  We show that accounting for internal character among interacting,
heterogeneous entities generates rich phase transition behavior between
isolation and cohesive dynamical grouping. Our analytical and numerical
calculations reveal different critical points arising for different
character-dependent grouping mechanisms. These critical points move in opposite
directions as the population's diversity decreases. Our analytical theory helps
explain why a particular class of universality is so common in the real world,
despite fundamental differences in the underlying entities. Furthermore, it
correctly predicts the non-monotonic temporal variation in connectivity
observed recently in one such system.
