The Psychology of Religion, Chapter 16: Sacrifice

Most religions have some form of sacrifice alluded to in their theology. Sometimes this involves literal offerings—killing and burning animals, or destroying valuable objects. Other times it is “bloodless”: giving money, time, obedience, or the renunciation of pleasures through fasting, abstinence, or celibacy. In all these cases, the underlying idea is similar: something costly is offered up, with the hope of securing meaning, favour, purity, forgiveness, protection, or communal belonging.

There are also sacrificial motifs that move disturbingly close to human sacrifice. In the Abrahamic traditions, for example, the willingness of Abraham/Ibrahim to sacrifice his son, is presented as a peak test of obedience. In Islam it is commemorated annually in Eid al-Adha, the “Festival of Sacrifice,” in which animal sacrifice functions as a memorial of that story. And in Christianity, the theme of sacrifice is carried into the central story of Jesus: a dramatic moral and symbolic reframing of sacrifice into self-sacrifice, offered “for others.”

These stories share a hidden architecture: substitution. The ram caught in the thicket dies in Isaac’s place; the Levitical scapegoat is loaded with the community’s sins and driven into the wilderness to carry them away; and Christianity universalizes the logic completely, casting Jesus as the “Lamb of God” whose single sacrifice is meant to end the need for any further sacrifice at all. Much of the moral force of sacrifice lies here—in the idea that suffering can be transferred, that one life or one death can be made to stand in for another.

Across much of the ancient world, sacrificial traditions were common, and they were often brutal. Ancient Greek religion had animal sacrifice. Vedic religion in India revolved around yajña, sacrificial ritual. Ancient China too had elaborate sacrificial practices directed toward ancestors and higher powers, sometimes involving animals and—as the royal tombs at Anyang attest—at times human beings. The Aztecs are especially notorious for human sacrifice, though the true scale is debated and was very likely inflated by their Spanish conquerors.

Why would an all-powerful deity, especially one associated with the highest standards of morality, want a dead animal or a burnt work of art as a gift? One might think that a god worth revering would consider it a gift if you were to help other people or care for the natural world, rather than destroy objects or kill living things. But sacrificial systems do not usually work that way.

It is worth noting that this objection is not a modern or anti-religious invention; the traditions raised it against themselves long ago. The Hebrew prophets are scathing on exactly this point: “I desire mercy, not sacrifice,” says Hosea; Micah asks whether the Lord wants “thousands of rams” or rather that one do justice and love mercy; Amos has God declare that he despises the festival offerings, demanding instead that “justice roll down like waters.” The same suspicion runs through Greek philosophy from the Euthyphro onward. The most humane corrections to religion have often come from inside it—and the critique of sacrifice is a striking early example.

Reciprocity, Magical Thinking, and Social Technology

Sacrifice is, in my view, an extension of ordinary human ideas about reciprocity and gratitude—infused with magical thinking. In a community we do favours, give gifts, and care for one another. These behaviours can be altruistic, but they are also supported by norms of reciprocity. If one believes that a mystical power controls destiny, fertility, weather, health, wealth, or military success, it becomes psychologically “reasonable,” within that worldview, to give that power a gift—hoping for a return.

And once a person enters this mindset, the logic can become self-sealing. If you make sacrifices and misfortune still comes, you can conclude the offering wasn’t sufficient, wasn’t sincere enough, or wasn’t given with the right purity of heart—so you must increase it next time. If something good happens afterward, it feels like proof that the sacrifice worked, and should be repeated. In this way, practising sacrifice can become an escalating, brutal, and destructive behaviour. The sacrificed animals—often the most vulnerable and least able to “consent” to the human story being told about them—do not get much say in the matter.

Another motivation for sacrificial rituals likely came from the brutal necessities of ancient life: hunting animals, or killing domestic animals for food. Most humans bond to animals easily, and it would be psychologically troubling to watch an animal struggle and suffer. Ritual can function as moral anaesthetic: a way to consecrate violence, to assuage guilt, and to turn a grim necessity into a story of gratitude, order, and meaning.

Two scholars loom over any modern account of sacrifice, and it is worth situating these intuitions against theirs. Walter Burkert, in Homo Necans, argued that Greek sacrificial ritual grew out of the guilt and anxiety of the Palaeolithic hunt—that the solemn choreography around the killing of the animal is, at bottom, a way of managing the unease of taking life, which is close to the “moral anaesthetic” idea above. René Girard, in Violence and the Sacred, proposed something darker: that sacrifice channels the contagious, escalating violence of a community onto a substitute victim—a scapegoat—whose death discharges the tension and restores peace, after which the victim is often sacralized. One need not accept either theory wholesale to notice that both converge with the argument here: sacrifice is a technology for metabolizing the violence and anxiety that group life generates.

Sacrifice can also be political performance. Public ritual can consolidate hierarchy, especially priestly hierarchy, display power, intensify fear, and signal unity. Sacrifice makes shared belief visible and costly. It puts loyalty on display. It shows who is serious, who is obedient, who can be trusted, and who has the authority to declare what counts as holy.

This is also where sacrifice connects to group psychology. Some scholars have argued that costly rituals—things you would not do unless you were committed—operate as signals that strengthen trust and cooperation within a group, partly by filtering out free riders. A community bound together by shared sacrifice can feel safer, warmer, and more morally serious to its members. But that same mechanism can harden boundaries and intensify suspicion of outsiders.

And costly sacrifice does not merely send a signal to other people; it also works on the person making the sacrifice. As we saw in the earlier discussion of initiation, people are generally reluctant to admit that they have suffered for nothing. So the greater the sacrifice, the stronger the pressure to reinterpret the suffering as meaningful, noble, or necessary. That helps make sacrificial systems self-protective and self-reinforcing. The cost itself becomes part of the “evidence” that the belief must matter.

Kin Altruism

Reciprocity has a deeper and older root than social custom. It is a strongly selected trait to favour and help genetic relatives, sometimes even in self-sacrificial ways. If a person carries a trait that inclines them to help close relatives, that trait will tend to persist down the family line, because close relatives are disproportionately likely to carry the very same gene that produced the tendency. This is the core logic of kin selection: an allele that prompts costly help toward relatives can spread when the reproductive benefit to those relatives, weighted by the probability that they share the allele, outweighs the cost to the individual—even when that cost is steep.

But humans do not walk around calculating degrees of genetic relatedness. Instead, we rely on crude, fast estimates—cues that, over most of human history, were often correlated with kinship and shared ancestry. People who live near each other, marry each other, and raise children together will, over generations, tend to share not only genes but also language, accent, customs, dress, habits, and social norms. They may also tend, on average, to resemble one another physically more than they resemble people from a distant village, tribe, or lineage. Conversely, people who look different, speak differently, or practise very different customs are often from a different village, tribe, or family network—and therefore are, on average, somewhat less likely to be as closely related as the people who share one’s immediate cultural and familial world.

Similarity of appearance, familiarity of accent, shared habits, shared rituals, shared dress, and shared taboos can all become proxies—very imperfect proxies—for “one of us.” Religion gives people common dress, common restrictions, common foods, common sacrifices, common songs, common stories, and common enemies. In other words, it manufactures the feeling of kinship, even among people who are not literally kin.

A caution is in order here, because the inference from “looks different” to “treated as an enemy” is looser than it first appears. A well-known body of experimental work suggests that the mind does not actually track race, or physical similarity, as a fundamental category at all; what it tracks is coalition—who is allied with whom. In these studies, subjects’ tendency to sort others by race could be sharply reduced within minutes simply by giving them a different, more salient cue to who was on which team. If that is right, then physical appearance is encoded only insofar as it has historically predicted alliance, and it can be overwritten when a better predictor is supplied. This does not weaken the argument so much as relocate it: religion’s real power is that it floods the mind with vivid, durable coalition markers—shared dress, shared rites, shared sacrifice—and thereby recruits a coalitional psychology that is older and deeper than any doctrine.

The mind appears to have evolved to be slightly more generous, trusting, and self-sacrificing toward those who are more likely to be “one of us,” and correspondingly less generous, more suspicious, or more emotionally distant toward those who feel like “not us.” These tendencies are not destiny, and they are not moral justification—but they appear to be among the psychological and evolutionary foundations of prejudice. They are precisely the sorts of inherited inclinations we must learn to recognize, challenge, and actively override.
Belonging and Group Boundaries

Religion can sometimes widen the circle of felt family. But it can also strengthen the distinction between those inside the group and those outside it. Once sacrifice, loyalty, and group identity are fused together, shared customs can take on unusual emotional and moral weight, and group boundaries can begin to feel especially important. The stronger those boundaries become, the easier it is for outsiders to be viewed with suspicion, distance, or moral distrust. This does not mean religion always produces hostility, or that it does so uniquely; these are broader features of human social psychology, and the willingness to sacrifice for one’s own group has been linked, in some evolutionary models, to hostility toward rival groups—the two developing together. But religion can give them a sacred language, a ritual structure, and a greater sense of seriousness. In that way, stronger religious boundaries can contribute to increased exclusion and, in some cases, increased hostility between groups. Religion does not invent this psychology, but it can reinforce it.

References

Aronson, E., & Mills, J. (1959). The effect of severity of initiation on liking for a group. The Journal of Abnormal and Social Psychology, 59(2), 177–181. https://doi.org/10.1037/h0047195

— The classic effort-justification experiment: participants who endured a harsher initiation came to like the group more. It grounds the point that the cost of a sacrifice tends to deepen, rather than weaken, commitment to the belief it serves.

 

Burkert, W. (1983). Homo necans: The anthropology of ancient Greek sacrificial ritual and myth (P. Bing, Trans.). University of California Press. (Original work published 1972)

— A foundational account tracing Greek sacrifice to the guilt and anxiety of Palaeolithic hunting, and reading ritual as a way of managing the unease of killing. It is the principal scholarly source behind this chapter’s “moral anaesthetic” idea.

 

Choi, J.-K., & Bowles, S. (2007). The coevolution of parochial altruism and war. Science, 318(5850), 636–640. https://doi.org/10.1126/science.1144237

— A formal model showing how in-group self-sacrifice (“altruism”) and hostility toward out-groups (“parochialism”) can evolve together, each making the other adaptive. It supports the chapter’s claim that the warmth of belonging and the suspicion of outsiders are two faces of one mechanism.

 

Girard, R. (1977). Violence and the sacred (P. Gregory, Trans.). Johns Hopkins University Press. (Original work published 1972)

— Advances the “scapegoat” theory: that communities discharge their own escalating, mimetic violence onto a substitute victim, whose killing restores order and who is then sacralized. It is the second major theoretical lens against which this chapter’s argument is positioned.

 

Hamilton, W. D. (1964). The genetical evolution of social behaviour. I. Journal of Theoretical Biology, 7(1), 1–16. https://doi.org/10.1016/0022-5193(64)90038-4

— The founding paper of kin-selection theory, introducing the rule now named for Hamilton: a gene for helping relatives can spread when the benefit to kin, discounted by relatedness, exceeds the cost to the helper. It is the precise basis for the chapter’s account of self-sacrificial kin altruism.

 

Kurzban, R., Tooby, J., & Cosmides, L. (2001). Can race be erased? Coalitional computation and social categorization. Proceedings of the National Academy of Sciences, 98(26), 15387–15392. https://doi.org/10.1073/pnas.251541498

— Experimental evidence that the mind encodes race not as a primitive category but as a cue to coalition or alliance, such that race-based sorting drops sharply when a competing coalition cue is made salient. It is the key reference for the chapter’s caution that appearance matters only as a proxy for “us versus them,” and can be overwritten.

 

Sosis, R., & Alcorta, C. (2003). Signaling, solidarity, and the sacred: The evolution of religious behavior. Evolutionary Anthropology, 12(6), 264–274. https://doi.org/10.1002/evan.10120

— A widely cited review of costly-signaling theories of religion, arguing that hard-to-fake ritual commitments stabilize cooperation by screening out free riders. It underpins the chapter’s treatment of sacrifice as a costly, trust-building social signal.

 

The Binding of Isaac appears in Genesis 22:1–19; the parallel Qur’anic narrative is in Surah As-Saffat (37:99–113), where the son is not named. The prophetic critique of sacrifice is found at Hosea 6:6, Micah 6:6–8, Amos 5:21–24, 1 Samuel 15:22, Psalm 51:16–17, and Isaiah 1:11–17.

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