Human sacrifice helped build complex civilizations
Killings helped reinforce power of social elite
Mr. Watts studied more than ninety historical cultures of Austronesia - the mostly island cultures that stretch from Asia to Hawaii. He found that as groups evolved from smaller egalitarian societies to more complex and socially stratified societies, human sacrifice increased in prevalence.
These ritual killings likely enhanced the power and privilege of leaders and ruling castes, and might have also served as a way of dealing with rule-breakers and trouble-makers.