A little something about the eye:

-The retina is located on the back of the eye and it contains all of the photoreceptors that collect light and pass action potentials to the optic nerve. Although the retina is located in the eyeball, it is actually part of the brain so when you are looking deep into someone's eyes, you are actually seeing their brain. Gross!

-In the photoreceptors of the retina, you have cone photoreceptors (cones) and rod photoreceptors (rods). Cones and rods differ in both structure and the photopigment they contain. Rods have long, cylindrical outer segments with membrane discs that contain the photopigment Rhodopsin. Cones have shorter, tapering outer segments with one of three different kinds of photopigments (red, green, or blue). Since rods have more membrane discs, they are over 1000 times more sensitive to light than cones. Thus, rods are activated in lowlight situations, while cones are used to differentiate colors in an abundance of light.


Now the fun part:

-There are two different "schools of thought" in designing car dashboards. One view is that the lights should be a dim blue color in order to take advantage of the rods' light sensitivity. The other thought is to use bright red lights that activate cones in order to leave the rods 'unsaturated' or unused, thus increasing the driver's night vision.


Which kind of dashboard lights would you rather have?

(Personally, I'd like to have bright red dashboard lights because those seem to be more common in expensive cars. So, logically, if my car had bright red lights on the dashboard, then that'd probably mean that it was an expensive car and I enjoy expensive cars.)