical contexts, a broad-breadth model is desirable if cross-cultural analysis is sought. This paper tackles this problem by starting from the theoretical proposition that human groups are characterised by a non-linear relationship between size and per-capita fitness. Increasing group size has beneficial effects, but once a certain threshold is exceeded, negative frequency dependence will start to predominate leading to a decline in the per-capita fitness. Such a relationship can potentially have long-term implications in the spatial structure of human settlements if individuals have the possibility to modify their fitness through group fission–fusion dynamics. I will illustrate the equilibrium properties of these dynamics by means of an abstract agent-based simulation and discuss its implication for understanding long-term changes in human settlement pattern. Results suggest that changes in settlement pattern can originate from internal dynamics alone if the system is highly integrated and interconnected.