See here. Also, see Bryan Caplan on folk economics and Robin Hanson on signaling (both can be found on Econtalk/Econlog). Somewhat prescient was Nietzsche who talked about morality (that is, ordinary moral feelings) as ‘herd instinct in the individual’. People have evolved for egalitarian, communal, jungle life. Those of us who aren’t are sort of nature’s crapshoot.