A rearview mirror system comprises a spotter mirror for providing an image of an object in a vehicle's blind zone to the vehicle's operator. A recognition enhancement device is provided with the spotter mirror for drawing the attention of the driver to the spotter mirror when an overtaking vehicle enters the driver's blind zone. The signaling display is activated by a sensing system which senses the presence of the overtaking vehicle in the blind zone. An electrochromic element is incorporated into the spotter mirror to reduce the intensity of light transmitted from the object and reflected from the spotter mirror. Activation of the electrochromic element to darken the spotter mirror will induce the operator to observe the object in the spotter mirror.