Matching Darwin's "Tree of Life," the "Tree of Intelligence" Comes Crashing Down
Freed from the constraints of naturalism (nature is all there is), the animal mind is a fascinating topic. Great writers have reflected on the way their cats think. The cat is a convenient subject for two reasons. One is this, no one advertises a common inheritance of humans and cats. We meet on equal terms.
That said, the most farflung outcome of the current effort to naturalize the mind, despite Darwin's horrid doubt, is the quest to map our own minds onto those of primate apes and other mammals. We constantly hear the false news that we share 98 percent or 99 percent of our genes with chimpanzees, and therefore we must greatly resemble them.
False news? Yes. If that claim were taken seriously, it would spell the end of genetics as a source of useful information. (Is there anyone who cannot tell the difference between a human and a chimpanzee?) No, such claims belong rather on a philosophical continuum with evolutionary psychology. If evo psych's claims were sound, they would merely demonstrate that no evolution has been observed in the human species for two million years. But the value of all such claims is precisely that they are not taken seriously. They serve rather to undermine the idea that humans are unique, with little regard for the logical consequences of any specific assertion.
It is the same with claims about animal minds. Scientists and science reporters routinely claim that apes and humans behave similarly. Apes are said to, among other things, mourn their dead, suffer self-doubt, make dolls, have police, go to war, and use "innovative, foresighted methods." The point of such claims isn't that apes really think like people, but that we really don't.
Strangely, it's been crazier. In the Seventies, Nim Chimpsky (Pan troglodytes) was raised from infancy as a human baby and even breastfed by a woman. (The daughter of the surrogate mother explained in retrospect, "It was the Seventies.") And in the Nineties, celebrity skeptic Carl Sagan was confident that a chimpanzee like Nim would, with assistance, write a memoir recounting such an experiment.1 Nim never truly learned any language, and ended up, not happily it seems, in an animal sanctuary.
So there was a wall and the experimenters hit it, notwithstanding their conjuring in Darwin's name.
It is true that chimps can learn to spring simple snare traps that are set for them without getting hurt. But does that really put them on a continuum with humans? They do not do nearly as well as human toddlers on an abstract reasoning test.
Not only is there a vast gulf between human and chimpanzee intelligence but chimpanzees are not alone on the other side. For example, dogs perform better on one kind of intelligence test than chimpanzees: Dogs can understand finger pointing where chimps cannot. That's remarkable when you consider that dogs do not have fingers but chimps do. Is one permitted to wonder why, if chimpanzees have the active mental life that some researchers claim, they are still swinging in the trees?
The multidisciplinary project of demonstrating that the human mind is conceptual clutter in the repertoire of science faces another huge obstacle as well: Apart from the vast superiority of human intellect, there is no clearly demarcated tree of intelligence in animals anyway.
Suppose humans were more intelligent than chimpanzees -- but only on a continuum (rather than abruptly, by several orders of magnitude). And all primates were more intelligent than all other mammals, and all mammals were clearly more intelligent than all other vertebrates, including birds. The resulting picture would support a simple, materialist view of the human mind as the eventual outcome of the random evolution of the vertebrate brain.
But that doesn't happen. When Darwin's tree of life crashed, it brought down the tree of intelligence too. Recent research has shown that grey parrots and ravens can solve some puzzles as well as apes. One is tempted to ask if that makes them more closely related to humans than other birds are. As close as chimps are? If not, why emphasize ape intelligence to make the point about a close relationship?
Contrary to a decades-long assumption in science, we are now told that "the avian pallium [grey matter] supports cognitive abilities similar to, and for some species more advanced than, those of many mammals." For example, one parrot, Avisa, showed a reasoning skill for finding food that "So far, only great apes have been shown to master ... 'inference by exclusion.'"
In intelligence, researchers say, crows are "feathered primates." And New Zealand crows get smarter by the study. Some claim that their causal understanding (within limits) rivals that of 5-7 year old children. Or 7- to 10-year-old children. But then, even the intelligence of the chicken "startles," according to Scientific American ("communication skills on par with those of some primates"). The chicken?
Pigeons' performance with numbers up to nine is "indistinguishable from that displayed by monkeys." New Caledonian crows can use three tools in succession to reach food, and can also enact Aesop's fable by dropping stones into a jar of water till floating food rises.
But here is another problem as well: Only some birds are especially intelligent. What factors determine whether a given bird is a raven or a dodo? Puzzles that arise from the evidence are not usually elaborated. The chimpanzee's intelligence is thought to derive from having a brain similar to a human one, due to common descent. Yet if a bird's differently structured brain can achieve the same level of individual intelligence, then intelligence may be something other than we now conceive it to be.
And then there are the reptiles. Crocodiles use tools, as do birds. Monitor lizards are said to have "acute intelligence." An anole lizard turns out to be as smart as a species of smart birds used in animal intelligence studies (tits). The key research problem was that the low-metabolism anoles required only one grub a day each, which slowed down the research considerably. The researchers could not apparently bribe them by offering more grubs. Yet the primitive "reptilian brain" is taught to kids as part of a coping skills lesson.
And fish: The orange-dotted tuskfish thrives by digging a clam out of the sand, carrying it over to a rock, and repeatedly throwing it against the rock to crush it. Naturalists explain the matter by insisting that natural selection just naturally selected that behavior, oblivious to the question of whether a fish brain could naturally select such a behavior. If life forms can just "naturally select" becoming smarter, what is going on in nature anyway? Could we use this in the school system?
Invertebrates aren't even less intelligent than vertebrates, or not necessarily. One species of octopus has learned to dig up and use discarded halved coconut shells as a shelter. Neatly halved coconuts are a human discard, so the behavior may have been learned in recent millennia.
It is not even clear that intelligence must reside in the brain. An underground amoeba colony consisting of thousands of brainless blobs, facing a food shortage, hurry into a single blob, a tiny slug that crawls toward the soil surface. Some amoebas push the slug to move. Others behave like police, who ingest infectious bacteria, but then leave the blob and die.
Above ground, in another location, the slug resembles a fungus. It can attach itself to an animal's foot, then drop off at a food source. One such blob replicated the highway map of Canada, just for suitably placed bread crumbs. Once they sense that the food supply is secure, they devolve into one-celled animals again.
Researchers are unearthing evidence that, far from being unresponsive and uncommunicative organisms, plants engage in regular conversation. In addition to warning neighbors of herbivore attacks, they alert each other to threatening pathogens and impending droughts, and even recognize kin, continually adapting to the information they receive from plants growing around them. Moreover, plants can "talk" in several different ways: via airborne chemicals, soluble compounds exchanged by roots and networks of threadlike fungi, and perhaps even ultrasonic sounds. Plants, it seems, have a social life that scientists are just beginning to understand.
Yes, as farmers and gardeners have long suspected, plants can "hear" bugs walking and defend themselves. Plants can also, as it happens, lie and defraud other plants. They lead anything but solitary and sedentary lives.
How to resolve all this? One method would be to assume that a higher intelligence grants intelligence to life forms, for their temporal needs. That appears obvious, but doesn't coincide with naturalism. So other explanations are demanded. Prominent neuroscientist Christof Koch speculates that humans, worms, and the Internet are all conscious. Others claim that rocks are also conscious. Hush, your coffee cup wants to tell you something you need to hear.
Or maybe not. One characteristic of consciousness is a goal of some kind, which fired pottery lacks.
Oh, you wanted to know the other reason why the cat is a convenient subject for reflections on the animal mind? Writer Claire Berlinski explains:
But one of the best things about cats -- they do not have the power of speech -- also makes them the worst things possible if you're trying to write some kind of history involving them. They leave no written records. They don't even pay taxes, no less write memoirs. No one has any idea what an 18th-century cat might have had to say for itself, though I reckon it's pretty much what a contemporary cat would, which is to say, nothing.
Shouldn't the animal's role in its natural environment be its own best witness?
So what is intelligence, really, and how is it acquired? One approach to intelligence, suggested by the theory of intelligent design, considers search space: What size of search space can a life form use for solutions to its problems?
We live in an intelligent world, but we have been taught not to see what that means. Whatever the answer is, it won't be found in Darwin.
(1) Carl Sagan, The Dragons of Eden: Speculations on the Nature of Human Intelligence (New York: Random House, 1977), 126.
Editor's Note: Here is the "Science Fictions" series (the human mind) to date at your fingertips (the human mind).