The Biology of Our Best & Worst Selves: Robert Sapolsky (Transcript)

Here is the full text of neuroscientist Robert Sapolsky’s talk titled “The Biology of Our Best & Worst Selves” at TED Talk conference. In this talk, he shares his cutting edge research into the biology that drives our worst and best behaviors.

CHRIS ANDERSON: So Robert spent the last few years thinking about how weird human behavior is, and how inadequate most of our language trying to explain it is. And it’s very exciting to hear him explain some of the thinking behind it in public for the first time.

Over to you now, Robert Sapolsky.

Robert Sapolsky – TED Talk TRANSCRIPT

Thank you. The fantasy always runs something like this.

I’ve overpowered his elite guard, burst into his secret bunker with my machine gun ready. He lunges for his Luger. I knock it out of his hand. He lunges for his cyanide pill. I knock that out of his hand. He snarls, comes at me with otherworldly strength.

We grapple, we fight, I manage to pin him down and put on handcuffs.

“Adolf Hitler,” I say, “I arrest you for crimes against humanity.”

Here’s where the Medal of Honor version of the fantasy ends and the imagery darkens.

What would I do if I had Hitler? It’s not hard to imagine once I allow myself. Sever his spine at the neck. Take out his eyes with a blunt instrument. Puncture his eardrums. Cut out his tongue.

Leave him alive on a respirator, tube-fed, not able to speak or move or see or hear, just to feel, and then inject him with something cancerous that’s going to fester and postulate until every cell in his body is screaming in agony, until every second feels like an eternity in hell.

That’s what I would do to Hitler.

I’ve had this fantasy since I was a kid, still do sometimes, and when I do, my heart speeds up — all these plans for the most evil, wicked soul in history.

But there’s a problem, which is I don’t actually believe in souls or evil, and I think wicked belongs in a musical. But there’s some people I would like to see killed, but I’m against the death penalty.

But I like Schlocky violent movies, but I’m for strict gun control. But then there was a time I was at a laser tag place, and I had such a good time hiding in a corner shooting at people. In other words, I’m your basic confused human when it comes to violence.

Now, as a species, we obviously have problems with violence. We use shower heads to deliver poison gas, letters with anthrax, airplanes as weapons, mass rape as a military strategy. We’re a miserably violent species.

But there’s a complication, which is we don’t hate violence, we hate the wrong kind. And when it’s the right kind, we cheer it on, we hand out medals, we vote for, we mate with our champions of it.

When it’s the right kind of violence, we love it.

And there’s another complication, which is, in addition to us being this miserably violent species, we’re also this extraordinarily altruistic, compassionate one.

So how do you make sense of the biology of our best behaviors, our worst ones and all of those ambiguously in between?

Now, for starters, what’s totally boring is understanding the motoric aspects of the behavior. Your brain tells your spine, tells your muscles to do something or other, and hooray, you’ve behaved.

What’s hard is understanding the meaning of the behavior, because in some settings, pulling a trigger is an appalling act. In others, it’s heroically self-sacrificial.

In some settings, putting your hand one someone else’s is deeply compassionate. In others, it’s a deep betrayal. The challenge is to understand the biology of the context of our behaviors, and that’s real tough.

One thing that’s clear, though, is you’re not going to get anywhere if you think there’s going to be the brain region or the hormone or the gene or the childhood experience or the evolutionary mechanism that explains everything.

Instead, every bit of behavior has multiple levels of causality. Let’s look at an example. You have a gun. There’s a crisis going on: rioting, violence, people running around.

A stranger is running at you in an agitated state — you can’t quite tell if the expression is frightened, threatening, angry — holding something that kind of looks like a handgun. You’re not sure.

The stranger comes running at you and you pull the trigger. And it turns out that thing in this person’s hand was a cell phone. So we asked this biological question: what was going on that caused this behavior? What caused this behavior? And this is a multitude of questions.

We start. What was going on in your brain one second before you pulled that trigger? And this brings us into the realm of a brain region called the amygdala. The amygdala, which is central to violence, central to fear, initiates volleys of cascades that produce pulling of a trigger.

What was the level of activity in your amygdala one second before? But to understand that, we have to step back a little bit. What was going on in the environment seconds to minutes before that impacted the amygdala?

Now, obviously, the sights, the sounds of the rioting, that was pertinent. But in addition, you’re more likely to mistake a cell phone for a handgun if that stranger was male and large and of a different race.

Furthermore, if you’re in pain, if you’re hungry, if you’re exhausted, your frontal cortex is not going to work as well, part of the brain whose job it is to get to the amygdala in time saying, “Are you really sure that’s a gun there?”

But we need to step further back. Now we have to look at hours to days before, and with this, we have entered the realm of hormones. For example, testosterone, where regardless of your sex, if you have elevated testosterone levels in your blood, you’re more likely to think a face with a neutral expression is instead looking threatening.

Elevated testosterone levels, elevated levels of stress hormones, and your amygdala is going to be more active and your frontal cortex will be more sluggish.

Pushing back further, weeks to months before, where’s the relevance there? This is the realm of neural plasticity, the fact that your brain can change in response to experience. And if your previous months have been filled with stress and trauma, your amygdala will have enlarged.

The neurons will have become more excitable, your frontal cortex would have atrophied, all relevant to what happens in that one second.

But we push back even more, back years, back, for example, to your adolescence. Now, the central fact of the adolescent brain is all of it is going full blast except the frontal cortex, which is still half-baked. It doesn’t fully mature until you’re around 25.

And thus, adolescence and early adulthood are the years where environment and experience sculpt your frontal cortex into the version you’re going to have as an adult in that critical moment.

But pushing back even further, even further back to childhood and fetal life and all the different versions that that could come in. Now, obviously, that’s the time that your brain is being constructed, and that’s important.