They were evolved for a world in which people lived in very small groups, rarely met anybody who was terribly different from themselves, had rather short lives in which there were few choices and the highest priority was to eat and mate today.
Si sono evoluti per un mondo in cui le persone vivevano in gruppi molto piccoli, non incontravano quasi mai qualcuno che fosse molto diverso da loro, vivevano vite abbastanza corte in cui le scelte erano poche e le priorità più importanti erano mangiare ed accoppiarsi subito.