Steve Levitt
Appearances
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So what we're talking about is substituting between senses. Are there other forms of this, products that are currently available to consumers or likely to become available soon in this space?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
According to Eagleman, the brain is constantly trying to predict the world around it. But of course, the world is unpredictable and surprising, so the brain is constantly updating its model. The capacity of our brains to be ever-changing is usually referred to as plasticity, but Eagleman offers another term, live-wired. That's where our conversation begins.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Elon Musk's company Neuralink has gotten a ton of attention lately. Could you explain what they're trying to do and whether you think that's a promising avenue to explore?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So what we've been talking about so far has been sending signals to the brain. But what Neuralink is trying to do is take signals out of the brain. Is that right?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I've worn a continuous glucose monitor a few times. So you stick this thing in your arm and you leave it there for 10 days. And every five minutes, it gives you a reading of your blood glucose level. It gives you direct feedback on how your body responds to the foods you eat, also to stress or lack of sleep that you simply don't get otherwise.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I learned more about my metabolism in 10 days than I had over the entire rest of my life combined.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
What you're talking about with these nanorobots is obviously in the future, but is there anything now that I can buy and I can strap on my head, and I know it's not going to be individual neurons, but that would allow me to get feedback about my brainwaves and be able to learn in that same way I do with a glucose monitor?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I could imagine that I would put one of these EEGs on and I would just find some feeling I like, bliss or peace, or maybe it's a feeling induced by drugs and alcohol. And I would be able to see what my brain patterns look like in those states. Then I could sit around and try to work towards reproducing those same patterns.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Now, it might not actually lead to anything good, but in your professional opinion, total waste of time you trying to do that?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
You know, I'm a big believer in data, though, and it seems like somebody should be building... AI systems that are able to look at those squiggles and give me feedback. The thing that I'd so hard about the brain is that we don't get direct feedback about what's going on, which is how the brain is so good at what it does.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
If the brain didn't get feedback from the world about what it was doing, it wouldn't be any good at predicting things. So I'm trying to find a way that I can get feedback. But it sounds like you're saying I got to live for 20 more years if I want to hope to do that.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So in my lived experience, I walk around and there's almost nonstop chatter in my head. It's like there's a narrator who's commenting on what I'm observing in the world. My particular voice does a lot of rehearsing of what I'm going to say out loud in the future and a lot of rehashing of past social interactions.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Other people have voices in their head that are constantly criticizing and belittling them. But either way, there's both a voice that's talking and there's also some other entity in my head that's listening to that voice and reacting. Does neuroscience have an explanation for this sort of thing?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Language is such an effective form of communicating and of summarizing information that at least my impression inside my head is that a lot of this is being mediated through language. But I also have this impression that there are parts of my brain that are not very good with language. Maybe I'm crazy, but I have this working theory that the language parts of my brain have really co-opted power.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
The non-speaking parts of my brain, they actually feel to me like the good parts of me, the interesting parts of me, but I feel like they're essentially held hostage by the language parts. Does that make any sense?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So when you talk about the spectrum, it makes me think of synesthesia. Could you explain what that is and how that works?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
People make a big deal out of it when they talk about musicians having this, and they imply that it's helpful, that it makes them better musicians. Do you think there's truth to that, or is it just that if 3% of the population has this, then there are going to be some great musicians among them?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So you've created this database of people who have the condition and you find a pattern that is completely and totally bizarre. And that's that there's a big bunch of people who associate the letter A with red and B with orange, C with yellow. It goes on and on. And then they start repeating it, G. In general, though, you don't see any patterns at all.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
People can connect these colors and letters in any way. Do you remember when you first found this pattern and what your thought was?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So when you saw this, you must have been thinking, my God, this is important, right? Exactly right. The question is, how could these people be sharing the same pattern?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Now, I have to imagine that the way we teach in traditional classrooms with a teacher or professor at a blackboard lecturing to a huge group of passive students, as a neuroscientist, that must make you cringe, right?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
And you want to contrast that with just-in-time information. Exactly. I need to know how to fix my car. And so the internet tells me, and then I can really remember it because I need it.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
You were more ambitious than me. I would just ask my mother. And I have since learned that every single thing my mother taught me was completely wrong. But I still believe them. Because of this part of the brain that locks in things that you learn long ago, I still have to fight every day against the falsehoods my mother taught me. I wish I had told her to take me to the library.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
David Eagleman is a professor, a CEO, leader of a nonprofit called the Center for Science and Law, host of TV shows on PBS and Netflix, and the founder of Possibilianism.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
When I went to school, I feel like they taught me the brain was organized around things like senses and emotions, that there were these different parts of the brain that were good for those things. But you make the case that there's a very different organization of the brain.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
And so in support of Possibilianism, maybe a better name could be in order, you wrote a book called Sum, that's S-U-M. So it's Sum, 40 Tales from the Afterlives.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
When I heard about the book, I saw the subtitle and I thought, I have zero interest in reading a book about the afterlife. I totally misunderstood what the book was about. And then I certainly didn't understand that some was Latin.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
People are super excited right now about these generative AI models, the large language models. What's your take on it?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Do you think that it is a solvable problem to give these models, a theory of mind, a model of the world? Yeah.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
If we were to come back in 100 years, what do you think would be most different? I know that's a hard prediction to make, but what do you see as transforming most in the areas you work in?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
There was a point in time among economists that there was a lot of optimism that we could really nail macroeconomics, inflation and interest rates and whatnot. And we could really understand how the system worked. And I think there's been a real step back from that. The view now is, look, it's enormous complex system. And we've really, I guess, given up in the short run.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Are you at all worried that's where we're going with the brain?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
They say as you get older, it's important to keep challenging your brain by learning new things, like a foreign language. I can't say I found learning German to be all that much fun, and I definitely have not turned out to be very good at it. So I've been looking for a new brain challenge, and I have to say, I find echolocation very intriguing. How cool would it be to be able to see via sound?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I suspect, though, that my aptitude for echolocation will be on par with my aptitude for German. So if you see me covered in bruises, you'll know why. If you want to learn more about David Eagleman's ideas, I really enjoyed a couple of his mini books, like Live Wired, which talks about his brain research, and some 40 Tales from the Afterlives, his book of speculative fiction.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So let me pose a question to listeners. Imagine you have a newborn baby and he or she looks absolutely flawless on the outside. But then upon examination, the doctors discover that half of his or her brain is just missing, a complete hemisphere of the brain. It's never developed. It's just empty space.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I would expect that would be a fatal defect, or best the child would be growing up profoundly mentally disabled.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So I first came to your work because I was so blown away by the idea of human echolocation. Yeah. only to discover that echolocation is only the tip of the iceberg. But could you talk just a bit about echolocation, how quickly, with training, it can start to substitute for sight?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
And then in these studies, you put a blindfold on a person for two or three days and you try to teach them echolocation. If I understand correctly, even over that timescale, the echolocation starts taking over the visual part of the brain. Is that a fair assessment?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So in your book, you talk about REM sleep. And honestly, if I had sat down and tried to come up with an explanation of REM sleep, I could have listed a thousand ideas. Your pet theory would not be one of them. So explain what REM sleep is and then tell me why you think we do it.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
I love podcast guests who change the way I think about some important aspect of the world. A great example is my guest today, David Eagleman. He's a Stanford neuroscientist whose work on brain plasticity has completely transformed my understanding of the human brain and its possibilities.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Have you convinced the sleep scientists this is true? Or is this just you believing it right now?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So we talked about echolocation, which uses sound to accomplish tasks that are usually done by vision. And you've started a company called Neosensory, which uses touch to accomplish tasks that are usually done with hearing. Can you explain the science behind that?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Just make sure I understand it. Sounds happen, and this wristband... hears the sounds and then shoots electrical impulses into your wrist that correspond to the high and low frequency?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Do people train? You give them very direct feedback? Or is it more organic?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
Okay. So hearing their own voice for the first time through this. Oh God. Yeah. That's interesting.
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So then it seems like if I'm deaf and I see the dog's mouth moving, and I now associate that with the sound, do the people say that they hear the sound where the dog is? Or is the sound coming from the wrist?
Freakonomics Radio
Your Brain Doesn’t Work the Way You Think
So you also have a product that helps with tinnitus. Could you explain both what that is and how your product helps?