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Joe Rogan Experience #1344 - Joseph LeDoux

Joseph Ledoux is a neuroscientist whose research is primarily focused on survival circuits, including their impacts on emotions such as fear and anxiety. His latest book "The Deep History of Ourselves: The Four-Billion-Year Story of How We Got Conscious Brains" is now available.

Joe RoganhostJoseph LeDouxguestJamie Vernonhost
Sep 5, 20191h 47mWatch on YouTube ↗

EVERY SPOKEN WORD

  1. 0:0015:00

    Here we go. Joe,…

    1. JR

      Here we go. Joe, thank you. Thank you for being here. I really appreciate it, man.

    2. JL

      Oh, it's a pleasure to be here.

    3. JR

      This is a fascinating subject. I've been really looking forward to talking to you 'cause, uh, the conscious mind and how we, how we evolved our conscious mind, how we have our conscious mind. I mean, that is, uh, one of the more unique things about being a person.

    4. JL

      It is.

    5. JR

      How did it happen?

    6. JL

      Oh. (laughs)

    7. JR

      (laughs)

    8. JL

      Well, it's only a four-billion-year story, as the subtitle-

    9. JR

      Oh, we have some time. (laughs)

    10. JL

      ... of the book says. (laughs) Good. (laughs) So, shall I tell you how I got-

    11. JR

      Sure.

    12. JL

      ... into it and, uh, where, where, how I ended up thinking about that problem? So I'd been working on how the brain detects and responds to danger for most of my scientific career. Uh, a little bit before that, I'd actually studied consciousness in these people who have their brains split apart to control epilepsy, called split-brain patients. So I got interested in consciousness and also in how behaviors that might be produced non-consciously, uh, affect what we know about ourselves. So, uh, we see ourselves doing something, and then we kind of consciously build that into our narrative of what we are. But a lot of what we do, we do non-consciously. And when we interpret it, that kind of, uh, solidifies the fact that you have a non-conscious system that's controlling your behavior, when in fact you, you didn't do it, but that system did, so you gotta make sense of it and generate an explanation, a narrative. So that, uh, that was where I got started, and I tried to figure out, well, what would be some ki- kinds of non-conscious systems and said, "Well, maybe emotion systems are producing behaviors that we don't fully understand." And I started studying that and ended up, uh, figuring out how this part of the brain called the amygdala receives information about the environment and then controls, orchestrates all the responses, fight-flight kinds of responses to help you protect yourself. And the, um, you know, s- after many years of doing that, I started asking, "Well, how far back does this ability to detect and respond to danger go?" We know that bugs and flies can do that, and research had been done showing that, uh, bugs and flies have certain molecules in their brain that are important in these kinds of protective defensive behaviors and including the ability to learn about them and store those as memories. So it's easier to work on those little tiny, um, uh, invertebrates than it is to do studies in a complex brain, even like a rat brain, which is pretty complex. Um, so given that what these people had discovered about invertebrates, I and others who were studying, uh, mammals decided to see if the same molecules might be involved in mammalian learning, and in fact it was. So now that raises the question, you've got the same molecules doing the same thing, the same molecules, the same genes doing the same thing in ancient invertebrates and in, uh, and animals like us. So you ask, where back in time is the ancestor that made that possible? You know, if we've got the same genes, either it kinda happened spontaneously separately or there's a common ancestor. And indeed there's a common ancestor, and that goes back to the first organism, first animal that had a bilateral body, which means it had a left, right, front, and a back, uh, and a top and a bottom. So it has kind of three-dimensional sides. Before that, there were animals like jellyfish that were radial, they had, but no front and back. They just have a, a top and a bottom. And before that, there's sponges, which have no front, back, top, bottom. They're just kind of randomly organized. So that's kind of the, that's the story of animals, sponges to jellyfish to these bilateral animals. So the ancestor, uh, the, the, the bilateral animal that we're talking about gave rise to those two lines, one that became all these invertebrates like flies and bugs and snails and octopus and all those things, and another to animals like us, vertebrates, all the, um, fish, reptiles, mammals, birds, and so forth. So those are two separate lines that inherited these genes that make the memory and defensive behavior possible. So you say, "Well, how far back then it, does it stop there?" And no, it doesn't because you can find those genes on through jellyfish and then keep going into single-cell organisms. Now, these are like protozoa, uh, things that give you intestinal, um, their, uh, intestinal parasites so they can, you know, give you upset stomach. And, um, things like amoeba, paramecia that you might have heard of in, you know, biology class in high school or something. Um, these have no nervous system, and yet they detect and respond to danger, they learn about their environment, they do all these sorts of things. And where did they come from? Well, if you go all the way back to where they came from, uh, even simpler kind of organism, s- still single-cell, of course, like bacterial cells. Now these guys go back to the beginning of life. The first cell that ever lived some 3.7 billion years ago that gave rise to the entire history of life was a bacterial-like cell that started dividing. Now what's interesting, that cell that started dividing is the mother of every bacterial cell that ever lived. So that cell is, uh, it's, it's more like its rep- you know, that cell is still alive because it's, they reproduce by cell division. So that stell- cell just keeps reproducing, and part of that first cell ever is still with us today in all the bacterial cells that are, that are around. Uh, it's kind of a mind-blowing thing, isn't it? (laughs)

    13. JR

      It's incredibly mind-blowing. (laughs) Do we have any idea why the first cell decided to divide?

    14. JL

      Well, (clears throat) i- it, this, I shouldn't say it's the first cell that decided to divide. This, it's the first cell-

    15. JR

      Bacterial cell?

    16. JL

      It's the first cell that-... was able to, to sustain life long enough to give off offspring that could s- sustain and sustain and sustain.

    17. JR

      Uh-huh.

    18. JL

      So there were probably lots of experiments before a kind of cell or kind of group of cells had the right stuff to be able to do that. So they ... those others never made it because they didn't have quite enough of what it took to be a cell that could do that. (smacks lips) So the first cell, I mean, it's kind of a hypothetical cell. It's called LUCA, the last universal common ancestor of life.

    19. JR

      Whoa.

    20. JL

      Yeah. (laughs) And that ... so that's about 3.7, 3.8 billion years ago. Um, but it could have been a bunch of cells, you know, a collection of cells, cell types, uh, that, that ... one of which then, you know, populated all of life.

    21. JR

      The weird thing about life is not just that it's different and it varies so much, but that it's e- it's ever-increasing in its complexity.

    22. JL

      Well-

    23. JR

      If you go back to the single cell and then you come all the way-

    24. JL

      (clears throat)

    25. JR

      ... to today, to a person-

    26. JL

      Right.

    27. JR

      ... like what a weird-

    28. JL

      Yeah.

    29. JR

      ... sort of transformation it is.

    30. JL

      Well, uh, you know, it's dangerous to talk about as if we're moving towards some kind of goal, you know, like-

  2. 15:0030:00

    Mm-hmm. …

    1. JL

      is, say, a person with social anxiety might find it easier to go to the party, they're less timid, but still anxious while they're there. And the reason is, that we now know, is that damage to the amygdala in a person doesn't necessarily also eliminate the feeling of fear. It gets rid of the, the body responses, but not the feeling.

    2. JR

      Mm-hmm.

    3. JL

      So it was a misunderstanding of what behavior can tell us. We treat behavior as if it's an ambassador of the mind, but behavior is really a tool of survival that goes back to those first cells that ever lived who had to defend against danger. Bacterial cells move in the... in the water and then they come across, like, you know, a, a gradient of some chemical that's a toxin. As soon as they detect that, they bounce away and go in a different direction. If they are go-... if they find a gradient of something that is a nutrient, they keep going and, and absorb it. So they have the ability to detect what's useful and harmful in their lives. These are not... these are not there for psychology, they're simply there to keep the organism alive. And many of the behaviors that persist throughout the whole history of life are like that. They're there because each of the cell and... cells in the body has to, you know, do all these things to stay alive, and so the organism as a whole has to do it as well. Defend against danger, incorporate nutrients, balance fluids, thermoregulate, reproduce. So these are survival tools, not mind tools. Now, we can use our mind in conjunction with these things, uh, and because we can, we conflate every time we're freezing in the front of a snake to the fact that the fear is what's causing it. But the fear is a separate process. It's the awareness that that stuff is happening to you.

    4. JR

      The awareness that that stuff is happening to you. So-

    5. JL

      So, so no self, no fear.

    6. JR

      Oh.

    7. JL

      That's my T-shirt there. (laughs)

    8. JR

      Whoa. That's deep.

    9. JL

      That's my merch on the, the book. (laughs)

    10. JR

      (laughs) Now, how do things like Xanax work? What, what's the mechanical process?

    11. JL

      Okay. So the, um... that's a part of the class of drugs called benzodiazepine, and they, um, will... they bind to receptors in the brain. The brain has receptors for all kinds of, uh, uh, chemicals, and many of these things are things that exist in nature, and what... that they want... that they bind to is a receptor called the GABA receptor, which is the major inhibitory transmitter in the brain. So when you have a benzodiazepine binding to a GABA receptor, what it's gonna do is increase inhibition. So the... you know, the kind of simple reason why those things can help is they kind of inhibit, so they tone down the brain a bit, and so things that would normally trigger a response no longer trigger it. So it's like increasing the threshold for something to bother you in a sense.

    12. JR

      And a lot of people enjoy that with alcohol. They're not supposed to?

    13. JL

      Well, uh, alcohol also attacks those receptors-

    14. JR

      Yes. Yeah.

    15. JL

      ... so it's like, uh... you get double the, the effect.

    16. JR

      Right. Is that why they tell people, "Don't have Xanax with alcohol"?

    17. JL

      Uh, yeah, 'cause you can... you know, if you... if you take a lot of Xanax and drink a lot of booze, you can OD.

    18. JR

      Or you could just say crazy things-

    19. JL

      (laughs)

    20. JR

      ... and not, not totally be aware. Do you remember that story about a woman? She was, uh, I believe she was a publicist, and she got on a plane-

    21. JL

      Good.

    22. JR

      ... and she was flying to Africa, and she, uh, said, "I'm going to Africa. Hope I don't get AIDS. Just kidding, I'm white. LOL."

    23. JL

      (laughs)

    24. JR

      She thought she was just being funny-

    25. JL

      Uh-huh.

    26. JR

      ... and you laughed, and- (laughs)

    27. JL

      (laughs)

    28. JR

      ... she landed in Africa-

    29. JL

      That must have been a surprise. (laughs)

    30. JR

      Ooh. Do you know the story?

  3. 30:0045:00

    Is this because we…

    1. JL

      our special kind of consciousness, uh, enables. But it has a dark side, which is, it also allows us to be incredibly selfish and self-centered and narcissistic, and to, uh, support tribes and groups. And, you know, um, unless we ... I mean, I think our, that the world survives best when y-It's either completely isolated, all the cultures are isolated, or if we could also somehow be together in a more unified way, 'cause the direction we're going now, where each country is isolating itself, but is- is still so entangled with all the others is a recipe dis- for disaster.

    2. JR

      Is this because we evolved essentially without long-term travel? I mean, we kind of evolved to stay in whatever area the resources were in when we were hunters and gatherers-

    3. JL

      Mm-hmm.

    4. JR

      ... and then somewhere along the line, somebody figured out boats and how to get on a horse-

    5. JL

      Yeah.

    6. JR

      ... and the- the next thing you know, you're visiting people.

    7. JL

      I think it's more about, um ... you know, we have a- a- a special kind of inquisitiveness that we can ... because we can mentally model the next step and plan what are the options, you know, try to anticipate the, uh, the problems that are gonna come up, and take those steps. Um, and- and that's a pretty special thing. But it also allows us to plan in a kinda devious way, where, you know, me or my group is gonna benefit, and, uh, if mine benefits, I don't want the other one to benefit 'cause we gotta keep everything separate.

    8. JR

      Hmm.

    9. JL

      So it's- it's, you know, consciousness, our kind of consciousness is our- our, you know, greatest achievement, but also probably our worst aspect.

    10. JR

      Oof. But it's- uh, hmm. But it's what makes us human.

    11. JL

      It is.

    12. JR

      The- imagining humans with no consciousness is impossible.

    13. JL

      No. No, th- there's no way to go in that direction. That's, uh-

    14. JR

      So is- is the key to this thing, as the human race, is it managing our consciousness? Or perhaps maybe work like yours, giving us the tools to understand one of the mechanisms involved, that maybe that can help us sort of navigate our biological traps and-

    15. JL

      Maybe. (laughs) I mean, uh, I think it's ... you know, certainly we don't ... I think the- ... I- I mean, I have no idea what your position on, uh, climate change is, but, uh, personally I think that things are happening and something needs to be done.

    16. JR

      That's clearly things are happening.

    17. JL

      And that- you know, there was a- I read a couple of editorials, uh, probably in The New York Times or something, uh, a couple months ago. One was about how yes, the- you know, things are changing and, uh, we have a right to worry, but, you know, we shouldn't worry about the Earth as, um- you know, the famous quote is, "Gaia's a tough bitch." So the Earth will survive, but the configuration of life on it is unlikely to continue to be the same under those conditions. The more the- everything changes, the conditions of life change, and the first things to go, um- and this is what happened to the dinosaurs- are large energy-demanding organisms, because as the conditions change, um, y- you know, the- the climate that we've lived in, we've succeeded because we were able to benefit from that kind of climate. But as the climate begins to change, our kind is not gonna be able to succeed as well because those conditions are- you know, the waters are rising, the deserts are, uh, expanding. All these things are happening and it's just not gonna be, um ... you know, species don't last that long.

    18. JR

      Right.

    19. JL

      A few- few million years and they go. So our time may be ... (laughs)

    20. JR

      Well, we've only been around for what?

    21. JL

      Uh-

    22. JR

      300, 400,000 years and something?

    23. JL

      Mm ... well, it depends on what- what we are.

    24. JR

      Who you call we, right?

    25. JL

      Yeah, but-

    26. JR

      And the Neanderthals were around quite a bit longer than that.

    27. JL

      Yeah.

    28. JR

      And they're not here anymore.

    29. JL

      So, uh, we don't have a- uh, I mean, I think that we can use our minds to try and, you know, help us get through this, but that's only gonna work if we can do that collectively. That's the scary part. We have to work together collectively as a world because these are not local issues. These are global issues.

    30. JR

      Yeah. Right.

  4. 45:001:00:00

    Mm-hmm. …

    1. JL

      about emotion and language. So it's often said that an emotion like fear is universal across the world, but I don't think that's actually correct. What's universal is danger.

    2. JR

      Mm-hmm.

    3. JL

      And the way fear is interpreted by different cultures is obviously different. I mean, different, uh, the Asians have a different kind of a, um, perspective on fear. Every culture has their own perspective on fear. So f- it's ... Fear is the, you know, the, the kind of cultural assembly that you have in your brain in response to danger. So every culture has to have a language of fear, but not because fear is universal, b- because danger is universal.

    4. JR

      Mm-hmm. And what they interpret as danger is different.

    5. JL

      Right.

    6. JR

      And fear, for one person, something could, could create fear, whereas for another person, the exact same situation would not-

    7. JL

      Right.

    8. JR

      ... depending upon their personal experiences and maybe even their genetic makeup?

    9. JL

      Well, yeah, I mean, g- you know genes contribute, so we, um ... Every part of our brain is under some kind of genetic influence, so every f- for example, the amygdala will be genetically kind of slightly more revved up in one person than another, so a little more sensitive to danger. And so that person might be responding more to danger in part because of genes, but also maybe because of experiences that they've had. Uh, and so then the conscious mind is seeing those responses and starting to conclude, "Oh, I'm an anxious, fearful person." And that ... all of that information gets collected in what's called a fear schema, which is a body of knowledge of everything you know about danger and including the way you rea- you react to danger and your, uh, just, you know, who you are in terms of danger. And so whenever w- you encounter danger, that schema is what's called pattern completed. So presence of a, a threat in the world is enough to go into your brain and activate those memories about danger that give you, uh, in a non-conscious representa- you know, an activation of this fear schema that is what then bubbles up into consciousness. That's your experience of fear, is what has been activated in your fear schema.

    10. JR

      Knowing what you know and then watching whatever anxieties or fears may play out in your own mind-

    11. JL

      Mm-hmm.

    12. JR

      ... is that, for lack of a better term, a mind fuck for you?

    13. JL

      (laughs)

    14. JR

      You know what I mean? You, you-

    15. JL

      Well, I mean-

    16. JR

      ... 'cause you've studied this so much-

    17. JL

      Yeah.

    18. JR

      ... but then you're human-

    19. JL

      Yeah.

    20. JR

      ... so I assume you have the same anxieties and fears.

    21. JL

      I have a lot of anxieties. Yeah.

    22. JR

      And we all do.

    23. JL

      Yeah. And truthfully, it, it helps to some extent. So I used ... Uh, in 1996, I published a book called The Emotional Brain and a few years later, I, I started finding out from therapists that, um, the, uh ... Uh, a lot of patients were reading the book with their therapist, and they were saying that it was really helping them understand w- why ... you know, how different things were happening, that the, uh, the amygdala was causing them to react in certain situations. But their fear was their conscious understanding-... of those reactions, and those are not the same thing. And that separation helped them, you know, navigate their own situation in, in, in a situation of danger, separating out, "Okay, that's my... body is responding this way, my mind is responding this way, and these are two separate things I need to work on and control."

    24. JR

      D- have you studied various ways that people mitigate anxiety and fear, like meditation and yoga, and all these different things that sort of change people's states?

    25. JL

      Mm-hmm.

    26. JR

      Those-

    27. JL

      I mean, I haven't, I, you know, haven't studied it myself, but, um, uh, I have researched it a bit. Uh, I've tr- I try to do meditation myself, because, uh, I think it's the... probably the most direct and effective way in the moment to... you know, I'm sitting in the room outside waiting for you, I just... had my hat and sunglasses on, just trying to chill out and meditate a little bit, get ready for you.

    28. JR

      Mm-hmm. Do you do that on a regular basis?

    29. JL

      Uh, you know, it's, it's hard to maintain it, 'cause, uh, life gets busy, and it seems like at the hardest time to do it is when you need it most, right? (laughs)

    30. JR

      Yeah. I think it's one of those things like hygiene, where you just sort of have to say, "Well, it's hard to take a shower."

  5. 1:00:001:15:00

    Hmm. …

    1. JL

      to something I'm unconscious of by naming it. Follow that?

    2. JR

      Hmm.

    3. JL

      Other animals can only respond non-verbally. So they don't have that other kind of response that is only reflecting a conscious state. So I'm not saying they don't have anything, but scientifically it's very hard to- to know what they have. And the fact that we can study, uh, we know in, for example, fear, that the fear itself probably doesn't depend on the amygdala.... but the, all the behavior that we see does makes us p- have to be cautious about observing behaviors that look like they're based on fear, love, and all these other emotions, when we can't really know, because we can't measure that.

    4. JR

      Oof.

    5. JL

      Uh, I mean, it's a tough problem. Again, I'm not saying it's not there.

    6. JR

      (laughs) .

    7. JL

      It's just like-

    8. JR

      Right, I get it.

    9. JL

      ... scientifically, you know, you have to s-

    10. JR

      You have to be stringent.

    11. JL

      ... what's the evidence? (laughs)

    12. JR

      Yes, yeah you have to... Now, now measuring it in humans is, I mean, there's this concept of people, "I'm an emotional person."

    13. JL

      Mm-hmm.

    14. JR

      You know, "I'm emotional." Like pe- "I get emotional." Like, people love to say-

    15. JL

      Yeah.

    16. JR

      ... those, those kinda-

    17. JL

      Mm.

    18. JR

      ... things.

    19. JL

      I d-

    20. JR

      What, a- are... Is it possible to measure varying degrees of emotional response in terms of, like, how it's affecting a person physiologically, whether or not these emotional responses are physiological or whether you've gone down a well-grooved psychological path that you've been d- sort of participating in your whole life so that-

    21. JL

      Right.

    22. JR

      ... you have these o- sort of triggers? This happens and then, "Oop, I'm gonna, I'm gonna start crying." This happens, "Oop, I'm gonna get angry." And people sort of fall into those paths without self-reflection, without this ability to be objective and introspective and go, "Why am I reacting this way?"

    23. JL

      Mm-hmm.

    24. JR

      Like, what... "Maybe you should stop being so emotional, Joe." Right? Is it, anybody ever said that to you?

    25. JL

      (laughs) . Uh, p- I guess my wife has said.

    26. JR

      I'm sure. I'm sure.

    27. JL

      (laughs) .

    28. JR

      Well, what does that mean?

    29. JL

      Yup.

    30. JR

      Like, what, w- you know what I mean?

  6. 1:15:001:23:46

    Hmm. …

    1. JL

      and I don't know what the effect of aging on the egg is.

    2. JR

      Hmm.

    3. JL

      Uh, I just don't know.

    4. JR

      Well, there's also a big factor with the male sperm.

    5. JL

      And male sperm, yes.

    6. JR

      And they're thinking that's one of the main contributors to autism-

    7. JL

      Right.

    8. JR

      ... is older men.

    9. JL

      And schizophrenia supposedly, uh, uh, I've heard, um, uh, that, you know, older fathers are more likely to-

    10. JR

      Mm-hmm.

    11. JL

      ... have, uh, male sons that are schizophrenic.

    12. JR

      Yeah, that makes sense. It all makes sense.

    13. JL

      I don't- I wouldn't say that is a fact, but I- I've heard that.

    14. JR

      Well, it all makes sense that there'd be some-

    15. JL

      Yeah.

    16. JR

      ... glitches in the matrix, so it's-

    17. JL

      Yeah, I mean, we're not, you know, we're not supposed to live that long. (laughs)

    18. JR

      No. Are we not? But what- what are your thoughts on people that are trying to live longer and- and trying to sort of, uh, squeeze out as much time as they can-

    19. JL

      Yeah.

    20. JR

      ... on this rock?

    21. JL

      I don't know. It's like, I see a lot of old people that just don't want to live anymore and I understand that. Y- you know, your body starts falling apart, your mind is going, "What's the point at that point?"

    22. JR

      Yeah, I get that.

    23. JL

      To me-

    24. JR

      But what about the people that can keep it together?

    25. JL

      Yeah. Yeah, I guess if you keep it together you wanna, like, you know, okay, let's- let's go as far as we can. (laughs)

    26. JR

      (laughs)

    27. JL

      Let's go to the moon and, uh-

    28. JR

      Right.

    29. JL

      ... go to Mars.

    30. JR

      Well, pharmacological solutions to... I mean, if we- if there was some sort of a genetic component that they identified-

Episode duration: 1:47:16

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