Language

Something remarkable happened with the origin of language. Culture emerged and the rapid spread of ideas. Even stranger, this development which produced modern humans left no evolutionary traces.

Language as viewed here is a form of coupling among P-worlds. Therein lies its power. Once a rich form of coupling is available to multitudes of rich autonomous dynamical systems, they will self-organize into new forms of structure. We know enough about dynamics and complex systems to be quite certain about this. Imagine, if you will, the organization of individual atoms into different forms of crystalline lattices, though with dynamical systems, the structures are, themselves, dynamic.

This organization now allows novel phenomena to propagate across multiple P-worlds. And culture arises. See the "Memetics" link for more...