  We simulate single and multiple Ising models coupled to 2-d gravity using
both the Swendsen-Wang and Wolff algorithms to update the spins. We study the
integrated autocorrelation time and find that there is considerable critical
slowing down, particularly in the magnetization. We argue that this is
primarily due to the local nature of the dynamical triangulation algorithm and
to the generation of a distribution of baby universes which inhibits cluster
growth.
