For David Eagleman, neuroscientist, technologist, entrepreneur and one of the most interesting science writers of our time, nothing about the brain is foreign. Born 52 years ago in New Mexico, he studies brain plasticity, synesthesia, time perception and what he calls neurolaw, at the intersection of knowledge of the brain and its legal implications. His book Incognito. 2011's The Secret Lives of the Brain has been translated into 28 languages, including Spanish in Anagrama, and now returns from the same publisher with another ambitious work, A Living Network, centered around a fundamental idea in current neuroscience : that the brain is constantly changing to adapt to experiences and learning. His scholarship is not only first-rate but also first-hand, but his brilliant, crystal-clear writing – a perfect reflection of his mind – transforms one of the most complex topics in current research into a triumph for the reader. We spoke to him via video conference in the first interview he has given to a Spanish medium in the last decade.
Could a newborn's brain learn to live in a fifth-dimensional world? “We still don’t know how much genetics and how much experience is in our brain,” he answers via video conference from California. “If we were to raise a baby in a fifth-dimensional world, which would certainly be a very unethical experiment, we might find that the child can figure out how it works there. The general theme of brain plasticity is that everything is more surprising than we thought, in the sense that the brain is a design capable of learning anything the environment presents to it.
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Eagleman pulls out a large bowl of salad from somewhere, pops what fits on his fork into his mouth, and continues his argument: “Your example of the fifth dimensional world is highly hypothetical, but what we know of course is that.” Babies born anywhere in the world, be it in a hyper-religious culture or in a secular country, in an agriculture-based economy or in another technologically overdeveloped economy like here in Silicon Valley, adapt their brains to each of these environments. My children adapt to using a tablet or cell phone just as easily as other children in other places adapt to farm equipment. So we know that our brains are actually very flexible.”
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The distinction between genetics and experience, or between nature and nurture, is not as clear as it seems. It is widely believed that genes build the brain and then the environment takes over by changing the strength of connections between neurons (synapses) or making new contacts. But to make new connections and modulate old ones, the same genes that built the brain in the first place must be reactivated. I asked you this question.
“The way we think about the biology of the brain is that experience brings about changes at all levels. So you're right, genes must be involved in brain plasticity. While plasticity is usually studied at the level of neuronal cells and the synapses they form, strengthen or weaken, the main reason is that it is easier to measure. Experience changes the brain at all levels, and the distinction between synapses and genes is not real, but an arbitrary boundary drawn by us human observers,” he replies.
A long century of neurology has shown that the cortex (or cerebral cortex), the outer layer that gives the brain its wrinkled appearance, is divided into hundreds of specialized areas: seeing, hearing, speaking, projecting, managing emotions, and everything else. However, anatomists have not found major differences between the circuit architecture of some areas and others, and no specific genes for each area are known. What does that mean? One of the lessons of Eagleman's new book is that the brain is the same everywhere. “The cortex uses the same trick, the same circuit architecture, in every area. The only reason we see differences – this area is dedicated to visual information, this one to hearing – is because everyone receives different input cables,” says the neuroscientist.
For example, information from the eyes travels to the back of the brain via the optic nerve, and therefore this area becomes what we call the visual cortex. However, when you go blind, that same cortex becomes auditory, tactile, or other things. There's nothing fundamental about this division of the brain, explains Eagleman: it's just a matter of which input cables are plugged into one area or the other, i.e. what type of information it receives.
Mysterious development
The development of the brain is currently as mysterious as how it functions. The six million years that separate us from chimpanzees is barely the blink of an eye on an evolutionary scale, and some scientists believe the key lies in the sheer enlargement of the cerebral cortex, which has tripled compared to chimpanzees and australopithecines. Eagleman is one of them. “Our cortex is much larger than that of any of our animal cousins, and that is a large part of the magical change in them.” There are other parallel changes, such as a large larynx, which allows us to communicate quickly through spoken language, or an opposable thumb, which is also a big help, but the main difference is the size of our cortex.
The scientist continues: “This implies that there is a much larger area between the input and the output (the input and output information), so in most animals these two areas are very different when one receives sensory information and one must send out a reaction.” close to each other, but in our case they are further apart. The result is that when you see something, you can make different decisions. When I'm presented with food, I can take into account that I'm on a diet, or that I don't want to eat that right now because I'm doing intermittent fasting, or whatever, before I commit to eating it.
Eagleman teaches neuroscience at Stanford University in California, but his work as a researcher and teacher falls far short of his deep and restless mind. He is the CEO of Neosensory, a company he co-founded dedicated to developing technologies to enable the blind and deaf to restore some of their abilities by recruiting areas of the brain normally devoted to other things to restore the lost to replace sense. He is also the chief scientist of BrainCheck, a digital platform that helps doctors diagnose cognitive problems.
In addition to writing quality informative books, he writes and hosts the television series The Brain with David Eagleman and the podcast The Interior Cosmos with David Eagleman. The backbone of all this frantic activity is harnessing the brain's knowledge to support medicine in innovative and creative ways.
“Consciousness is the great unsolved mystery of neuroscience. There are those who believe that they are just algorithms.”
The next question was inevitable. And yes, Eagleman used ChatGPT. He says that what's fascinating about these large language models (LLM, the kind of systems that ChatGPT is one of) is that we are currently in a time of discovery rather than invention. “Most of the things we have invented in the past – a washing machine or a coffee maker – we know exactly how they work because we designed them,” he says. But these LLMs are full of surprises and do things that no one expected, not even their programmers. “That's great. I think what they do really, really well is find connections that we had never thought of before. LLM models have read everything published in the world, have an all-encompassing memory and can do unexpected things Find links when you ask them the right question.”
Eagleman believes ChatGPT's capabilities are extremely valuable to science. “30,000 new papers (peer-reviewed academic articles) appear every month and I can't read it all, but the LLM can. I recently published an article in which I propose that there are two levels of scientific discovery. Stage one is about putting things together that I just didn't know, and ChatGPT can help with that. But that’s different from second-stage discoveries, where you have to imagine a model that doesn’t exist.”
“Albert Einstein,” Eagleman continues, “wondered how he would see light if he rode a photon, and this thought experiment led him to the special theory of relativity.” What he did was not put together things that were already in the scientific literature, but rather to come up with a new model and thus develop a simulation. And I'm currently not so sure whether artificial intelligence can do that. I think that’s why we scientists still have work to do.”
Scientist David Eagleman in his laboratory at Baylor College of Medicine in Houston, Texas, in 2009Joe Baraban
But Eagleman is also a writer. And he also believes that he will keep the job on the other side of him, because although ChatGPT can write “surprisingly cool” answers to various questions, he is not particularly creative as a writer. “You and I can structure paragraphs or go back to an earlier passage, and ChatGPT is far from that, at least for now. So no, I’m not worried as a writer either,” he says.
But I'm telling you that AI can copy you:
—You are a master at finding analogies, metaphors and vivid examples. Maybe the model can analyze his books and imitate him in all this, I ask him.
“Writing is hard, you know,” he replies politely. I would really be surprised if ChatGPT could write a good book in 10 years, but I'm not convinced it can. Writing a good book requires gathering new ideas and models, thinking about them, and asking yourself: What kind of story can I tell and introduce this concept at the beginning of this chapter? How do you connect it to what comes next and then and then? While I'm writing a book, I think about all these levels at the same time and what the reader's experience can be, and how to relate to what came before, what the rhythm sounds like, it's like composing a symphony. Since ChatGPT and the rest of LLM only think about what word to type next, they can't think about all levels at once.
Eagleman explains that it's so hard to imagine ChatGPT that “he's read every book, every blog, every website and remembers everything.” This shows that we are also essentially something of a statistical machine and that The result is much better if you copy these statistics and know which word is next to the other in every text that humanity has produced. than we imagined.”
Mind/Machine
One of Eagleman's research areas is mind-machine interfaces, small electrode plates implanted in the brain to help blind or deaf people. How do these electrodes connect to the right neurons?
“We know the area we want to control. For example, if you try to move a robot arm, you puncture the area of the cortex that normally controls the arm, capturing not one neuron but a whole collection. If someone puts a weight on your wrist in a normal situation, it won't take long for you to modulate your brain's commands to move your arm in this new situation and not knock over the coffee cup, and the same thing happens with patients too. Our brains are used to changes in the body. It's like saying: This is the goal I want to achieve. So how do I get there with what I have? For this reason, mind-machine interfaces do not need to make precise contact with the neurons. The person knows they want to move a robotic arm and figures out how to do it.”
The cortex is made up of repeating units called columns, with tiny surface area but containing millions of neurons in a stereotypical organization of circuits. They repeat over and over again throughout the cortex, says Eagleman, “like the ribs of a snake.” Everyone is interested in knowing what this column, this basic unit of the brain, does. There is a lot of data, but we still don't understand what it is about. According to him, “the structure of the cortex transforms data into representations useful for acting in the world, and this requires the abstraction of details.”
Will machines achieve some form of consciousness? “Everyone has an opinion about it, but we don’t really know. Consciousness is the central unsolved mystery of neuroscience. One idea is the computational hypothesis, where everything is made of algorithms and we have consciousness when we recreate those algorithms in silicon. “Other schools believe there is something special about the biology of the brain that we haven’t discovered yet.”
It's amazing what a salad can do.
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