Why sacrifice?

The Atlantic has an article looking at the matter of human sacrifice; why it was a "thing", and why it stopped.

A pretty interesting topic, with no clear answers.  Seems that some anthropologists argue that it only worked as a social control factor for a society that stayed relatively small - under 100,000 people, say.  Above that, it became de-stablising.

Others argue it went out of fashion as religion improved, so to speak:

But though sheer military might may have been the underlying cause of the disappearance of human sacrifice, the members of the victorious societies likely didn’t see it that way. They probably saw the rejection of human sacrifice as a logical extension of the golden rule, or as a religious imperative. The Harvard psychologist Steven Pinker has argued that societies became less violent as they became better at abstract reasoning. In other words, people spurned violence against others on the grounds that they wouldn’t want it done to them. Turchin and colleagues disagree: With staggering frequency, they argue, it was religion rather than reason that turned people away from ritualized brutality. But a different kind of religion—one that deified not a mortal god-king, but a supernatural “big god.” These were the forerunners of today’s major world religions, and those who spread them railed against human sacrifice. “They basically said, God is repelled by this,” says Turchin.

These new religions—such as Judaism and Zoroastrianism—were born roughly during the first millennium B.C., and though they have yet to prove it, the Seshat group suspects that they provided the social glue that allowed societies to reach newly intricate heights. Without these religions, the researchers think, the complexifying process would have stalled long before it produced the nation-states and multistate federations of today.