Why do certain colors have certain associations?
(examples: red means stop, green means go, yellow means caution)
-and what are some of the others?
Is there any history behind any of these associations as to how they turned into a certain meaning? (why did black become mourning?)
Is this a cultural definition or could there be a genetic cause amongst human beings to react to a color a certain way?
Red became an “urgent” color because in nature poisonous creatures had that color on them as a warning display. Examples: black widow spider, coral snake, some poison dart frogs etc. It’s also associated with fire, so it naturally became used by us as a warning color. The color black for mourning isn’t as universal, for example in some religions white is the color of mourning. (Scroll down for mention of this fact.)
Cecil addresses the subject in this column: Who decided red means “stop” and green means “go”?
How about blood? I’d think that would contribute to the association of red = dangerous.
I am old enough to remember when stop signs (as opposed to traffic lights) were yellow octagons. I would guess that it was in the early 50s that almost overnight, the stop signs became red octagons. But it was quite obviously a really good idea and spread really quickly.
Hari Seldon, what country do you memories come from out of curiosity?Antigen, that too to an extent. Bloodflow could be a good thing also, as in “Dinner’s on the table!”. 
In ancient Tamil Nadu, red was an auspicious color used in epithets of deities. The name of the Hindu god Shiva comes from a Dravidian word for red. As the color of blood, it symbolized the life force.
cecil actaully mentions this in the article loopus linked,
i like these histories given about tamil nadu, stop signs, and the poisonous animals
i find these associations fascinating