Giblet wrote:Green makes sense. Our eyes are poor in the red spectrum, and road signs are not arbitrarily green. They are in fact green because we can see that better than other colors....
Ciro Pabón wrote:
About why red and green for traffic lights, I've heard many theories, but I think it's simply a carryover of "traffic lights" for ships.
Green road signs???? All the danger/prohibition signs I see on roads have a red circle or red triangle.
My understanding is that red is associated with danger, green with safety. It's all to do with our prehistoric ancestors. If you're struggling to survive in jungle/savannah etc, then it is a handy evolutionary trick for non-green things to jump out in your perception. Non-green things can be food (fruit) or dangerous (tiger).
It's no coincidence that passive things in nature that just want to sit quietly in the corner have dull drab greeny colours, while active things that want to be seen are not green. That's why fruit changes colour when it is ready to be eaten. Dangerous animals are often brightly coloured, sometimes with angular patterns (those little poisonous frogs).
There are other studies that claim a gender difference, women are better at pattern and colour recognition relating to plant foraging (ie subtle differences in shade and texture) while men are better at spotting dramatic changes and angular patterns (sabre tooth tiger, spears, axes).
Next time you are on a busy street, glance around and see how many things you spot that are green rather than red. You'll struggle. Look in a car park. Or perhaps a magazine stand. You'll see red red instantly. You'll only see green if you look for it.
So, I'd say red for danger is about human perception, not physics. So when you see a bright red light and slam on the brakes, you may think it is due to your driver training. It is actually something deep inside you that screams "aarrrghhhh sabre tooth tiger!!!!"
