The Line Becomes Finer

In the past year as I’ve explored neuroscience in greater depth than ever before, what have struck me are the similarities, rather than the differences, between the brains of animals and that of ours. So many things I’d previously perceived as uniquely human are shared by an astonishing breadth of our relatives, near and distant. As always, when I want to learn more about a scientific subject I blog about it. Here is my mama bird science regurgitation; I hope it permits you to see our co-earthlings in a new light.

Humanity has evidently come a long way since the father of modern philosophy, Reneé Descartes, justified cruel experimentation with animals by declaring they did not have souls. According to, Descartes believed that animals cannot reason and do not feel pain. Can you imagine believing that if you torture an animal and it screams and cries that it’s just a robotic reaction, no different than if a potato were screaming? Then again, if a potato could scream, it would not quite be a potato. Descartes maintained that humans are the only conscious living beings who have minds and souls, can learn, can speak language, can actually experience pain. He believed it was foolish to have compassion for non-human animals. In his own words: “But the greatest of all the prejudices we have retained from infancy is that of believing that brutes think” (Reneé Descartes, 1649). Gary Francione wrote in his Introduction to Animal Rights that Descartes and his followers held public demonstrations in which they inflicted severe pain onto animals (examples: nailing the paws of dogs onto boards, cutting open their chests to reveal the beating hearts, burning, otherwise mutilating) in order to have the opportunity to educate the crowd to not feel sympathy for these organic ‘machines’ that were only ‘functioning properly.’

Thank god that the issue of consciousness in animals is no longer up for debate in the scientific community. And beyond that: I was very pleased to learn during my training for research animal handling that daily intellectual stimulation is a requirement for the care of research monkeys and apes; to deny them play and learning is inhumane and punishable by law. Theologically, however, the subject of animal consciousness remains contended; see this argument carried out through the medium of vintage church marquee in which a Catholic church comically competes with a Presbyterian church for the souls of pre-believer passersby by promising to grant one dog a soul with each conversion.

Scientists recognize that many things historically considered to be exclusively human traits are not such. We’ll start with one of the most primitive: tool use. Elephants, bears, bottlenose dolphins, sea otters, mongooses, badgers, many birds, apes, fish, and even insects have been observed using tools. In fact, there’s an entire Wikipedia page dedicated to tool use by animals, with examples, of course. Let’s define this so we’re all on the same page: a tool was characterized by one scientist named Benjamin B. Beck as “the external employment of an unattached or manipulable attached environmental object to alter more efficiently the form, position, or condition of another object, another organism, or the user itself, when the user holds and directly manipulates the tool during or prior to use and is responsible for the proper and effective orientation of the tool.”

Insects, guys. No, basic tools defined thus are not the dividing line. However, a stricter definition, “complex” tool use, seems to be more credible; it requires that two or more tools be incorporated in a certain order to accomplish a task, or else the tool must be built from multiple elements. Even so, chimps fit that bill. According to journalist Kate Yoshida, a group of chimpanzees in Gabon extract honey using a chronological succession of five tools, all which are essential to the process. Chimpanzees alone of all non-human primates have been observed using a single material to construct a variety of tools (e.g. they use leaves to make sponges as well as probes to reach insects), and they are choosy about the materials, traveling considerable distances to obtain the correct tree species to construct the probe. William McGrew writes in his article “Chimpanzee Technology”: “Almost 50 years ago, Jane Goodall watched an adult male chimpanzee in the Gombe Stream Reserve, Tanzania, make and use a blade of grass to ‘fish’ termites from a mound for food. Her mentor, Louis Leakey, declared, ‘Now we must redefine “tool,” redefine “man,” or accept chimpanzees as humans!'” While we get the idea, many other things such as cognitive abilities and number of chromosomes separate our species. Still, all the time, the line becomes finer. 

Thanks to advances in technology that give us near mind-reading power (a little scary, no?), we know that chimps engage in very similar resting-state brain activity as we humans do (where examples of resting-state thoughts include when the mind wanders to “past social interactions, potential future social interactions and to problems you need to solve.”) Team member Dr. Preuss said the findings suggested that “humans and chimpanzees share brain systems involved in thinking about one’s own behavior and that of others.” The functional brain imaging revealed differences in addition to similarities, but the differences are never so shocking to me. My mind is still in process of opening. That a chimp can sit and think about his day and anticipate hanging out with his friends is incredible to me. Disparities: humans showed more resting state activity in regions of the brain associated with the analysis of meaning compared to chimps. And humans are the only animals known to think in words, as evidenced in the high activity in language regions of the brain during imaging. Read the Science Daily article for more information, and read this Cell Press Review to learn more about cognitive limits in chimps (we don’t think they understand the concept of false beliefs, for example).


Nevertheless, while we outperform chimps in many higher processes, Caltech scientists have shown that chimps are better strategists than humans. Researchers administered a game theory test in which a human and chimp pair of opponents competed for rewards (food for chimp, money for human) by trying to predict the opponent’s decisions. One player was seeker, one was hider. The rules were simple: two rectangles appeared on a computer screen and the seeker must choose the one he thinks the hider will choose; the hider must choose the one he thinks the seeker will not. Astonishingly, the chimps consistently defeated their human competitors. They  scraped dangerously close to the theoretical success limit defined by John F. Nash, Jr., winner of the Nobel Prize for his game theory discoveries. It’s thought that chimps’ superior short-term memory and their more competitive natures may have contributed to the observed result. But slice it how you like: in at least strategic thinking, chimps have humans beat.

There are a few other things that I was surprised to learn this week during my research. Animals have been known to commit suicide. See also: Seven Cases of Animals that Committed Suicide. (Of course, the jury is still out as to whether these animals were aware of what it meant to end their own lives.) Apes have learned sign language, and one chimp used it to ask a zoo visitor to set him free (video here). Rats possess metacognitive abilities, as proven in 2007 by researchers at the University of Georgia (the test subjects were found to understand whether they possessed knowledge of the answer to a test). Chimps and dolphins are two animals considered to be self aware for reasons including: they can anticipate the effects of their actions, and they recognize themselves in a mirror (i.e. a chimp whose face was painted would try to wipe it off when it saw the paint on his reflection). With astonishing memory and reasoning abilities, a crow has solved a difficult eight-step puzzle as detailed in this BBC special. In her book Animal Madness, Laurel Braitman writes about mental illness in animals–examples: depressed gorillas, compulsive parrots, and a cow with anger management issues. And there’s so much more information out there.

As a final challenge to your preconceptions: even plants can see, smell, feel, learn, and remember

In conclusion, I am not a vegetarian and do not think that complete abstinence from consumption of animals is necessary or even healthy for most people. I would like to kill and pluck my own free-range chicken someday–I’m sure it would not only be healthier and happier than those chickens from Tyson Foods or similar, but I would also feel more gratitude as I ate it. Of course, I highly discourage the consumption of close relatives such as monkeys, for ethical and health reasons. I would not eat a dog or cat, and there are many other lines that I’ve personally drawn. But let’s be considerate, thankful, and respectful of the organisms that we use for sustenance, companionship, and research. We are not the only rightful inhabitants of this planet, after all.

Discussion Topic: Do you have a pet that seems quite intelligent at times? Name something it’s done that has surprised you.