We conduct numerical simulations on a simple model of a two-dimensional ste
ady-state sheared foam, and define a quantity Gamma that measures stress fl
uctuations in the constant-area system. This quantity reduces to the temper
ature in an equilibrium system. Wie find that the relation between the visc
osity and Gamma is the same as that between viscosity and temperature in a
very different system, namely a supercooled liquid. This is the first evide
nce of a common phenomenon linking these two systems.