  The effects of the exchanges of both pseudoscalar and vector mesons among
constituent quarks on the mass spectra of light baryons are investigated,
paying particular attention to the contribution of tensor and spin-orbit terms.
It is shown that the latter ones heavily affect the calculated spectra at
variance with the empirical observation of the weakness of the baryon
spin-orbit splittings. The relativistic suppression of the strength of the
interaction among light quarks is argued to be a possible way to reproduce the
light-baryon mass spectra.
