From chapter "The Great Chain of Being"
There are at least four problems with the notion that humans are smarter and superior because of the size of our brains.
The first is that it’s the same old tautology. In math, a tautology is “a logical statement in which the conclusion is equivalent to the premise.” You could also call it circular logic. It’s like the old joke, “The first rule of the tautology club, is the first rule of the tautology club.” Here is the tautology. Humans have big brains. Humans decide big brains are a sign of intelligence and/or superiority. Therefore, because humans have big brains, humans must be more intelligent and/or superior. Now, that was a surprise, wasn’t it?
The second problem, and we’ll discuss this more later, has to do with whether it is meaningful or appropriate to attempt to make intelligence comparisons across species. Humans are more intelligent at what? And so far as this larger exploration—human supremacism—humans are superior at what?
The third problem is that I’m not convinced we think only with our brains. I think we think partly with our brains, but also with our whole bodies, and with our surroundings. If creatures think only with brains, how, for example, do wasps, with brains only one-millionth the size of human brains, correctly differentiate between photographs of the faces of other wasps? I thought only “higher” animals, like, uh, the highest of the high animals, humans, were able to differentiate between photos of their friends. And how do honeybees know how to communicate through dance? As one writer states, “Honeybees don’t have much in the way of brains. Their inch-long bodies hold at most a few million neurons. Yet with such meager [sic] mental machinery [sic] honeybees sustain one of the most intricate and explicit languages in the animal kingdom [sic]. In the darkness of the hive, bees manage to communicate the precise direction and distance of a newfound food source, and they do it all in the choreography of a dance. Scientists have known of the bee’s dance language for more than 70 years, and they have assembled a remarkably complete dictionary of its terms, but one fundamental question has stubbornly remained unanswered: How do they do it? How do these simple [sic] animals encode so much detailed information in such a varied language?”
My fourth problem with the notion that humans are smarter than and superior to all others because we’ve got really big brains is that if we do think with our brains, we have to recognize that there are plenty of beings with brains larger than ours. Hell, human beings 5,000 years ago had brains 10 percent larger than those of human beings today. I guess that means we’re 10 percent stupider than we were back then. This would explain many things, from fundamentalisms of all stripes to pop culture to presidential politics to environmental policy to the existence of bright green environmentalism to the stupid arguments of human supremacists. Neanderthals also had larger brains than do humans, which might explain why Neanderthals never created insurance advertisements claiming that something is so simple even a caveman can do it. In any case, if intelligence or superiority is measured by brain size, humans lose. Average human brain weight is somewhere around three pounds. Walruses are nearly as big, at almost two and a half pounds. Elephants are much larger, at more than ten pounds. And whales run from four and a half pounds up to more than seventeen pounds.
But wait, I can hear you say, changing the rules as we go, actual brain size isn’t important. Brain size to body mass ratio is what leads to intelligence, and specialness, and all sorts of scrumptious wonderfulness that makes humans meaningful and everyone else meaningless! Of course a big animal needs a big brain to control its movements. Or something.
Let’s leave off the fact that big animals don’t really need big brains— the Stegosaurus weighed four or five tons and had a brain weighing less than three ounces—and take this one at face value. The human brain is about 2.5 percent of our body weight. Sadly for us, this is about the same as it is for mice. The brains of small birds make up about 8 percent of their body weight. The brains of shrews are about 10 percent of their body weight.
Well, that’s embarrassing. I guess since we didn’t win either of those contests, we’ll have to come up with another way to determine intelligence. As one author puts it, while arguing that humans are unquestionably more intelligent than anyone else: “Neither absolute brain weight nor the relationship between brain weight and body size provide us with sensible criteria for comparing the intelligence of different species.”Of course they don’t; any sensible criteria would make it so we’re number one.
We could have predicted that supremacists would be quick to propose lots of variants on this same human supremacist theme: for example, that intelligence is determined by the quantity brain size minus spinal column over body weight, and on and on.
It doesn’t really matter, so long as we win.
But the whole “humans are smarter/superior because of brain size” theory has a bigger problem than either whales or shrews. The bigger problem is fungi. As I wrote in Dreams, “Did you know that fungi are intelligent? I didn’t. But [Paul] Stamets writes [in Mycelium Running], ‘I believe that the mycelium operates on a level of complexity that far exceeds the computational powers of our most advanced supercomputers.’ And he backs this up. Fungi demonstrate simple straightforward intelligence (even measured by our own narcissistic standards); if you put a slime moldat one end of a maze, it will grow randomly until it finds food. If you take a piece of this slime mold and put it in the same maze, it will remember where the food is, and grow directly toward it, with no false turns. Further, if you compare the information-transferring organization of mycelium to the organization of the Internet, you’ll find that, as Stamets says, the ‘mycelium conforms to the same mathematical optimization curves that Internet theorists and scientists have developed to optimize the computer Internet.’ Or rather, the Internet conforms to the same curves as the mycelium.” Fungi can be seen as huge neurological nets. Back to Dreams, where I begin by citing Stamets, “‘I believe that mycelium is the neurological network of nature. Interlacing mosaics of mycelium infuse habitats with information-sharing membranes. These membranes are aware, react to change, and collectively have the long-term health of the host environment in mind.’