It's fairly common that anime characters tend to have "wilder" hair than most people we see in real life. This can be seen as far back as [*Neon Genesis Evangelion*](http://en.wikipedia.org/wiki/Neon_Genesis_Evangelion_(anime)) (though somewhat mild) from the 90s (though some older anime, like [*Akira*](http://en.wikipedia.org/wiki/Akira_(film)), do not have this characteristic).

The "wilder" hairstyles tend to have [interesting colors](http://4.bp.blogspot.com/-xkTubO9nehY/T_29QvnXstI/AAAAAAAAATQ/cWs2zw7eVdg/s1600/Sailor+Moon+characters.jpg) from throughout the rainbow (pink, blue, green, etc.) that are only seen in real life with dyes or highlights. They also tend to be [spikier](http://images.wikia.com/gurennlagann/images/1/17/Kamina_with_sword.jpg), another trait not seen in real life (probably because gelling one's hair that way *every day* is quite tedious).

![enter image description here](https://i.stack.imgur.com/k6pF9.jpg)

Why do anime and manga characters tend to have this spiky, colorful hairstyle? What is the cultural origin of such a style? (And did the growing trend of [Japanese teenagers spiking their hair in a similar style](http://www.hairstyles123.com/hairstylepics/japanese/japanese_hairstyle_36.jpg) originate from this?)