The second Planet of the Apes movie, Beneath the Planet of the Apes, turns 50 this week, and it's just one of many, many films exploring the idea of a primate planet. There were the five original films, Tim Burton's 2001 reboot, and the three latest movies, starting with 2011's Rise of the Planet of the Apes.
What's clear from the series' long history is an enduring desire for tales of humans interacting in meaningful ways with our closest evolutionary relatives.
To see a great ape is to look into the past and see ourselves. It's understandable why stories like these scratch a particular itch in our psyche. It's impossible to look upon a chimpanzee, orangutan, gorilla, or bonobo and not see the humanity in their eyes. To wonder what they're thinking. And to also wonder if, with just a little help, they might be able to communicate clearly to us.
Today, the only way to satisfy those desires is through our fiction. And we've done that to the tune of nine movies and counting. Still, we can't help but continue to wonder: Is it possible, through an evolutionary or technological nudge, for great apes to rise to human-level intelligence?
Before we investigate the possibility of advanced intelligence in great apes, we must first set the stage. It's commonly held that apes are as intelligent as human toddlers, though that might not be as good a comparison as we previously believed. Likewise, they might not actually be such perfect analogues of our prior evolutionary selves. As it turns out, apes might be even smarter than we give them credit for.
Recent research, carried out at the University of Adelaide, suggests modern great apes might be more intelligent than our early hominid ancestors. Australopithecus had similar brain sizes, and the brain-to-body ratio is one indicator of intelligence in a species. Comparing those between early hominids and modern apes gave some indication. But it isn't the only factor. Another is blood flow to the brain.
When comparing the skulls of modern gorillas to those of Australopithecus, researchers found canals nearly twice as large in gorillas. Chimpanzees and orangutans, while smaller-brained, also had larger canals than those of early human ancestors. This indicates high blood flow, which suggests the potential, at least, for higher intelligence, irrespective of the brain-to-body ratio.
In short, looking at great apes might still give us a window into our own past, but that view is more recent than we previously expected.
Further, when trying to place modern apes on an intelligence scale, past research has been somewhat lacking, at least as it's laid out in an Animal Cognition article entitled The Mismeasure of Ape Social Cognition, by David A. Leavens, Kim A. Bard, and William D. Hopkins of the University of Sussex, the University of Portsmouth, and Georgia State University, respectively. The article discusses the various ways research involving apes has played fast and loose with variables.
Studies designed to compare the intelligence of apes with human children often aren't as controlled as, perhaps, they should be in order to come to confident conclusions. The most important variable discussed is that of social conditioning, of which human children enjoy over a lifetime, and of which apes aren't. In essence, human children are afforded an immeasurable amount of test preparation, by way of constant interaction with other humans, to which the apes are not privy.
As a result, any conclusions reached about the innate intelligence of apes is muddied. There is, of course, no clear solution to this dilemma. One could raise an ape, from birth, in a human environment — or, alternatively, raise a human child, from birth, with apes — and then make comparisons. But those "solutions" have obvious and serious ethical concerns.
All of this suggests, at least, that apes are likely more innately intelligent than we give them credit for. We simply don't have the tools to accurately measure their abilities, and we are otherwise biased toward human-centric measures.
Additionally, there is no clear measure of what intelligence means. We can't honestly suggest that the only measure of intelligence is being able to successfully achieve what humans do. To be sure, there are things we are very good at, and which apes are less skilled at. On the other hand, there are particular tests apes excel at, and humans fail miserably. This is clearly illustrated by memory tests carried out at Japan's Primate Research Institute.
In the test, numbers are laid out in random order and location on a screen. The task is to remember where all of the digits are located and recall them accurately. The trick is, as soon as one number is touched, the rest are covered over by white squares.
Chimpanzees not only outpace humans in this sort of memory recall, but they do it incredibly fast and with a high degree of accuracy. Were this the standard measure of intelligence, chimpanzees would beat out humans without any doubt.
This demonstrates that intelligence is not as black and white as we like to think. Humans are clearly smart, on the whole, but only when measured by the things we consider to be important.
Researchers at PRI have suggested a sort of Cognitive Trade-off Hypothesis, by which humans lost this kind of rapid recall in favor of other talents. The parts of the brain that previously might have allowed us to excel at this rapid recognition and short-term memory were sacrificed so that we might be able to improve at other tasks, which were more important to our survival.
It's probably true to say, then, that both humans and apes are intelligent, just in slightly different ways.
The question then becomes: Is it possible for apes to become intelligent in the ways in which humans are?
There are lots of sci-fi stories about animals that have been made smarter or more human-like, including The Island of Doctor Moreau and Umbrella Academy's Pogo. But could we actually bring those animals to life?
There are two methods by which non-human animals could reach human levels of intelligence.
The first, of course, is the method by which we got here: evolution.
There has been some recent evidence that some apes and monkeys are now in an equivalent to the human Stone Age. It's unclear whether this is a recent development or one that we've only just noticed. Whatever the case, these animals have checked one of the intelligence boxes previously ascribed only to humans.
It's also worth noting that evolution is not a scale, along which all animals travel. We tend to think of our own evolution as a path from Animal to Human. And, from a certain point of view, it was. But natural selection doesn't care about the guidelines we ascribe to progression. Evolution is not a ladder that species climb, it is a process driven by environmental pressure that can push a species in myriad directions.
All species alive today have evolved just as much as we have, but in different ways. Great apes are not less evolved than us, just differently so. As such, there's no definitive reason that they should move toward human levels of intelligence. Unless, of course, their environment requires it.
If an intelligent ape is the goal (though it's questionable whether it should be), it might require a technological intervention, one of which we might be capable.
In 2019, researchers in China led by Bing Su at the Kunming Institute of Zoology placed a human version of the gene MCPH1 — a gene that relates to brain size and is believed to possibly be involved in the evolution of human intelligence — into 11 rhesus macaque embryos.
When the macaques were two to three years old, scientists tested their memories, which were found to be in excess of their peers. This suggests that by modifying the DNA of non-human animals, in specific ways, we might be able to push their intelligence beyond their natural bounds.
Again, we run up against ethical concerns with this type of research.
Say we were successful in creating an animal with significantly advanced intelligence. Where would that animal fit in the world? Surely, it could find only frustration and be potentially ostracized by those of its own community. Could it live happily among us? Would we end up with an animal intelligent enough to understand what was done to it, doomed to suffer all of its life?
Proponents of such research suggest that the findings could help to reverse or prevent cognitive disorders in humans. But it is our responsibility, as the bearers of these technologies, to clearly investigate not only our motives, but the potential repercussions.
Discussion of these kinds calls into question any and all research involving animals, but especially those animals so closely related to us. When we look into the eyes of apes and see ourselves, we might consider extending not only our curiosity, but also our compassion. Perhaps visions of animal experimentation and uplift are better suited for our screens than our laboratories.