Most of us don’t have grandma for dinner. Not even when there’s nothing else in the pantry.
It’s not that she’s too stringy, or tastes funny, either. According to University of Wrocław psychologist Michal Misiak and evolutionary biologist Petr Tureček from Charles University in Prague, regular acts of cannibalism aren't worth the risk of societal collapse.
Ask any foodie who has a passport full of dining experiences; we’ll swallow all kinds of insect. Dine on ammonia-soaked shark. Or even slurp on the dung-dusted entrails of a garden-variety ruminant. Eating another person as a part of an enduring cultural practice, however, is universally frowned upon.
What about tales of man-eating cannibals, you say? In nearly all cases, such accounts are fabrications concocted to justify the subjugation of another culture.
Where cannibalism is clearly ritualistic, it is typically accompanied by strict rules on who can eat, and how the meat is eaten.
It may not have always been the case, either. The archaeological record has examples of human bodies being processed and eaten as if they are just another form of prey, hunted and stripped of their meat.
So if we know there are good calories in a human body, and are happy to make exceptions, why are we all so willing to let a mountain of steak and ribs go to waste today?
According to Misiak and Tureček, unchecked cannibalism is a sure-fire way to spread infectious diseases that put the entire population at risk of collapse, meaning in all but the worst-case scenarios, humans are the worst choice of food for other humans.
“Analyzing the expected energetic balance across levels of food availability and cannibalism order reveals narrow ecological conditions in which cannibalism yields a positive expected balance and broader conditions in which it is strongly disfavored,” the pair write in their recently published study.
Most food-borne pathogens are easy to deal with through cooking. Whether it’s E. coli in your hamburger or Salmonella in your chicken, a quick fry and it’s toast. Even the few that survive are unlikely to spread beyond the consumer.
When the predator has the same physiology as the prey, pathogens have a much easier time jumping from one host to the next and causing mischief.
A shape-contorting protein known as a prion is a notable example. Responsible for neurological conditions like kuru and Creutzfeldt-Jakob disease, it remains infectious even when heated and can persist in its host until they themselves become Sunday roast. At which point it infects another generation of consumers.
The researchers found that cannibalism allows such pathogens to become an epidemic far more easily, destroying populations with ease.
It’s hard to say whether the disgust we feel over cannibalism is a psychological trait we’ve inherited through some kind of selection, but the fact that any cannibalistic culture is likely to fail at some point due to disease could help explain its rarity.
Throw in the fact that going to war for your food is far harder and riskier than chasing down a deer or two, ditching cannibalism becomes a no-brainer.
“Although cannibalism can provide nutritional benefits, it also entails costs, including acquisition risks, digestion, and most critically, infection risks that may escalate with repeated consumption,” the researchers conclude.
This research was published in PNAS.
Source: University of Wrocław via ScienceX
Fact-checked by Bronwyn Thompson
