  We discuss the possibility to cleanly distinguish, in electron-positron
annihilation into fermion pairs at a high energy collider, the indirect
manifestations of graviton exchange from those of four-fermion contact
interactions. The method is based on cross section asymmetries emphasizing the
spin-2 character of graviton exchange and is explicitly applied to the ADD
scenario for gravity in extra dimensions. The availability of initial beams
longitudinal polarization is also taken into account. For typical c.m. energies
and time-integrated luminosities foreseen at the International Linear Collider
[\sqrt s=0.5-1 TeV, L_{int}=50-1000 fb^{-1}], a 5\sigma identification reach as
high as 3.5-5.8 TeV for the mass scale M_H relevant to the ADD model can be
obtained, while the size of the reach on the mass scales Lambda characterizing
four-fermion contact interactions can be of the order of 45-65 TeV.
