Rodrigo Quian Quiroga, neuroscientist: ‘Forgetting is the essential trait of intelligence’

The scientist who discovered the ‘Jennifer Aniston neuron’ warns that artificial intelligence ‘is very far from approaching’ human intelligence, but it is not impossible

Rodrigo Quian Quiroga
Rodrigo Quian Quiroga, neuroscientist and researcher at the Hospital del Mar Research Institute.Albert Garcia
Jessica Mouzo

There is a fine line between science fiction and reality. In most cases, it is only a matter of time before fantasy and scientific research cross paths and their boundaries become blurred, says neuroscientist Rodrigo Quian Quiroga: “What was science fiction until a few years ago is already science.” But can machines be self-aware like HAL 9000 in 2001: A Space Odyssey? Is it feasible to achieve the immortality proposed in Open Your Eyes, and manipulate memories, like in Total Recall?

Quian Quiroga, a graduate in Physics, ICREA professor, and researcher in the Perception and Memory group at the Hospital del Mar Research Institute in Barcelona, Spain, has just published (in Spanish only) a work that reviews this transition from science fiction to real life — with reference to iconic films of the genre — through the great scientific advances of the time. “Inception and Total Recall play with the idea of implanting memory. And that has already been done [in mice] at MIT: scientists optically stimulated specific neurons and managed to implant a false memory. It is proof of concept,” Quian Quiroga says.

The scientist specializes in the study of the neural mechanisms of memory and discovered the so-called grandmother cells (or “Jennifer Aniston neurons”). These are nerve cells in the hippocampus that respond to specific concepts after an experiment carried out with photos of familiar people: “They reflect the conscious perception [of something] and not the visual stimulus,” the researcher explains. He considers the finding fundamental in the construction of the individual.

A lover of philosophy, he is one of the privileged few who do not possess a cell phone — “I can afford not to have one. The cell phone kills those moments of boredom in which it seems that you are not doing anything, but suddenly the cogs in your mind start spinning, and ideas emerge that you hadn’t thought about.” In his book (Cosas que nunca creeríais. De la ciencia ficción a la neurociencia), Quian Quiroga also takes the opportunity to reframe some of mankind’s big questions about consciousness, sense of identity, and free will. “The book is a hoax: it is not science fiction or neuroscience. It is a treatise on philosophy,” he admits with a laugh.

Question. Channel 53. Neuron 2. What's going on there?

Answer. That was the Jennifer Aniston neuron. When we evaluate a patient with refractory epilepsy for surgery [where the area of the brain in which the seizure originates is detected and removed], electrodes are placed inside the brain to identify where the seizures are coming from. And that allows me to record the neurons. What we do is we show photos to the patient, and we see if any of the neurons we are recording respond to any of the photos we show. This happened with a patient in the United States, when I saw that channel 53, neuron 2, responded to photos of Jennifer Aniston and nothing else.

Q. What is that neuron trying to tell you?

A. It is representing the concept of Jennifer Aniston, because it responds to any photo of her. It’s not that it responds to a visual stimulus because it has light from here or there, or because Jennifer has styled her hair in this or that way. It responds to her, no matter what she looks like. This was the first of many neurons that I found that responded to a concept. What we see is that there are neurons in the hippocampus — an area of the brain that is essential for memory — that respond to concepts, and associations between concepts, which are the skeleton of the memories of our experiences. What I infer from that is that, if you did not have this type of neuron, you wouldn’t be able to encode memories. These neurons are key to recognizing the experiences you have with those concepts.

Q. Why do we remember some things and not others?

A. One of the first things that surprised me when I started getting into neuroscience is how little we remember. Our memory is based on remembering very little information and making a construction based on that. That’s why we have false memories. We are constantly constructing a reality from very little information. Our brain’s capacity for memory is very limited. In each person, we tend to find neurons that are related to things that interest them, and it is because they form memories for those things. In other words, if my sister passes by, I will form a memory because she is my sister, but if another person passes by, I will not because I don’t know her, I am not interested in remembering it. You tend to form memories of things that are familiar or emotionally salient, which is something that impacts you greatly, for better or worse.

Q. Do we need to forget?

A. Yes. I think that in our society we place too much value on memory. We tend to confuse intelligence with memory, and that has a big impact because that is how we are assessed at school. We have this tendency to want to remember more because it gives us the impression that people hold us in higher esteem. And guess what: the key to the functioning of human intelligence is not what we remember, but the amount we forget. I believe that forgetting defines human intelligence, it is the essential characteristic of intelligence.

Q. Why?

A. When you encode concepts you are forgetting details. By developing thinking based on concepts, I am leaving aside a lot of details, and that allows me to make much more advanced associations. I believe that human intelligence is based on being able to extract what is essential, set aside the details, and have thoughts. And that means forgetting. This level of abstraction is exclusive to humans, and that is the great peculiarity of human memory.

Q. Is that where machines can’t compete to overtake human intelligence?

A. I don’t think there is a scientific barrier by which I can say that machines will not be able to become like us, because I don’t see why something that is encoded by neurons cannot be encoded by transistors. It’s not that organic living matter with carbon has different properties than what you could build in a circuit. But I believe that artificial intelligence (AI) is still very far from approaching human intelligence. There are advances that are extraordinary, but even so, they are not even close to human intelligence.

Q. Is there anything that is still science fiction but that worries you because it could become real?

A. What is on everyone’s lips right now is AI. But it doesn’t worry me. It makes me curious. There are two big questions about AI that fascinate me: one is whether we will ever get AI to wake up, in the sense that it suddenly becomes aware of its own existence. And another question is whether we can one day get AI to develop what is called general intelligence. That is, you learn something in one context and apply it in a totally different context, like if you go out on the street and something happens to you that has never happened to you in your life, but you know what to do because you have an idea. It’s common sense. You make inferences, draw analogies, and so on. It’s knowing how to behave in new situations. That is general intelligence and, until today, it is in its infancy in artificial intelligence.

Q. So, general intelligence is what separates us from machines, then? You say that you see that they are far from becoming more intelligent than humans.

A. You mustn’t be blinded by shiny new things. 25 years ago, we all said that chess was an impregnable barrier for a machine. And suddenly, Deep Blue beat Kasparov. And today there is no chess player in the world who is capable of beating a computer. So, in playing chess, the machine has surpassed us. But you can’t use the rules you learn playing chess to solve a theorem, to write a report, or to recognize faces. That’s what AI is missing.

The neuroscientist Rodrigo Quian Quiroga at the Barcelona Biomedical Research Park.
The neuroscientist Rodrigo Quian Quiroga at the Barcelona Biomedical Research Park.Albert Garcia

Q. Is understanding consciousness the greatest challenge for neuroscience?

A. We are already answering that question. The big question we asked ourselves a while ago was how the activity of neurons is able to create sensations. For example, the sensation of pink, the sensation that I like something, or of seeing you. And I think that question is somewhat answered. It is a philosophical fallacy. It is believing that there are two different things. The sensation of seeing you is nothing more than the activity of neurons. Now the question has changed. The big question is, what specific process in the human brain do we have to copy for a machine to wake up? And we still don’t know that.

Q. Another topic that the book touches on is dreams. What is the purpose of dreaming?

A. We don’t know. When someone wants to give you a serious answer, they will tell you that it is an epiphenomenon. That just means something that is a consequence and that has no function. I’m reluctant to accept that because, sometimes, the constructions of dreams are so fabulous that to say they have no function feels inherently wrong to me. Besides, you have a lot of evidence that we can be very creative during sleep. For example, Paul McCartney dreamed of the song Yesterday and wrote it when he woke up. I believe that dreams strip you of reality, and that triggers your creativity.

Q. You also address free will from the context of the film Minority Report. You say that “the conscious decision is a consequence of unconscious processes in our brain.” So free will is an illusion? Do we have no real ability to decide?

A. Yes, you have the ability to decide. The problem is that we have deeply rooted Cartesian dualism. We think that the mind is something different from the brain. So, when you say that we do not have the ability to decide, you have to realize it is your brain that makes the decision: it is you. You imagine that there is something ethereal and magical, that you call the mind, and that it exercises its will and makes its decision and implements it through the brain. But where is that mind? What is the mind if neuron are all there is? The mind is the behavior of neurons. And the exercise of will is you making decisions based on the activation of your neurons. Decisions are the result of the activity of neurons, and the activity of neurons is a deterministic process. Whether a neuron fires or not is connected with the stimuli it receives from other neurons or from the outside. The decision-making process is deterministic, it is predetermined, which happens to be so complex that it is as if it were not complex. So the fact that it is predetermined doesn’t change anything because there is no one who can predict it because it is extremely complex.

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