  A comparison between an analytical calculation of the polarizability of a
mesoscopic interacting system in the random phase approximation and numerical
exact diagonalization results is presented. While for weak interactions the
analytical calculation fits the numerical results rather well, deviations
appear for stronger interactions. This is the result of the appearance of
intermediate range correlations in the electron density, which suppresses the
polarizability below its classical value. The relevance to quantum dot systems
is discussed.
