Do Humans and Apes Differ Only by Degree?


Do animals possess the same kind of intelligence as human beings? If we say that apes have less intelligence than humans, does this make them inferior to us?


Ever since Copernicus put the Sun at the center of the Solar System, scientists and other modern thinkers have diminished the role of humankind in the Universe. We have gone from being the crowning glory of God’s creation to a hairless ape stuck on a small planet circling a mediocre Sun in the distant reaches of one arm of the Milky Way Galaxy. Some of the most widely read authors in the evolutionary camp (such as Carl Sagan and Stephen Jay Gould) emphasize the lack of our uniqueness and the luck of our existence. Man occupies neither the center of the Universe nor the preeminent place in the living world; we are the product of the same natural, evolutionary processes that created the animals.

According to the most extreme version of this view, it is the utmost arrogance to identify any characteristic that distinguishes us from animals. Any differences we perceive are merely a matter of degree, and for all the things we do better, there are other things we do worse. The chimpanzee, in particular, is worthy of coequality because it is supposed to be our nearest living relative. Some even have gone so far as to suggest that this kinship puts a burden on us to make laws granting special rights to apes (Cavalieri and Singer, 1993; cf. Maddox, 1993).

The problem with such extreme positions is that they provide no reasonable stopping point. If we include chimps in our “community of equals,” then why not include all primates, all mammals, all animals, all living things? If the apes’ rights advocates can devise criteria that divide us and the apes from other animals, then can we not also devise criteria that divide ourselves from the apes? In other words, can we say that there are no essential differences between humans and, say, chimpanzees? Or, to put it another way, are there enough similarities to make us treat chimps on the same level, or almost on the same level, as members of our own species?

My gut reaction is to wonder why these chimps are still swinging from tree to tree, while the members of our species are able to walk on the Moon—and upright at that! To think like this makes me guilty of “speciesism,” the apes’ rights advocates would say. Apply the same reasoning to other humans, they charge, and it would put me in the position of saying that white European males are superior because Africans or Asians never have walked on the Moon. I would counter that regardless of sex or skin color, such a feat was something that members of our species were able to do, and something that chimps never could think of doing.

Does this make the chimps inferior? This word “inferior” means lower than, or below, another thing, but labeling something as inferior usually requires a judgment call. For example, inspectors at a factory may judge the work of one individual as inferior to the work of another. If this is the way the word is being used, then I cannot say that apes are an inferior product; they were created with the same physical perfection as humans. Further, God’s stewardship grant compels us to show respect for all creatures that have been entrusted to our care. That there is a special relationship between God and man neither renders the ape inferior nor opens the floodgates to animal cruelty.

If apes are not inferior to humans, is it true that they are as intelligent as humans? One of the big success stories in looking at the human-like qualities of apes is a chimp (specifically, a bonobo) known as Kanzi (see Savage-Rumbaugh and Lewin, 1994). Through many years of intense training and close social contact with humans, this remarkable animal has attained the language abilities of an average two-year-old human. Kanzi goes beyond the mere parroting or “aping” of humans: he really can communicate his wants and needs, express feelings, and use tools. Inasmuch as Kanzi can accomplish these things, does this prove that chimps are merely hairy, child-like versions of humans?

Without detracting anything from Kanzi, fundamental differences remain. Unlike human children, chimpanzees do not naturally pick up language from trained apes. Such abilities have been drilled into Kanzi, and each new trainee must be taught by humans. Also, chimps: (a) do not have a special region in the brain devoted to language; (b) have a much smaller brain overall; and (c) lack the anatomy to speak the words they may think. In summary, humans have an innate, built-in, hard-wired ability to acquire and communicate complex language from the moment of their birth; chimps do not.

Sheba, another remarkable chimp, has demonstrated the ability to count and think abstractly. She was taught that whenever presented with a choice between two quantities of an object, she would receive a reward if she gave the greatest quantity to another chimp. However, when the objects were changed to food items (gumdrops), she never would hand over the dish with the greatest quantity. Each time she chose the plate with the most gumdrops, the researchers would take it away quickly before she had a chance to eat (Fischman, 1993; Gonick, 1994). She could not learn that keeping the greater share gained her nothing—no gumdrops and no reward. In other words, her food instinct got in the way of her numerical ability. Although you and I may prefer to get the biggest piece of pizza, we may suppress that desire for the sake of politeness or because someone needs it more than we do. Apes, apparently, have no override button when it comes to food.

Perhaps part of the reason for Sheba’s apparent selfishness is that she lacks empathy or “transcendental perspective.” This is a uniquely human ability that allows us to project the effect that our actions might have on someone else’s thinking or feelings sometime in the future. For example, I am able to wash the dishes in the hopes that my doing this will please my wife who is due home in a couple of hours. Anthropologists have found that animals do not act in this way, even if the lines of communication are open through simple language skills, as in the case of Kanzi. So, although chimps may learn to think abstractly, they lack the ability to form complex social relationships based on the communication of such ideas (Gibbons, 1993). Empathy also is the reason animals live outside the moral sphere. Sheba cannot be accused of selfishness for not handing over the plate with the most gumdrops because she is incapable of knowing that this is something she ought to do.

Some researchers speculate that the sort of foresight inherent in empathy and other human endeavors, such as sophisticated tool making and long-term planning, may be related to the fourfold difference in size between the cerebral cortex of chimps and humans (Calvin, 1994). Again, this is not merely a matter of degree: the chimp brain is not a one-fourth scale model of a human brain; rather, there is a fundamental difference in the way the two brains work.

Are chimps intelligent? The answer is yes. Do chimps possess the same kind of intelligence as humans? The answer would have to be “no.” Humans are more intelligent, and they possess additional forms of intelligence. What we must remember, also, is that the greatest capabilities of the apes belong to a handful of superstars like Kanzi and Sheba. Even these animals lack the empathy, foresight, and language capabilities of all but the youngest or most intellectually challenged of our own species.

Chimps and other apes may be worthy of respect (or eve natural sympathy as McShea [1994] suggests), but they cannot share our experiences, understand our stories, or be accountable to our rules of living. They are not inferior, but neither do they differ from merely by degree.


Calvin, William H. (1994), “The Emergence of Intelligence,” Scientific American, 271[4]:100-107, October.

Cavalieri, Paola and Peter Singer (1993), The Great Ape Project (London: Fourth Estate).

Fischman, Joshua (1993), “New Clues Surface About the Making of the Mind,” Science, 262:1517, December 3.

Gibbons, Ann (1993), “Empathy and Brain Evolution,” Science, 259:1250-1251, February 26.

Gonick, Larry (1994), “Sheba’s Last Theorem,” Discover, 15[6]:114-115, June.

Maddox, John (1993), “The Kinship of Apes and People,” Nature, 364:185, July 15.

McShea, Daniel W. (1994), “On the Rights of an Ape,” Discover, 15[2]:34, February.

Savage-Rumbaugh, Sue and Roger Lewin (1994), “Ape at the Brink,” Discover, 15[9]:90-96,98, September.


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