Cognitive bias vs cultural group selection: origins of rituals of human sacrifice

Religious human sacrifice does not often occur in modern contexts, but it was a common practice in many ‘ancient’ societies. It doesn’t seem to have any apparent benefit and therefore it seems necessary to explore evolutionary reasons for its existence as a religious ritual.

One prominent hypothesis, known as the cultural group selection model, claims that religious rituals facilitate in-group cooperation which enables group advantage and is why such rituals continue to appear. In particular, costly signalling theory suggest that participation on costly rituals show an individual’s commitment to the group, increasing trust between members.

However, I don’t believe that this can explain human sacrifice rituals because through showing one’s commitment, an individual dies and can’t reap the benefits of proving their trustworthiness and group cohesion won’t be increased.

I would suggest that the most relevant theory for sacrifice as a method of group cooperation is that sacrificial rituals are a method of social control used by rulers and the social elite [1], through fear and punishment. DNA from Aztec sacrificial sites show that the majority of those sacrificed were enemy soldiers and slaves [2] i.e. those who committed wrongdoings.

Studies of 93 traditional Austronesian societies revealed that the presence of human sacrifice is much higher in highly stratified societies than in egalitarian ones [3]. The people who performed the sacrifices were high status individuals like priests whilst the sacrificed were mostly lower status. This suggests that human sacrifice was used to maintain highly unequal social structures and their cohesion.

However, this alone cannot account for costly human sacrifice rituals, particularly because human sacrifice evolved before highly stratified societies emerged. It implies that human sacrifice may have been a necessary condition for these societies to evolve, rather than be a result of them.

Therefore, we need to consider the cognitive biases that may account for such counterintuitive rituals.

The main idea is that human belief in the supernatural is the main reason behind religious ritual because they provide a platform for communication between the sacred and profane levels, according to Hubert and Mauss [4]. This is consistent with human sacrificial rituals because their main goal is to establish a good relationship with the sacred order.

Aztecs in Mexico would often volunteer themselves for sacrifices to the sun god, Huitzilopochtli in mass sacrifices because they believed it would ensure them safe passage to the afterlife. This also discredits the idea that all human sacrifice was forced and used as a means of social control.

It is believed that humans’ susceptibility for detecting agency in nature is responsible for the cognitive template that supports the belief in supernatural agents [5]. Without this, there is no reason for individuals to participate in such costly rituals.

The origin of previously mentioned mass sacrifices in Aztec Mexico come from the belief that the sun needed human nourishment. Attributing human-like characteristics to the sun is a clear example of seeing agency in nature, otherwise known as Hyperactive Agency Detection Device.

Additionally, human sacrifice rituals target cognitive biases because they are intensely arousing events which are easily remembered. In order to become part of a religious system, religious events must be memorable so that they can be transmitted across generations, according to Whitehouse. It explains which human sacrifice continued to be practiced.

To conclude, I believe that cognitive biases are more responsible for the origins of human sacrifice and account for their recurrence throughout religions despite their highly costly nature. Social cooperation does contribute, but I think it better explains the continuation of such rituals rather the cause.

References

[1]

R. Sosis and C. Alcorta, “Signaling, Solidarity, and the Sacred: The Evolution of Religious Behaviour,” Evolutionary Anthropology, no. 12, pp. 264-274, 2003.

[2]

D. Roos, “Human Sacrifice: Why the Aztecs Practices This Gory Ritual,” 11 October 2018. [Online]. Available: https://www.history.com/news/aztec-human-sacrifice-religion#:~:text=According%20to%20Aztec%20cosmology%2C%20the,with%20human%20hearts%20and%20blood.. [Accessed 10 December 2020].

[3]

E. Benson, “Human sacrifice may have helped societies become more complex,” 4 April 2016. [Online]. Available: https://www.sciencemag.org/news/2016/04/human-sacrifice-may-have-helped-societies-become-more-complex.

[4]

R. L. Faherty, “Sacrifice,” Encyclopaedia Britannica, 2020.

[5]

E. Palermo, “The Origins of Religion: How Supernatural Beliefs Evolved,” 5 October 2015. [Online]. Available: https://www.livescience.com/52364-origins-supernatural-relgious-beliefs.html.

Image Credit - Fine Art America