  Understanding the relationship between symmetry breaking, system properties,
and instabilities has been a problem of longstanding scientific interest.
Symmetry-breaking instabilities underlie the formation of important patterns in
driven systems, but there are many instances in which such instabilities are
undesirable. Using parametric resonance as a model process, here we show that a
range of states that would be destabilized by symmetry-breaking instabilities
can be preserved and stabilized by the introduction of suitable system
asymmetry. Because symmetric states are spatially homogeneous and asymmetric
systems are spatially heterogeneous, we refer to this effect as
heterogeneity-stabilized homogeneity. We illustrate this effect theoretically
using driven pendulum array models and demonstrate it experimentally using
Faraday wave instabilities. Our results have potential implications for the
mitigation of instabilities in engineered systems and the emergence of
homogeneous states in natural systems with inherent heterogeneities.
