Does biology trump free will? A behavioural scientist argues we have little choice

It’s natural for people to feel they’ve arrived where they are in life because of choices they’ve made along the way.

But behavioural scientist and best-selling author Robert Sapolsky makes the case that, when we consider biology and how the environment shapes us, we’re nothing more than biological machines without a shred of free will.

Sapolsky spoke with Quirks & Quarks host Bob McDonald about the ideas in his latest book, Determined: A Science of Life without Free Will. Here is part of their conversation. 

Now, you argue in your book that there’s no such thing as free will, something you’re being very vocal about for years. What do you mean by free will?

This one plays out all the time in people’s intuitions and in courtrooms and all of that. OK, you got some defendant sitting there and you’re trying to decide what to do and you figured out the person actually did the act, so that’s behind you. And then what is done is three questions are asked. Did the person intend to do what they did? Did they know what the consequences were likely to be? And did they realize they had options they could have done otherwise? And if the answer is yes to all of those, that’s it. They’re responsible. 

For my money, this is completely misguided. And what it’s like is trying to review a movie, only seeing the last three minutes of it. Because what that doesn’t do is ask the absolute critical question [of] where intent comes from in the first place. And where that intent came from, is every single thing in that person’s past over which they had no control that made them who they were at that moment that they intended to do that. 

It’s all one seamless arc and there isn’t a crack anywhere in there to shoehorn in free will.– Robert Sapolsky, behavioural scientist

So what’s the biological basis to your argument?

Well, you look at some behaviour and you ask a biologist’s sort of question which is, why did you do that at that point? And that’s actually a whole hierarchy of questions. 

You’re asking which neurons in your brain just did something a second ago and which ones turned off? But you’re also asking, what was it in your environment in the last minute that triggered those neurons to do that? And you’re also asking, what did your hormone levels, that you’ve had since this morning, have to do with how sensitive your brain was or wasn’t to those stimuli?

And you’re asking, did you have trauma in the last four months, or did you find love or did you find God? Because all of those things would have changed the construction of your brain.

You’re also asking, well, what was your adolescence like and your childhood when you were building your brain, and your fetal life, where you sure had no choice as to whose womb you wound up in — and because of that, the blood coming from your mother was carrying all sorts of hormones and nutrients and stuff, that was guiding the construction your brain.

Then, of course, you got to ask what your genetic makeup is. And then you even have to ask something as nutty as what kind of culture were your ancestors inventing 400 years ago? And what sort of ecosystem were they in that prompted that? Because that had everything to do with how your mother was mothering you from your first minute of life after birth.

If you’re talking about genes and behaviour, by definition, you’re also talking about the evolution of them. And you’re also talking about your childhood that epigenetically programmed your genes to do this or that for the rest of your life. And you’re also talking about the proteins those genes made for you 15 minutes ago. 

It’s all one seamless arc and there isn’t a crack anywhere in there to shoehorn in free will. 

Let’s go through some of these contributing factors that you just listed there that can impact our decisions or what we do, like the environment or the culture we grew up in. How’s that going to affect us?

Go look at the people you came from, wherever they were back when, and look at them from 400 years ago. Studies have actually looked at this and asked, “what was their infectious-disease load back 400 years ago? How much were they struggling with, like horrible epidemics of things that were killing people?”

Which is another way of asking, “how uptight were they about strangers coming in who could be carrying in who knows what infectious thing?” And it turns out, the larger the infectious disease load somebody’s ancestors had 400 years ago, that’s a part of a significant predictor of whether or not they like the idea of more immigrants coming into the country right now, because you were raised in a culture sculpted by that ecosystem and culture.

But how’s that going to affect my having free will or not? 

Cause by the time you were ten months old, your brain was already beginning to figure out who made you anxious and who didn’t. And that had something to do with how familiar the faces were around you. So by about 10 months of age you would be made nervous by faces of people your parents didn’t have around much rather than excited.

Now you also mentioned hormones. How much of a role do they play in how we act?

Huge amount. Let’s take testosterone. If they were higher than average for you this morning and you’re looking at a face with a neutral expression, you are now significantly more likely to decide that the face looks threatening, angry and unfriendly.

And thus you’re seeing the world differently than other people do because of what your hormones were doing at breakfast today. And thus you’re more likely to make an anti-social decision rather than a pro-social one.

But you’re saying “more likely,” not 100 per cent likely. So saying our decisions are influenced is not the same as having no free will. 

You’re absolutely right, these are all “on the average” and “tendency towards,” and “influences” — all of that — and we know this because it’s 2023, and 10 years ago, we knew about half of this. And 25 years ago we knew one quarter of this.

We know without perfect predictability that if a kid grows up in a single parent household with a mother who’s working four jobs to meet the rent and they’re dealing with substance abuse issues, gangs in the neighbourhood and poverty, that this kid is approximately 80 fold more likely to wind up having a history of anti-social violence by age 25, than a kid growing up in the suburbs with two professional parents who sang them lullabies and read them books.

We know enough already to decide that a system that decides that each of those people was actually responsible for their terrible outcome or their wonderful outcome, that something’s wrong with this picture.

This Q&A has been edited for length and clarity.