Robert Sapolsky: How we came to be what we are, Humans

Did you know that we all show signs of prejudice? That oxytocin actually is not the love drug we all thought it was? Or that serotonin shows a direct correlation to ancestral migration? These are all areas that Professor Robert Sapolsky a renowned American neuroendocrinologist encountered whilst writing his magnum opus on human behaviour for over ten years.

Behave: The Biology of Humans at Our Best and Worst is an earth shatteringly encompassing work that even the late Oliver Sacks said is “A ground-breaking synthesis of the entire science of human behaviour.”
Sapolsky set out to  to bring together almost every discipline in science to connect the dots on why we behave the way we do, how we do it and how we got to where we are as humans. In an era where the us vs them attitude grows day by day, Professor Sapolsky learnt one thing through his empirical quest into the human,  that there are grounds for optimism for the human condition.


So let’s start from the beginning, the brain. It’s such a fascinating, complex organ. In the book there are so many different aspects as to what makes us human but I guess the brain is one of the main playgrounds of behaviour?

Certainly. Everything that amounts to behaviour is a result of your brain in effect telling your body to do or say something. So the brain as a mediator of behaviour is the final funnel of all of that and in some ways the point of the whole book is, everything from the smell you experienced 2 seconds before to evolutionary pressures a million years ago all influence how likely the brain is to produce a particular form of behaviour.

So where are we trying to get to with this book? If things are so finely tuned that it affects us on the most minute level.

In a lot of ways I am by nature extremely pessimistic and this book has forced me grudgingly to see that there are a lot of grounds for optimism about the official human predicament. What’s most impressive about these facets of biology influencing behaviour is that they change over time, they change with experience, so we are utterly different organisms than our ancestors were and there are some astonishing examples out there of change of people no more remarkable than you or I turning out to do moments of incredible goodness. There’s even a way of guessing at what the kind of biology is that underlies events like that.

Reading the book, this kind of narrative kept recurring to me, and maybe I’m wrong, but that we’re all just terrified primates in the Savannah 100,000 years ago, that’s still there and we just try to cover it up.

In lots of ways we are just like our hunter-gatherer ancestors except, and it should be added, that we have genes that have only evolved in the last 10,000 to 20,000 years, something to do with say lactose intolerance. We are just like our ancestors except we live in communities filled with anonymous interactions with strangers, where we are coping with an astonishingly different world and show some evidence of adapting.

How would you say that modern culture or future culture, where we are moving in a very technological direction, will change our genetics? Is there any research on that possibility?

At this point, I think it has all been too recent to do anything like affecting gene pools. One of the most fascinating studies that I cite in the book looks at certain gene frequencies that are to do with dopamine receptors for example. Dopamine as a neurotransmitter is very relevant to reward and variants of this gene are associated with sensation seeking, novelty seeking, things of that sort. And you see that there is an echo of this gene’s distribution throughout humans, basically the further your ancestors migrated from Africa over the last 50,000 to 100,000 years, the higher the prevalence of this itchy, ‘I need to keep moving and explore the world’ variant. The people whose ancestors made it out of Africa and all the way to Asia and have crossed the Bering Strait all the way down to South America, that is where there is the highest incident in the world. It’s virtually a straight line of correlation between the distance migrated and the prevalence of this gene variant.  So there’s not enough time yet to show what the more modern cultural innovations will do but the coevolution intrinsic in that is just fascinating.

There are examples in your book about prejudice, how our brains are incredibly attuned to skin colour etc. Do you think any of the genetics play a role in that?

One of the strongest ‘bad news, good news’ topics covered in the book is that we have an extremely strong propensity towards creating these us vs. them dichotomies – considering ‘us’ as being preferable and having strong aversions to ‘them’. We make those dichotomous assumptions within milliseconds and our brains break the world up into us vs. them in a fraction of a second, setting us up to be not so nice to the ‘them’ group, so we are very hardwired for breaking the world into that.

But the good news is that we are so clearly manipulated into changing who counts as an ‘us’ and there are hardly any of these categories that we use to separate the world, like race, ethnicity, gender, that in some other setting can’t be manipulated into a completely different context. It’s virtually inevitable to me that we view the world in terms of these dichotomies, but it is also anything but inevitable as to who is going to count as an ‘us’, as we can change that in a matter of seconds. 

And was there some evolutionary reason, a primitive purpose to have this us vs. them scenario? Was there never a point that we should try to be more connected to everything?

No doubt it would be great if somehow everybody could at least count as an ‘us’. You see this in humans who have had damage to their amygdala, a part of the brain very central to fear and aggression, and people with a number of extremely rare disorders that basically take out your amygdala and nothing else in your brain. These people essentially view the world as nothing but ‘us’, which is really quite striking. One could make a very easy adaptive argument for why most social organisms out there have a propensity for us vs. them – it’s very hardwired. For example this hormone oxytocin, people love it because it appears to be the world’s most pro-sexual hormone, it mediates mother-infant bonding, trust and emotional expressivity and all sorts of wonderful things, until one looks more closely. There is great work showing that oxytocin promotes these pro-social behaviours in people who are like you, people ‘in’ the group, and what it does to ‘outsiders’ is it makes you crappier to them, makes you pre-emptively aggressive. There is clearly just a fault line in our brain between ‘us’ and ‘them’.

One of the things that you mention in the book is how conservatives and progressives typically differ psychologically, which is interesting considering the growing political divide we see now.

That’s one of the areas that I knew zero about before writing the book and then found the most fascinating. Yes there are all sorts of well thought out views and philosophical theories that underlie the differences between progressives and conservatives, but you look closely and especially in the realm of social issues an awful lot of that is predicted by aspects of people’s temperament and personality. If in general novelty and ambiguity makes you really anxious, you are very likely to be a social conservative. If you view the future as exciting and that it will bring cool new things, you tend to be a progressive. If instead your viewpoint is that the best things were in the past, that’s a much more conservative outlook. Some of my favourite studies that came up in researching for the book were on the fact that if you tend to have a very low threshold for disgust, so looking at a photo of maggots in an open wound makes you really queasy, statistically you are more likely to have conservative views about social issues. The rumour that we are a purely rational species when making decisions is just nonsense.

Do you think that if more people were aware of these internal sensitivities then society would be different? Or do you think that ignorance is bliss in a way?

Most of the time it’s bliss but some of the time it’s not because it’s influencing our stances on pretty consequential things. Another one of my favourite studies in there was across a large data set of judges who were making decisions for parole boards, and across something like 5000 parole decisions, one of the strongest predictors of whether or not someone would get parole or not was how many hours had passed since the judge had eaten. It’s amazing, when we’re hungry we are less empathic, less compassionate, and that even extends to judges – the notion that right after lunch the judge would grant parole to person A and 4 hours later they throw person B back in the slammer, and that judge could have sat there and given you this whole lecture on Emmanuel Kant and whatever explaining the reasoning when instead it had a whole lot to do with the judge’s blood sugar levels!

Something you talk about in the book is what religion does to the body, so when you talk about the simple reason behind a judge making a decision, how does the body explain religious beliefs and those strongly held views?

That area, which I tread on very carefully in the book, is one that I have thought about a lot, mostly in one of my previous areas of research to do with the effects of stress on health and this idea of why religiosity winds up to be good for people’s health. As an atheist I have to admit that this is a perfectly solid finding. Religious people tend to cut back on certain lifestyles that hold risk factors. You also have religious communities of social support typically, but once you get past all that, religiosity in and of itself has some protective elements for health. Why is that, well the cornerstones of psychological stress are lack of control, lack of predictability, lack of outlets and social support, and all religion does is give levels of explanation – there is a reason why things happen. So that’s stress reducing – there is a reason and a benevolence behind it and even better, there is a special benevolence for people who pray like you do.  

What would you like this book to say to people?

Probably the most useless conclusion that people could take from it is also the most accurate one, which is ‘Jeez this stuff is complicated!’ The one that I hope people don’t take away from it is, ‘Wow this stuff is complicated. There’s nothing we can do about these aspects of behaviour.’

What would be ideal for me is if people recognise that it is complicated and say that we have to be really cautious and prudent and humble when we go about thinking that we understand some bases of behaviour, especially when they are behaviours that we are judging harshly.

Behave: The Biology of Humans at Our Best and Worst  is out May 2nd on Penguin