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Revenge of the Lizard Brain

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There’s a scene in Fear & Loathing in Las Vegas in which the writer, high out of his mind on hallucinogens, watches a roomful of casino patrons transform into giant lizards and lunge at each other in bloody combat. Under the veneer of civilization, the scene suggests, we’re all still reptiles, just waiting for the moment to strike.

Strange as it seems, this drug-fueled vision reflects a biological theory that, back in the ‘60s, looked like it might be gaining some traction: Paul MacLean’s infamous “Triune Brain” theory, whose basic idea is that every human brain contains three independent competing minds – the reptile, the early mammal, and the modern primate.

Like the Fear & Loathing scene, the Triune Brain idea holds a certain allegorical appeal: The primal lizard – a sort of ancestral trickster god – lurking within each of us. But today, writers and speakers are dredging up the corpse of this old theory, dressing it with some smart-sounding jargon, and parading it around as if it’s scientific fact. This isn’t just late-night-radio fringe stuff, either: it’s showing up at TED and in Forbes.

To understand what it is, exactly, that these people are claiming, it helps to know a few key points about MacLean’s – shall we say – unique personal views on neuroanatomy. Take, for instance, the basal ganglia – that bundle of neural structures near the base of the forebrain. They’re crucial for learning and reinforcing habits, like nail-biting and toothbrushing. Back in the 1960s, biologists thought the forebrains of reptiles and birds were mainly composed of basal ganglia (they aren’t), so MacLean decided to group these structures, along with the brainstem, under the label “reptilian complex.” This “R-complex,” MacLean claimed, was responsible for the “aggression, dominance, territoriality, and ritual displays” of our distant reptilian ancestors.

MacLean also noticed that some of the more complex neural structures folded around the basal ganglia – such as the amygdala, the hypothalamus and the cingulate cortex – play central roles in emotions like disgust, nervousness, doubt and so on. So he figured these brain areas must’ve arisen in the earliest mammals to cope with tasks like family bonding and child-rearing. He gathered them under a heading and slapped the label “paleomammalian complex” on it.

Finally, MacLean noted that the neocortex – the uppermost, outermost layer of the brain – is found only in mammals, and is linked with “high-level cognitive abilities” like abstract planning, tool-making, language, and self-awareness. Thus, he termed it the “neomammalian complex.”

But MacLean wasn’t done. He went on to hypothesize that these three “complexes” not only represented three distinct stages of brain evolution, but remained three separate, semi-independent brains, “[each] with its own special intelligence, its own subjectivity, its own sense of time and space and its own memory.”  MacLean was saying, in other words, that every human brain contains three independent subjective consciousnesses.

All in all, a truly mind-blowing trip to lay on your friends. Problem is, MacLean’s pet hypothesis doesn’t hold up under scrutiny. For example:

  1. Basal ganglia are found in the brains of the earliest jawed fish, which means MacLean’s “reptile complex” originated long before the first tetrapods wriggled onto land.
  2. The earliest mammals already had well-formed neocortices, which means at least some “high-level cognitive abilities” predate mammals altogether.
  3. Many reptiles exhibit “paleomammalian” behaviors such as familial bonding and child-rearing, and many birds exhibit “neomammalian” skills like tool-making, verbal comprehension and dialect development.
  4. In functional terms, a human brain doesn’t behave like a series of separate “complexes,” but as a unified whole. Some neural networks do inhibit others – but the shapes of those networks have nothing to do with “reptilian” or “mammalian” layers.

How is it, then, that modern authors as educated as Seth Godin and Rick Hanson (among others) are writing entire essays that present “the lizard brain” as well-documented scientific fact? How does Godin keep a straight face onstage as he tells us that “the lizard is a physical part of your brain” and that “the reason we call wild animals ‘wild’ is because they have lizard brains”?

It’s because the idea makes a weird kind of intuitive sense. We’re bundles of instincts and inhibitions and desires that don’t fit neatly together. It’d be comforting, in a way, if we could pin those conflicts on little lizard brains – just name those ancient demons and drive ‘em out, like we did in simpler times.

Whether we like it or not, though, the lizard is simply us. Every habit and hangup, every dread and desire in our minds is dependent on neural pathways that were once laid down by our personal experiences. Like every other organism on earth, we carry the history of a long, successful lineage in our genetic and biological makeup. The question of what to do with those resources, though, isn’t predetermined by the past. It’s up to you.

Image: Genesis12, modified by Ben Thomas

Ben Thomas About the Author: Ben Thomas is an author, journalist, inventor and independent researcher who studies consciousness and the brain. A lifelong lover of all things mysterious and unexplained, he weaves tales from the frontiers of science into videos, podcasts and unique multimedia events. Lots more of his work is available at Follow on Twitter @theconnectome.

The views expressed are those of the author and are not necessarily those of Scientific American.

Comments 25 Comments

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  1. 1. bekhterev 1:27 pm 09/7/2012

    Good job.

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  2. 2. bsebadger 2:45 pm 09/7/2012

    Thank you for debunking this decades-old myth. I really hope this silly little idea fades out of popular culture.

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  3. 3. plswinford 3:13 pm 09/7/2012

    Our brains are not that plastic. Our subconscious (or if you prefer, nonconscious) is a majority of our brains. And twin studies illustrate how much is preset.

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  4. 4. DancerTiffy 5:59 pm 09/7/2012

    I believe there is a lot of truth to the Triune Brain theory. Humans have evolved up a long pathway of species of various forms and attributes. I also know that the human brain has evolved from the relatively simple to the relatively complex and that many parts of our brain were evolved by species not human. I could go on and on with this but this article in no way convinced me of anything.

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  5. 5. jgrosay 6:28 pm 09/7/2012

    I’d say that whatever a name you choose for the different structures in the human brain, and its correlates in animals, we must admit that some similarities exist between species so apart, both in evolutionary terms and in functioning, but the idea has always kept on coming into my mind, that in every place in the brain where a population of neuronal bodies exists, or “gray matter”, some “computing” capacity is there, and thus some functions are more or less linked to this brain region, be it basal ganglia, brain stem or cerebellum. An important part of the brain is made by the “conectome”, neural pathways that do carry information and link the activities of some regions of the brain to others. The classic descriptions of clinical conditions such as the one that gets the name “thalamic animal” would be some kind of an evidence that at least, part of the concept of independent brain regions and of the functions connected to these regions may be true.

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  6. 6. BenThomas 12:52 am 09/8/2012

    @DancerTiffy – You’re right that many structures in our brains evolved in earlier species… but do people born with only a brainstem act like lizards? Of course not; they’re limited to autonomic functions like heartbeat and respiration. Without the rest of the brain, that’s about all a human brainstem can do on its own. The “lizard brain” might be an interesting metaphor, but it makes no sense in light of how we know the human brain actually works.

    @jgrosay – Sure, some functional networks in the brain work semi-independently; but the kind of computative modularity you’re talking about is organized around processing “hubs” (like a map of airline routes) rather than semi-independent layers:

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  7. 7. jtdwyer 6:25 am 09/8/2012

    Nice article. Off the top of my head (so to speak), I think these reptilian ideas began as researchers noted that developing fetus’ seem to progress through varying forms of ‘older’, ‘less developed’ species before producing a fully human final form.

    I haven’t heard these more recent reptilian philosophies, but I suspect they are the results of leapin’ lizards jumping to conclusions, or some more nefarious profit motivation intended to encourage those lizards to leap…

    BTW, if one consumes enough hallucinogens, others may really look like lizards, irrespective of any behavioral resemblances. Have you heard the term ‘lounge lizards’, or have they now become extinct?

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  8. 8. Steves12 8:30 am 09/8/2012

    I appreciate you pointing out the inaccuracies in the Triune concept. However, the Lizard Brain concept is a very useful one for those of us in Addiction Medicine. It allows our patients to easily understand the dynamics and the tensions between the higher functioning neocortex and the more ‘hardwired’ reward centers in the limbic system. It also gives us a jumping off point for teaching strategies for building robust neuronal connections to allow the prefrontal cortex to communicate more forcefully with those centers in the limbic system which become dysfunctional in addiction disorders

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  9. 9. BenThomas 3:33 pm 09/8/2012

    @jtdwyer – The “reptilian brain” idea does seem to have been influenced by reptilian features in developing brains (a.k.a., the old “ontogeny recapitulates phylogeny” argument) but this idea was also proven inaccurate decades ago: I do think you’re right, though, that the desire for fame and profit probably had more than a little influence on these speakers’ desire to use the “lizard brain” in their talks…and apparently the lounge lizards in the audience aren’t up to second-guessing those claims. I’m betting that’s a species that won’t go extinct for quote a while!

    @Steves12 – I agree that the concept has a metaphorical usefulness… but it’s also important is to make clear distinctions between metaphor and scientific fact. I’d think there must be a way to explain prefrontal/limbic connectivity without resorting to out-of-date hypotheses.

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  10. 10. zstansfi 3:41 pm 09/8/2012


    You’ve made several non-sequiturs there. Brain plasticity generally refers to modifiability of brain circuits throughout life. Brains do, in fact, show quite a bit of plasticity, but it isn’t clear from your post why this is relevant. Much of our daily brain function is present below conscious awareness, but this is not logically related to either plasticity or “reptilian brains”. Twin studies illustrate the importance of genetic similarities in development outcomes, but this is not the same as being “preset”, and again isn’t relevant to whether or not humans have a triune brain.


    None of your statements address anything relevant to the Triune Brain theory, which states that the human brain is composed of 3, mutually-independent circuits which represent discrete stages of development that are evident in various other species with which we share common ancestors. This is quite different from saying, as you do, that the human brain shares a common lineage with other mammalian brains. The critical difference is that as newer brain regions developed across evolutionary history (e.g. neocortex), these regions began to interact with evolutionarily older regions. Thus, the so-called “reptilian brain” or hindbrain and midbrain regions have structural and functional differences from the homologous regions in reptiles. They perform many similar functions, but how these functions are performed is not an exact recapitulation of how it would have been performed by those species.


    Nonetheless, the division between “hardwired reward centers” and “higher functioning neocortex” is at least partly semantic, given the questionable nature of a strong modularity hypothesis. As a result, the extent to which dysfunction at a particular set of synapses (e.g. within canonical reward circuits) can be said to be independent of “higher functioning neocortex” in addictive behavior is in question.
    The question then becomes, is there evidence that telling people their addiction is due to competition between a reptile brain and a human brain promotes recovery from drug addiction? If not the use of this term may well be extraneous.

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  11. 11. lump1 4:31 pm 09/8/2012

    I think that more useful evidence against this hypothesis would be to dispute the “three semi-independent loci of consciousness” claim. The objections raised here all basically line up to make one point: Each of the structures is older than was alleged. But so what? That doesn’t really cut against the heart of the view, which is that “we each have a monster deep inside our brains”, or something like that. It’s that sort of picture that caught people’s imagination. If the “monstrous” part turns out to be older than reptilian, that’s kind of besides the point. What needs refuting is that this part does any of our thinking at all, or that if it does, it struggles against the newer brain layers.

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  12. 12. VIP 5:20 pm 09/8/2012

    “Revenge of the Lizard Brain”.
    I don’t understand why anybody has any problems here. It is very obvious that life on this planet emerged in the seas, then moved to land and then evolved into many species. The transformation from fish to lizard to what we are now is not disputable. Of course our brains contain background from previous species, is that hard to understand?

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  13. 13. BenThomas 5:43 pm 09/8/2012

    @lump1 – You’ve hit it right on the head: the idea of independent “layers” of consciousness is one of the theory’s main weak points. Still, there are also quite a few biological facts that don’t line up with MacLean’s hypothesis, and I felt it was important to point those out too.

    And you’re absolutely right: the “lizard brain” is undeniably a powerful metaphor. As with any metaphor, though, it’s crucial not to confuse the map with the territory.

    @VIP – Yep, the fact that primates evolved from reptiles, which evolved from fish, is indisputable and easy to understand. The problem with MacLean’s hypothesis is that is claims the existence of three separate conscious minds in every brain. The problem is that this claim has no factual support, and actually conflicts with our understanding of evolution, biology, and neurophysiology.

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  14. 14. pinetree 2:05 am 09/9/2012

    Having bred uromastyx lizard and owned a few tortoises, I can say I have seen really every basic “human” behavior in them including conniving, ganging up, lust, concern, etc. They have on occasion out smarted me, which admittedly may be a low barrier. The basic point being they are not stupid dull animals, although I can’t speak for snakes because I prefer my reptiles with legs.

    That said the “three layered” brain is a thinly veiled repackaging of the id, the ego, and super ego also done as the child, the adult, and the parent. Three-fors are popular. But to be fair whether three layers represent evolutionary progress, there may be something to multi-layered models for whatever reason.

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  15. 15. pinetree 2:15 am 09/9/2012

    Also curious what makes you think TED speakers don’t scam their audience like other self promoters? The metaphor of lizards as monsters does not reflect most lizard behavior because they are far from the top of the food chain where the real monsters live: cats and humans that hunt for the pure pleasure of killing other creatures. Perhaps if such metaphors are used they have the whole thing inverted morally – its the humans you can’t trust, but outside of breeding season most lizards are laid back.

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  16. 16. vinodkumarsehgal 6:22 am 09/9/2012

    The behavioral pattern in human beings and higher category mamels is a function of MIND and brain serves as a hardware for the mind. What is the origin and anatomy of mind and how is is linked to brain? These are the issues which are not properly understood by Science of the day. In view of this, it will not be appropriate to trifurcate mind purely upon the biological trifurcation of brain.

    The entire discussion revolves around one basic presumption that mamels have evolved from reptiles and that evolution goes forward in some linear fashion. Human’s knowledge of history spans up to past a few millennia only. Cognitive abilities of human beings 5-10 millenna ago, the period for which we know about history with some degree of certainty, do not seem to to be much inferior than human beings of 21st century.

    Though archeologists date back up to 40-50000 years only when the modern human appeared on the earth but we should also keep in mind that modern cosmologists hypothesize the age of universe at 13.72 billion years. Period of 40-50000 years is nothing nothing in comparison to 13.72 billion years. If universe has emerged from some intelligent design or without intelligent design by Nature only, neither design should be so unintelligent nor Nature so frugal that it may allow human beings to remain in existence for just 40-50000 years only and for the 99.99 % of the period, universe may remain barren without human beings

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  17. 17. BenThomas 2:51 pm 09/9/2012

    @pinetree – Yeah, it’s hard to deny the similarities with Freudian psychoanalysis. I think “three-fors” remain so popular, as you say, because we all feel tugged between our “animal” instincts and our abstract ideals. More than anything else, though, that’s just evidence that evolution has conserved many of our ancestors’ instincts and integrated them into a central nervous system that’s capable of producing abstract thought. In other words, it’s evidence that even when your mind feels divided, your brain is still physiologically unified.

    Re: your comment about TED speakers, I’ve lately been seeing a rash of self-promotional folks (from a variety of fields) use the conference as a platform for advertisement, rather than for reporting verified findings. I know TED has always been a blend of science and entertainment, but lately the latter seems to be heavily outweighing the former. Which is a shame, because some of my favorite neuroscientists (Gero Meisenboeck, Oliver Sacks) have delivered brilliant TED talks in the past.

    Anyway, you’re probably right about those laid-back lizards: I think all our lives would be improved by a few hours of sunbathing every morning.

    @vinodkumarsehgal – You make a very valid point: Without knowing much about the minds of our ancestors, it’s hard to make concrete statements about which aspects of our subjective experience originated where. Even so, neurobiologists are getting an ever-clearer understanding of what kinds of thoughts can be thought by different kinds of animal minds – as this video discusses in detail:

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  18. 18. DougT 6:43 pm 09/10/2012

    Ben Thomas, its nice to see you are open to discussion on this and willing to interact and clarify points. I want to comment on your four example points on the theory does not “hold up under scrutiny” and suggest that your criticisms themselves to not hold up. That even if he missed some of the nuances of evolutionary history, there is still something to his theory.
    1) As lump1 pointed, it does not matter that the reptilian complex may have originated earlier. That just means he may have mis-named it.
    2) The existence of “well-formed neo-cortices” in early mammals does not make them equivalent to the neo-cortices of primate brains. There is something that happened in the evolution of primates, in their brains, unique to us humans primates that makes us qualitatively different than mammals.
    3) Some reptiles and birds may have developed similar paleo- and neo-mammalian skills, respectively, but I would say that just points to something called convergent evolution of traits that increase survival, much the way whales and others mammals whose ancestors returned to the seas and developed almost identical bodies to the fish-types (that had stayed there all those millions of years) does not disprove the evolutionary history of fish.
    4) As a registered psychologist and clinician I actually find this the strongest piece of MacLean`s theory. I would say the evidence that we work as a unified whole is far less convincing than the idea that we have conflicting brain processes going on all the time, and they map on nicely to MacLean`s three brains. For example:
    a. Ever had a sexual drive arousal/ interest (reptilian brain) that wasn`t in alignment with your rational or emotional brain interest? Could you stop it?
    b. Ever eat more food (often emotionally driven) than your belly (reptilian process) said was enough?
    c. Ever feel strongly about where to go with a decision even though all the rational (intellectual) processes said to make the other decision? Research on highly successful CEOs indicates after weighing all the evidence rationally, they make their final decision with their “guts”.
    d. How about the public speaking phobic who knows intellectually that no one is going to heckle and harass him or her (emotional brain) when they speak in public, but still has a panic attack (emotional brain) as they prepare to do so.

    So yeah, I would say that the recent resurgence in embracing MacLean’s triune brain theory is because it does map so well onto human behaviour, and our culture is far more comfortable with referencing neurobiological and neurophysiological theories than the traditional clinical frameworks Pinetree pointed too, even though they point to the same thing.

    In my work I use the terms intellectual, emotional, and physical brains instead of MacLean’s terminology, but they point to the same “semi-independent complexes”. Heck cognitive behavior therapists (CBT) are finally accepting that people going through desensitization hierarchies have to feel emotions and sensations in their body for it to work. This fits with the recent emergence of emotionally oriented therapies stepping up to fill the void between cognitive (i.e. intellectual brain) and behavioral / medical (reptilian brain) therapies out there, as well as the construct of “emotional intelligence” into our culture. Note the implicit triune brain showing up here in the therapies.

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  19. 19. BenThomas 12:29 am 09/12/2012

    @DougT – First off, thank you for taking the time to engage with my contentions in such a methodical way. This kind of discussion is exactly what I hoped to spark.

    Before I get into my main points, I feel I need to clear up some apparent confusion that’s been developing in this comments section: In no way do I dispute the fact that the vertebrate brain has a long and multifaceted evolutionary history, and that many of its structures and functions developed piecemeal over time. What I dispute are MacLean’s contentions a) that the brain – any brain – can be neatly parceled into semi-separate “complexes,” and b) that each of these these complexes generates an independent *subjective* consciousness.

    Onward to points of agreement! With your background in clinical psychology, you’re more qualified than I am to discuss what concepts a patient will understand and respond to in a treatment setting, so I won’t attempt to dispute you there. I also agree with you that, if MacLean had simply misidentified the boundaries and attributes of his proposed complexes, but we’d later found his overall framework to be supported by all known data, the Triune Brain might still be salvageable as a theory.

    The point I was making in #s 1-3 is that clear functional distinctions between “reptilian” or “paleomammalian” brain complexes are almost impossible to make at all from a standpoint of evolutionary neurobiology, due to the close-knit functional integration among many of these structures. I probably should’ve made that point more clearly.

    As for point #4, I don’t dispute the idea that “we have conflicting brain processes going on all the time” – in fact, I pointed this out in the article. But the nested-hub hierarchical layouts of functional brain networks can’t be separated into “layers” or “complexes” – and, as I mentioned in the article, the shapes of those functional networks span structures dating from all eras of vertebrate brain development. In connectomics, there’s simply no network corresponding to anything like a “reptile” or “paleomammalian” sub-brain. If such a study on brain network functionality does exist, please pass it along – I would be shocked and intrigued to read it.

    As Pinetree and I discussed above, there’s no denying that the Triune Brain concept makes sense as a metaphor – and in fact, a variety of threefold consciousness models have enjoyed widespread popularity since the mid-19th century, probably for this very reason. However, as Pinetree also pointed out, patients could just as easily substitute the Freudian id/ego/superego for the three “brains” you name, and the model’s mechanics would remain essentially unchanged. This doesn’t say anything about the theory’s objective validity, one way or the other.

    Finally, the core of MacLean’s theory – the contention that every human brain contains three independent subjective consciousnesses – is neurobiologically unverified, and possibly unverifiable in any non-subjective way. I could claim I have eight consciousnesses in my mind (as Timothy Leary did) and no scientist could objectively disprove that assertion. But then, of course, we’d be talking about internal conceptual models, not independently testable biological traits.

    To return to our original point of agreement, none of this says anything about what conceptual frameworks produce demonstrable results in a clinical setting. But my question is, why is it more useful to tell a patient about his/her “emotional brain” than his/her hypothalamic-pituitary axis – a structural network whose role and composition are well-documented and well-understood?

    Here’s an analogy: My mother used to take me to the zoo when I was four years old or so; we’d stand and watch the tigers, and my mother would point each species out to me: “There goes the Bengal tiger! There goes the Siberian white tiger!” Meanwhile, other nearby mothers would be telling kids my same age, “Look at the big kitties, sweetie! See all the big kitties?”

    Is telling patients about “big kitties” really the most truthful, helpful way to inform them about the world?

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  20. 20. link5817 10:36 am 09/12/2012

    More critical thinking about these issues would certainly advance the science of mind, but there is much to take issue with in your post (e.g., none of your 4 examples constitute refutations of, or even clear understanding of, MacLean’s understanding of evolution or neurobiology). Maybe I can best summarize these issues in response to your statement that, “the problem with MacLean’s hypothesis is that is claims the existence of three separate conscious minds in every brain. ” It is precisely this kind of oversimplification of the issues that perpetuates the kinds of misunderstandings reflected in your post. Aside from your gross mischaracterization of MacLean’s vast theoretical and empirical work in this area as a “hypothesis,” I challenge you to find anywhere in MacLean’s published works a claim for the existence of “three separate conscious minds.” In the meantime, you may better appreciate the “layer” concept in relation to the biological structure and psychological functioning of the brain by examining work reviewed by, e.g., Berntson & Cacioppo (2008), Derryberry & Tucker (2006), Lewis & Todd (2007), etc.

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  21. 21. vinodkumarsehgal 3:27 am 09/13/2012

    I find one important point being ignored in the whole discussion. Mental behavior is being exactly mapped upon brain anatomy on one to one basis. Dynamics of mental behavior is much more complex than brain dynamics. Even if brain trifucation may be a reality as per Maclean’s theory this may not necessarily transfer to trifucation of mental behavior.

    Mental thought process and consciousness never operate in compartments and thought process always emerges as a unified whole. Brain comprises of some tangible material stuff, therefore, it may be objectively feasible to compartmentalize brain but what about thoughts? Currently Neoro Science has no answers to many intriguing issues of mind viz : What is the nature and composition of mental thoughts? Of what stuff thoughts are composed of? Are brain characteristics the only factor in the generation of thoughts or there are some more factors? What is the origin of thoughts? What is the relation between mind and brain? and so on so on

    When we are not fully aware of the thought process it will not be logical to speak of evolution of thought process based upon only evolution of brain. Evolutionists may have some knowledge of brain of human beings or higher mammalians during the period some 10 or 100 million years ago from study of fossils or other tools ( though validity of such studies may have its own limitations) but such studies may not reflect into mental behavior.

    I think before compartmentalization of mind into reptallians, pleaomammalians and neomammalians behavior and linking these behavioral segments with with 3 distinct territories of brain, it will be desirable and prudent to i) To have a better understanding of the composition of mental thoughts ii) To have better knowledge of the interface of mind and brain iii) Apart from brain structure, there may be host of other factors in the creation of thoughts. To identify those factors and understand their role in thought generation.

    One of the important issue affecting modern neuro biological sciences has been that link between brain and mind has been taken to be too simplistic. Without understanding the composition and nature of MENTAL process, any set of mental behavior is straightforward linked to some exclusive area of brain

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  22. 22. BuckSkinMan 3:40 am 09/13/2012

    Hmm, Ben Thomas’s thesis is itself antagonistic toward a particular set of other theses. Looks more like ideological conflict, the kind of thing we see in politics all the time.

    The mind seems inherently subjective and prejudiced in ways that indicate we are what we think we are “inside” with little regard to objective facts or (except for sociological scheming) the perception of other people. Notice how our “relationships” are all based on what we agree with in other people’s statements and actions. Notice too how quickly relationships are ended by disagreement over non-objective “facts.”

    Illustrating grandly: there’s a clear division between people who believe themselves to be omnivores vs carnivores or vegetarians. These groups form into camps – not because of objectively observed fact but because there are these types of people who seek support for their views versus the contradictory views of others. The outlandish claims of vegetarians (eating only vegetables is “kinder” and leads automatically to “better health”) prove the belief-based theory better than any objectively written scientific finding. Equally laughable (and often joked about) is the view that we are innately carnivores. Most evidence indicates we evolved in opportunistic fashion to take advantage of whatever food stuffs might be available at any given time. Deciding for ourselves has proven very dangerous and divisive – otherwise how do you explain “ideologies” which battle each other in the political arena? True Believers strive constantly to “ban” the practices of other True Believers by making their views into law.

    Especially notice: how, every day, we see proof that “minds” or “brains” aren’t that good at discerning objective reality from subjective “beliefs.”
    So for my money: any theory which accounts for the nonsensical and contradictory “results” our brains produce is a valuable step forward.

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  23. 23. BenThomas 12:39 am 09/15/2012

    @link5817 – “I challenge you to find anywhere in MacLean’s published works a claim for the existence of “three separate conscious minds.”

    Challenge accepted. “These three brains might be thought of as biological computers, each with its own peculiar form of subjectivity and its own intelligence.” – Paul D. MacLean; A Triune Concept of the Brain and Behavior, p.8. MacLean repeats the same claim on p.21.

    Per your other point, MacLean himself refers to the Triune Brain concept as a hypothesis repeatedly throughout his published work. That word in itself connotes no disrespect, any more than calling Newton’s theory of gravity a theory. That’s simply what it is.

    I’ll add those papers you recommend to my “to read” pile!

    @vinodkumarsehgal – “Mental thought process and consciousness never operate in compartments and thought process always emerges as a unified whole.” Excellent point. Indeed, the question of how exactly that happens – known as the “binding problem” has plagued philosophers and scientists for at least a century. Though technology continues to give us higher and higher resolution images of brain activity, we’re still a long way from a verifiable answer.

    “it will be desirable and prudent to i) To have a better understanding of the composition of mental thoughts” Once again, you’ve pinpointed a problem pointed out by several prominent philosophers of mind, such as David Chalmers and Cristof Koch: our language and conceptual framework for introspection is still maddeningly vague. Maybe Buddhist monks can tell exactly where one thought ends and another begins, or where stimulus gives way to desire – but most of us still talk and think about these things in essentially the same way as a person from 300 years ago.

    For a philosophical perspective on this, I think you’ll find this paper very interesting:

    @BuckSkinMan – Your first point is right on the money – in fact, the fact that this issue is so ideologically polarizing is a major reason why I chose to examine it critically. Clearly I’ve hit some nerves.

    “So for my money: any theory which accounts for the nonsensical and contradictory “results” our brains produce is a valuable step forward.” Any such theory *could* represent a step forward, but for the theory to qualify as science, it must make specific predictions that can be tested by experimental evidence, and falsified or validated by that evidence.

    As Sherlock Holmes said (according to Doyle), “It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”

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  24. 24. vinodkumarsehgal 2:05 am 09/15/2012

    @Ben Thomas

    About 40 years ago in 1973-74, I came across a great Saint/Yogi in India. After spending about 50-60 years, (at that time), in Samadhi ( deep meditation and contemplation), he had written about his experiences in a lucid and graphic manner in some books. One of such book “Science of Soul” described that our physical body, with brain as the physical hardware apparatus for thinking, is engulfed in a higher dimensional body designated as astral body. The astral body is also composed of matter and energy but those matter and energy are not the same as known to Physics of today. The way brain is an internal organ of our physical body similarly mind, intellect and 10 senses ( 5 of motor function and 5 of knowledge function) are part of astral body. The operative part of astral body resides in physical brain. Thought are generated by the interface of mind and intellect ( as residing in astral body) and brain as residing in physical body. At that time, I was only about 17 and not mature enough to comprehend the mechanism behind interface of astral and physical body. Years of pondering and re-pondering, created conceptual clarity in me.

    However, issue has been that I can not interpret and understand the mechanism of astral body and its interface with physical body in the language of Physics and neuro science/ neuro biology — the language which Science of the day understands and appreciate. I have also not come across any scientist or scientific source who might have done any objective research work on astral body and its interface with brain. In fact, most of scientists do not believe in the existence of any astral body over and above this physical body and brain, so how they will dedicate their time and resources for such research?

    The book is not on the net, otherwise I would have communicated the reference.

    Link to this
  25. 25. link5817 11:59 am 09/17/2012

    Ok, no need to quibble here over definitions of “hypothesis” and “theory”
    The more pressing issue relates to our apparently different definitions of “consciousness.” For example, in the quote you provided from MacLean, there was no reference made to the concept of consciousness (as I would define consciousness, as in “conscious awareness”). In other words, my read of MacLean’s claims about “subjectivity” and “intelligence” relate primarily to how different areas of the brain represent information and only secondarily to how those representations may influence conscious awareness. MacLean’s claim, as I read it, was that different areas of the brain represent information in qualitatively different ways. This is the view reflected in the citations I provided (and there are 100s of other papers reflecting similar conclusions). In the simplest terms, sub-cortical representations are characterized by their “here & now” form, whereas cortical representations are characterized by their “there and then” form. In these terms, “conscious awareness” would be characterized by (a) a “here and now” form when what is activated and re-presented at the conscious “level” are primarily sub-cortical representations and (b) a “there and then” form when what is activated and re-represented at the conscious level are primarily cortical representations. In other words, MacLean’s claims are less about consciousness and more about how different areas of the brain represent the world in different ways. The different ways that the world is represented by different areas of the human brain appear to be associated with how brain parts and processes characterizing, for example, the average reptilian and mammalian brains have been integrated into the modern human brain. Finally, although the brain appears from the point of view of conscious awareness to function as a single, integrated system, closer analysis reveals many divergent processes, some of which seem as likely to conflict with than to complement each other (hence, the familiar feeling of having “mixed feelings” about something or “confusion” about which action is the most appropriate in any given situation).

    Link to this

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