Additionally, simply because there may be social pressure towards some trait or value does not mean this value is completely arbitrary. (ie, "another, better society could do away with trait X, if only they were better educated!") For an easy example, think of traits such as bravery, love, trust, or honesty. There's much social pressure towards these traits (at least within some small groups) but that's not to say that these traits are totally arbitrary, just that social pressure is one of the primary mechanisms by which these innate traits are enforced.
