When Other Species Are Smarter
It is easier to place human intelligence in evolution than we had thought.
Posted Mar 29, 2018
Resistance to evolutionary theory is partly driven by ideas of human uniqueness or intellectual superiority. So what are we to make of evidence that other species sometimes outdo humans in cognitive tests?
Early efforts to tap into the minds of apes by teaching them sign language turned out to be a rather humiliating failure when it transpired that the subjects were relying heavily upon cues provided by overly helpful trainers.
Why ask apes to do something that humans are very good at, but apes are not good at? Why not test apes on something that they are very good at, such as locating ripe fruit on a tree or predicting where the ripe trees are on any given day?
Brain Size Isn't Everything
A young male chimpanzee was trained on a touch screen to memorize a series of numbers from one through nine that were displayed at random locations on the screen and were replaced by white squares as soon as he began tapping (1). The numbers had to be tapped in the correct order.
His competence at doing this was remarkable enough. What really floored researchers was the fact that, even with extensive practice, humans could not do nearly so well on this spatial memory task.
Interestingly, one does not need a large great-ape brain to be good at spatial memory — a bird brain may do. Clark's nutcrackers hide tens of thousands of pine nuts in several hundred locations, scattered over many square miles. In winter and spring, they remember the locations well enough to recover most of the food (2).
Humans are not nearly so good at remembering where we put items that we use every single day, such as keys, gloves, or cell phones. Our pockets contain a very small number of such items, but we are constantly forgetting where we left them.
Feats of cognitive virtuosity, such as those of Clark's nutcrackers, can be accomplished with the relatively small brains of birds, and even insects, such as digger wasps, not only remember where their larvae are buried in the ground, but also bring the correct amount of food, depending on how big the young happen to be.
Crows and magpies are comparatively large-brained, for birds, but their skulls are tiny compared to any primate's. Despite this, crows solve experimental problems at about the same level as chimpanzees. Shockingly, magpies demonstrated that they can recognize themselves in mirrors, indicating that they share self-awareness with large-brained apes, dolphins, and whales (3).
Even if some species are self-aware, there is a common perception that other species remain little more than warm-blooded machines, incapable of detailed planning, that lack self-control, are at the mercy of their impulses, and are unable to think deeply about their past experiences or have insight into what they know.
Each of these prejudices has yielded in some degree to careful experiments. Anyone who works with great apes knows that they are capable of a cool-headed deliberation that is sometimes described as Machiavellian. Chimpanzee males form alliances that sometimes permit a pair of allies to knock the alpha male off his top-ranking spot, even though they are smaller and less physically aggressive.
Chimpanzees are skilled at strategic thinking and deceptive behavior. For example, a low-ranking chimp who is sexually aroused by a receptive female will conceal his erection from the alpha male, but show it to the female as a sexual invitation (4). The male then departs into the jungle using a circuitous route. If the invitation is accepted, the female departs in a completely different direction and circles around so as to meet up with the male. In this way, their tryst is completed without the risk of being attacked by the dominant male.
Experiments show that primates have good episodic memory, and that they can recover buried food with lengthy delays before gaining access to the site where they had witnessed the reward being hidden (4). Moreover, they avoid finding the food when other individuals are present, suggesting that they realize this is a sure way to lose it. So they know what they know, and realize that others know less.
The same may be true of elephants in Indonesia, who are fitted with bells that help their handlers (mahouts) keep track of them. Some silence the bells by stuffing them with grass so as to move around undetected (4).
An impartial reading of the evidence is that human cognition is continuous with other species, rather than being qualitatively different. Human uniqueness enthusiasts may still comfort themselves with the notion that humans are exceptional due to the shared information that we use to control our environments.
The Social Learning Fallacy
Yet, this view was due to ignorance about how other species adapt to their environments. When researchers provisioned Japanese macaques with sweet potatoes, young animals began washing their food in sea water, and the habit spread through the population.
Social learning is not peculiar to primates, of course, and is probably a feature of the behavior of all vertebrates, from Israeli black rats learning how to extract the seeds of pine cones, to Italian rats diving to the bottom of the Arno River to retrieve shellfish, to leopards teaching their youngsters how to hunt, to moose learning which animals to be afraid of (5).
Accepting Our True Place in Nature
In the end, there are really no sharp boundaries between the cognitive capacities of humans and those of other species.
That should not be too surprising considering that we are products of the same process of evolution by natural selection. Nervous systems evolve so as to help animals respond effectively to changes in their environments.
Related species encounter similar problems and solve them in similar ways. So it is inevitable that we would share many cognitive features with other vertebrates and primates, and a great deal with other great apes.
We are not alone in having remarkable cognitive abilities. Other species have far better brains than we often give them credit for.
1 Lanner, R. M. (1996). Made for each other: A A symbiosis of birds and pines. New York: Oxford University Press.
2 Inoue, S., and Matsuzawa, T. (2007). Working memory of numerals in chimpanzees. Current Biology, 17, R1004-R1005.
3 Prior, H., Schwarz, A., and Gunturkun, O. (2008). Mirror-induced behavior in the magpie (Pica pica). PLOS Biology 6 (8) e202. doi:10.1371/journals.pbio.0060202
4 de Waal, F. (2016). Are we smart enough to know how smart animals are. New York: W. W. Norton.
5 Richerson, P. J., and Boyd, R. (2004). Not by genes alone: How culture transformed human evolution. Chicago: University of Chicago Press.