According to one embodiment of the present invention, an electrochromic rearview mirror assembly for a vehicle includes an electrochromic mirror (110, 920) having a variable reflectivity, a glare sensor (160, 234) for sensing levels of light directed towards the front element from the rear of the vehicle, an ambient sensor (232) for sensing levels of ambient light, a display (146, 170) positionedbehind the partially transmissive, partially reflective portion of the reflector for displaying information therethrough; and a control circuit (230, 900) coupled to the sensors and the display. The control circuit determines whether daytime or nightime conditions are present as a function of the ambient light level sensed by the glare sensor to control a contrast ratio of light originating from the display and light reflecting from the partially transmissive, partially reflective area of the reflector.