An interferometric modulator is provided having a faster deformation time constant on actuation than relaxation time constant upon release from actuation. In some embodiments, apertures are formed in a mechanical membrane to decrease pressure, including liquid and/or gas pressures, on the membrane when actuated. In other embodiments, a dampening layer is disposed in close proximity above the membrane to apply greater downward pressure on the membrane and therefore slow the motion of the membrane when released from an actuated state. Other embodiments comprise structures, such as a heating element or vacuum device, to manipulate pressures above and/or below the mechanical membrane to affect the mechanical persistence of the display device.