The debate as to whether an "electronic" effect is responsible for perturbations in the normal behavior of supported metal catalysts has seized the attention of scientists for many years. Unfortunately, many of the proposed so-called "electronic" models can now be more satisfactorily explained in terms of either the surface concentration or the size of the ensembles present on the support surface. In this study we have used both ferroelectric and selected ceramic support media to demonstrate that at specific temperatures the catalytic activity of a supported metal particle can be enhanced to a significant degree. The observed improvement in the performances of these systems can be correlated with changes in the structure of the support media and to the different dielectric constants exhibited by these materials. A further aspect that must be taken into consideration is the finding from high-resolution TEM examinations that even after mild reduction at 350 degrees C there was evidence that in the vicinity of metal particles the support underwent transformation to a lower oxide state.