Consciousness Explained (D. Dennett): Part VIII; The Baldwin effect

We are the result of natural selection. Natural selction works by 1) allowing mistakes in the genome of an animal's offspring and 2) selecting the offsprings whose genome makes them better at survival/reproducing. If you are not familiar with this concept, go to buy "the selfish gene" from R. Dawkins (a live changing book).

The Baldwin effect is a mechanism that speeds up natural selection in a very peculiar way. It require you to have a plastic nervous system, in short: an ability to learn. If there is a "good trick" out there for an animal to learn, e.g. a behaviour that would greatly enhance an animal success at reproducing, any animal having this good trick hard-wired in its genome would be at an advantage. However, since having this "good trick" within it would be an all or nothing story, there maybe lacking a sufficiently progressive slope for natural selection to opearte swiftly. Hence, the time for this trick to be hard-wired in every animal within its species might be very long indeed. See left side of the figure below:

However, species not having this good trick hard-wired in their genome but having a plastic brain wired in such a way that they are capable to learn that trick during their livetime, are able to evolve the hard-wirering of this trick much faster. Here is how it works: Animal A has a brain slightly more able to learn the good trick than animal B. Animal A has therefore an advantage over animal B and will therefore probably leave more offsprings. Amongst said offsprings, animal A', due to a fortunate mutation, is still beter at learning the trick than its parent was, A' acquires it faster in his livetime than his siblings and therefore outcompete them and makes more offsprings. Amongst the kids of animal A', animal A'' is gifted with a further fortunate mutation that makes him particularly able to learn the good trick...and so on and so forth until the good trick (or at least the ability to learn the trick damned-easy) is practically hard-wired in the genome. What the Baldwin effect provides is a gentle slope for natural selection to operate on (see right side of the figure above). Any small improvement in the learning ability of the individual gives him a higher chance to hit on the good trick(s).

This makes clear the big advantage that a plastic brain provides to a species.

Book Review: Consciousness explained.Part VII. The evolution of consciousness

Daniel Dennett proposes the following evolutionary scenario for consciousness:

1) In the environment on earth before the appearence of life, some molecules acquired the ability to replicate (Richard Dawkins would call them replicators). This creates a point of view from which the world's events can be roughly partitioned between the favorable to this replication, unfavorable to it or the neutral".

2) "As soon as something gets  into the business of self-preservation, boundaries become important, for if you are setting out to preseerve yourself, you don't want to squander effort trying to preserve the whole world: you draw the line."

3)Next in line comes a certain ability to react to direct stimuli upon contact. E.g. engulfing food you touch or coiling away from harmful things you touch. This is the most rudimentary type of nervous response. It is a very crude way to predict the future. If I don't recoil, I will get eaten/destroyed/damaged.

4)Next, comes short range anticipations like the ducking reflex that permits to avoid being hurt be a projectile. Such reflexes are hard wired, including in humans (newborn infants have it). An interesting fact Dennett points out is the ability of many animals (from fish to humans) to be particularly sensible to the presence of a vertical axis of symmetry in its visual field. This is presumably caused by the fact that in our evolutionary past the most likely item in our environment having such an axis would have been a predator, a prey or a mate facing you. He argues that the fact that such alarm mechanisms are so crude, has the advantage of being fast and economical at the cost of many false alarms (the vision of a quasi symetrical tree for instance). For such a trick to be selected by evolution, it only has to give to its owner a slightly higher than otherwise chance to survive or to mate.

5) Once such a signal is detected, a further evolutionary advantage is achieved by a discrimination process capable to determine (at least in a crude way) if the first crude signal was a predator, a prey or a mate. In some fish, the vertical symmetry signal triggers an "orienting response", i.e. a swift interuption of ongoing activity. Dennett says that we have many such subsystems running unconsciously and performing specialized tasks.
When an alarm signal is recieved, e.g. due to the perceiving of symetry, our system stops and all our senses are open to maximize the input of information. If the alarm is confirmed, we get a rush of adrenaline and we react by e.g. fleeing. He says monst animals have such a system and he sees such "orienting responses" as a precursor to what we call our state of conscious awareness.

6) The animal acquired the ability to trigger such an "orienting reponse" also as a consequence of internal stimulis (not only external inputs such as symetric objects).

7) "Regular vigilance" turned into "regular exploration" where the animal frequently acquire information for its own sake, just in case it turns out useful in the future. E.g. primates with their saccaded eye movements scan uninteruptly their environment.

That's already a nice start I think...

Will California suffer a earthquake between now and March 26th 2011?

I honestly do not know what to think about that. I will know on March 27th however.

Do you find this video relaxing?

Put the audio level low. This is an experimental video making use of our "orienting response reflex" by presenting to us new information every 2.5 seconds. During the "orienting response" which is a mental state in which most animal find themeselves when presented with something new, our heart rate is decreased and our brain blood vessels dialtes in order to increase our brain readiness to acquire information in order to react vis-à-vis this "something new". This vidéo is from ansgar1965 and is experimental (not tested, you are the cobayes. So what do you think? is it relaxing?)

Book Review: The Facebook Effect (D.Kirkpatrick)

I just finished listening to the corresponding audiobook. The book was really enjoyable and interesting. Key to the success of Facebook seems to be the very long term vision of his creator. The company was also very strategic in the way it developed. One example: Facebook decided to open at US campus already using another social network but when doing so, it also opened at all surrounding US campuses in order to create "pressure" from outside and to "gain" the campus for itself. The ambition of Facebook seems to become a kind of platform on the internet (just like windows is a platform). Another ambition of Facebook seems to provide to its member a kind of "identity card" that would become the standard identification method on the net. It also seems to ambitions establishing a currency. In a nutshell, it is a kind of worldwide government with extensive democratic control that Facebook aims for. His boss is depicted as being an idealist who does not put money as its priority at all. He is presented as being someone willing to bringing openness and transparency on the web.
Again, the book is very entertaining and I really enjoyed listening to it. It is motivating and it gives some ideas of what to expect in the future of internet.

Consciousness Explained: the contribution of a reader

I received an interesting comment from a reader (Jason Weber) that shed some more light on this book:

"I definitely suggest reading Sweet Dreams: it is very well written."

-I will order it…and read it in two or three years probably


"I took a look at your blog and enjoyed reading Part V of your book review."


-Glad to hear that.


"I have a question and a few comments if you do not mind. First off, what page did you find the quote for Dennett's alternative explanation for delay in consciousness?"

- p.164, 3rd§, line 2 : « Orwellian alternative »

"I ask because this sounds more like an "Orwellian revision" than Dennett's model for consciousness.
As I understand it, he does not support either an Orwellian or Stalinesque explanation, "...and the question Orwellian or Stalinesque? (post experiential or pre-experiential) need have no answer" (Dennett, Time and the Observer, http://ase.tufts.edu/cogstud/papers/time&obs.htm )."

-You are right that Dennett does not support either Orwellian or Stallinesque alternatives. I think I was wrong when I said that it is “his alternative explanation”. Actually he simply remarks that there is an Orwellian alternative to the Stallinesque model. Which I suppose makes his point that both explanations are possible, which is pointing to his multiple draft model.


"Thank you for bringing your blog to my attention, because I had forgotten how vehemently Dennett disagreed with Libet on the interpretation of those experiments."


-Strangely enough, I myself already read twice this part of the book and also forgot about it. Then I heard again about Libet type experiments and got quite excited about them, without realizing that I read a critique of them in Dennett. This really justifies my present effort to document what I understand from this book.


"Those experiments are very interesting to me and I had taken them at face value for a while."


-They are very interesting to me too. I am sympathetic to the idea that actions are decided before to be consciously felt as being decided…although I feel my confidence shaking a bit while reading this book.


"Your blog helped me to focus on some mistakes I had made. I do think that the unconscious parts of the brain plays a role in determining consciousness…"


-me too. I agree with Dennett that consciousness is probably distributed in the brain and that each location that get conscious, was not necessarily so the instant before. No single area for consciousness experience (I would have said otherwise six months ago. I might still change my mind ).


"…but that Libet's results and interpretations need a closer examination. Dennett provides that, so let me try to clear up exactly what Dennett does not like about Libet's experiments....

Daniel Dennett's criticisms of Benjamin Libet's famous experiment on intentionality:

In principle, I do not believe that Dennett disagrees with the notion that unconscious parts of the brain cause consciousness."-you are right


"He disagrees that attaining an absolute timing of conscious events from verbal reports is possible because consciousness does not happen in a centralized location in the brain.
That is the disagreement. Dennett notes that the representations of visual events occur, "...in various different parts of the brain, starting at the retina and moving up through the visual system...brightness...is represented in some places and times...location in others...and motion in still others" (Consciousness Explained, p.165).
Consciousness comes from many parts of the brain. For instance, he does not seem to believe that a single neuron or a single system in the brain possesses the state of consciousness all the time."


-It seems to me that it is indeed his position but I have a hard time understanding why the lack of a central location for consciousness prevents absolute timing of conscious events. Even if a conscious event appears distributed in space or at a location only temporarily made conscious, timing seems still possible.

"It follows that unconscious parts of the brain cause consciousness or change to the state of consciousness."


-indeed


"Dennett disagree with Libet because of his interpretation that the unconscious parts send there messages to a central conscious part of the brain."


-ok, I would need to re-read this part to check that it is indeed what Libet thinks and not Dennett’s interpretation of what Libet thinks. I think that even by abandoning the Cartesian theater, it is still coherent to interpret the results of the experiment by saying that the conscious “feeling” that a decision is made is felt after the decision. E.g. the decision is made due to a certain number of neurons being turned on at various locations…and 350 ms later we feel it because these locations changed “state” or maybe (my hypothesis) because this event “get burned” thereby creating a memory (at these same locations, e.g. by strengthening connections).


"Dennett states that, "...cognition and control -- and hence consciousness -- is distributed around in the brain, no moment can count as the precise moment at which each conscious event happens" (Consciousness Explained, p. 169). If measuring the absolute timing of a conscious event is possible, then we must assume that consciousness happens in one place and at one time in the brain."


-Not one place, only one time. No? Even if spatially distributed, it could be simultaneous or within a time relatively short compared to the delay observed by Libet.


"Dennett's model differs, not because unconscious agents cause consciousness but, because consciousness is not thrown together in one spot in the brain (e.g. the pineal gland). For Dennett, different systems contain different parts of the stories that make up consciousness but there is no place where representations come together to form a central conscious story of events."


-That is well understood.


"The most telling quote from Dennett in the chapter of Consciousness Explained that discusses Libet's experiment is this,

"Couldn't consciousness be a matter not of arrival at a point but rather a matter of representation exceeding some threshold of activation over the whole cortex or large parts thereof? On this model, an element of content becomes conscious at some time t, not by entering some functionally defined and anatomically located system, but by changing state right where it is: by acquiring some property or by having the intensity of one of its properties boosted above some threshold"

(p. 166)."


-I like this idea. It makes sense to me. I think consciousness intensity and memorization intensity are linked. Being conscious could be what it “feels” to memorize.


"The state change Dennett mentions is key: it is not that he believes that every part of the brain that has the capacity for consciousness is always conscious. I take it that he means that those parts change state from unconscious to conscious but do not do so until they receive enough clout to contribute to the distributed conscious experience. As different parts of the brain become conscious, the story changes; I think that is what Dennett means by multiple drafts."


-I think you are right and I think I now understand better this chapter. Thanks! I will re-read it nevertheless to be sure my new understanding fits with what he writes.


"Chapter six is difficult to understand so I hope I am properly representing Dennett's theory above. Feel free to correct me or to ask questions. Thank you,"

Time and the Observer

ase.tufts.edu

Two models of consciousness are contrasted with regard to their treatment of subjective timing. The standard Cartesian Theater model postulates a place in the brain where "it all comes together": where the discriminations in all modalities are somehow put into registration and "presented" for sub

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Here is part of a message of reply from Jason:

"...This might help to illuminate why Dennett is suspect of absolute timing of subjective experience:

In the last paragraph, I say that the "....state change Dennett mentions is key..." That is not exactly true. In fact, he warns that this view could lead us back to the Cartesian Theater, "...if it is claimed that the real...timing of such mode shifts is definitive of subjective sequence" (Dennett, Consciousness Explained, p. 166). His key point in chapter six of the book is that the, "...temporal sequence in consciousness is...purely a matter of the content represented, not the timing of the representing (Dennett & Kinsbourne, Time and the Observer, http://ase.tufts.edu/cogstud/papers/time&obs.htm ). Let's imagine an analogy to explore this point: mom is coming to visit you. Let's say that she decides Friday that she is coming to visit you on Monday. She sends you an email detailing her decision. Unfortunately, you do not check your email all weekend. Then, when Monday comes, you are utterly surprised to see your mom's smiling face when you open your front door. You then check your email and discover the news or your mother's decision to visit that day. The timing was such that you did not find out the news that your mother was visiting on Monday until she showed up on your doorstep. However, the decision was made and the message was sent earlier (i.e. Friday). This is why Dennett & Kinsbourne indicate that, "...temporal... details do not tell us directly about the contents of consciousness" (Time and the Observer, http://ase.tufts.edu/cogstud/papers/time&obs.htm ). Just because a message is sent does not mean we instantly become aware of it subjectively.


On your comment: "-ok, I would need to re-read this part to check that it is indeed what Libet thinks and not Dennett’s interpretation of what Libet thinks."
--I think you are correct that it is Dennett's interpretation of what Libet thinks.

Time and the Observer

ase.tufts.edu

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-Thank you very much for your comments, they were helpful. Thank you also for accepting me posting your message on this blog.

Christophe

Book Review: Consciousness Explained (D. Dennett): Part VI:The Precognitive Carousel

Dennett reports an experiment made by Grey Walter. It consisted in presenting a carousel projector for showing slides to patients having electrodes implanted in the motor cortex of their brain. The patients were given a controller with a button for them to push on when they wanted to switch from one slide to the next. Actually, the controller was a dummy controler and the slides where changed in function of the signal received by the electrodes. The results? The patients experienced that the slide projector was anticipating their decisions. The slides would change just before they had decided to change them. This again seems to point to consciousness arising after that the decision is made. Dennett however once again express his view that timing of conscious events is not possible. an opinion of him that I still need to study further before to accept it or to reject it.

I received an interesting message on Facebook from a reader (Jason Weber). I will probably post it as a note to chapter V.