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The Entangled Brain: How Perception, Cognition, and Emotion Are Woven Together
A new vision of the brain as a fully integrated, networked organ.
Popular neuroscience accounts often focus on specific mind-brain aspects like addiction, cognition, or memory, but The Entangled Brain tackles a much bigger What kind of object is the brain? Neuroscientist Luiz Pessoa describes the brain as a highly networked, interconnected system that cannot be neatly decomposed into a set of independent parts. One can’t point to the brain and say, “This is where emotion happens” (or any other mental faculty). Pessoa argues that only by understanding how large-scale neural circuits combine multiple and diverse signals can we truly appreciate how the brain supports the mind.
Presenting the brain as an integrated organ and drawing on neuroscience, computation, mathematics, systems theory, and evolution, The Entangled Brain explains how brain functions result from cross-cutting brain processing, not the function of segregated areas. Parts of the brain work in a coordinated fashion across large-scale distributed networks in which disparate parts of the cortex and the subcortex work simultaneously to bring about behaviors. Pessoa intuitively explains the concepts needed to formalize this idea of the brain as a complex system and how to unleash powerful understandings built with “collective computations.”
Popular neuroscience accounts often focus on specific mind-brain aspects like addiction, cognition, or memory, but The Entangled Brain tackles a much bigger What kind of object is the brain? Neuroscientist Luiz Pessoa describes the brain as a highly networked, interconnected system that cannot be neatly decomposed into a set of independent parts. One can’t point to the brain and say, “This is where emotion happens” (or any other mental faculty). Pessoa argues that only by understanding how large-scale neural circuits combine multiple and diverse signals can we truly appreciate how the brain supports the mind.
Presenting the brain as an integrated organ and drawing on neuroscience, computation, mathematics, systems theory, and evolution, The Entangled Brain explains how brain functions result from cross-cutting brain processing, not the function of segregated areas. Parts of the brain work in a coordinated fashion across large-scale distributed networks in which disparate parts of the cortex and the subcortex work simultaneously to bring about behaviors. Pessoa intuitively explains the concepts needed to formalize this idea of the brain as a complex system and how to unleash powerful understandings built with “collective computations.”
280 pages, Paperback
Published November 15, 2022
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Displaying 1 - 8 of 8 reviews
November 27, 2022
This is an exceptionally well written and edited book. The concepts are about as heavy and complex as you can get, but Pessoa does such a fantastic job of making it all intelligible while also making it compelling so that I continued to the end. That's not an easy task, especially when getting into the details of how the brain functions. At one point toward the middle I was predicting that this was about to go way over my head, but he reeled me back in as I went on. Forget the small details of brain circuitry of what goes to what (I'll never remember), focus on how those details develop and support the larger conceptual points he's making that point to a needed paradigm shift in the way we conceptualize what the brain is and how it functions. Truly remarkable read. My hat is off to Pessoa. Few authors, much less scientists, can do what he just did with this book.
March 15, 2023
I recommend "The Entangled Brain" to everyone who wants a concise update of our current understanding of the brain. One theme is that many popular ideas are actually obsolete because the brain is much less "modular" than long assumed. No matter what function you chose, it is likely the result of many parts of the brain interacting (thus the title "Entangled Brain")
Pessoa also explains clearly why the idea of "the limbic system" is also obsolete.
This book was written for a general audience and does not require any background in science or neuroscience.
Pessoa also explains clearly why the idea of "the limbic system" is also obsolete.
This book was written for a general audience and does not require any background in science or neuroscience.
August 28, 2023
'The Entangled Brain' is a well-written, smooth read - but that doesn't make it a good book. There are 3 issues that stand-out.
1) The subtitle is TOTALLY misleading. This book hardly is about perception, cognition and emotion: Pessoa instead makes the case that the (distinct) brain areas that are generally considered to be responsible for perception, cognition and emotion are highly entangled, and that they cannot be "neatly disassembled into a set of independent parts". If you are looking for specific examples of how certain emotions influence perception, or vice versa, or how perception influences cognition, etc., look elsewhere. There hardly are any examples to be found in the book. What Pessoa provides is essentially a long list of nerve connections between the basal ganglia, the thalamus, the frontal lobe, the pallial amygdala, the ventral striatum, the superior collictulus, etc., etc.
By doing so, Pessoa does give a good overview of brain anatomy, and covers a bit of history of brain science too - with classical examples like Phineas Gage, Broca's Tan Tan, and a fair amount of others. I also have to stress he convincingly demonstrates his main thesis: the brain as an highly integrated organ, a very complex system with all kinds of loops, feedback and feedforward connections. If you want to know more about the specifics of that, this book might be for you.
2) It is unclear who he argues against. Pessoa often writes about neuroscientists that look at the brain as if it consists of fairly separate building blocks, with one area responsible for language, another for emotion, another for memory, etc. But he never names any recent papers or books that do so - he only refers to the New York Times archive twice, to show how a certain part of the brain is (was?) used in a newspaper. I'm just an amateur science lover, having read a couple of books about brains and the likes - check out my list of reviewed non-fiction to find out which - but from what I can gather, the opinion of Pessoa isn't really contested, and the fact that the brain is a complex neural network is pretty standard fare - even in the New York Times. I could be wrong here, but either way it would have been better if Pessoa had added specific sources.
3) Pessoa tries to argue against reductionism and the brain as a mere causal input-output organ. But he fails twice.
As for reductionism, he argues that a functioning brain can't be reduced to smaller components. I agree: you need all the components of the brain to have a healthy, functioning brain. BUT that does not make reductionism as a philosophical undertaking invalid: it just shows that to understand certain complex systems, you don't need to reduce things totally to its lowest possible level. Maybe that's why some reductionist tend to speak of 'mechanism' instead, and Pessoa admits the brain functions in a "mechanistic" way, "in the sense that all parts function according to the standard rules of chemistry and physics."
Because, what is often at stake in these debates is the principle of causality, as some scientists want to uphold the idea that the human brain (and so humans too) can somehow escape causality - like Pessoa in a way tries with the notion of "emergent" behavior. 'Emergence' refers to properties that are not present at the lower levels - but that's not what reductionist try to argue: no-one claims every property is found at every lower level. For if we can escape causality, we are free, but if we can't, the freedom of the will becomes a problematic notion. Pessoa never talks about free will in this book, but does try to stress the human brain as a flexible organ, responsible for flexible behavior, behavior that's "emergent" & "complex" - yet no-one that argues against free will claims that our behavior is not complex, or not situationally flexible, or not emergent from our protein brain.
When Pessoa tries to show that behavior is emergent and complex, and not just the result of input-output causality, this is where he fails too. He admits the brain can be thought of as a circuit in between sensory and motory cells. But his notion of input is misguided. Consider this crucial passage on page 153-154, under the telling heading "Decoupling Sensory Signals from Motor Responses":
"In chapter 3, we discussed a circuit involved in both defensive and appetitive behaviors centered on the optic tectum/superior collicus of the mid-brain. This system is extremely important across vertebrates. In rodents, it helps the animal decide if it should flee when movement is detected overhead or possibly approach and explore further if the movement is in the lower visual field. But the animal's behavior is flexible and not fixed by the input - the context in which it occurs, encompassing both external and internal worlds, is critical."
The problem with this part is that the context obviously is part of the input too. You cannot argue for the brain to be an entangled system, and then consider the input to the optic tectum to be only some visual input. The body's internal state (all kinds of sensors measuring appetite, hormone levels, pain, fatigue, etc.) offers constant, diverse inputs into the brain as a system, influencing how its subsystems operate. The same goes for the context, the "external" world: obviously the input is not limited to vision of some movement in the lower visual field. There's the other visual input, but simultaneously also input of all other senses (sound, temperature, tactile, smell, taste,...). On top of that, the brain is a system that evolves over time, something Pessoa does admit, coincidentally on the next page: the system learns. So also input (of whatever kind) received in the past, should be considered as well.
All that makes a sentence like "the animal's behavior is flexible and not fixed by the input" highly misleading. Pessoa here talks about one specific form of input (vision in the lower field) but the gist of his argument gets him to the "decoupling of sensory signals from motor responses", as if the brain somehow overcomes causality.
On page 218 he even goes as far as suggesting there might not be a close link between brain and behavior: "Now, when researches study the rat's brain under such conditions, a close relationship between brain and behavior is established. But as Paré and Quirk warn, the tight link might be apparent insofar as it would not hold under more general conditions. Neuroscience is experiencing a methodological renaissance."
In the final chapter, we get the following, a bit baffling statement on page 221: "In considering the benefits of such ubiquitous mixing of sensory and motor information, the investigators [Stringer et al. 2019] ventured that behaving effectively depends on the combination of sensory data, ongoing motor actions, and internal-state variables."
To which I would say: no shit, Sherlock. Notice again that ongoing motor actions and internal-state variables are decoupled from sensory data, while I would argue that also motor action and internal-state variables are very much part of our sensory data. In trying to (justifiably) break down the walls between brain regions, Pessoa keeps up some other walls that are conceptually just as problematic.
Let's consider a final passage, on page 212, in a chapter about unlearning fear:
"The decision to take flight is not just triggered by threat detection and involves computations that rely on multiple external and internal variables. Together, escape behaviors are far from simple stimulus-driven, stereotypical reactions. The mechanisms involved engage specialized circuits refined by eons of evolutionary times."
I get it, behaviorism and conditioning are a bit creepy. Scientists want to get away from Watson and Thorndike. But why even add the words "stimilus-driven" in the above part? True: real life rat or mice behavior is complex, not-stereotypical, not the same as in a 40 x 40 x 40 cm white laboratory box. But are "multiple external and internal variables" really no part of the brain's input? Aren't those variables stimuli too? Yes they are. Again, Pessea singles out on specific stimulus (predator detection), points at the fact that stuff is more complex, and then uses that cast doubt on the entire idea of "stimulus-driven" input behavior, as if the additional complexity isn't part of the input/stimulus.
All and all, a disappointing read.
More non-fiction reviews on Weighing A Pig Doesn't Fatten It
1) The subtitle is TOTALLY misleading. This book hardly is about perception, cognition and emotion: Pessoa instead makes the case that the (distinct) brain areas that are generally considered to be responsible for perception, cognition and emotion are highly entangled, and that they cannot be "neatly disassembled into a set of independent parts". If you are looking for specific examples of how certain emotions influence perception, or vice versa, or how perception influences cognition, etc., look elsewhere. There hardly are any examples to be found in the book. What Pessoa provides is essentially a long list of nerve connections between the basal ganglia, the thalamus, the frontal lobe, the pallial amygdala, the ventral striatum, the superior collictulus, etc., etc.
By doing so, Pessoa does give a good overview of brain anatomy, and covers a bit of history of brain science too - with classical examples like Phineas Gage, Broca's Tan Tan, and a fair amount of others. I also have to stress he convincingly demonstrates his main thesis: the brain as an highly integrated organ, a very complex system with all kinds of loops, feedback and feedforward connections. If you want to know more about the specifics of that, this book might be for you.
2) It is unclear who he argues against. Pessoa often writes about neuroscientists that look at the brain as if it consists of fairly separate building blocks, with one area responsible for language, another for emotion, another for memory, etc. But he never names any recent papers or books that do so - he only refers to the New York Times archive twice, to show how a certain part of the brain is (was?) used in a newspaper. I'm just an amateur science lover, having read a couple of books about brains and the likes - check out my list of reviewed non-fiction to find out which - but from what I can gather, the opinion of Pessoa isn't really contested, and the fact that the brain is a complex neural network is pretty standard fare - even in the New York Times. I could be wrong here, but either way it would have been better if Pessoa had added specific sources.
3) Pessoa tries to argue against reductionism and the brain as a mere causal input-output organ. But he fails twice.
As for reductionism, he argues that a functioning brain can't be reduced to smaller components. I agree: you need all the components of the brain to have a healthy, functioning brain. BUT that does not make reductionism as a philosophical undertaking invalid: it just shows that to understand certain complex systems, you don't need to reduce things totally to its lowest possible level. Maybe that's why some reductionist tend to speak of 'mechanism' instead, and Pessoa admits the brain functions in a "mechanistic" way, "in the sense that all parts function according to the standard rules of chemistry and physics."
Because, what is often at stake in these debates is the principle of causality, as some scientists want to uphold the idea that the human brain (and so humans too) can somehow escape causality - like Pessoa in a way tries with the notion of "emergent" behavior. 'Emergence' refers to properties that are not present at the lower levels - but that's not what reductionist try to argue: no-one claims every property is found at every lower level. For if we can escape causality, we are free, but if we can't, the freedom of the will becomes a problematic notion. Pessoa never talks about free will in this book, but does try to stress the human brain as a flexible organ, responsible for flexible behavior, behavior that's "emergent" & "complex" - yet no-one that argues against free will claims that our behavior is not complex, or not situationally flexible, or not emergent from our protein brain.
When Pessoa tries to show that behavior is emergent and complex, and not just the result of input-output causality, this is where he fails too. He admits the brain can be thought of as a circuit in between sensory and motory cells. But his notion of input is misguided. Consider this crucial passage on page 153-154, under the telling heading "Decoupling Sensory Signals from Motor Responses":
"In chapter 3, we discussed a circuit involved in both defensive and appetitive behaviors centered on the optic tectum/superior collicus of the mid-brain. This system is extremely important across vertebrates. In rodents, it helps the animal decide if it should flee when movement is detected overhead or possibly approach and explore further if the movement is in the lower visual field. But the animal's behavior is flexible and not fixed by the input - the context in which it occurs, encompassing both external and internal worlds, is critical."
The problem with this part is that the context obviously is part of the input too. You cannot argue for the brain to be an entangled system, and then consider the input to the optic tectum to be only some visual input. The body's internal state (all kinds of sensors measuring appetite, hormone levels, pain, fatigue, etc.) offers constant, diverse inputs into the brain as a system, influencing how its subsystems operate. The same goes for the context, the "external" world: obviously the input is not limited to vision of some movement in the lower visual field. There's the other visual input, but simultaneously also input of all other senses (sound, temperature, tactile, smell, taste,...). On top of that, the brain is a system that evolves over time, something Pessoa does admit, coincidentally on the next page: the system learns. So also input (of whatever kind) received in the past, should be considered as well.
All that makes a sentence like "the animal's behavior is flexible and not fixed by the input" highly misleading. Pessoa here talks about one specific form of input (vision in the lower field) but the gist of his argument gets him to the "decoupling of sensory signals from motor responses", as if the brain somehow overcomes causality.
On page 218 he even goes as far as suggesting there might not be a close link between brain and behavior: "Now, when researches study the rat's brain under such conditions, a close relationship between brain and behavior is established. But as Paré and Quirk warn, the tight link might be apparent insofar as it would not hold under more general conditions. Neuroscience is experiencing a methodological renaissance."
In the final chapter, we get the following, a bit baffling statement on page 221: "In considering the benefits of such ubiquitous mixing of sensory and motor information, the investigators [Stringer et al. 2019] ventured that behaving effectively depends on the combination of sensory data, ongoing motor actions, and internal-state variables."
To which I would say: no shit, Sherlock. Notice again that ongoing motor actions and internal-state variables are decoupled from sensory data, while I would argue that also motor action and internal-state variables are very much part of our sensory data. In trying to (justifiably) break down the walls between brain regions, Pessoa keeps up some other walls that are conceptually just as problematic.
Let's consider a final passage, on page 212, in a chapter about unlearning fear:
"The decision to take flight is not just triggered by threat detection and involves computations that rely on multiple external and internal variables. Together, escape behaviors are far from simple stimulus-driven, stereotypical reactions. The mechanisms involved engage specialized circuits refined by eons of evolutionary times."
I get it, behaviorism and conditioning are a bit creepy. Scientists want to get away from Watson and Thorndike. But why even add the words "stimilus-driven" in the above part? True: real life rat or mice behavior is complex, not-stereotypical, not the same as in a 40 x 40 x 40 cm white laboratory box. But are "multiple external and internal variables" really no part of the brain's input? Aren't those variables stimuli too? Yes they are. Again, Pessea singles out on specific stimulus (predator detection), points at the fact that stuff is more complex, and then uses that cast doubt on the entire idea of "stimulus-driven" input behavior, as if the additional complexity isn't part of the input/stimulus.
All and all, a disappointing read.
More non-fiction reviews on Weighing A Pig Doesn't Fatten It
August 11, 2023
Popular Neuroscience at its best
This book is truly satisfying to read. Apart from the merits that you can read in the rest of the reviews, I need to say that The Entangled Brain contains the best explanation of Nonlinear Dynamical Systems that I have come across. After failed past attempts to understand what this theory stands for despite extensive online research and conversations with mathematicians, I now feel I have a very solid grasp of it. Pessoa does an incredible job putting things in the right context to make them understandable for the non-experts.
This book is truly satisfying to read. Apart from the merits that you can read in the rest of the reviews, I need to say that The Entangled Brain contains the best explanation of Nonlinear Dynamical Systems that I have come across. After failed past attempts to understand what this theory stands for despite extensive online research and conversations with mathematicians, I now feel I have a very solid grasp of it. Pessoa does an incredible job putting things in the right context to make them understandable for the non-experts.
November 15, 2023
It's a fine book but I honestly don't agree with a lot of what he said about modern neuroscience. Like just so many weird takes. Also DUH the brain is interconnected NO ONE IS SAYING IT ISN'T. You are not a revolutionary for saying that connections are bidirectional and that carbon dioxide fear isn't amygdalar. Like WE KNOWWWWW. I think this book would be fine for someone who isn't into neuroscience but for someone who is it's just supremely boring and dumb.
May 12, 2023
Introduced its message way too late in the book.
I also felt that the idea that brain networks show temporal progression was not substantiated enough in the book.
However, this book had some interesting points. I especially agree with the criticism that neuroscientists idea of causation is prob not applicable to such an interconnected structure as the brain.
I also felt that the idea that brain networks show temporal progression was not substantiated enough in the book.
However, this book had some interesting points. I especially agree with the criticism that neuroscientists idea of causation is prob not applicable to such an interconnected structure as the brain.
November 4, 2023
The author argues there are no brain substrates for cognitive functions. Brain dynamics underlie these functions. These changes over time can be expressed using vectors in n-dimensional space. The number recording sites determines the number of dimensions.
September 21, 2023
It's astonishing how dry, demotivating, devoid of intuition or excitement this book is, and all while dancing around a point that fits into maybe half a sentence.
Displaying 1 - 8 of 8 reviews