The behavior of pinning points at dislocations during internal friction measurements is discussed. Diffusion of pins along the dislocation prior to breakaway of the dislocation from the pinning points and in the lattice subsequent to breakaway is qualitatively considered. Both types of motion lead to time dependence of the internal friction and the variation of this time dependence with temperature and strain amplitude is discussed. It is shown that a study of these effects can lead to an understanding of the contribution of the amplitude‐dependent viscous damping and of the amplitude‐dependent hysteretic damping to the total specimen damping. An experimental technique is described which allows a separation of these two contributions. This technique is applied to Al and Al&sngbnd;Mg alloys at high and low temperatures and the existence of these two damping contributions is demonstrated.