Humans kill animals for food, but could it also provide another psychological function? A study recently published in the Personality and Social Psychology Bulletin provides evidence that the killing animals helps people dampen the awareness of their own mortality.

The research was based on terror management theory, which posits that humans unconsciously uphold certain cultural beliefs to manage the anxiety aroused by the awareness of death. One way of managing this anxiety is to deny that humans are merely mortal animals. The findings from the new study suggest that the killing of animals can make people feel superior to nature and therefore more than just regular animals.

Uri Lifshin of the University of Arizona at Tucson, the study’s corresponding author, told PsyPost that the research was inspired by the mass extermination of Jews and others during World War II.

“I grew up in Israel as the grandson of two Holocaust survivors, so I guess it was always important to me to understand why people commit terrible atrocities like war and genocide,” he explained. “After learning how genocide and prejudice is often fueled (or enabled) by dehumanization of the victims, it struck me that the root of the problem is probably our relationship with animals. It seemed ‘superficial’ to me that the ‘mainstream’ solution to prejudice is to humanize others, rather than to touch on the actual problem – our similarity to animals and our mortality.”

“People can always be stripped off of their humanness and be seen as animals as the Jews were in the Holocaust – because at the end of the day that’s what we are! So I figured that if we ever want to be able to understand and prevent instances of genocide, we must address our mass killing of animals first. Of course I have to give much of the credit to Ernest Becker – particularly in his book Escape from Evil (hence the name of my article), and also to previous terror management research (inspired by Becker) that was led by Jamie Goldenberg and colleagues, who showed how our need to disassociate ourselves from animals is rooted in our denial of death.”

“The other reason is that I was horrified by the reality of killing animals – particularly of killing pets in animal ‘shelters’,” Lifshin said. “After reading Nathan Winograd’s book Redemption, which clearly shows how even animal rights organizations continue to kill millions of animals even when it can be avoided, I was certain that psychological forces play a huge role in these phenomena, and I was determined to provide empirical evidence for that. By the way, I’m not a vegetarian.”

In a pilot study with 72 participants, the researchers found that students who were more supportive of killing animals reported lower fear of death along with lower death-related anxiety.

The researchers then conducted five separate follow-up experiments, with more than 700 participants in total. They found that reminders of mortality caused participants to support the killing of nonhuman animals, but not fellow humans. This relationship held even after controlling for the potential effects of gender, preexisting attitudes toward killing animals or animal rights, perceived human–animal similarity, religiosity, and political orientation.

Lifshin told PsyPost there were four main takeaways from the study: “A) That the killing of animals serves a psychological function for people – it’s not just about practicalities and physical needs. B) That unconscious motivations and cognitions affect the way we treat animals; C) Our need to manage our awareness of death is one of the reasons for human evil; that people do evil things to gain psychological protection. D) That an understanding of the dynamic of terror management theory may be helpful to mitigate these effects (for example that a self-esteem boost can reduce support for killing animals).”

All of the participants in the study were American college students — an obvious limitation. Lifshin said he looks forward to conducting more research on the topic.

“One thing that I think we should focus on next is to better understand how to utilize these insights to reduce some of the unnecessary killing of animals,” he told PsyPost. “For example, by understanding the partially reciprocal nature of terror management defenses, one can find different ways to attenuate negative attitudes and behaviors towards animals – like we did with the self-esteem boost in Study 4.”

“So for instance, perhaps enhancing people’s sense of immortality or reminding them of their close relationships may also do the trick. Other strategies that may help reduce the killing of animals include enhancing people’s awareness of the effect, promoting pro animal norms and values, humanizing animals and making animals sacred. Perhaps we can also learn from cross cultural research that would examine these effects in cultures that see animals as something holy, like Buddhists in Nepal, India or Tibet, who believe that they reincarnate into animals after death, and often great measures are taken to ensure the wellbeing of animals.”

“The other thing is that we still need to obtain more empirical evidence about ‘the link’ between killing animals and killing dehumanized enemies and how this may be related to terror management theory,” Lifshin added. “And after we accomplish all this, perhaps we can come up with a more comprehensive model that will explain the human motivation and capacity to commit genocide and will outline ways in which it may be avoided. We still have a long way to go.”

The study, “The Evil Animal: A Terror Management Theory Perspective on the Human Tendency to Kill Animals“, was also co-authored by Jeff Greenberg, Colin A. Zestcott, and Daniel Sullivan.