Stanislas Dehaene, neuroscientist: ‘Free will is real. No one can predict what you are going to do’

The French researcher talks to EL PAÍS about the latest advances in brain research, how exposure to language affects learning and the dangers of technology

Stanislas Dehaene
Neuroscientist Stanislas Dehaene in Madrid.Andrea Comas

Stanislas Dehaene has been studying the brain for 35 years, and in that time, he has witnessed it reveal many of its secrets. Now, it is even possible to locate specific memories and erase them – an experiment that has so far only been carried out in mice. As brain research advances, it raises important ethical questions, says the French neuroscientist, who has written several books on the subject.

“At the moment, these technologies are developed mostly in a research setting and absolutely with the combination of the person involved and mostly for the benefit of humanity,” Dehaene, who was is a professor at the Collège de France and director of the INSERM Unit on Cognitive Neuroimaging, told EL PAÍS while in Madrid to present the Spanish version of his latest book, Face à face avec son cerveau (or, Face to face with one’s own brain). “But I would really like to also have a discussion in society about the implications, for instance, of the military having access to this technology.”

In his work, Dehaene explains the latest advances in brain research in a way that can be understood by the general public. He also highlights the importance of knowing ourselves as we are – not as we would like to be – so that we can adapt education to the workings of our brain.

Question. Are discoveries in neuroscience being used to improve educational programs?

Answer. My personal work has become much more applied. For the past five years, I’ve been working as the president of the Scientific Council for Education in France, which was created by the French government to try to help redesign an education system on scientific principles.

Q. What are the main mistakes we make when it comes to educating children?

A. I want to say, first of all, that not everything is wrong, on the contrary. But there are some things to improve. Number one is I think we have often underestimated children. There’s this idea from [Swiss psychologist Jean] Piaget that kids develop slowly with a very rigid agenda year by year. And we know now from cognitive science and neuroscience that in fact young children have much more sophisticated abilities. In language, where they acquire 10 to 20 words per day, much better than any computer at the moment, much better than the AI. And also in mathematics, where they have very early competencies for not just phone numbers but also for space and for integrating number and space together.

They usually have very strong intuitions and it’s more a matter of relating what you are teaching, and particularly mathematics, to their intuitions. They have trouble in mathematics often because they cannot see that new symbols are related to what they already know. They are taught as if it were a completely abstract domain where they see no meaning at all. The other mistake is to think that all children are different. In cognitive science we are seeing a lot of similarities. When people learn to read, it’s always the same circuit that comes online and there is variability at the scale of a few millimeters, maybe a centimeter at most. So it is not true that that you need to adapt pedagogy to every child, there are principles of learning that apply to all.

Q. But in a class of 20 kids, some learn much faster than others.

A. That’s true, but that doesn’t mean that you do not have to teach in the same way, they all benefit from the same methods.

Q. You say that everyone's brains are basically the same, but what makes us different is education.

A. First, the differences between children in terms of how far they are along the education process start way before school. We know, for instance, that there are huge differences in vocabulary, depending on whether you come from a poor family or a rich family, and especially how much language is related to the child. This is way before school starts, but school is central to reducing social differences, trying to bring a common culture regardless of the socioeconomic status and environment where you come from.

There is a beautiful study with children of five or six years old that shows that the amount of dialog in which the children were engaged has a direct impact in the activation of one of the main language areas in the brain. The main message is that you can make a huge difference to your children even before school by enriching their environment in the domain of language but also in the domains of mathematics, for instance, by having simple games and brainteasers in the home environment.

Q. Although some people may have difficulties learning to read or write and not everyone has the same ability, almost everyone knows how to do it quite well. However, a large part of the population does not have basic knowledge of mathematics.

A. Math requires effort and that is the first thing that is very important to understand. Every child must make an effort to learn. It’s not true that there is effortless mathematics. There is also a sort of neglect of mathematics as part of our culture. At the level of the brain we see that there are completely different networks for language and for mathematics, which barely overlap. That means we cannot expect that just because you have a linguistic culture, you will develop all of the same mental tools that mathematics can give you. I argue very strongly for a reinforcement of the mathematical culture.

A big misunderstanding is that mathematics is about numbers. Especially in primary schools, it’s all about calculations, but it’s really not mathematics. Mathematics has been defined by mathematicians as the science of patterns. It’s about understanding regularities and logical organization. So it is an enormously helpful set of tools for everyday life. I’m thinking, for instance, of graphs where you have the ability to plot one quantity in x, one quantity in Y, and to show how multiple data points, maybe hundreds, evolve and how you can perceive all of them as one graph. This is something that we should value much more in our society. I think we should teach it because it’s almost like a new reading and it’s completely different. It requires different brain circuits and both are equally important in our work in society.

Q. Is the ability to use mathematics or language in the human brain? Would it have developed over time or did brilliant minds need to develop it?

A. In my research, we look at the initial abilities of young children from the Amazon or the Himba in Africa, and we study the abilities of adults who have not been to school. And it’s interesting to see that there is a sort of nucleus of intuitions that everybody has. For instance, everybody has the idea that numbers grow and become fuzzier and that they correspond to space, with small numbers on the left, large numbers on the right. Everybody also has a sense of shape, and we find that everybody agrees that squares are more regular than parallelograms. So there is a universal basis of elementary domains like shape, number, logic, probability that you can trace to our evolution. And then, of course, the beauty of the human brain is that it can expand itself by education. We recycle circuits that are old like those used for numbers.

For example, the invention of Arabic numerals dramatically expanded our sense of numbers. Uneducated people or children’s understanding of numbers is limited to small or fuzzy numbers. They cannot tell the difference between 13 and 14. Education allows you to develop an accounting system, maybe on the fingers first and with words, and suddenly you develop a precise sense of numbers. So we all have the same basis. We all have the same potential. Although afterwards there is a process that takes us to other levels and that does depend on specific inventions. Descartes’ coordinates, for example, were a wonderful gift, because suddenly they opened a whole space of representations.

Q. Today, we think of numbers and letters as the basis of civilization and it is hard for us to think of a system for organizing and transmitting information without them, but is it possible that in the future we will invent other new, more effective systems?

A. In my new book, I describe the latest advances in neuroscience, which allow for two-way communication with the brain. I think this may be an interesting path for the future. Imaging techniques already allow us to read to some extent what someone has on their mind. We can discover the mental images that they are creating. If they project the image of an imaginary letter, we can see it, we can decode it. And in the other direction we can begin to write into the brain. It requires some electrodes, so it’s still pretty invasive. But in a monkey, by implanting electrodes into the visual cortex, they’ve been able to write a letter A or a letter O, and the monkey sees it and points to the letter. So with these sort of devices, how far can we go? The technology is incredibly advanced.

Q. How will the possibility of accurately knowing what happens inside our mind and even being able to make predictions affect our freedom?

A. It’s a complicated issue because in the minds of some people, it means that there is a degree of freedom from physics. It’s almost a dualist idea. The idea that thoughts would be free from the hardware and the physics of energy and can be chemistry and so on. That’s not true. There’s no way we can escape and no degree of randomness is helping in that aspect. Even if there is a little bit of this in quantum physics, that is not what we mean by free will.

What I think we mean by free will is that we are capable of exercising our deliberation. That’s why the word deliberation is related to free will. It means that we can bring information to the mind, consciously, think about the possibilities, consider them, consider their consequences according to what we know, and then we make a choice. That’s what we mean by freedom, and in this sense, it’s very real. There is a space in the brain and conscious workspace where we can bring information and do this sort of slow deliberation, completely detached from the external world. In this sense, free will is real. No one can predict what you are going to do. Even you have to follow this process, you cannot take shortcuts. You can’t say, ‘no, I don’t have free will.’ You have to go through that process to take your decision.

Q. For the last century and a half, technology has been changing at an accelerating rate. But our brains are not evolving at the same speed. Could this make it difficult for them to adapt?

A. There are a number of principles that we cannot change, whether we like it or not. We are our brains and the brain is very slow to evolve. There has not been time for a biological evolution that allows adaptation to technological changes. We’re stuck with a system that we have to respect and learn to use better. Some things will not change. For instance, the need to sleep. There is a mythology that says some scientists or politicians do not sleep, or sleep very little. This is just plain false. If they don’t, they lose attention and learning ability. We should all learn to make better use of our brains rather than deny their biological nature.

I do think that society, in some ways, is evolving in a direction that is incompatible with the needs of the brain, and the need for sleep is one such case, as is the need for social contact and the need for language for young children, which is being denied. I find this a very dangerous trend. We have a lot of evidence that young children need spoken language or at least some language within the first 18 months of life. If they don’t get language, they will suffer lifelong atrophies. I see this as a strong message to parents because I see many parents being trapped on their phones and away from speaking to their children. When people discuss the danger of cellphones, they talk as if the problem was screens for children. But the problem is mostly screens for parents, because they keep them from interacting with their children. Technology restricts the learning environment of children by parents.

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