Why is Fear Yellow?

I've never understood in the Yellow spectrum of light why it represents fear. I think of yellow more as like joy or something like being bold.. What do you think??

its the coller of piss which is what id do in my pants if i ever saw something like godzilla walking down the street

that would take a bit of unnecessary research. why not Google?
something i do remember reading when i was a kid was that in samurai times,
disgraced samurais wore yellow to mock their old masters, and in return there old
masters labeled their color as a sign of cowardice.
 
now hows this for an oxymoron?
 Xanthophobia - the fear of the color yellow and/or the word yellow.

Yellow has always been a sign of cowardice and it worked for a Hitler esc. villain to spread fear, so Johns just went with it.

This is a Bad Example, but Pikachu's Yellow and he's not a coward for a little guy he's pretty brave.. Also kind of another bad Example Bumble Bee is yellow and he's courageous. And stuff.. Bad Examples...

Yellow is the color of fear and cowardice .

Truth is, colors don't have any true aspect to emotions (including fear or cowardice). But why not yellow, we can fear anything as long as it can scare us. Some of the slasher have non-scary names; Chucky, Jason, Pinhead, Freddy. We fear them because they have proven to be scary. I could fear yellow if some killer who only wears yellow was killing people in my neighborhood.

"its the coller of piss which is what id do in my pants if i ever saw something like godzilla walking down the street "

False  
Evidence 
Appearing 
Real 
 
shouldn't have any in your lives

Here's some Good Examples. Yellow and Blue costume + Huge Claws and a Bad ass attitude= Wolverine. Another Good Example is a human Man that can channel Chi into his Fist to make it hard as Iron!!!!!! Are those any good???

What are ya, yella?

"What are ya, yella? "