In the present method of programming a memory device from an erased state, the memory device includes first and second electrodes, a passive layer between the first and second electrodes, and an active layer between the first and second electrodes. In the programming method, (i) an electrical potential is applied across the first and second electrodes from higher to lower potential in one direction to reduce the resistance of the memory device, and (ii) an electrical potential is applied across the first and second electrodes from higher to lower potential in the other direction to further reduce the resistance of the memory device.