Much fodder is made by the right in discussing where morality and societal ethics come from. The notion that the US is based on the Ten Commandments is often thrown out even though the First Commandment is have only one God and the First Amendment says we will accept you with any or no god. Certainly this won't end a debate so the theist will press with the question of seeking a source to morality.
The answer clearly is that morality and ethics are based in mutually beneficial interactions. You can't rape someone because you make them not want to be a part of the group or society and you take away their choice. In short, the rapist not only damages the victim, but also societal cohesion. Take Marijuana being illegal. It's a perception that it damages society and as generations pass it's becoming acceptable and the norm because we as a society no longer feel that it causes Negros to rape white women! (Hearst ran ads in his papers to this effect in the 30's) Example
. We've grown in our understanding and realize that little to no damage to society will come of legalizing the drug and so now it's just a matter of the tide continuing to turn. No damage to cohesion, it's acceptable.
I ran across a video of Chimps learning the power of cooperation. I think that it shows Chimps learning the value of helping one another. It clearly shows how a small next step mentally gets them to understand the value of working together. This is where societal morality and ethics starts. It shows how close chimps are to getting the bigger picture. A small fractional mental development would be all that is needed to take them from understanding the concept of help and sharing when shown, to simply choosing to do so on their own. Am I reading too much into this vid? Or do you think that the point is close to correct?