  We analyze the phenomenon of system size stochastic resonance in a simple
spatially extended system by exploiting the knowledge of the nonequilibrium
potential. We show that through the analysis of that potential, and
particularly its "symmetry", we can obtain a clear physical interpretation of
this phenomenon in a wide class of extended systems, and also analyze, for the
same simple model, the effect of a general class of boundary conditions
(albedo) on this kind of phenomena.
