  One of the main results in canonical quantum gravity is the introduction of
spin network states as a basis on the space of kinematical states. To arrive at
the physical state space of the theory though we need to understand the
dynamics of the quantum gravitational states. To this aim we study a model in
which we allow for the spins, labeling the edges of spin networks, to change
according to simple rules. The gauge invariance of the theory, restricting the
possible values for the spins, induces propagating modes of spin changes. We
investigate these modes under various assumptions about the parameters of the
model.
