The specification discloses an automatic rearview mirror which more accurately responds to the glare-reduction needs of the vehicle operator. The mirror includes a reflective element, a light sensor, and a control circuit for regulating the reflective state of the mirror in response to the light sensor. The light sensor includes a detector responsive to electromagnetic wavelengths and a filter for filtering the wavelengths received by the detector so that the spectral response of the light sensor approximates the spectral response of the human eye or standard C.I.E. observer. The light sensor therefore detects the same wavelength intensities as does the vehicle operator.