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Simon Laub (Aarhus, Denmark, Europe)
1 of 1 people found the following review helpful
Understanding Consciousness and the Brain.
, January 21, 2015
Stanislas Dehaenes book ''Consciousness and the Brain'' is a really good book about current attempts in neuroscience and experimental cognitive science to understand consciousness and the brain.
The brain is obviously an astonishingly complicated and intensely intricate thing, filled with billions of spiking neurons talking to one another, evolved over millions of years. So, it is no surprise that it is difficult to understand. Indeed, perhaps it is more surprising that we can actually understand some parts of it...!
Dehaenes book adds to the feeling that we can actually understand some parts of what might be going on - Which is a quite an achievement. The book has a good balance between overview and details, between giving us an understanding of what might be be going on in the brain without drowning us in details about the brains microcircuits.
Take visual perception.
Dehaene introduces us to some of the problems that our visual system has to deal with.
Our retina is full of imperfections.
- There are blood vessels running in front of the photoreceptors. As we do not see this, it follows that our brains ''cleans it up''. And luckily so, it would not be good to look at the world and constantly be distracted by bloody curves.
- In the retina the input is blown up toward the center. Yet, we don't have a tunnel like experience of the world.
It follows that the brain corrects this.
- Outside the center of our gaze, the retina contains very few color sensitive cones. But we are not color blind outside the center of our gaze. We do not walk around in a black and white world that suddenly becomes technicolor at the center of our attention.
Again, in order to give us a full technicolor world, the brain is doing a lot of behind the scenes processing that pieces together a world in color.
- In the "blind spot" in our retina, at the place where the visual nerve goes into the brain, the retina is without light receptors. No problem, the brain fills in with tectures that look like what is around the blind spot.
- Our world is not shaky, eye and head movements has been corrected, and the scene has been reinterpreted based on knowledge about similar scenes.
And all of this is done unconsciously before anything is presented to the conscious self.
And (it is all) brilliantly presented in Dehaenes book.
The ancient greeks asked us to know ourselves.
But Dehaene cleverly notices that we can never know ourselves completely. All of the unconscious processes - most of what we are - will forever remain hidden! And with these processing mechanisms hidden, we will never be able to predict how we will behave outside our comfort zone of past experiences.
Dehaene ties it all together with Bernard Baars's ''global workspace'' theory of consciousness.
In this model, what we experience as consciousness is the global sharing of information. There might be millions of mental representations floating around in the brains unconscious regions, but one can be selected because it is relevant for the present goals.
And, in consciousness this representation can be made available to other systems in the brain.
(More detailed) In Dehaenes words, what we perceive in consciousness may be likened to the sculpting of a statue. Starting with a raw block of marble, and chipping away most of it, an artist progressively exposes his vision.
Inside the brain we have hundreds of millions of workspace neurons, just firing away at their baseline rate. We then perceive the world by silencing most of them, keeping only a small fraction active. This active set of neurons then give us the contours of conscious thought.
In the book, Dehaene is careful to back his ideas up with experimental data. This also happens here. The silencing of neurons can actually be measured in form of the P3 wave associated with conscious thought.
I.e. during conscious perception, only a few neurons are active, while the rest are silenced. The neurons who codes features that are irrelevant get a signal to stay quiet! And because many more neurons are inhibited than are activated, all of these voltages end up forming a large wave on the head - the P3 wave that can be detected when consciousness occurs.
A wave that indicates what the thought is not about!
It is some other voltages that indicate exactly what the thought is about, lasting as long as we keep the objects in our minds. And collapse when the objects goes out of the mind.
It is an absolutely awesome book, I only have one tiny little problem with it, which is strongly related to how neuroscience operates under the ontological assumption of physicalism, according to which only the fundamental phenomena studied by (current) physics exist.
This assumption might very well be true, but reading in the book you get the impression that the hard problem of consciousness will be solved (soon?) within this framework.
I.e. the hard problem of going from electrical signals to actually sensing (subjectively) sounds, feelings etc. is glossed over a little too quickly imho.
Finding neurons that correlate with the contents of consciousness might indeed be a first step. But what the next steps will be (on the roads towards explaining consciousness) is still unknown. As is the theories that will get us there. It is not just smooth sailing from here. It could have been stated more explicitly in the book.
Still, I wont deduct any stars because of that.
It is still a great read.
The souls frail dwelling house.
, January 14, 2015
According to Shakespeare, the brain is the ''The souls frail dwelling house'' (King John. Act 5, Scene 7). And after reading Joseph LeDouxs 2002 classic, ''The Synaptic Self'', the brain certainly feels frail.
The book is all about the exact chemistry involved in the synapses between neurons.
The chemistry that makes neurons work, and communicate with each other. And how that chemistry in the end makes a brain.
Certainly, there is a lot of frailty here. Changing the chemical components of the brain just a tiny little bit, can have huge effects on how we think.
(Obviously) The book does not give us all the answers about how the brain works. But the book is an excellent primer on synapses in the brain, and how this could eventually lead to something as amazing as a human mind.
Indeed, the story about synapses in the brain is wildly fascinating.
And the book contains both an overview on how synapses actually works, how the chemistry involved might be changed, and with what results.
It all starts off with memory. We are our memories. Where memories are intimately connected to what goes on in synapses in the brain.
Changes in these synapses could perhaps improve memory by altering the molecular basis of synaptic plasticity.
Ultimately, it might be possible to find a drug that speeds up learning.
And it is not just speculation. There has been some success, rats given the compound ampakine seems to be learning faster.
Perhaps because this drug increase the efficiency in synapses, and thereby facilitate LTP (long-term potentiation) induction.
And ampakine isn't the only chemical at work in the brain.
Other chemicals are at work in connection with stress. LeDoux offers a very illustrative description of what might be going on. A pretty scary story actually.
During stressful conditions, the concentrations of cortisol rises in the bloodstream. It travels through the bloodstream to the brain, where it binds to receptors in the hippocampus. Here, it disrupts normal activity and weakens the ability to form memories.
Indeed, stressed rats do porly in tasks that require the hippocampus, such as spatiel learning.
If the stress continues, hippocampal cells begin to degenerate and die. Depression might follow.
Not surprising, stress hormones also have an adverse impact on the prefrontal cortex, and may contribute to why people make bad decisions under stress.
The stress is often caused by exposure to fears and anxieties (for an extended period of time). If this allows the amygdala to run the show unchecked, fear takes root in working memory, which will then further alter the processing of other areas. Eventually, everything becomes biased by the emotion that has made camp in working memory. Not good...
But excellently explained in LeDoux's book.
And this isn't even the worst way to change chemical balances in the brain. Balances that are so important in keeping us sane.
When people take LSD they can have powerful hallucinations. Furniture in a room can assume grotesque, threatening forms, people can turn into strange unknown creatures.
So, if LSD produces these psychotic states by altering neurotransmission in the brain, sanity might require a certain right level of these neurotransmitters!
It follows that changing these transmitter levels might be a way of treating many mental ilnesses.
Many books about the brain focuses solely on cognition. How the brain ''calculates'' things.
Forgetting emotion and motivation. Which is a bit troubling if it should be considered a study of the whole mind.
I.e. you might be able to play chess without emotion and motivations. Indeed, perhaps, you play even better, if you are not distracted by emotions like love, anger or fear.
But feelings and strivings must be included in order to understand the whole human mind.
Behaviour that is guided by things like compassion, or guilt over actions not taken - can only be understood in the light of emotion and motivation.
Very satisfying, LeDouxs book treats emotion and motivation just as seriously as cognition.
Even though he is very upfront with the fact that much is still unknown when it comes to emotion and motivation in the brain.
The book also has some interesting sections about seeing the human mind from different levels, viewpoints.
I.e. some people don't like to be told that they might exist at other levels than the level of conscious awareness.
Reductionism to the level of synapses does come down well everywhere.
And LeDoux acknowledges that it is a problem in reductionism that it can lead you to describe phenomenon at the wrong levels.
E.g. describing a poem at the level of the atoms that make up the book the poem is found in, doesn't make much sense. Phenomenons needs to be described at the right level.
Here, LeDoux has some important observations about how different points of view can support each other, and enrich each other, without necessarily invalidating each other.
A great read.
1 of 1 people found the following review helpful
Adventures in Brain Land.
, December 29, 2014
When most of us say that we want to to know ''how the brain works'',
Chris Eliasmith suspect that we don't just want to know how a single neuron works, or what brain centers have increased activity when we (e.g.) read, or what chemicals are in abundance when people are depressed.
No, this is all part of the answer, but we want more!
We want to know what goes on in the mind, starting from perception to and all the way to an action. In some detail, but also with an overview. We want to "really" understand.
Obviously, this is a tall order. But as understanding human cognition is understanding who we are - we will proceed anyway...
And here Chris Eliasmith's book is an excellent guide and helper for this, our most important journey.
Many books out there are big on speculation and light on anything you can model.
But seriously, if you can't model it - somehow - can you then be said to understand it?
We need the ''wheels'' and ''gears'' of cognition, and we need modelling at an ''appropriate'' level.
We don't want to model each neuron with 100 equations or so, if it is not really necessary.
We just want to capture the essential features.
In order to bridge the gap between the neural level and the level of human-like cognition, and come up with this "appropriate" level for the models, the book introduces us to the concept of semantic pointers. In my understanding, this is a kind of symbol, a compressed version of the information contained in a more complex representation.
And this is where things begin to become interesting.
As I understand Chris Eliasmith, semantic processing in the brain might start a kind of simulation. And in that way be central to how we think.
Certainly, simulation is crucial. Chris Eliasmith writes that
"When people are asked to think and reason about objects (such as a watermelon), they do not merely activate words that are associated with watermelons, but seem to implicitly activate representations that are typical of watermelon backgrounds, bring up emotional associations with watermelons, and activate tactile, auditory, and visual representations of water melons".
It follows that good brain models should somehow capture such mechanisms.
Take home message: Semantic processing and simulations will be important in the coming phases of understanding cognition and building cognitive models.
And, playing around with the models presented in this book seems to be an important first step in that direction.
Still, are the models in the book "good enough"?
Well, they can take image sequences as input and produce motor behaviour as output.
The scale is somewhat "modest" (2.5 million neurons) compared to
other models, but in terms of what it can do, it is currently the largest functional simulation of a brain, demonstrating recognition, classification, motor behaviours etc.
So, Chris Eliasmith is certainly correct in stating that it has something to offer to the current state-of-the-art.
Indeed, a very impressive number of brain centers are modelled with (the books) Semantic Pointer Architecture Unified Network (Spaun).
Obviously, the whole brain is not modelled yet, and equally obviously, it is still only a simplified model (good or bad) of what might be going on in a brain.
Afterall, building a brain is a difficult thing to do....
Still, there is good input in the book about models for visual processing (modelling what might be going on in the brains V1,V2,V4 an IT areas), action selection (modelling the Basal Ganglia) and motor processing (modelling the primary motor cortex) and much, much more.
Still, there are many unsolved problems in this land of modelling.
For example, when we assume that an object has a backside even though we cannot see it, we are often said to be relying on mechanisms of perceptual inference.
Current models do not have a unified theory of inference, but, remarkably, Eliasmith thinks SPA can help us understand inference by characterizing it in the context of a functional architecture. This is really encouraging.
Again, the scope IS very impressive.
And so is Eliasmiths intellectual honesty when he writes that "emotion and stimulus valuation are largely absent (in the model). These play a cricial role in guiding behavior and need to be integrated into the SPA".
This is where it all gets very interesting, a complete model should obviously have a lot about feelings - Feelings are afterall what makes us "own" our thoughts, our own mind, and they are the background to all of "the cognitive calculations" that we have been introduced to in the book.
So, it is disappointing (for this reader) that there is so little about feelings.
In other (less comprehensive) books the omission wouldn't have been felt so hard, but given the amount of material covered here it does feel like a let-down.
Why? Is it because we currently only have neural correlates of say "pain", but no one who has offered us a convincing explanation of how neurons can make a "calculation" that we experience as "pain". If so, then I certainly would have liked to hear Chris Eliasmiths speculations on this. And how we could possibly proceed here.
Anyway, the brain is a big thing, and including the whole thing in one book is probably somewhat optimistic...
And it is certainly a sign of a good book that you want more, not less.
A great read.
After reading the book I already miss Harold and Erica
, October 22, 2014
In the book we follow the lives of the fictional characters Harold and Erica.
And through them we get a lot of amazing insights
to what science really teaches us about real human lives.
The blend of fiction underpinned by science is a treat to read,
and Brooks certainly deepens our understanding of the science
by introducing us to these two lives.
Sure, there are certainly a lot of words in the book.
But as Brook teaches us, words are necessary
for guiding thought and communication.
And we can know a lot from the words
a person sends out. Indeed, these words are the tip of the iceberg of the intelligence
they are coming from.
As a matter of fact, the easiest way to measure someone else's intelligence
is through their vocabulary. And people who are
getting to know each other probably subconsciously measure
each others vocabularies to see if they are on the same
Which btw. speaks well for Brook's own intelligence.
The information we deal with in our world has
many sources and Brooks tries to give justice to them them all.
From our deep evolutionary past we get genetics.
Culture and Religion goes back thousands
of years and shapes us and out thoughts more
than we are ever aware of.
Families goes back decades, if not centuries, and determines where we start
in life, and what ideas we are brought up with.
Education goes back a couple of years and
helps us with the here and now we
are situated in.
And all sources are important in forming us to the become the people we
Still, it is not easy to describe our minds -
Afterall, they are enormously complicated
things with an endless series of processes going on in parallel.
An eco system consisting of patterns, reactions and sensations
all competing for control over an organism.
And with no captain sitting somewhere high
above everything else calling the shots.
But, through the story of Harold and Erica
Brooks cleverly brings in new viewpoints to help
us understand what might be going
It is all very illuminating and a pleasure to read.
1 of 2 people found the following review helpful
Order Out of Chaos
, October 17, 2014
What a great book by Jon Meacham!
According to Meacham: Philosophers think, politicians maneuver.
And Jefferson was both, and could do both. Such is the art of power.
Jefferson delighted in archaelogy, paleontology, astronomy, botany and meteorology. He edited the New Testament, removed the passages he found supernatural or implausible, and arranged the remaining in the order he thought they should be read.
That is, when he was not busy gardening, or being president, or a slaveowner.
To his foes, Jefferson was an atheist and a fanatic, a francophile who could not be trusted.
He was indeed many things. But he was also the man who formulated the idea of American progress, that the future could be better than the present or the past, and that the finest hours lay ahead.
He lived in a time when nothing was certain.
Indeed, in his own mind he lived and governed in the middle of a ''Fifty Year's war''.
With revolution, and british invasion.
And much more. It was a time when nothing was certain.
For a philosopher this sounds like way too much reality. But luckily, Jefferson was also a man of the enlightenment. Reasoning could point to a better future.
While in England (as en envoy of America) he would spend a few days surveying English gardens together with John Adams. Imagine that, the second and third president of the United States spending hours discussing how landscapes could be cultivated.
But perhaps, to them politics was just another form of gardening. Liberty too requires patience and fortitude.
Jefferson was also a man of huge contradictions. His personal slave, Jupitor, would follow him as his personal servant and traveling attendant during the years of Jefferson's law study and practice. From 1774 to 1826 Jefferson had about 200 slaves at any one time. Over the years he would own more than 600 slaves.
And yet he was the author of the Declaration of Independence:
We hold these truths to be self-evident, that all men are created equal.
Really, you think...
When his wife, Martha Wayles Skelton, died on September 6, 1782, after 10 years of marriage at the age 33, Weakened by childbirth, Jefferson was inconsolable and was led from the room almost in a state of insensibility by his sister, who, with great difficulty, got him into his library where he fainted, and remained so long insensible that they feared he would never revive.
On her deathbed Martha made Jefferson, then 39, promise, that he would never remarry.
Which he never did.
But there is a twist.
Among the witnesses to the pledge was the slave Sally Hemmings, who, by the way, was Marthas half sister.
You couldn't make this up, but it gets worse.
Sally Hemmings would later go with Jefferson's youngest daughter Mary (Polly) to London and then to Paris, where the widowed Jefferson, 44 years old at the time, was serving as the United States Ambassador to France. And it was in this period that Hemings and Jefferson are believed to have begun a sexual relationship. In the end Sally Hemmings would give birth to 6 children, all with Jefferson as the father.
There are varied and wondrous possibilities in the human experience. And perhaps that is why Jefferson is still with us after all of these years. According to historian Jon Meacham: In his life there is this thirst for knowledge, the capacity to create, the hunger for accomplishment, the love of family. A legacy of leadership of thought and of men.
And then there are these huge contradictions, flaws, sins.
And there is this need for power and control, so carefully masked, that many had troubles detecting it.
The world can be a very disorderly place. And he was the leader of a rebellion, against the order, for disorder almost. But not quite. Behind it all there was the gift of enligthenment. The gift of reason and the gift of extracting order out of chaos.
Giving life meaning, truth.
What a job. What a life. And what a great book.
2 of 3 people found the following review helpful
Culture and experience matters, not only biological determinism
, October 15, 2014
Sure, we are a product of biology, but we are also a product of culture and experience.
There is indeed something after genetics and evolution.
And we have have heard way to little about this in recent years.
So, imho this is long overdue, and in this very complelling book by
Jesse J. Prinz we get "the other side". I.e. a lot about how culture and history turns us into the people we are.
The story takes us from babies dressed up in pink or
in blue, and being treated by parents accordingly.
To morality in hunter gatherer societies versus
agricultural societies. Where is it moral
to be a cannibal, and where can you
Language is what allows us to talk about the
whole thing - and Prinz makes a good case
for statistical learning as the basis
of language - instead of an innate language module, it convinced me.
There is a lot less innate than
we usually think, and a lot more learned than we usually think.
I take a lot of the critique of this book to be about
where nature nature starts and nurture takes over,
and I think this books finds a much better balance
than we see in other books.
3 of 5 people found the following review helpful
Excellent food for thought
, October 10, 2014
The creation of a superintelligence is something
we can only vaguely see through the fog of everyday trivialities.
Even though it is probably the essential task of our age.
Indeed, human civilisation is at stake here.
Certainly, Nick Bostrom makes a pursuasive case that
this might be the case and that we should actually care.
As readers, we might be somewhat hesitant,
but as we digg deeper it becomes clear that
superintelligences might be centuries away, but
what will eventually happen gets decided now,
and we should probably care just a little about these
If the machine intelligence revolution goes well,
the resulting superintelligence could almost
certainly devise means to indefinitely prolong the lives
of existing humans and much more.
If it goes bad, humanity could end there and then.
So, how should these superintelligences be controlled?
Should we have them within a ''box'', unable to interact with the
outside world, except through certain restricted channels.
Or should we set up tripwires? A mechanism that performs diagnostics on a system
and effects a shutdown, if it detacts dangerous behaviour.
Or should we build the systems in such a way that
they can only have modest, non-ambitious goals.
The more we digg into these questions the more it becomes
apparent that these are not just esoteric questions from
some distant future - but highly relevant questions
that we will eventually have to answer.
And thinking about this future questions certainly
gives us some valuable lessons that can help us deal with
less deadly, but still important, questions
from our own time.
A good introduction to a really, really hard problem
, October 1, 2014
Most people are probably more comfortable talking about
"easy" brain problems, such as how
the brain processes e.g. visual information (which is actually also
a hard problem...just not as hard as the hard problem of consciousness).
But in this book it is head on with the
hard problem of consciousness. How our brains turns feelings,
thoughts and perceptions in an inner world.
This books actually tries to give us a glimpse
inside consciousness, and invites us to see how feelings, perceptions and
thoughts, this whole, private inner world
we experience might arise
in a universe that is made of molecules?
All viewpoints might not given, and parts of
it might be overturned by the discoveries of tomorrow,
but still the book offers a
fascinating and exciting journey into this really, really hard problem
1 of 1 people found the following review helpful
It is all about perspectives.
, September 24, 2014
An awesome book! Not that it is particular fancy pancy, long or particular difficult to read and understand. No, it just quietly says a lot about thought and meaning. An accomplishment, as thought and meaning are not easy subjects.
Many hard battles are avoided in the book by just taking a sensible middle road.
Concerning how we get from neural firing and information processing to experiences (Sitting outside in the sun, hearing kids playing, being there), what David Chalmers calls the hard problem, Jakendoff simply says that he doesn't think the question is tractable at this point in the sciences of the mind and brain.
So, he just thinks we should set it aside for now.
Not saying that we will have solved it in 15 years time, or that we will never solve it.
Meanwhile, there is plenty of other stuff to do, such as being more precise about the connections between brain neurons and experience.
What particular patterns of neural firing and information manipulation are correlated with which particular aspects of experience?
Free will is one of these confusing things that are built into consciousness.
Taken from our ordinary, daily life perspective, Jackendoff assures us that we do have free will. But, if we take a more neuro-scientific perspective, the brain must be doing something to give us the feeling of free will.
Not the kind of bloodthirsty arguments we might see in other books. Instead Jackendoffs arguments ring true.
So, what are people?
Going back to at least Descrates the thinking has been that: Humans have souls, are conscious, are rational, have language and have moral responsibility.
Where the modern world seems to disagree. Science isn't to sure about the soul (Many scientists will tell us that there is no such thing, and only a few will leave room for something unknown, such as Chalmers ''Hard Problem of Consciousness'').
Jackendoff summarizes by saying that in the end we get this message from the modern scientific world: ''There is nothing special about you. You are just a chance product of mindless evolutionary processes operating in a insignificant corner of the universe. Your life has no meaning. In fact, there is not even a you, there is just a clump of neurons interacting''.
Given these kind of arguments, Jackendoffs doesn't think it is a great mystery that there is public resistance to teaching evolution in schools.
Between such a picture and one in which you are meaningful and even sacred, where it matters what you do, and where there is a God that cares about you, which would you choose? He writes.
''If science tells me I don't exist, and that there is no right and wrong, then to hell with science''.
Jackendoff says he misses a way to resolve the crisis, where our lives becomes meaningful and sacred by the way we live these lives. But by that sentence alone he has almost solved it for us.
In the end it is all about perspectives.
Finding the right thoughts and ideas has do with finding the right perspective.
According to Jackendoff there is no such thing as an overarching, perspective free truth about the world. For each problem it is important that we find the right perspective.
If we take the wrong perspective, we end up saying weird things like that there is no Me, there are no sunsets etc.
Questions about the world tend not to converge on one set of answers...
Following his arguments, you see that this is not ''giving up'', but actually a way to sharpen our tools, so that we can do better.
An awesome book.
An awesome book
, September 22, 2014
That brings a lot of ideas about the brain together, and tells us what growth and change is all about.
Norman Doidge tells us that like all good theories, brain localization can be exaggerated.
Going back to observations that damage to specific areas led to loss of specific mental functions - brain localization became the idea that every brain function has only one hardwired location.
And damage to that area meant that the brain could not recover that lost function.
But, actually, the areas that process images, sounds and smells are not completely different,
they have some similarities. And the brain is more plastic than we have been taught. Things can be rewired in many ways that was previously thought impossible.
Certainly, the book convincingly makes the case that when a brain map is not used, the brain can reorganize itself, so that another mental function can take over that processing space. A blind person might use functions in visual cortex to handle tactile sensations Etc. Indeed, we can probably all develop new capacities by using existing brain circuits in a slighty different way.
It is all pretty confusing, but also pretty awesome. It gives us all hope that we can
all grow and develop even when we get older.