[en] The dynamics of a neutral spinning particle in electromagnetic fields is investigated. The interference with unpolarized neutron beams is reasonably interpreted as the observation of spin precession in electromagnetic fields which has a dynamical origin. It is shown that only for a particular choice of the initial polarization of the spin the conditions for the Aharonov-Casher topological phase shift and the scalar Aharonov-Bohm effect can be fulfilled. The recent experiment on the Aharonov-Casher phase shift with neutron interferometry can be considered as a test of a new anyon model, which is a result of spin precession in the local electric field. (orig.)