Sapolsky’s Theory: How Evolution Affects your Behavior

Robert Sapolsky’s theory of behavioral biology claims that behind every human action is a biological explanation. The concept centers around the idea that in order to truly understand human behavior, we must study it at all levels — from what happens inside the brain a nanosecond before a behavior occurred all the way to the time when humans and apes last shared a common ancestor.

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behavioral biology

Sapolsky’s theory of Human Behavioral Biology claims that behind every behavior, is a biological process that is the product of natural selection. If Sapolsky is right, this implies that to truly understand human behavior, we would have to know exactly what happens in the 100 trillion connections of the brain a nanosecond before the behavior occurs. And consider what took place about 5 million years ago when humans and chimpanzees shared their last common ancestor. And all of the stuff that happened in between.

For example: when we see someone who has done something wonderful and altruistic or something brutal and savage, we can ask ourselves; why did he do that just now?

And when we ask that, we are asking something about what neurons in different parts of their brain did a fraction of a second ago.

But we are also asking about what environmental stimuli in the previous seconds, to minutes, triggered those neurons.

And we are also asking what did hormone levels that morning have to do with making those neurons more or less sensitive to those triggers.

And then we are often running into neuroplasticity, how his experience changed those neurons in previous months.

Then you are back to adolescence and childhood and all the way back to his fetal life, which has a huge amount to do with what sort of brain we are going to have as adults.

And even further back genes come in and culture because the way you were raised within minutes of birth reflects the culture that your ancestors were coming up with centuries ago.

And at the bottom of the barrel, why we evolved into this kind of species instead of that kind.

Things are complicated

If you trust Sapolsky’s theory of behavioral biology you may, at this point, realize that things are much more complicated. While a simple “she did A, so he did B” may fulfill your need to bring order into this chaotic world, it is likely not going to be the full explanation.

Sapolsky’s life

Sapolsky was born in New York, and he spent his youth reading about and imagining living with silverback gorillas. By age 12, he was writing fan letters to primatologists and during high school he taught himself Swahili.

Later he spent twenty-five years observing the same group of baboons in Africa every summer and then went on to study and teach behavioral biology at Stanford University.

Sapolsky left for those who try to understand others the following advice:
“We are complicated! So you better be really sure and really careful and really cautious before you decide you understand why somebody did something, especially if that is something you are judging harshly. It’s like trying to judge how a movie got to its conclusion by watching only 30 seconds of it.”

“I agree with this. There is so much we don’t understand about behaviors right now and yet we are looking in the wrong direction for answers. People need to listen to more evolutionary psychologists/biologists than they do social scientists and the world would be a far less dishonest place. Great presentation! Subscribed!”

– Ganesh Prem


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Classroom exercise

Help your students develop critical thinking skills; hold a debate! Whether you establish pro and con teams, or pratice presenting one’s own opinion, make sure you cover the basics of the topic discussed together and remind the students that everyone is entitled to have their own opinion on things 🙂

Use our prompts below, or our other videos, for inspiration and let us know how it goes in the comments below!

What do you think? Is Sapolsky’s theory solid and can we actually never really explain a behavior without taking the full picture into consideration? Or is there something like a soul that takes decisions regardless of what happens to us biologically?

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