It's a bit of a cliche but, like everything else, it's relative. A word only has meaning because it has been given meaning, a pencil is called a pencil because someone called it a pencil, chances are someone that has never seen a pencil before would never call it a pencil, something is only considered to be tall because it is taller than other things similar to it etc... The same applies to your example, a colour is only considered to mean go because someone said it did.
The problem is, because everything is like this, you can then say that nothing has a meaning a decide to just randomise all of the interface, random positions for buttons, random colours, random shapes. I guess you just have to go with what will mean the same thing to the largest number of people. (on an aside, why does a triangle mean go? That /really/ seams arbitrary but practically everyone knows it means this do it's still a good thing to use).


Although with regards to that specific example, red is often a warning in the natural world, if the fear of it is built i rather than learned (and if it applies to people too) then that colour would have meaning. Although even if it is learned then that's still meaning if the world is consistent about it (it always amazes me when the entire of the natural world has the same couple of colours that act as warnings, you'd think in isolated parts of the world a different colour might happen to become a warning (although perhaps how much it stands out makes a difference too)).
I think there are other examples where almost anyone would infer the same meaning from the colour of it. Say if you had one of those torch apps and you could control the brightness with a slider that is black at one end and a much brighter colour at the other (say bright yellow or white) and I think no matter how stupid or young the person (as long as they were unstupid enough to at least know what they are trying to do (in this case change the brightness) they would still assume a lighter colour would make it brighter and a darker one would make it darker.

I think the boldness/how bright they are (or wether they are a different colour to the rest of the app) would still make a difference to anyone as it might make them stand out more or less. Using this you could draw peoples' attention to a specific element.


P.S. Yay for spelling colour correctly