  We investigate experimentally the role of spatial coherence on optical beam
shifts. This topic has been the subject of recent theoretical debate. We
consider Gaussian Schell-model beams, with different spatial degrees of
coherence, reflected at an air-glass interface. We prove that the angular
Goos-H\"anchen and the angular Imbert-Fedorov effects are affected by the
spatial degree of coherence of the incident beam, whereas the spatial
Goos-H\"anchen effect does not depend on incoherence. Our data unambiguously
resolve the theoretical debate in favour of one specific theory.
