When an intense laser pulse hits a stationary electron, it performs a trembling motion at the frequency of the light field. However, this motion dies down after the pulse, and the electron comes to rest again at its original location. If, however, the light field changes its strength along the electron's trajectory, the electron builds up an additional drift motion with each oscillation, which it retains even after the pulse. The spatial light intensity acts like a slope that the electron slides down.