Social structures are usually considered in terms of either morality or personal liberty. I find both of these fairly dull. What interests me is what (if any) selection pressures they exert. If you have a society with an entrenched version of the “marshmallow test,” a society which shuns those who fail, are you selecting for future time orientation and a well developed pre-frontal cortex? What effect will this have on a population over 1000 years? If no evidence of such selection is apparent, why not?