Humans – Are We Just Another Primate?

Inspired by Chris Holdgraf’s recent post comparing humans and computers, I decided to discuss another aspect of humanness—our biological heritage—and why we are unique to our animal counterparts.

We're not so different, you and I

For this, I present to you Robert Sapolsky: Stanford professor, neuroscientist, and author. I adore Sapolsky’s witty style of writing, and when I found out he would be speaking at the California Academy of Sciences, I reserved my ticket immediately. It was no surprise to find that Sapolsky’s style of lecture was as richly conversational, intelligently humorous, and sparklingly scientific as his books.

In his lecture, “Humans: Are We Just Another Primate?”, Sapolsky discusses how alike humans and animals are, and tells story after story about animals (particularly primates) behaving in ways that we once reserved as uniquely human.  Humans did not reinvent the brain, so in a world where we share mostly the same neurotransmitters, structure, and genetics with flies, what is it that gives us our humanness?  In Sapolsky’s words, “When are we special, and when are we anything but?”

Sapolsky divided his lecture into three tiers of human uniqueness. First, he described attributes that were once thought to be uniquely human but are also present within the animal kingdom. Second, he described instances in which humans take a basic evolutionary design and do something novel with it. Finally, he described human abilities  that have absolutely no precedent in the animal kingdom. It is this last category that makes humans human.

Let’s start with examples from Sapolsky’s first two categories: when animals do as humans do, and the “above and beyond” element unique to humans:

  • Murder. The most gruesome example of a trait once thought to be uniquely human is the propensity to premeditate the killing of those within one’s own species. Recent observations have shown that intraspecies genocide exists within the animal kingdom. But there is something that humans possess uniquely beyond this brute aggressiveness, and that’s passive aggressiveness. This difference arises from the fact that animals experience stress from physical taxation (think stress alarms going off in a zebra as he springs away from a lion on the African savanna) whereas recent humans experience greater psychological stress (think glucocorticoid stress hormones flooding the system of a commuter in rush hour traffic).  I would interject though that non-human animals, both wild and domestic, also feel psychological stress when held captive by humans.
  • Empathy. We are also not the only creatures who experiences empathy, as observation of the animal kingdom clearly shows. Nonetheless, what we do experience that is rare to non-humans is  empathy for others outside of our own species. This notion of uniqueness begins to erode slightly with ever-mounting evidence of inter-species empathy between animals, though Sapolsky stands that these events are still too rare to be broadly applicable. Where we do stand firmly unique is in our ability to feel empathy towards an abstraction and for what is not even real. Plenty of humans have been brought to tears simply by watching the hardships of a cartoon character made up of pixels on a screen (though I would argue that it is the humanness within other species and within an abstraction that we are actually feeling empathy towards).
  • Theory of mind. The ability to attribute one’s mental states to oneself, and to understand that others have thoughts, feelings, beliefs, and intents distinct from oneself (covered previously by Josh Shiode) is not just for humans, either. Sapolsky described experiments that suggest that primates not only have the ability to recognize what another might be thinking, but will act upon this knowledge accordingly. But what humans do possess alone is secondary theory of mind: the ability to keep straight who knows what about whom. And if Sapolsky’s definition—”to understand that that individual doesn’t know that that individual knows that that individual understands something about that individual”—is difficult to comprehend, then you can understand why this complicated ability is reserved for humans!
  • Tit-for-Tat. Experiments in game theory are not limited to first year  psychology students. Experiments with bat communities and fighting fish show that animals are often all for tit-for-tat and will help others who help them in return, but as soon as they think that the other is no longer in cahoots,  they too will stop cooperating.  But animals can only do this in a literal sense.  Humans take this to the next level, and can trade one favor for something seemingly unrelated.
  • Goals. If you think that only humans have goals, you would again be wrong. Goal directed behavior is all about the anticipation of pleasure through dopamine pathways, which is why my dog will perform a slew of silly tricks for the promise of a treat. What we humans  hold uniquely, however, is in the length in time delay between work and reward. A reward must promptly follow a behavior for an animal to associate the two, but humans will toil for years in anticipation of an ultimate reward. In fact, a promised reward need not be of this life or even this world. Followers of certain religions happily go about their lives with the expectation of a reward after death. Says Sapolsky, “There’s no monkey out there who is willing to lever-press all the time because of what St. Peter is going to think somewhere down the line.”
  • Culture. We like to think that culture is a product of human civilization, but culture – the non-genetic transmission of learned behavior – is certainly not uniquely human. Primates also learn from each other, particularly child from parent. In one example Sapolsky gave, new baboon clan members were able to overcome natural baboon tendencies and to take on the culture unique to that clan. But we humans still one up even these primates with the sheer complexity of our culture. We are able to act not just based upon those within our family or group, but out of ideology, theology, an idea, a god.

Then Sapolsky turned to his last category: what do humans do that is unprecedented in the animal world? His answer: in spite of our classic mammalian brain, we are able to personify, and to use and process symbols, parabolas, metaphors, figures of speech, and analogies.  In fact, we sometimes confuse real life with the metaphorical, a product of “our brain’s evolutionary challenge to come up with something as novel as moral abstraction and have it duct taped into to some part of the brain that lizards use.”

For example, the insular cortex—the part of the brain responsible for the likes of both homeostasis and emotion (and the self-awareness, perception, and interpersonal experience that goes with it)—activates not only when you eat or smell something disgusting, or even think about something disgusting, but also when you are confronted with something morally revolting. The anterior cingulate of the brain activates in the same manner whether you are in physical pain or literally “feeling” someone else’s.  In this way, the brain is processing abstract thoughts in a very literal sense.

There are numerous psychological studies on metaphor and linking physical actions to mental abstraction, a subject studied profusely by Berkeley’s own cognitive linguist George Lakoff. Physically washing our hands actually makes us feel cleansed of our sins. Holding warm coffee will lead us to associate a warm personality to someone we are talking to, and a cold drink will help sway us to the opposite conclusion. Our susceptibility to the power in symbolism and our trouble in separating the real from the abstract is a uniquely human quality.

Also uniquely human, to paraphrase Kierkegaard, is our ability to believe in two things simultaneously and to have faith that persists in the face of the impossible. Sapolsky suggests that this just might be the most human aspect of all. “As a strident atheist, this [believing two opposite things at once] strikes me as one of the most irrational, nutty, magnificent things we are capable of as a species.  The more something cannot be, the more we have to make sure it is.”

He says that as we become wise to the world, we realize that the world is much too big for us to effect change. We believe that individuals are too small to matter, and yet it is because of this that we must work hard to make the world better anyway. The more irrefutable the evidence that we cannot change things, the more we must make it our moral motivation to make a difference.

Sapolsky admits that we could very well be missing something about animals due to our inability to understand their subtle “language”, but even as we discover more and more meaning within animal cues, the ability to have abstract thoughts and an emotional response to an abstraction remains uniquely human (although he also admits that there are many animal attributes recognized today that were at one point held “undeniably” human by experts of the past and that what remains our “humanness” could very well change).

“We do smelly stuff just like hamsters, and we do strange things with our stress hormones”, he says. “But at the end of the day, this realm of being able to take abstractions and turn metaphors into things as powerful as the most visceral of sensory effects and to do all of this in a context of moral imperatives, we are on an entirely different planet from other species.”

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  1. Jeanne

    I thoroughly enjoyed this article, thank you.

  2. Bill Reitter

    Loved Sapolsky’s book “The Trouble With Testoserone”, full of amazing insights and wit…especially about religion, which he views as a particular form of insanity or mental illness. But society does not see it this way when it becomes part of the culture. Then the non-believers are viewed as the “Crazy ones”! :]

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  4. Cherryl

    Humans ARE animals!!

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