What does "proxy" mean here?
"...So, the prediction it makes in particular is that, although babies and children can distinguish between different races, it shouldn't matter to them. They should only take race seriously later on in development in some societies and not others when they're aware that race skin color is a proxy for coalition. "
It is some parts of what a professor said in an online morality course I took.
I looked up dictionaries but it doesn't seem to have a meaning for voting. Does it have another meaning in this context above?