The Biology of Behavior with Dr. Robert Sapolsky
The Biology of Behavior with Dr. Robert Sapolsky

World-renowned neuroscientist Dr. Robert Sapolsky travels around the world sharing his expertise on the biology of behavior.

Through the generosity of the Clare Foundation STEM Speaker Series, Dr. Sapolsky recently spent a day on campus. The Stanford University professor, MacArthur Fellow, and author, delved into the topic of biology and behavior with Upper School students.

"How do we understand the biology of us?" asked Dr. Sapolsky. Through decades of research, Dr. Sapolsky has studied what happens to the human brain seconds, days, weeks, and years before a violent act occurs. "What sensory stuff was triggering that behavior?"

"As a species, we have had a real problem with violence," said Dr. Sapolsky. "But we are also the most amazingly altruistic, cooperative species the primate world has ever seen. Some of it's obvious, but much of what is going on we don't have a clue what the sensory information is that is causing our brains to do what they do."

Dr. Sapolsky told students it all starts in the part of the brain called the amygdala. "The amygdala is about violence, it's about aggression. If you stimulate the amygdala in a human, a monkey, in a rat, you will get unprovoked violence." Dr. Sapolsky explained that the amygdala is also about fear. "This is the part of the brain that is about fear, and threat and anxiety. The amygdala gets information really fast, but it is not terribly accurate and disastrous things happen."

The insular cortex is also connected to behavior. This is the part of the brain that senses disgust, including moral disgust. "When something is so sickeningly wrong that we feel sick to our stomach, it is because of this crazy thing in this part of the brain." But there is a problem, explained Dr. Sapolsky.

"Somebody's morally disgusting behavior is somebody else's perfectly normal lifestyle. The thing about disgust is it's a moving target."

Next Dr. Sapolsky discussed the intricacies of the frontal cortex. "It is all the self discipline stuff. No surprise, a lot of what the frontal cortex does is send projections to the amygdala and what it does is says 'don't do that.' Resisting the temptation to lie is your frontal cortex keeping you from falling into doing that."

Finally, the body's dopamine system is about reward and the work you are going to do to get that reward.

"Righteous punishment stimulates the dopamine system like mad," said Dr. Sapolsky. He cited a study involving judges who oversaw 5,000 parole board decisions. "Your blood sugar levels have something to do with how well your frontal cortex works. What was the single best predictor of whether somebody got sent back to jail or was freed? How many hours it had been since the judge had eaten a meal."

Parolees who came before a judge right after they had eaten had a sixty percent chance of being paroled. "Four hours later- zero percent chance, which is crazy except that we know the biology. Your blood sugar levels have something to do with how well your frontal cortex works. And, your frontal cortex is what you need when you sit there and think about how this person has had really different circumstance in their life than I have had. Maybe I need to view the world from their perspective."

"And what is even crazier is you get one of those judges two seconds after they have made one of those decisions and you say 'why did that guy get sent back to jail for 47 years and this person got freed,' they're not going to say 'oh, because my blood sugar levels were higher for that.' They are going to talk about some philosopher they learned about. They are going to have no idea it was their blood sugar levels," said Dr. Sapolsky.

He explained further that the frontal lobes of teenagers are not fully formed until the mid-20's. "That is why teenagers are into problems with impulse control and sensation-seeking and thrill-seeking." The adolescent years are when the frontal cortex is sculpted.

After the Upper School presentation, Dr. Sapolsky spent time with students in AP Biology and Honors Biology classes.

The goal of the specialized series is to expose students and faculty to dynamic, innovative, and creative thought leaders across a range of STEM areas and sectors.

The series debuted in January with David Maiullo and That Physics Show. In early February Princeton University professor Dr. Bonnie Bassler shared her research and expertise on how bacteria communicate.

Statistician and mathematician Dr. Talithia Williams, known for making sophisticated numerical concepts understandable, will be the fourth speaker in the series. She is scheduled to address the Upper School and work with students in calculus-based statistic classes on Thursday, March 8.