  We show that an effective field theory that includes non-standard couplings
between the electroweak gauge bosons and the top and bottom quarks may yield
negative contributions to both the S and T oblique radiative electroweak
parameters. We find that that such an effective field theory provides a better
fit to data than the standard model (the chi-squared per degree of freedom is
half as large). We examine in some detail an illustrative model where the
exchange of heavy scalars produces the correct type of non-standard couplings.
