Professor Deacon: Busting the Lizard Brain Myth

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This is the 23rd episode of the Mind Your Noodles podcast. In this episode Tripp Babbitt interviews Dr. Terry Deacon of the University of California – Berkeley.  A download on how to build a brain-friendly organization is available at
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Show Notes

Mind Your Noodles Podcast – Episode 23

The Blog that Brough me to Professor Deacon

Dr. Deacon’s Story

The Triune Brain – Some Truth, Mostly Fantasy

Ernst Haeckel – Ontogeny vs. Phylogeny

The Myth Dispelled – The Telencephalon

Hats on Hats

Front Part of the Brain Needs to Predict

Homology Defined

Multiple Parts of the Brain Affect Fight, Flight Response

Basal Ganglia in a Loop

Simplifications Can be Useful

Thinking Fast and Slow

Brain is Regulated by Front Part of the Brain

The Asterisk of Left Brain-Right Brain and Triune Brain

The Problems of Oversimplification


Species and Social


Evolution of Language




Tripp: [00:00:03] Take care of the brains that take care of you with the Mind your Noodles podcast or keep you up to date on the latest neuroscience research and practices to keep your brain healthy. And strategies to help your organization be brain friendly.


Tripp: [00:00:25] Hi, I’m Tripp Babbitt, host of the Mind Your Noodles podcasts.


Tripp: [00:00:30] And my guest today is Professor Terrence Deacon of the University of California, Berkeley. Welcome, Professor Deacon.


Professor Deacon: [00:00:40] Thank you.


Tripp: [00:00:41] I’ve been following quite a bit of work in the area of neuroscience, and I came across a blog by a gentleman by name of Daniel Toker, and he wrote that that the lizard brain was a myth, that we don’t have a lizard brain. And I have actually spent a whole podcast episode going through the whole triune brain. And even though it was called that, actually the three pieces, the reptilian, the mammalian and the neocortex and there are a lot of consultants out there preaching this in the community. And I came across and I think I saw this blog, apparently Daniel Tucker is up as a peer to D candidate and neuroscience. And he brought up your name. And I thought, oh, my gosh, what is this? And so I started digging it a little bit more deeply. And you kind of are dispelling this whole myth. But before we get into that, I if you just introduce yourself because you have such an interesting history, you went to Harvard and. Well, I’ll just let you tell your story first.


Professor Deacon: [00:01:51] I actually became very interested in systems theory, information theory, cybernetic theory and so on as a young student in the 1970s. And I then discovered the work of a philosopher, but almost by chance, a man named Charles Sanders purse American philosopher, writing at the turn of the last century and became so fascinated with his work and particularly his ideas of semiotics theory that is undercutting ideas about language and thought by understanding it in terms of signs and interpretive processes. That really blew my mind. I thought that systems theory, theory and systems thinking probably resolved. A lot of these problems in its cybernetic theory might be the answer to all of these issues. Pearse writing one hundred years earlier I think showed that it was clearly not going to finish the story that our beliefs that have now led to sort of the computational view of cognition and so on really were misguided. And so a person’s philosophy really captured my attention. I applied as a result to go to Harvard to study versus work. I as a graduate student, people read my little bits of writing on purpose, accepted me into the program. I got there, but I was not given access to what I thought was the gold standard, which was all of person’s unpublished work was stored in a library at Harvard. I was not given access to it. After each year I sort of gave up and said, okay, I do some different. And because of my other interests, including the system’s interest in my biological interests, I began to move towards neuroscience. I eventually got a P D and biological anthropology, but my work was entirely neuroscientific at the time, studying the processes in monkey brains and the structures and connections in monkey brains that were corresponded in interesting ways to those involved in the human brain, involved in language.


Professor Deacon: [00:03:56] And my work subsequently focused on what makes human brains different, why they stand out, why we can do what we doing in other species. Don’t do it. I spent my career pursuing that information and I’ve only actually recently as sort of I’ve moved on from Harvard, Harvard Medical School, Boston University. And so I’m out here to the University of California, Berkeley sort of refocused my attentions back on some of those early questions I was asking at the time. But as a result, a lot of my career has wandered through this realm of trying to understand how brains develop and evolve and do what they do. And so Daniel Tucker, whom you met mentioned, was one of the teaching assistants working with me, teaching a class one year. I teach a class pretty much every year on the evolution of brains of how vertebrate brains have evolved over time, in fact, going all the way back to insect and worm brains as well. But with a focus on what’s unique about human brains. So that’s where I come to. And early on in my work, I actually spent some time interact. With mostly at conferences and lectures with a man named Paul MacLean, and Paul MacLean was the guy who developed the idea of the triune brain, of a reptilian brain, an old mammalian brain, a neo mammalian brain. To talk about sort of how brains were organized and how he thought they evolved. We learned a lot since then, since his ideas in 1950s and 60s. And that’s probably what we want to talk about today.


Tripp: [00:05:28] Yes, absolutely. Because after I came across Daniel Toker’s blog post, I started then going through and looking at some of the books that I read. And some people are perpetuating this fantasy or myth. I think you use the word fantasy when we were exchanging emails. But the myth of this triune brain. So this is really embedded as a lot of times. Some things do in our culture because that’s the last thing that people remember. It was publicly known. And so therefore, this theory seems to perpetuate itself. And so what let’s start into this. And as I I’m not going to be on the level that you are. And I want to make that clear. I know you’ve been on a couple other podcasts with people or who who are scientists and those types of things. I’m in the business world and trying to figure out what we can apply to the business world. But there’s two things that kind of came through my mind as I started to read some of your writings and some of the things that Daniel Toker has put out there. And there’s the evolutionary piece that I think that you’ll be able to speak to very deeply. And then there’s the kind of functional or practical piece of that. So does this mean that if there wasn’t a reptilian mammalian prefrontal cortex, does that mean the fight flight does it isn’t associated then with the reptilian brain or do we need to talk about it differently? So there’s some of those types of things I’d like to write to to get.


Tripp: [00:07:07] And so that we can come up with some language that makes sense for people. So I’ll let you start where you think is the best place to go.


Professor Deacon: [00:07:15] Well, I think the first person first place to start is to recognize that every theory like this has a grain of truth.


Professor Deacon: [00:07:24] Number one, but also reflects sort of the biases of the way we sort of think about these problems superficially. And and remember also that when somebody tells you that the brain is made of three parts or two parts left and right part, for example, another famous story that you got to recognize, that’s an incredible simplification brain for the most complex things we’ve ever studied. And so it shouldn’t surprise you that there’s a lot of over oversimplification.


Professor Deacon: [00:07:59] I mean, super oversimplification. And somebody says there are two parts. And that’s what you really need to know where there’s three parts and that’s what you really need to know. Nevertheless, there is some truth to both of those stories. Yes, the right and left side of our brains do work a little bit differently. And there’s some interesting differences. There’s a whole lot more similarities there. And when somebody says no, there’s three parts and they sort of correspond to sort of our evolutionary past in some interesting ways. Well, of course, that’s a simplification, but there’s probably a little tiny grain of truth in there as well. And so the real challenge is to sort of separate the dirty bathwater from the baby, so to speak, and to understand which is which, and then figure out which applies and we can use in different contexts. So I’m not going to tell you that thinking about reptilian brain in an old mammalian brain and a new mammalian brain somehow has no useful pedagogical and heuristic value. It does have a little bit. But the danger is, you know, taking it too far. And the danger is thinking that that can explain many things that it can’t explain. So let me now back up and just try to lay out what that theory was and how it began. And that is really. From the 19th century and through the middle of the 20th century, we had this tendency, particularly in the popular press, to think about evolution like we think about social process progress.


Professor Deacon: [00:09:32] That is, things get added on. Things get better and get added on. New things come in and they replace old things or they work on top of old things. So, you know, we have the horse and buggy and we replace the horse by a motor. But it’s still in the buggy, so to speak. That sort of view of progress was also applied to thinking about biological evolution. We thought of biological evolution as well. You’re adding new things. And a man named Ernest Heckle, a German who was probably the first person to really take Darwin’s ideas and spread them on the continent, had this view, had this sort of process view that evolution was adding new things on top of old things, the old things were still there. We just had new things that sort of added on top of it. That idea became very, very popular. There’s, in fact, a card of a sort of collection of almost neologisms, but that this capture, this view Haeckel used the phrase ontogeny recapitulates phylogeny. Now, that might sound like gobbledygook, but what it actually meant was ontogeny is development during your life coming up from an infant, from an embryo to an adult. That’s ontogeny recapitulates basically means replays it. Does it again. And phylogeny is, of course, the evolutionary series of steps that, for example, led to an organism. So his idea in that statement was that during development, we sort of pass through all these stages that we evolve through and that embryos are sort of like a little bit like fish even argue the embryo, the human embryos at a particular stage have gills and early stage. But it was quickly found out that that’s not the case. And currently we recognise that, in fact, Darwin probably had a better way of talking about it. He actually described this process as descent with modification, a much simpler idea, which simply says that what you start with at one point in evolution, then it’s still there.


Professor Deacon: [00:11:46] It just gets modified. And these two views have really distinguished these different ways of looking how brains both develop and evolve and therefore how they might function. So let me see if I can build up the story in the two sides of this version.


Professor Deacon: [00:12:03] Ok, the one version is that way back in the past, there were fish brains and then something was added on top of it in reptiles. And that’s the reptilian brain. And there’s a sort of the the fish being even simpler than that.


Professor Deacon: [00:12:17] And then somehow in the transition to mammals, you added a new section of the brain, such a MacLean called the cold or paleo mammalian brain that was involved in doing something that reptiles don’t do, he thought. And that is bringing emotions into the story where reptiles were just involved in the innocent blind drives and fish with blind drives. You add onto this emotion and motivation, and as a result of that, you also get mammals taking care of their offspring and having fight and flight responses that are not just automatic, but now have strong subjective content to it. And then finally said that when you get to primates and ourselves, there’s something additionally and which is that he called it the neo mammalian brain. And his metaphor was in effect, this is sort of like stacking hats on top of hats that the brain was developing forward and forward and forward, and the last hats were added on top of it. And in fact, many people have argued that the last had in humans was what they call the neo neo mammalian brain sometimes. And that was the prefrontal cortex, the very front part of our cerebral cortex, which somehow added on the cerebral cortex itself being the neo mammalian brain.


Professor Deacon: [00:13:43] Sometimes it’s even called neocortex. Even in neuro anatomy these days. And then the prefrontal cortex, the part that’s maybe supposed to be just for humans, is that the neo neocortex, the newest, newest cortex, turns out that all of this is fallacious in the sense that there is no part of your brain in my brain that doesn’t have corresponding precursors all the way down to fish. And we typically recognize that the front part of the brain, which we would call our cerebral cortex, that. Turns out to cover most of the brain when you look at the human brain is not a new part of the brain that’s added onto old parts. It’s that the front part of the brain that’s even in fish apart we call the telencephalon Teleology telen  like in telescope or a telephone is the most forward one. The one that’s out there that’s far distant, most front of the brain. That’s how it was given its name. The teal and settle on, which is what gives rise to all of this cortical structure we call neo mammalian brain. Giving that from that train and brain perspective was already there in fish.


Professor Deacon: [00:14:57] All fish have a telencephalon. It’s just that in fish it doesn’t quite look like cortex. And in fact, in reptile brains it doesn’t look like you have cortex.


Professor Deacon: [00:15:10] The cortex is a name, a technical name for the skin of something. So we oftentimes call the surface of your skin a cortex. We call the bark of a tree its cortex. For example, it refers to skin and it looks as though in mammal brains, uniquely in mammal brains, the surface of the teal and settle on becomes a sheep’s like structure that can be folded up, which is why human brains look all folded. It’s a sheet of cells that gets all folded up. That’s the steps the cortex turns turns.


Professor Deacon: [00:15:47] It turns out that one of the reasons that Paul MacLean and others began to think about this additional hat on tops of hats, perspective of the brain is because reptilian brains, fish brains and even bird brains don’t actually have the telencephalon into a cortex. It’s actually what we call a nucleus that is a bunch of cells that is just a sort of a a ball or a mug.


Professor Deacon: [00:16:18] So that was like a module of cells. That’s all just clustered together. Doesn’t have a sheet like appearance. It’s only in mammals that that part of the brain becomes sheet like we still are struggling to understand that. But it gave the a pit appearance to those who were early in the field that somehow of these nuclear like structures and by nuclei, of course, I don’t mean anything fancy, I just simply mean a ball of cells. It looked as though deep down underneath the cortex and mammal brains, there were nuclear structures. There were balls of cells, clusters of cells. And therefore, it may be that the cortex was added on top of that. We now know that what actually happened is that brains that were nuclei hated. That includes bird brains and reptilian brains and fish brains and frog brains and so on, that basically they transformed those nucleus structures were transformed into sheet structures. So it’s not that it’s newly added on, it’s been newly modified. And this is why Darwin’s phrase descent with modification is the more accurate way to talk about it. What’s happened is those structures were already there to some extent, but they got continually modified in the course of evolution.


Professor Deacon: [00:17:40] Now, there is another sense in which there is this kind of hierarchy a little bit like MacLean’s idea of a triune brain. And that comes from the fact that what’s happened is that particularly in mammals, but also in birds and even in reptiles on the telencephalon this most forward part of the brain, except as brains have gotten bigger in evolutionary time. What’s happened is the front part has expanded faster than the rest. And so in the human brain, we when we look at it on the surface, all we see almost is just the cortex and these other nucleus structures. These more basic structures in the brain seem to be down lower. And so overshadowed by this as brains got bigger over the course of evolution than they did, in fact, get larger over the course of mammal mammal evolution in particular, but also in birds that in effect this most forward chunk of the brain, the telencephalon and cephalon, by the way, means simply brain.


Professor Deacon: [00:18:44] So it’s telencephalon is sort of the most front part of the brain by by definition, by by the way, we define defined those terms. It just simply got bigger, faster as brains got bigger. And so it does look like superficially it does look like these parts of the brain that were there and all species on some of them didn’t change a whole lot and others changed a lot more. And so in one sense, this is the baby in that bath that is these parts of the brain that didn’t. Change as much are more involved in automatic behaviors. They’re more involved even in the emotional behaviors that MacLean called the paleo mammalian brain. Those parts have as brains have enlarged, have not enlarged as much as the cortex. And that turns out to be an interesting feature that says that, well, to some extent, although we don’t have a reptilian brain, that’s just a part of our brain. There is part of our brain that has not changed as much from our reptilian ancestors as other parts have. And so that’s the baby in his bath.


Tripp: [00:20:02] So we get this idea, the proto reptilian brain, which is the reptilian brain as people reference it, which has the brain stem, the mid brain is basal ganglia. Then you have your paleo mammalian brain or what’s references to mammalian brain that has the make LA hip, hippocampus, hypothalamus and some other structures that they call the I guess that MacLean called the limbic system and they have this neo mammalian brain. And now you’re saying there’s something on top of that basically not not not in terms of hats on hats, but that there is another layer.


Professor Deacon: [00:20:38] So no, actually it’s not quite that simple is that the structures, the telencephalon, which gives rise to most of the larger parts of a bird brain or a reptile brain, which is the most forward in the development of the nervous system. That is the most front part of the brain has just simply enlarged faster as brains got bigger both in birds and reptiles and in us.


Professor Deacon: [00:21:06] The difference is in the transition from birds and reptiles to mammals, which, by the way, happened while the dinosaurs were still around. Was that the part of the bird brain in the mammal brain? That tail and settle on was mostly just sort of cells filling up a volume in mammal brains instead of filling up a volume.


Professor Deacon: [00:21:28] Those same cells seem to have created a sheet that allowed it to fold and fold and fold. So you don’t see folds, for example, on bird brains because it’s not a sheet. But it’s the same structure, just structurally different and not anything added.


Tripp: [00:21:45] Okay. All right. Well, okay. That that makes sense. And it goes with some of the things you said you said earlier, too. But from a so so we get an idea now of evolutionary how how things came along and how our brain was formed that these parts were there an essence or. And again, I’m probably simplifying it too. Beaten it up badly. The other structures were there already. They just didn’t do anything. In essence,.


Professor Deacon: [00:22:14] They were doing something in every brain. Okay. So. So in it, for example, different fish brains the telencephalon was more involved in chemical analysis of things you might say like smell fish don’t exactly smell, but they have chemo sensory systems event. The front part of the brain was mostly involved in in part because chemicals in the water or chemicals in the air like in smell are a good predictor of something around you that might be relevant. It’s a distance information and what you want is to have distance information so you can predict the future where you should go or shouldn’t go.


Professor Deacon: [00:22:55] The front part of the brain does mostly predictive like stuff, and it does so in fish, in frogs, in snakes, in birds and in us. Does predictive stuff. But as you can imagine, as animals get larger and their environments get more complex. Prediction becomes more and more important. And so it shouldn’t surprise us that the predictive part of the brain grew faster than these other parts of the brain. It was it’s still doing prediction for you. And I know what we’re doing right now is a lot of prediction. This case, symbolic prediction and that sort of thing, conceptual predictions and all. But it’s still what the brain was doing all the way back in fish. It’s just that now it’s doing it in a different domain that requires a lot more stuff, a lot more parts to it to do it. We haven’t added a different kind of part. What we’ve done is simply taken what was there an exaggerated elaborated in different directions.


Professor Deacon: [00:23:57] So that’s the way to think about this. So it’s not. There was some new part that wasn’t doing something. And it’s so that the old parts are now not overcome and not doing what they used to do. All of these parts are doing the same kind of things they were doing in fish.


Professor Deacon: [00:24:13] We call this relationship homology and that is the same. Structures. Were doing the same kinds of things back there, but doing it in a slightly different way in a different species.


Professor Deacon: [00:24:28] So a simple idea of homology that people can really easily understand is the bones of your hand. For example, the bones of your hands. We can find the same corresponding bones making up the wings of a bird. They have all the same corresponding bones because both birds and mammals inherited from their distant past. All of these bones in the same positions, but some of the bones in our hand are elongated and some are shortened in the bird wing. Some of the bones are made quite long and thin, and some are short and way, way down. For example, the thumb is way shortened, the index finger way longer. The same bones are now doing something remarkably different for you, and I can allow us to type on typewriters, for example, or to make tools for a bird. It can allow it to soar in the air. The homologous says that in effect, they’re working the same way. But now, because of the modifications, they can do very different things. So you have to think about the brain in the same way. All the same parts were there, but different parts got modified over time in different lineages to become birds, mammals, reptiles and so on.


Tripp: [00:25:47] Ok, let’s let’s go to some of the basic pieces here and tell me if anything changes. So even I understand the hat, it’s not hats on hats that that that makes perfect sense to me. And so that takes care of the evolutionary piece. But does the for lack of a better term. Maybe we should reference them just as the stem, the mid brain, the basal ganglia.


Tripp: [00:26:09] But those things still are attributable to breathing, feeding, dominance, aggression, temperature, regulation, balance and things like that. That didn’t change, is that correct?


Professor Deacon: [00:26:19] It changes in the following sense. OK. And that is we have this because we think in machine terms, we think that some place in the brain does this one thing in large measure. There are areas that specialize in different aspects of a process. So we do find specialization, but oftentimes we find that it’s modified at different levels at the same time. So fight and flight, for example, or just simply fear response. This is something that. Yes, is modified. I mean, it’s produced by activities in certain parts of the brain, like the amygdala, like the mid brain.


Professor Deacon: [00:27:03] But it’s also organized in the cerebral cortex. You would have a very different experience of it without the cerebral cortex being there. But this is true also for even the reptile brain. It’s tail and settle on was involved in that. Certain odors were going to produce fear, potentially produce avoidance behavior. Predictions are about what you want and don’t want, where you should go and shouldn’t go. What’s scary and what’s not scary, that’s going to still be there.


Professor Deacon: [00:27:37] It’s just going to be developed differently depending on how much of that experience is now being taken up by the telencephalon the predictive part or these other parts of the brain. It’s it’s interesting. You mentioned the striatum, for example, the stray it was thought by MacLane to be part of the older brain. In fact, part of the reptilian brain, even it turns out that it’s actually telencephalon. It’s just a part of that telencephalonn that separated off from the cortex in mammals brains.


Professor Deacon: [00:28:12] Whereas in bird brains you can’t tell which is which easily, except by using special techniques that allow you to see what chemicals are expressed, what genes are turned on in these regions.


Professor Deacon: [00:28:22] But we now know that in these areas that were mis categorized as being sort of a different part of the brain or doing more automatic functions. In fact, we’re not the basal ganglia for it is a good example of this. In Parkinson’s disease, it’s a case where the basal ganglia is not getting a certain neurotransmitter which helps it regulate things, but it regulates is complicated behaviors. So a Parkinson’s patient has trouble grasping objects, initiating, walking, changing their gait under different circumstances and has tremors. This is not just automatic behavior. This is, in fact, that this part of the brain has played a very crucial role in helping us organize complicated motor behaviors. And once it begins to be degraded in this respect, we can no longer initiate or stop behaviors as easily. Organized, complex, coordinated behaviors, so the mis diagnosis of whether it’s a whether it does this or that, whether it does an automatic behavior or whether it does a sort of predictive behavior, is also part of this error of thinking about the brain in terms of these separate divisions that do separate things that don’t interact with each other.


Tripp: [00:29:42] That makes sense. The thing that got me away from left brain, right brain was a lady by the name of Ann Herrmann Nehdi who who runs kind of a consulting business, are around behaviors and things. So she talked about the interconnectedness of the brain. And that got me away from left brain. Right brain and where you’re touching.


Professor Deacon: [00:30:02] And yet yet, ref. Left brain. Right brain is not completely wrong. Some of the ideas that we have there. Again, it’s the same story of baby in Bath Story. Once we learn more about how it works, it turns out that there’s a grain of truth there as well. And the key is to try to figure out, you know what? As I say, which is the baby, which is the bath, which is useful and which is not OK.


Tripp: [00:30:24] And then the as we get into you just said something very interesting to me, which is that about the ventral striatum, which has been associated, at least in the consulting community, to wanting to explore, be curious that that’s embedded into the ventral striatum and that that’s part of the basal ganglia. And you’re seeing a couple of things here. I think.


Tripp: [00:30:48] One is it’s not part of the basal ganglia that it’s so.


Professor Deacon: [00:30:53] Actually the basal ganglia is telencdephalon the basal get is is linked to the cortex.


Professor Deacon: [00:31:01] And in fact, all basal ganglia structures are caught up in a loop of activity, a loop of connections where cortical information goes into the basal ganglia. The basal ganglia sends its output through a couple of steps back to a structure called the thalamus. And it goes right back up to the cortex where it started a loop of connections, because the basal ganglia is an integral part of the cerebral cortex, although they’re separated in space and in structure, in animal brains in a way that they’re not so easily distinguishable. For example, in bird brains, they’re necessarily doing the same thing. They’re part of this predictive system of the tail and settle on.


Tripp: [00:31:43] Ok, so this gets back to then to kind of furthering this thinking of kind of the interconnectedness of the brains that not one, you know, and this is I know it’s old thinking, you know, where everybody thought that, you know, the bumps on your head were.


Professor Deacon: [00:31:58] Yes, exactly. Yeah.


Tripp: [00:31:59] You know, we’re associated with with a certain function of your body. And now that we’re getting into interconnectedness, we have more complicated names, but are in essence saying it’s not one area. It passes through a number areas in order to get the behavior, the outcome that that’s going to happen. And I think that that’s the kind of the thinking there. And we only learn that through observation of knowing, you know, how do people react when given a piece of information or, you know, what generates a curiosity, what’s what’s lighting up in the brain. I know the technology seems to be advancing in the ways that you’re able to look at the brain as I look at this. I don’t know where to go with it. Be honest with you.


Tripp: [00:32:46] You know, I’m sitting there thinking, OK, well, it seemed nice and tidy when we had left brain. Right brain. Now we got this, the triune brain, which I didn’t know it’s called that.


Tripp: [00:32:53] But, you know, MIT reptilian and it made it the, you know, nice and neat and everything. So where should we take this? I mean, should we how can this help an organization or a business? How can we become more brain friendly with some of the things that that are being learned in neuroscience?


Professor Deacon: [00:33:12] Well, I think that the first thing is to recognize that simplifications can be useful. I wouldn’t say that the triune brain story is un useful at all. It’s not the way the brain works. It’s not the way the brain evolved. And it’s also, I should say, not the way that we develop either. The idea that we sort of walk back through this sort of phylogenetic prehistory that young children are like reptiles and then they become more like simple mammals and then eventually they become, you know, that’s also a fallacy. So, you know, all the ways we could take this story literally will lead us to stray. On the other hand, recognizing that we do make certain judgments without thinking and therefore without using this predictive part of our brain, particularly when we’re threatened, when we’re surprised, or when we just have to make very quick automatic judgments. We don’t have the ability to predict. We don’t have the ability to sort of analyze stuff. And in fact, that’s when that’s.


Professor Deacon: [00:34:18] This system of what MacLean calls the new part of the brain, a neo mammalian brain. It takes time. It doesn’t act fast. And in fact, lowered down into the what we call the brain stem, the mid mid brain and so on. These are systems that are more automatic. So, for example, the mid brain, it’s this area, the cerebellum. If you think about is that little hind brain part that’s sort of separate, heavily folded thing of the back of the brain between that and the the forebrain, which includes the telencephalon. There’s what we call the mid brain or medicine settle on, which literally means mid brain.


Professor Deacon: [00:34:57] And there that system is heavily involved in controlling orienting behavior. So, for example, imagine a cat that suddenly, you know, walking in the dark. Here is a sound off to the right. Not only does its head turn suddenly and its eyes aim in that direction and its ears even aim in that direction. That’s the mid brain is really involved in sort of controlling this tourist. That is the head that has all these special sensors on it. And the mid brain is involved in orienting. And this is something that has to happen fast before we thought about something. So when there’s a sudden movement off to the right, for example, your eyes will move that way.


Professor Deacon: [00:35:42] Your head will move that. Like it’s hard not to be distracted. It takes effort. For example, it takes. And this is where the cerebral cortex plays a role in suppressing these automatic behaviors in the mid brain or deciding which of the things that’s affecting us are drawing our attention. We should focus on that means you have to suppress the tendency to orient towards certain things and focus on other things. But so what we are looking at, these parts of the brain, you need this kind of relatively automatic stuff to be done automatically so that you don’t always spend your time sort of assessing all the details and, you know, struggling through it and so on. So a lot of what you might call knee jerk reactions, some lifestyle, almost instinctual reactions or responses to things are in fact, cases in which these front part of the brain, which according to the try and brain, would have been thought of as this since the newest parts, in a sense, they don’t get engaged that easily. They take time to get engaged. And so what we need to do things fast, we’re using these lower, literally lower parts of the brain now are the older parts of the brain. No, they’re not older. They’re just they’re even in fish to do the same thing. Do automatic orientation. So they were there doing that and they’re doing that for us as well.


Tripp: [00:37:07] So before we get too caught up in trying to label things in, you know, we’re working with organizations. We’re trying to attribute the fact that that curiosity and you are wanting to explore is associate with a particular part of the brain. And maybe it would be better for us not to try and attribute things to you want to area, because there is an interconnectedness there of all those things, you know, or at least the left brain, right brain asterisk basically saying, well, for oversimplification, for communication, this is useful, but it doesn’t really work that way.


Professor Deacon: [00:37:50] Right. I think that’s exactly how I think about it. It is like you’re mystics for people that have no other knowledge of it. It’s just that if you then carry it out and certainly try to implant implement it. For example, there were many attempts to implement this sort of final genetic recapitulation idea in education, treat young kids as though they’re, you know, like reptilian, treat middle aged kids as though they’re just primitive mammals. You know, can we construct our educational system to to map this this mythology we had about recapitulation in development? Those were serious enterprises and they were as serious enterprises built on a misunderstanding. This kind of mythology of evolution is progress.


Professor Deacon: [00:38:39] Now that we’ve overcome that, we need to sort of deal. We see these kinds of assessments still being made, oftentimes not with a discussion of this part of the brain or that part of the brain, or you’re a right brain thinker or a left brain thinker. The way that sometimes is done when we try to cash that out in terms of applications, that’s when we start to get into trouble.


Tripp: [00:39:02] So I’m going to ask one more question, then we’ll get to my final question. But it’s associated with social. There’s there’s a lot being written right now about the importance of social to the point that social should be at the. Lowest part of Maslow’s hierarchy, because we wouldn’t survive without us being social and having to protect each other and things of that sort through the evolutionary process. Now people associate social with being in the neocortex, you know. Or I could get the word that you used, the neo mammalian brain.


Tripp: [00:39:42] You know, what do you know? And maybe the answer is I don’t. I don’t really study that part or anything, but. But what are your comments about, you know, the social aspect of the brain?


Professor Deacon: [00:39:53] So one of the things that we’ve discovered that not people doing neurological work as much, but people doing ethological work lurk looking at other animal behaviors. We’ve come to recognize how complexly social many species are. And and that is not just mammals. We now know the sociology of birds in particular are remarkable. One of these we know, for example, about mammals is that most mammal males don’t do a lot of offspring care and therefore don’t seem to bond well with offspring or even bond well across the sexes. We human beings have this capacity to tend to bond with our offspring and to bond with our mates and feel tremendous loss when there is something wrong with them or when they disappear or go away from us or die or get killed, that sort of thing.


Professor Deacon: [00:40:46] We sort of think of that as a sort of highest attribute. It turns out that it’s much more common in birds than in mammals. Many more birds bond as parents with each other and will go through tremendous grieving processes when they lose a mate or lose an offspring. Play a lot of role in trying to care for offspring, both males and females that we don’t see in mammals. So it’s not just having a bigger brain or a brain with a cortex or a brain with a neocortex, whatever.


Professor Deacon: [00:41:19] It’s it’s actually something that’s built into these processes. Now, let me go all the way back to fish. It turns out that there’s a number of fish that play a lot of roles in caring for offspring, a lot of male fish, for example, care for offspring. One of the classic ways that this happens is females lay a bunch of eggs on the on the bottom of your lake and a male comes along and finds his piles of pile of eggs and sheds his sperm over it and fertilizes all of these eggs. That male will now stay around that little nest site and defend those babies as they mature from other fish that are trying to eat them. In other words, he’s carrying is this is a social sort of caring like relationship. Does this fish have the same kind of subjective experience of bonding with his offspring? It’s not clear, but it’s an incredibly complex social behavior. And so that one of the errors we have is having this sort of hierarchical view that if there if it’s like us, it’s somehow more advanced. In many respects, birds are more like us than most mammals in their social behavior, in their bonding behavior. And I think this is a real surprise that’s come out not from neuroscience research, but from comparative animal behavior research. So, again, the social aspect of it is not something that’s late showing up in evolution. It’s there all along. But it’s definitely present in different groups of animals.


Professor Deacon: [00:42:55] Typically, for very special reasons, there’s animals that need to have a lot of bonding behavior, that need to have cooperative behavior, to defend nests, to defend resources, to defend offspring. If you need cooperative behavior for that, then you’re going to have more bonding going on. And that’s going to involve many of the same parts of the brain in all these different lineages of species. So some of the parts of the brain involved in fish in doing this sort of protective behavior are going to be also involved. Even in mammals, parts of the mid brain are parts of the hypothalamus. All parts that are also they are doing this work in fish.


Tripp: [00:43:36] Fascinating. I’m not sure how to apply that necessary from a human perspective in that we have this constant battle going on in business. You know, that competition is what propels us forward. And a lot of the things I’ve read over the years is that it’s more cooperation that that propels us, that that’s kept our species moving forward.


Professor Deacon: [00:44:02] Oftentimes we cooperate in order to better compete.


Tripp: [00:44:05] I probably have a thousand more questions, but I don’t wanna take up any more of your time today. So my last question is this is there any clarification, anything that we’ve talked about or an additional thought maybe had about some of our earlier discussions? Or is there anything I didn’t ask that you wish I would have?


Professor Deacon: [00:44:25] There’s a million questions, of course, that could be followed up in this.


Professor Deacon: [00:44:29] So the way I would put it is this both the left brain right brain distinction and the try and brain distinction are not terrible at giving us a hint of some of these differences. And they’re really they’re just sort of stands in for psychology there. You know, we’re using the brain because, you know, we sort of privilege knowledge about the brain is doing a better job of psychology.


Professor Deacon: [00:44:54] But actually a lot of this stuff is still useful in psychologizing about these issues. So in that respect, I think there’s still useful. I wouldn’t say forget about it entirely, but then to recognize that they are useful fictions, they are helping us organize these ideas, organizing these differences in tendency. And we’re using these brain terms as sort of surrogates to stand in for this psychological perspective that we’ve created. And once we learn that, then we won’t, in a sense, be tempted to try to legislate or organize our education or organize our businesses around these things. And once we do that, I think we’re much more successful at hitting. You might say the mean, you know, understanding when it’s useful and when it’s not useful, when to use it, to get into the problem, to sort of hint at some of the issues and then went to abandon it. And I think it’s that discernment that’s that’s important. It’s not that it’s one way or the other. It’s being able to discern when the simplification is no longer useful.


Tripp: [00:46:09] So you add that that that makes perfect sense. And, you know, I say, as I think of all the experiments that are being run now in neuroscience and those types of things, I just didn’t know if there was some way that we maybe would be a better way to maybe simplify things that that would be there.


Tripp: [00:46:33] And I think maybe the best way is to asterisks to all these things. The saying this is, you know, left brain, right brain triune brain useful for communication because we have no other way to communicate. But it’s really the tendencies that we’re looking for in order to understand and make changes to the organizations that we work in. And maybe that’s a view that we should take. When we look at these things, it’s just qualify it that that particular way.


Professor Deacon: [00:47:02] I think I would say I would add to this that I think there are a number of assumptions hidden in some of those things that we need to be wary of the assumptions that are behind them.


Professor Deacon: [00:47:13] So in left brain and right brain, oftentimes assumptions about consciousness and unconsciousness, maleness, femaleness sneak into these distinctions that are inappropriate, that don’t actually capture what’s going on. But we bring these culturally into the problem and then we just sort of say, OK, it’s in the brain, therefore it’s real. That’s a mistake. The same thing has happened with the try and brain story because it was a sort of hats on hat story. It felt like a progress story. And in progress, the things that are more recent are always assumed to be somehow better. And so we had this idea that in a sense, development is a progress, that if we organize our businesses according to the top part of it, it’s more progressive and it’s better somehow and the lower parts. And that’s where we get into trouble. We think about things as progress in terms of better and worse. The older is in a sense primitive. The primitive part is the stuff we have to overcome. All of these are in a sense biases that we bring into a culturally bias are thinking and we just try to redefine it by assigning it to places in the body, in the brain.


Tripp: [00:48:31] I do want to mention that your book, Incomplete Nature is out to the audience. Get a chance to read more on that. It’s a book, folks, that I am reading now. There is a lot to unpack on that one. And at some point in the future, I’d love to have Professor Deacon back on to talk about that. But I’ve got to get myself educated, looked at more because you challenge a lot of my existing thinking.


Tripp: [00:48:58] And I’m not I don’t understand why, but I do as I’ve as I look at Ludwig von Bertalanffy, what I did to the Deming philosophy, which is the philosophy that I follow around systems theory, you’re challenging some of the thinking associated with that.


Tripp: [00:49:17] But as with the try and brain some of those things, I’m sure there’s multiple qualifiers. And then you’re looking.


Professor Deacon: [00:49:23] Exactly


Tripp: [00:49:23] At this science world, as Berta Lampley did in systems, thinking that there’s something though to be borrowed or to learn for organizations in the way that the art they react. So at some point in the future, I’d love to have you back on to talk about that, but I need educate myself and to be able to ask interesting questions to you.


Professor Deacon: [00:49:46] All right, let me let me add one thing that you’re one of those we haven’t talked about is my work on the evolution of language. And one of my earlier books way back in the 90s, 97, called The Symbolic Species covers some of the stuff we’ve talked about today, but specifically goes after the question of, OK, given this ancient brain, a brain that has not added new parts. How can we do such unique, unusual thing that we’re doing right now, talking and understanding these symbols? The book is called Symbolic Species The, quote, Evolution of Language in the Brain. It basically talks about how it is that the very process of social communication has played a role in restructuring our brain in a way to make language more easily acquired. So that’s also an area that I think would be worth pursuing if people want to sort of dig further into this question.


Tripp: [00:50:42] Absolutely. And I if you gave me another book to add to my reading list so that that will be good.


Professor Deacon: [00:50:48] Well, that book is about the brain extensively where as Incomplete Nature. I intended it to say something about the brain. I never got to the neuroscience before I finished some 500 pages of trying to get things straight. So, you know, it’s a prequel in some sense to my 1997 book that sort of gets underneath the problems about brains and brain evolution and language.


Tripp: [00:51:15] Like I said, I put it on my Web site, which is Symbolic Species.


Tripp: [00:51:21] And then as I mentioned, the other book is Incomplete Nature, which is a more recent book.


Tripp: [00:51:26] Different kind of a different well, mostly different subject, I would say, building upon some of the learning that you have coming from a multiple different areas, anthropology and by gosh.


Tripp: [00:51:38] So, Professor Terry Deacon, we appreciate you being a guest on the Minor Noodles podcast. And we look forward to having you on in the future again.


Professor Deacon: [00:51:49] Thank you.


Tripp: [00:51:52] Thank you for listening to the Mind your Noodles podcast to get started and building a brain friendly organization. Go to mind your Noodles stock com forward slash overview. This document will take you through how to begin to build a brain friendly organization.


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