Stanford neuroscientist explores what is, and is not, unique about humans

L.A. Cicero Professor Robert Sapolsky delivered the 2009 Stanford Class Day address on Saturday, June 13 in Maples Pavilion.

“If you spend enough time around something like baboons, you start to look at humans differently,” said Robert Sapolsky, as he delivered an address to the university’s graduating class Saturday at Maples Pavilion.

“For example,” he said, “you find yourself paying a whole lot of attention to other guys and how big their canines are, thinking comparatively, or you look at somebody’s rump and you wonder how hard it would be to anesthetize them with a blowgun dart there.”

Sapolsky, a neuroscientist and the John A. and Cynthia Fry Gunn Professor, has spent part of each of the last 30 years studying wild baboons in East Africa. Blowgun darts have been his vehicle of choice for delivering anesthetic into baboons, whose bottoms provide the best target.

For more than 40 years, the Class Day Lecture has featured a world-renowned Stanford professor, selected by the graduating seniors.

Sapolsky discussed how to make sense of humans when viewing us as “just another species” of primate. Quoting an unnamed evolutionary biologist, he said, “All species are unique, but humans are unique-ier,” adding, “This may not be an exact quote.”

Not unique, but different

Over the years, many traits and abilities once thought to set humans apart from other species, including other primates, have been observed in those other species.

What makes us unique doesn’t have much to do with our genes, Sapolsky said. “We are not humans because we’ve invented a different type of brain cell, a different type of brain chemical. We are the same basic building blocks as even a fruit fly. That is not where our uniqueness is going to come from.”

“We have a few challenges,” Sapolsky said, “as we try to make sense of what we are as a species and where we fit into the animal world.” Among the challenges, he said, is dealing with circumstances where humans are no different from every other species out there.

Citing studies that showed that female hamsters sharing a cage will, in time, synchronize their ovulation cycles, Sapolsky noted that a study at Wellesley College in the 1970s demonstrated the same effect in female freshmen rooming together. And in both species, the more socially extroverted, dominant female was the one whose cycle was the standard to which the other females synchronized.

“So some of the time, what is a challenge is recognizing there is nothing fancy about us at all. We are just a basic off-the-rack mammal,” he said.

Other times, Sapolsky said, the challenge is “recognizing that we have got the same basic building blocks and plumbing in there, but we use it in ways that are unprecedented. Let me give you an example.”

Burning calories by thinking

“You have two humans, and they are taking part in some human ritual. They are sitting there silently at a table. They make no eye contact; they’re still, except every now and then one of them does nothing more taxing than lifting an arm and pushing a little piece of wood. And if it’s the right wood and the right chess grand masters in the middle of a tournament, they are going through 6,000 to 7,000 calories a day thinking, turning on a massive physiological stress response simply with thought and doing the same thing with their bodies as if they were some baboon who has just ripped open the stomach of their worst rival, and it’s all with thought, and memories and emotions. And suddenly we’re in the realm of taking just plain old nuts and bolts physiology and using it in ways that are unrecognizable.”

Sharing traits with vampire bats

Among other examples of traits once thought restricted to humans, but no longer, Sapolsky offered instances of vampire bats following the Golden Rule, or tit-for-tat behavior. Mother vampire bats normally share any food they bring back to the communal bat cave with everyone’s young. But, if a mother fails to share with other bats’ babies, the other mothers will stop sharing their food with her offspring until the first mother resumes sharing.

Another “human” quality we share with other species is empathy, which chimpanzees have demonstrated in comforting a chimp that has been attacked by another chimp without cause.

And many species, in addition to humans, kill their own kind in anger or in cold blood, Sapolsky said. “They kill strategically in ways that would make Machiavelli proud.”

But there are, Sapolsky said, some things humans do for which there is simply nothing like it in the animal world. The thing that he has found most defining about human beings is the ability to deal with contradictions. “The less it is possible that something can be, the more it must be,” he said.

To illustrate, he cited the case of a Catholic nun who ministers to prisoners on death row in Louisiana. These men, he said, are “some of the most frightening, nightmarish humans who have ever walked this Earth.”

When asked how she can spend her time with such men, Sapolsky said the nun answers, “The less forgivable the act, the more it must be forgiven. The less lovable the person is, the more you must find the means to love them.”

“As a strident atheist,” he said, “this strikes me as the most irrational, magnificent thing we are capable of as a species. We are not just a ‘unique-ier’ species, we are the ‘unique-ier-est,’ simply because of this. …

“And this one does not come easily … this contradiction, to take the impossibility of something to be the very proof that it must be possible and must become a moral imperative. The harder it is to do that, the more important it is.”

Good luck and good lives

Speaking directly to the graduating class, Sapolsky noted that in the course of their education, they had learned a lot about the ways of the world.

“When you’ve wised up enough, there is a very clear conclusion that you have to reach after a while, which is, at the end of the day, it is really impossible for one person to make a difference,” he said. But, he added, that conclusion is all the more reason the graduates must make a difference.

“You guys are educated, you are privileged, you are well connected, you are enormously lucky if you are sitting here at this juncture, and thus … there is nobody out there who is in a better position to be able to sustain a contradiction like this for your entire life and use it as a moral imperative,” Sapolsky said.

“So do it. And good luck and have good lives in the process.”