The memory of the guardian angel in our brain

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[Added April 2012]
seashell fractal

In his book “Thinking fast and slow” the Nobel prize winner Kahneman introduces
two fictitious characters “System 1″ and “System2″ to better explain how our brain works. These two characters can also better explain how our memory works.

System 2 is our slow, deliberate, analytical and consciously effortful mode of reasoning about the world that we apply when we try to compute for example
12×37 . It uses memory like a computer .

System 1, by contrast, is our fast, automatic, intuitive and unconscious mode of thinking. This is the reasoning that will make you jump
on the side walk when you hear a klaxon of an approaching car. And you discover
that this jump has saved your life. Its main purpose is to scan continuously the
environment in search of signs of danger. And when it finds something strange to produce an immediate reaction that saves us. For this reason I call System 1 the “guardian angel in our brain”.

System 1 uses memory in a peculiar way. It has two main problems to do its work:

  1. The analysis must be fast, so it activates continuously all neuronal pathways connected with what our senses are detecting. This activation (associative memory) brings as much as possible to memory to help to check
    that everything is ok. One of the results of this brain activity is the phenomenon of priming. The study of priming has shown that this activation is
    done in parallel on all words, objects and actions connected with what we are
    sensing (Strange odour in kitchen, gas, open the window, close the oven ….)

  2. System 1 has also the need to delete quickly some of the activated ideas
    that we don’t need any more in order not to overcharge our brain with unwanted stuff. This is done in an elegant and efficient way. This can be seen following
    System 1 as we walk in our house. In order to check that there is nothing strange it must load a map of the whole house in our memory to compare what we
    see with what we remember. This can be a lot of information but it seems that
    it is loaded in parts room by room. When we pass a door the information about the room behind us is replaced with the information about the new room.
    This works so well that sometimes when we arrive at the refrigerator we have
    completely forgotten what we wanted.

Click to remember forever

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[Added February 2012]
Medial surface of cerebral cortex - entorhinal cortex
It is possible that we can have in future a gadget that, just by clicking on it, can
make the recollection of what we are looking at, permanent.

Possibly, but you have to implant a wire in the enthorinal cortex of your brain. The click will just send a small electric charge in a group of neurons that seems to be connected to spatial memory consolidation.

In fact a new study on a small group
of people suggests that deep brain stimulation in this zone enhances spatial memory. The deep brain stimulation is already used in all cases when we want
to influence some behaviour that depends only on the neurons in a small brain region. For example tremor in Parkinson Disease.

The only problem is that
you have to find exactly where these neurons are for each patient. For the experiment about memory, there was a similar problem but this time connected with finding the part of brain tissue connected to epilepsy. The procedure needed a long time allowing the memory test to be done. What is interesting, is that
the stimulation of hippocampus didn’t produce any improvement!

Of course , given the fact that we have many types of memory (in this case
only memory in a spatial task was tested) it is unlikely that stimulating
a single zone would suffice!

Please put a door between them

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[Added November 2011]
The method of loci so well described by the book Moonwalking with Einstein
by Joshua Foer is based on remembering hundreds of loci . There are rules on
how to create them in such a way that they can be easily remembered. These include
the fact that they should have all about the same size, be well illuminated , well separated, … These rules are obvious since they make more easy the
recollection. New research by Radvansky and others
make more clear what means “well separated” and how it works. I couldn’t get
the original paper but a previous paper on the same subject:
Walking through doorways causes forgetting:Situation models and experienced space describes very well the experimental protocol. The experiments are done using computers and virtual reality techniques: you are requested to walk a space
containing many desks with objects on them. You carry an empty box and you
should pick an object and put it in the box. Than you carry it to another
desk. This will go on for some time and different objects. From time to time
you are asked what you have in the box. It is as simple as this. You have
to remember only what is the last object that you picked. Here the interesting
result is the following : if you use the same space and the same desks layout
but put one or more walls and doors between them, the number of times you
forget the object’s name increases. In the last paper Radvansky has demonstrated
that there is real forgetting because the person doing the experiment will
return after passing a few doors in the place where he picked the object and
there is no recovery of memory:i.e. the fact of passing a doorway will produce
a permanent forgetting. Radvansky explains this “the act of passing through a doorway serves as a way the mind files away memories”.

From this research it is also apparent another striking feature of our brain: it works in the same way in real world, in virtual reality, reading
about a scene, looking at the scene in a movie and of course imagining
the scene as they do in the method of loci. This may seem surprising but it
isn’t if you just replace our brain with a computer trying to move in
real world. Of course the computer doesn’t interact with real objects but only
with a stream of 2D images and other data. Using these it must create a 3D
model of the unknown real world. It is exactly what the brain does but it
does it so effortlessly that we may think that we are interacting with real
objects. This instantaneous simulation of reality is also done by our brain
when it reads a text , sees a movie or imagines a walk in a memory palace.

Now coming back to the method of loci. The essence of the method is that you
store all the information you want to remember in the loci of the memory palace.
Then you get this information back walking from locus to locus. As you do this,
it is important also, that, after you extract the information from a locus
(something like picking an object from a desk), this information shouldn’t bother you any more (since you have already used it) and so, to forget it, you
just imagine that you pass a doorway and you arrive at the next locus ready
to pick a new object.

Instead in real life you may want exactly the opposite when you have forgotten what you needed from the refrigerator. Before passing the doorway
use for example some hand gesture to remember and reverse the door’s effect
on memory. Or just keep repeating the name of the thing you need…

What are doing those virgins in Ravenna’s memory palaces?

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[Added November 2011]
The fast answer is : exactly what are doing the “virgins” during bunga-bunga parties in Berlusconi’s (real) palaces. For the long answer please read the
book Moonwalking with Einstein
by Joshua Foer. I try to summarize (of course mistakes are mine). This book is
all about method of loci. This method has been invented around 3000 years ago and is based on two important principles that allow the fast and permanent remembering of almost everything.

The first principle is the use of “loci” (places in latin) and is
based on the fact that our brain is very good at remembering places. JF describes this very well: if you are left alone in a house never seen before
for a short time (for example an hour), that hour of exploration is enough
to memorise hundreds of details of the house forever.

Now, if you only could read a book about a complex subject or a deck of cards in the same way as you “read” the house , you have discovered a way to memorize instantly everything. This is what the second principle of the method addresses: “images agentes” vivid images of “something” happening in the places
that you already know very well (i.e. the loci).

Now, what are the things happening around you that you best remember: mostly things where other people is involved and having emotional content.
For example, if we are in a situation which is dangerous for us , we store instantly everything happening around us and we automatically replay the scene
day and night (in our dreams) for many days until that scene becomes a permanent
part of our brain. This is what means “vivid images”: imagine a scene happening in one of the loci in which someone that you know well is doing something nasty, fearsome or simply funny or bizarre. Then this scene will stick effortlessly to your brain and , if it encodes a concept in a book or a card in a deck, this information would also be stored forever. Before you rush using the
method , be warned : you need a year of training to set up enough memory palaces (i.e. empty houses) and then to create effortlessly new images…

Now coming back to the virgins… Sexual images are of course among the more memorable so Peter of Ravenna, a 15th-century writer on the topic advised “If you wish to remember quickly, dispose the images of the most beautiful virgins into memory places”.

Is Daniel Tammet a liar?

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[Added November 2011]
In his wondeful book Moonwalking with Einstein
Joshua Foer speaks also about Daniel Tammet. This is the famous
autistic savant that has written a book explaining ,among other
things, how he was able to learn the first 22,514 digits of pi.
Joshua Foer attempts to convince the reader that Daniel Tammet is a liar.
Of course there is no doubt that Tammet has Asperger and that he was able
to memorise all these digits (or to perform other extraordinary feats involving memory). What he criticises is the explanation given by Tammet on how he
managed doing it. The reason is very simple: as he very well explains
in his book, there are methods that can enable anyone to do this and these
methods don’t require extraordinary powers like synaesthesia.
According to someone this is a “misstep” in Foer’s book : see for example
this review.
But my opinion is that in this case, it is better to use the Occam razor until
we have more evidence: why should we believe that this accomplishment was possible by extraordinary powers when normal methods suffice?

5000 years ago the biggest experiment in neuroplasticity has started

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[Added November 2011]
I have to catch-up after more than 3 years. This is an age for neuroscience research. I have read a lot of new books and I will report here about four
that I have found amazing for the subject of this page.
Let’s start with the wonderful Moonwalking with Einstein by Joshua Foer who has become by now the reference for
anyone interested in memory and isn’t an expert in the field. The best book
written on the Art of Memory after the classic by Frances Yates. Or perhaps better because Joshua Foer has spent a year putting the method of loci to work.
Enough on Joshua although I could continue for many pages, being his book so
well written and documented.

I will report then three books together:

The first is about examples of “Neuroplasticity”. I was thinking about the
exploit by Joshua Foer: could this be considered an example of neuroplasticity
in action? Does a year of training to remember a deck of cards in about a minute, change permanently the brain? I have no idea. But there is another
task where we are almost all good which is a lot more difficult than remembering
a deck of cards: reading and writing. This task can be learned at any age because it isn’t hardwired in the brain (like speaking and hearing ).
And it requires many years (some languages are more difficult then others).
The results are astonishing because one has to remember by heart complete
dictionaries. In addition the speed that we reach shows that the brain processes many elements of the written language in parallel. There is no doubt
that this exercise changes permanently our brain. It is also a kind of perfect
paradigm of the “right” way to teach a complex task (i.e. on how to teach a person to become an Einstein or a Mozart). Since in our families everyone learns
how to read and write sometime after 6 years, all younger people see their older
sibling and the parents do funny things with books and other written material.
So they are highly motivated and want to discover the secret behind this as
soon as possible. Well, this will take years, like it happened for Joshua, but
the final result is apparently a lot better that learning to play the best videogame.

Repeat to remember

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[Added October 2008]
John Medina book :Brain rules explains what we know about the brain after the Neuroscience discoveries in these last years trying to distill this knowledge in a list of possible ways to improve our learning in school or our intellectual work.
Medina concentrates only on well proven facts and has the gift to present these
results in a way that emphasize all their importance to improve our learning and working experience. For example when considering memory, he explains what we know about the mechanism behind short term (working) memory and long term memory.
Then he distills the single rule : repeat to remember. He clearly explains the importance of this rule reporting the well known case of patient HM without hippocampus and without the possibility to form new long term memories. This case shows some astonishing facts about memory:

  1. Hippocampus is crucial to form long term memories
  2. HM had still long term memories but starting from around ten years before the operation that removed the hippocampus. These are stored elsewhere in the brain.
  3. The formation of these long term memories requires years and literally thousands of memory rehearsals with transmission of signals between the hippocampus and the part of the brain where the memory will stay permanently.
  4. In all these years each recalling of the memory can bring it back to its volatile state and you can either lose it or modify it.

So, the only thing that really matters with creation of permanent memories is repeating at regular intervals for years.

Memory as kludge

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[Added June 2008]
Gary Marcus book :Kluge The Haphazard Construction of the Human Mind has a captivating description of human memory as a kludge produced by random evolution. This explains why our memory has so many faults. It explains less why it is so good.
If computer memory is the goal of a perfect evolution then why autistic people
that have almost computerlike memory are so unfit to social life?

But this doesn’t mean that memory isn’t a kludge , it is a wonderful kludge
but we know still very little about it. If we knew better we would try to exploit this kludginess to our benefit. The most deceiving part of Marcus Gary’s book
is the list of advices to help us cope with our mind kludge.

I am a programmer and I live of kludges. Most of the programs to which I
contribute are full of kludges. And I know that the best way to profit from
a kludge is with a cleverer kludge. These are missing in Gary Marcus book
probably because right now we don’t know enough well the divine hack (this is how we programmer call the ultimate kludge) that is behind our mind.

How to remember the first 22,000 digits of pi

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[Added November 1997]

I have read the book Born in a blue day by # Daniel Tammet. Daniel Tammet has a mild form of autism called Asperger’s syndrome and reports in this extraordinary book how he was able to memorise in a few weeks the first 22,000 digits of pi and then recall them in around 5 hours before a jury that checked the correctness of each digit. As with Luria’s mnemonist the secret seems to be synaesthesia. Daniel sees each digit as a distinct pattern : for example the 9 is blue and tall. To him a string of 10 random digits is like a landscape. In the book he makes some sample drawing of this peculiar landscape that he sees in the mind. What he has done is to build little by little a huge landscape in his mind representing all the 22,000 digits of pi.
In the day of the recall he had only to concentrate himself on the features
of this extraordinary mental painting extracting one by one all the pi digits.

Mirror neurons or : Why compute when you can search about actions

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[Added October 2006]
This article about mirror neurons has prompted in my mind the following ideas. In Computer Programming (I am a programmer) we use the following trick when we write programs: when some complex computation produces only a small set of results, we replace the computation with a search in the table of possible outcomes.It seems that the brain has done the same thing with mirror neurons.Mirror neurons are a set of neurons (the equivalent of the search table) that fire when we look another person doing something. So we have the neuron that fires when we see another person moving the hand forward to shake it with someone else. Another
neuron will fire if a person is moving the hand striking a nail head with a hammer, etc …, These neurons are extremely important to simplify the image
processing otherwise necessary to understand other people’s intents.
This can be understood seeing this task from a computer program point of view.
You have the images of an alien built in some strange ways, doing something. You have to infer from this stream of images what a person is doing.
A very complex problem indeed. But wait a moment!For us the “alien” isn’t an alien really: he/she is someone built like us and the possible outcomes
of a move are really very few. So you see why the brain prefers to hardcode these possible outcomes of our action in a “table” of a few mirror
neurons. So ,when the brain looks at someone doing something, it has only to search and choose which is the correct mirror neuron to fire.
Something it can do so quickly that we effortlessly understand what
other people are doing .

Another trick used by the brain is that
the mirror neurons for the action “drink from a cup of coffee” are
near the neurons that fire when we drink from a cup i.e. near the place where
are the neurons that start the same action in our body.In fact they are a subset of these neurons:i.e. the mirror neurons fire both when we drink a cup or see another drinking a cup. Mirror neurons were in fact discovered by chance by
Giacomo Rizzolatti and his colleagues at the University of Parma monitoring the motor neurons of monkeys.

What is interesting in this mirror neurons system is that we have it in part hardcoded from the birth: this explains why newborn babies can imitate adults. If you stick your tongue out of the mouth in front of a newborn baby , he does the same! But the system develops and changes during all life as we learn to do new things. The hand movements of an expert piano player fire
completely different set of mirror neurons in an observer who is an expert player himself or someone who doesn’t know how to play piano!

People with autism seem to have a deficit in this system. To understand other peoples intentions they have to make a lot of effort : reason about the
images and try ,by comparing these with other images they have in memory, to decide what’s happening. Just imagine how scaring this is: this person coming toward you with raised hands is going to greet you , to hit you or what else… They have no clue. This information overload explains
why autistic people fear other people’s
eye contact. It is something similar to our ability to recognize people’s faces. Normally this is effortless
and you can assume that we must have in our brain a “table” of neurons each one connected to a well known person that fires when we see this person. But when we lose this capacity (
Prosopagnosia) then to recognize a person you must make an effort and try to use other cues . An experience that is both scaring and difficult.