National Nonprofit Institute inserted adjunct professor at stanford university. Best known for his work on Time Perception brain plasticity and live wired his new book presents findings from his lab from dreaming to devices that revolutionize how we think about the senses. He will discuss bio hackers using echolocation and the present and future of ai. Im so excited to hear doctor eaglman talk today. Welcome, david. The floor is yours and i will be back in a little bit to moderate some q and a. Thank you. It is a great pleasure to be here. Ive been to politicsnd prose in person in the past and im soy i couldnt be the this year, but im pleased you can join me this way online today so id like to tell you a little biand a brief overvw about the main themes and ideas in the book and then were going to take questions. How many of you have ever seen a baby zebra get born so it can run with its little ls and it runs around the giraffes and dolphins born smming and how many have seen youight notice its a little bit different they dont run around after fr to five minutes and this is because instead of trying to hardwire everything at birth, Mother Nature found a simpler and more flexible strategy which is to allow the neurons to self modify based on their experience in t world in other words we let the rld shape u and this i a completely new strategy for Mother Nature but its worked really well in the sense that theyve takenver every corner ofhe planet. Weve looked at the internet, weve cured smallpox and so on. So its working for us and this is all due to the feature that they are not really hardware and you can think of them that way. But instead its what i call live where hence the title of the book and in the field we talked about this in terms you may have heard. The fact is this was a term coined a century ago by william james. You could take something plast plastic. There is a change in the structure of your brain and it holds on to that so thats why i use the word plasticity but in fact what i argue is it is so much more than that. Theres 86 billion neurons and each has a thousand connections with its neighbors which is the connections going on in the brain. Every moment of your life these things are unplugging and seeking and finding new places and so on. Its a dynamic set of rec that is not just something that you mold and hold on shape but its changing your whole life. So, this is Incredible Technology we dont know in Silicon Valley how to build things like this yet but we have proof of the technology because we are all Walking Around with. What i want to do briefly is give you a sense of some of the principles so theres about 30,000 papers in the literature and what im trying to do is figure out what are the main principles we can point to so thats what im going to try to tell you here. The first is unlike computers, it is extraordinarily flexible. I will give you an example of that. There was a case a 44yearold man, normal iq had pain so he went to the doctor to figure out what was going on and the doctor sent him to get a brain scan in case there was something going on there. It turns out what a normal brain scan looks like is Something Like this. This is right down the middle and number three points to this area called the lateral space in your brain filled with spinal fluid. The point is this gentle man his brain looked like this so the section was completely filled with spinal fluid and such pressure it pushed his brain up against the sides of his skull. But what the story illustrates is the remarkable flexibility because it didnt hamper his development or cognition and behavior and the thing is you cannot take your phone or laptop like that and hope that its still going to work. This is a whole different kind of beast that we are talking about. And of course we have many examples of this. When children have epilepsy that affects half of their brain, one hemisphere of their brain, they can go in for what is called a hemisphere ectomy where you remove half of the brain. You take it out. Originally surgeons would fill the empty space with sterile pingpong balls but it turns out you dont need to do that because the spinal fluid provides enough pressure so they leave it empty and the child has half a brain. You might think gosh, that poor kid. Thats the weird part as long as you do it under the age of seven, the child has perfectly normal cognition and can speak and do math problems and learn history and so on. They tend to have a slight limp on the side of their body because it controls the other side and they are a little bit weak. Otherwise they are perfectly fine. The book is full of examples to set the ball rolling that what we are talking about is the different beast than we are use to because i cant take my laptop and tear half the motherboard out and expect it to still function so that is principle number one. Prinple number two brains are locked into the silen and darkness and have no idea what your body looks like and yet when we look at the brain, what we find is that there is a map of the body, so i will not go into detail except to say the part of your brain that cares about the input coming from their body, there is a map and the same with your motor cortex putting information out to move it around and so this was discovered in the 60s so the question is how is there this map and the obvious answer is that it must be genetically be specified but it turns out that is not actually the correct answer. And we know that for many reasons. One of them though is lets say you lose an arm in an accident and it will adjust so that it says i not have an arm now and it changes the maps of the map is always changing predicated on what information is coming from the body. So, you know, this is a picture i talked about the hero of other british works but most people dont realize hes missing his right arm because it got shot off in one of his battles. He described what it was like but now we understand what happened to his brain and it happens fast. A quick analogy. How does the brain understand what the map should look like. I use the analogy of colonization. It is a fulltime business. So, what happened with the french in the new world, they had a lot of territory in the new world, but eventually, the french were sending over fewer ships than the spanish and ended up losing the territory and it is exactly the same thing with the brain if admiral nelsons right arm is sending few ships because it is now gone and the territory gets taken over. The key is nothing lies in the brain. Everything is taken over and its a very competitive system. Part of the way we can see that is people who are blind, people who are born blind. The vision is taken care of by the back of your head. Its taken over by sound, by touch, things like that. So its not like the visual syem. Let me put it this way, even though wlearn in the science 101 this part of the brains visual system, its only if your eyes are working and ifhe data is coming in then it becomes the visual system, but if theres nothing coming in and say thats cool im going to use this terriry for the neighboring countries, which in thisase are sound and touch. So, it is a very fluid system and this is one of the things to undersnd even though we tend to look at ithe way that a ild might look at a globe of the earth and think that all those country borders are somehow predestined or if we are into politics and world histo we know they could have come out very differentlyf the king had died or the battle tipped the other way. So its the same thing inhe brain despite the fact we learn about it it is an extremely fluid system. Then the thing i want to emphasize is the takeover of the territory is rapid and something that is a New Discovery for the last several years. What, i mean, by that is lets see we take a person and blindfold them and stick them in the scanner. What you find is you start seeing activity in their visual cortex based on sound and touch and that happens within about an hour. This encroachment starts to happen so what this tells us is it is a very competitive system happening and things are moving fast. The whole thing is sprung like a mouse trap so when it says wait a minute i am not getting vision coming back and starts making changes and there is an annexation that begins to happen. So my student and i realized some years ago this leads to a very new and interesting theory that weve now published on. In the quantic competition for the real estate, the visual brain in particular has the unique problem to deal with becae of the rotation of the planet. How do they deal wh this unfair disadvantage and we suggest it is by keeping the cortex active at night. The idea is what it is doing i dreams or the brains way of fighting takeover from the other senses. So you have a very specific circuitry in the brain that blasts activity into this cortex and its all it does by the way and it isxtremely specific. It goes to this part of the brain and thats wha happens during the night and so by understanding whats going on in the brain plasticity, we can really open up this wle set of theories and framework a about with the braiwhat the brain idor the hood and why. Okay. I want to tell you the next principle. I am moving fast through some highlights. The next is that the brain will wrap itself aroundew data streams. This is like the little buzzers on your cell phone and its capturing sound and turning it into patterns of vibration on the skin so what happened is i was speaking and my skin is feeling that going on from low to High Frequency. Heres a video by the way. This woman on the left and if you just look at the way the motors are mapped from the low to High Frequency you can see the sound and touch and if you look at the shoulders you can see the highfrequency. So the point is for people who are deaf, what we can do is feed the information through an unusual channel which is the skin instead of this sophisticated little biological machine that captures sound on the eardrum and breaks the frequency in terms of spikes capturing sound and breaking up the frequencies and sending it up the spinal cord into the brain. And the brain can figure out what to do with the information. Its trapped in the silence and darkness and all it sees are spikes. It doesnt know if it represents air compression are mixtures of molecules. All it sees is a spikes and what it is good at doing is putting together and understanding whats correlated with blood and figuring out how to understand that data. Here is an example of the first participant we ever tested with this. On the left and graduate students on the right. The graduate student says the word you and the gentleman that is completely deaf on the left writes down what hes understanding. This gentleman writes down the word where and scott says touch. And so, hes feeling this on his skin and is able to translate this pattern of vibrations into an understanding of what is being said. What we have done in the meantime, i ended up with a company out of my lab and its down to the size of a wristband that has motors in the band and it captures sound and theres a computer board translating the sound into patterns and vibrations on the wrist and heres the very first participant. So theres this Company Called the buzz and weve got this all over the world now. Its all the way from the theoretical concept to a device that is changing peoples lives all over. I will also mention im a scientific advisor for the show westworld so we had a cameo appearance in westworld. I dont know if any of you watch this show but this was season two, episode seven. The gentle man in the middle if you can see is wearing the vest. Whats happening here is he feels spatially where the hosts are located and he can do this accordingly. We are doing a translation into a spatial feeling. So suddenly they feel there is a host in the room but they were not expecting one. The vest might save you from robots going bad. What weve done is taken this idea and used it for people that are blind. In this case this gentleman can feel theres someone ahead of him, behind him, and if they are walking to the left or the right. Which actually makes it better than what a sighted person has being able to understand everything going around you in 360 and now navigation around that, hes never been here before. He can go right where hes going. So, theres much more to say about this. If anyone is interested in this general type of thing about creating new sentences, please check that out on the ted talk that i gave about this. But the book goes deep into why this works and gives dozens of examples about this. Let me move on to the next principle which is as i mentioned its trapped and he doesnt know what your body looks like but one example discussed in the book is dog bornithout front legs and so what does she do, she figures out how to walk on her back legs like a human. What this tells us is dogs brains do not arrive be pre programmed to drive dog bodies. What they want to do is get to food, get to stuff like that so they find out how to control the body that they are in and thats all there is to it. We see this in humans all the time and its the worlds best archer is aless. He got interested in archery and holds the record for the longest shot and this is because his brain can say okay, cool i wl pull this thing back and do it like that. Theres this woman thats completely paralyzed. This allows me to control the robotic arm, a very sophisticated robotic arm. She controls this with the motors in her cortex and imagines moving her arm and that gets translated into moving this robotic arm. She gets better and better at it because of the brain plasticity and shes figuring out okay when i think this it does this a little bit wrong so i will think about it a little bit differently. So you can have things outside of your body. And it turns out that this whole idea about how can you actually make livewire devices that figure out their body the way the brain does, we are just starting this. One colleague of mine at columbia makes a little robot called the starfish robot that isnt preprogrammed to know its body. Instead it figures out its body by trying out different moves and then seeing what happens to the body. So it actually figures out how to get somewhere to try to get over to the right side of the table here to get to the reward, so it figures it out but the key is you can snap a leg off of this and it figures out how to walk just like humans and other animals because it just figures out its body by trial and error. Okay. So, the next principle, actually this is the last thing i will mention and then i want to move to qanda. Part of the reason i think its so amazing to understand what is going on under the hood is because we can actually build new devices this way. Completely new principals on how we are thinking about things. So, one example i given the book you know, if you look at the mars rover spirit, it was a multibilliondollar project. We got it up to the red planet. If you compare that to a wolf that gets its leg trapped what the wolf will do iso its leg off a then fure out how to walk on two legs. That is what all animals do. They have a sense of relevance. They want to get to safety to seek water and so its actions are undergirded by the demands of its stack and the threat of predators. The wolf in deference to its skul so its bra drinks of information about the environmenand its capability in that environment, and in other words when it slamallow it to its brain translate those capabilities to the most useful motor output. So a wolf rries on because animals dont shut it down with of the damage and neither should our machines. So, in thlast part of the book i talk about how to build a completely different machine at in the case of the mars rover it chews its wheels off d figures out h to operate in a different way. All of this is to say theres so much amazing stuff happening and we are just scratching the surface. Everyone especially here in Silicon Valley is so impressed with whats going on but that is baby stuff going on compared to what is actually here, this strange material that we all have under the hood so now what i would like to do is answer questions about anything. Thank you for that. That was so cool and we have a bunch of great questions. I will start with kind of a broad topic people dont seem to have a lot of questions about. Its this idea about the brain remapping itself when the senses are deprived based on amputation or deprivation. I would ask. A. Thats a great question i have a whole chapter on that. They are all chained so the things that change fast have to sort of present enough evidence when somebody loses a limb parts of their brain change and readjust right away. But deeper areas still think its in their hand because their whole life they got information from that and so they get confused and sometimes they think they are still getting signals and they say that must be the hand that is being touched and there can be pain as a result of the interaction between the different layers. Older memories are more stable than so if youve ever known someone at the end of their life is may be on their deathbed dont remember what happened in the last month or year may be but they remembered their childhood just fine which is unusual. Under systems we dont have that property were older memories are more stable than newer memories. But the reason it happened is because the way things work their way down in the system they become more and more stable he was speaking in german on his deathbed. Another question about this kind of the same concept. What is happening in the brains of people that are put on ventilators to recover from covid, so not necessarily sensory input and as things we can see as the five senses, but when a body part is replaced with an external machine does that the same kind of remapping happen. An artificial heart, a respirator to take care of your lungs. You can lose limbs and stuff like that but you are still the same person. In contrast if you damage or lose a little chunk of brain tissue that can change you an entirely. Your decisionmaking and your capacity to name animals or understand music or a hundred other things. This is how we know that the brain is the densest representation of view in the whole body. In other words people often ask what about the rest of the body. Its like the greater metropolitan area but this is the urban center and you can change this stuff and replace it and there doesnt seem to be much of a difference at all but the brain is dead. I have a question. I am so interested in the idea that dreams are meant to make sure the other sentences dont take over. A great question. We just published a paper on this where we did deep research on the 25 different species and it turned out they are a close cousin we split off 70 million years ago from the one over here theres Different Levels of plasticity so for example it was pretty rapidly as opposed to homo sapiens so you can look at all of these measures to find out how plastic brain is versus how preprogrammed it is. Then we look at how much sleep they get which is what correlates and it turns out it correlates perfectly which is to say the less plastic the last dream must leave it to needs because it isnt in danger of getting taken over because it doesnt have that much plasticity but the more plastic you are the more dream sleep you have because you need to protect the brain because it is more danger of takeover of the visual cortex. So that is how we study it. And next as it turns out some people with antidepressants or inhibitors have less dream sleep so now we are going to be looking at that and doing studies on if Everything Else is, you know, hopefully approximately the same but you are not getting dream sleep at night, what is the effect and one of the things i noticed right away is people on these antidepressants say that their vision gets blurry. The doctors and the clinicians say its because of dry eyes and that might be right but that is what we would be looking into. That is awesome. In the different species theres a question about the Different Levels from human to human. Do human brains lose this as we get older and if so are there behavioral ramifications . Generally the brain gets less plastic as it ages. Most people view this as a bad thing. But in fact, the reason it happens is because the job of the brain is to build an internal model of the world out there. So, what the brain is trying to do is figure out how do i optimize my behavior in this world. What should i do, how do i get good at something so i can have a career. So this is the way that the brain is trying to do this. At all points. And what happens is you get better and better at it as you age and the reason it is less flexible is because you are putting together a pretty good understanding of how to operate in the world. And so, you know, thats why we become less plastic, but the important part is to always make certain you are challenging yourself with novelty so that you can build new ways of maintaining plasticity. I will give you a second thing about whats been going on for a long time, many decades and it turns out people that stay cognitively active their whole lives when they die some of it it turns out theyve had alzheimers disease but nobody knew it when they were alive and they didnt have the cognitive deficits because they were cognitively in the last moment there were other people and they were challenging themselves and so on. So even if it was degenerated with alzheimers they were building the road waves and new bridges were things have fallen apart. As opposed to people that retire and their lives shrink and they dont challenge themselves and they are not dealing with other people, that is the worst thing you can do so one of the main lessons that has emerged is the importance of challenging your brain with novelty all the time so that is the thing that you can do and what that means by the way is as sooner you get good at something, dont do that anymore. Do something you are bad at. Thats great and that he answers a question about aging without the effect of memory loss and cognitive decline what do you think is the evolutionary purpose of lucid dreaming and why can some people do it and other people take practice and cant ever do it . For anyone who doesnt know, lucid dreaming is when you become aware you are in a dream and essentially you can take control of a dream. It is very rare. Most people never have it in their lives or maybe once and theres ways to train to try to get better at it. I think that its something that the brain puts a lot of work into generating consciousness and then that turns off when you are sleeping and sleep has other functions like taking out the trash and consolidating things we learned during the day. So what happens is this accidental interface between the two that isnt typically supposed to happen. So, in answer to your question i dont think theres an evolutionary purpose to it, just a little bug that can be found sometimes. And then this question about dreaming. How do we see our dreams if we are not really seeing with our eyes . Is it our imagination or what is going on there . This is a very important and fundamental concept to get. What you consider vision is all about internal activity and what is happening in here. You dont even need your eyes to see as evidenced by dreams every night. Your eyes are closed and you are having a full experience. It turns out if you look at the circuitry carefully only 5 of the data, only 5 is coming in through the eyes and the rest is feedback loops and other things going on back here. So, vision isnt at all like a camera but its about the internal model you expect to be seeing out there and things like visual illusions that are very interesting like eightyearolds and neuroscientists, the issue that demonstrates does it even matter whats out there physically what you are seeing is what your brain is putting together and telling you. Colors dont even exist in the world. You have different wavelengths and your brain finds these to detest the right food for that experience. The no colors thing always freaked me out a little bit. Another person asked about whats going on in the brain then . In one sentence to make this switchover its making all these big changes theres a dozen ways it can go wrong. But thats the answer. Wears the initial feedback to train the words from the vibration . What you need to understand anything is having a correlation, so let me back up for one step and you had to learn how to use your ears so you watched your mothers mouth and theres the visual input then theres the auditory and putting together the correlation they are matched up and then you do things like clap your hands or knock on the bars of your crib and realize every time i do that i get spikes coming in here. Thats how you learn is the correlation. So, with a person who is the the death, they learned b learn by g the world. They see the dogs mouth move and feel the dog bark. At first they dont know what that is. But they say ive got to do things and put them together. In the case of learning words, training for two hours a day and so he sees the word and feels the word but thats how he makes the correlation. Thank you for the question. This other question, how is it different from reinforcement learning . The way you described in agent describing the reinforcement learning, im not familiar with the term. Maybe you are. Its taken out as the way of learning essentially feedback and its what tells you to strengthen this and weaken this and so on. A lot of what happens, some fraction of what happens in the brain is reinforced in the learning but its actually more than that as an example it isnt just about the reward and punishment though that is an important part of it. Its about the relevance to you. What matters in your environment and so on but its also about the tension and the model of the world and what the brain is good at doing is detecting if something doesnt quite match. Everything else is fine. We then paid attention to that and put the resolution sensors on to try to get more information. Chapter eight of the book i propose a new framework called the info tropism. They follow where the light is and if you move them what the brains do is change what they do to maximize the amount of data that they are getting from the world. Just one example is with your retina the back of your eyes you got these photo receptors. During the day the receptors have a very high Spatial Resolution and as it gets dark the receptors say there are not enough here so they start linking arms with each other so they have lower Spatial Resolution and the higher sensitivity they can catch them that way. What they are doing is maximizing the amount of information that they can take from the world at all moments. You might be interested in these notions of things like info tropism that go beyond reinforcement learning. Ai is a component of your book. Do you think theres anything about human intelligence, emotion, consciousness et cetera that emerged that ai will not be able to produce or are we on track . That is a great question as far as we can tell it is a machine, unbelievably complicated machine and something that bankrupts our language. Because of that there is no theoretical reason we shouldnt be able to simulate that on silicon or you can build it out with beer cans and all that. Now, that said, we are still a young the science so we may discover something and say we didnt realize that but we might be able to replicate that so they should be able to get there eventually. Will it happen in our lifetime i really doubt it. The reason is right now ai is extremely it is these wonderful things with superhuman performance, but its actually really stupid compared to a 3yearold child who can navigate the room and do all kinds of things. So its missing artificial generalized intelligence which is to say it can distinguish from superhuman performance but if you say distinguish pictures from bears or camels it would say it cant do it because it cannot generalize to other things. So where we are now i think is a very long way off. Can you talk more about are they using different pathways to perform mathematics or other equations . Its where they have a slight mixture of the senses, so they might look like j or b and it triggers an experience so for them it used to be thought of as rare. Its not considered a disorder its just an alternative perceptual reality the way some people see the world and other people dont see the world this way. Its called wednesdays and then they go blue but some of them can do mathematics a little bit differently precisely because numbers have colors and sometimes genders and personalities and shapes as well. So it helps them to hold on as an example if i tell you my phone number, you might forget it in the weeks from now. But you might remember it had a nice pattern to it and that helps you to remember so it proves we have a better memory. Totally. Okay, so we are about at the time to wrap up but there is anothetheresanother question ar opinion on brain computer interfaces and if you think that there are any nonmedical applications that are going to emerge in the future. So, it depends what you mean. Theres the kind of stuff i build which is a noninvasive wristband you put on for a couple hundred dollars and then have a new stream of data. On the other hand theres things like the presentation from the other day and that is about drilling a hole in your skull and inserting electrodes into the brain. Hes pushing on that and that would be useful for the clinical applications. Will it go beyond clinical, i doubt it even though the mythology consumers will do this so they can interface with their cell phone. In fact they will not do the surgery because theres always a risk of infection and death on the operating table and theres no point doing in open ended surgery so they can send a faster text so thats the answer. We are doing a whole bunch of products youre feeding information about the red light or stock market and things like that that go beyond the clinical realm, but i doubt that people would get in open answer like that. Maybe computers still are not a good idea today. Thank you so much, i do have one last question and that is what are you reading these days . I finished a couple of books about material science one is liquid rules and i just read a book about im forgetting the title Something Like craig childs. I totally blanked on the title, but its about being up in alaska looking at where the lands bridged used to be and the animals that lived there. Its absolutely beautiful. Again, thank you so much for spending time with us today. And i think everybody and the future events to ask the questions at one of those i hope everybody out in the audience continues to stay well and stay well read. The link is in the chat and you can find it on politics and prose website. Thank you so much. Take care. Thank you guys