I think acting instinctually is the base when in a community. Humans are conditioned to share the concept of empathy, and this more than anything else, IMO, is what forms our ethics and morality. Rest assured, less noble traits like fear, xenophobia, jealousy, etc do compete with that. We've simply found that shared empathy, shared ideals and cooperation are mutually beneficial in times that are less than desperate.

I don't need to know about the concept of theft or have a word for it to feel slighted that another took something from me or to imagine how another feels in that situation.

I see ethics and morals as 100% evolution driven. In order to explain this it has to be put into proper context. Something that I achieved about 15 years ago thanks to Michael Chricton. I probably would have come up with it myself at some point anyway, but I was still young and he put it into words for me that made sense.

Before we were even really describable as humans, our brains were evolving to be larger as we used tools more and more often. This meant that children were born less equipped for immediate ability to move around on their own like the vast majority of species on the planet do. Effectively children are born immature, because carrying to term would result in the death of the mother. We aren't big enough to pass a fully developed child through the vagina, and c-sections are hardly natural. Thus education becomes a priority. Most species have a whole bunch of instincts that we don't have any perception of. A child isn't born knowing how to walk or being physically capable of it. But a horse can pull it off quite fine. Since we don't have these instincts or development to work with, instructing children becomes a requirement. We have to teach our offspring more than other species do. The best way to insure the instruction and safety of children is to surround them by capable defenders and teachers. Hence a community is ideal. 10 parents can teach and defend against what 2 cannot. As a result of this it would be impractical to lower the number of defenders simply due to a disagreement, and could put the whole community at risk of predation or disaster. Very likely a couple of early communities were almost wiped out due to such things, and taught thereafter that killing a fellow was a bad thing. Hence murder is against our moral code.

Sparse circumstancial evidence of this is found in some old laws that are still on the books in some communities. Laws that make absolutely no sense to us, but must have made sense to those that made it. And likely had a good reason to make.

More evidence is found in linguistics as was mentioned in the topic post. Many languages have dozens of terms for a concept that other languages don't even refer to.

More than that, they would be less likely to reproduce.  And if they did reproduce, being not welcome in the community at large would make it harder to successfully raise a child.  

I think there might be a factor of this type of personality continuing because of the type of person who gets a woman pregnant, leaves, then the community of the woman helps raise the child.  Thus the unsocial traits can be continued in society.

Further, this might explain why marriage became so important, and why women who get pregnant and don't have a husband are generally seen as outcasts or have done something wrong.  The so-called honor-killing might even be related to this.

It id true that until we have words to express certain ideas, it is harder to develop more complicated ethics.  It's simply another reason to help educate more people.  

Shaun