Stories #3: Fishing Party

Here comes the 3rd episode of my series of translated travel posts. We’re halfway, guys! Please remember, these are old. My mind changed on some points since, and the one-child policy has been relaxed a bit, I believe.

September 8th, 2011

A few days ago, I went fishing with Sandra and a colleague. We had only one fishing rod for 3 persons, but I still caught 5 fishes in one hour! And that’s not counting the smallest ones.

We were fishing from the « poor people’s » river bank, but I took a picture of the rich people’s place:

When we went back at Sandra’s, she cooked us a magnificent lunch: dried bamboo shoots, cured pork, celery and paprika;

Some greens, and my fishes with garlic shoots;

Some cured fish in a spicy sauce;

Duck eggs cooked in rice;

It was freakin’ delicious!

Sandra is a good cook: she’s been cooking for her siblings since she was little. Sunny, on the other hand, pretty much never cooked at all: she’s the youngest of 6 kids. Her brand new husband doesn’t know how to cook either, so they always eat outside – restaurants are not much more expensive than cooking at home. The « one-child policy » isn’t a reality outside of well-off families, living in big cities where the government might perform controls. This was the case for most of my Chinese classmates in college, all single children. Really rich families simply pay the tax that grants them the right to have a second child. Anyway, once an illegal second child is born, what can the government do except fine you?

But when you look further than big cities and go to the countryside, and even as close than the ever-growing suburbs, the one-child policy is everything but a reality. I don’t think I’m exaggerating if I say that most Chinese families have 2 to 3 children.  None of the friends I made in 3 trips to China is a single child. Yet China has managed to keep its birth rate under control in the last years.

Here is a last picture. It is a dorm like the one Sandra lives in. It is quite better than the factory dorms, which don’t have doors or windows except for big bare holes in the walls. Sandra makes about 120$ a month. It’s a misery, even here where the cost of life is so low. The mold industry is facing a crisis. Sandra’s a salesperson but she has no formation or experience; this is simply the only possible job for people with good spoken English skills. Some do well; as for Sandra, she’s only got 2 orders in a year. She must ask money to her husband every month, or she couldn’t live a decent life. She made more money when she couldn’t speak English, she was in industrial design and was financially independent. But it’s hard to admit that you had a better life when you had no qualifications and that all your efforts and money invested in a language school just made you poorer… In a few months, she’ll quit, and become a housewife (at the great joy of her husband who lives in a different city at the moment; and certainly for her own happiness too). She’s in her 30s and she thinks it’s more than time she had kids. Here women have their first kid when they’re about 20 or 21, and while life expectancy in China is over 70 years old, I haven’t seen anyone over 50 in this city. Yet every morning, thousands of teenagers rush to the factory lines.

French food: Dame Tartine

Today’s shocking news: there is no Wikipedia page for the French song « Dame Tartine »!

Dame Tartine is a kid’s song, very famous in French folklore, and probably quite old too (apparently around the 19th century). I couldn’t even find an history of it!

I was initially looking for statistics about the contents of the song, so I made mine and I’ll share them in this post. You may wonder why so much fuss for a little song, but Dame Tartine is not any little song! It is a song entirely about food and sweets. You can find an English version here.

Here is a small excerpt:

[Lady Slice-of-Bread] married Mister Ring-cookie
His hair was beautiful cottage cheese,
His hat was a flat French cake,
His suit was made of canapés:
Pants of nougat,
Vest of chocolate,
Stockings of caramel
And shoes of honey.

Their daughter, the beautiful Charlotte
Had a nose of marzipan,
Very beautiful teeth of compote,
Ears of crackers,
I see her garnish
Her leisure dress
With a roll
Of apricot paste.

You bet it’s popular with children! Although some of the dishes named in Dame Tartine are so old that they have virtually disappeared from French kitchens.

So here are some numbers about Dame Tartine (Lady Tartine/ Lady Slice-of-Bread) :

36 different foods, drinks or dishes are cited in the song; they rhyme two by two but none is cited twice. That is 42 out of 240 words, 17.5% of the total length of the song!

Among these, 26 are sweets, 7 are savory dishes, and 3 are neutral (Tartine, Butter and Cottage Cheese) . About half are still very common in French homes. Some have completely disappeared.

4 main characters have food-related names: Lady Tartine, Sir Gimblette (almond flavored cake / ring-cookie), their daughter Charlotte (big cake made from fruit custard in a biscuit crust), her husband Prince Lemonade. The 5th one is the bad witch Carabosse (not food!).

Only 2 fruits are cited (dried grapes/raisins, and apricots), versus 4 vegetables: potatoes, capers, pickles and onion. All the vegetables appear only in the description of the Frightful Guard of the mighty Prince Lemonade… Booh, frightful vegetables!

There is only so much one can say about a kiddies song, but tomorrow if I have time I might add pictures of the food appearing in Dame Tartine. And don’t forget, as pleads the song in its last sentence:

Give at leisure,
Give, good parents,
Sugar to the children!

States of information and attractors

Today I will just publish several old drafts that were lying around. I actualized them a bit. There is no specific goal to this post, sorry!


There are so many definitions of information, sometimes contradicting one another. I wonder why it is so difficult to agree on what it is and how it is used.

The other day at an AI conference, someone gave a 1 hour talk about the future of a current popular AI approach, and said the world information several dozen times.
He did not define it once. I was burning to ask, what do you mean by information? Half of your hypotheses sound like they rely on one definition, and the other half on a totally different definition. What do you mean? Is your information something that exists in the world, or something that we can/must create by ourselves? Is your information something that gets inside me through my senses, or is it something external I can only interact with? These questions are important, because depending on the answer, information can be in finite or infinite quantities, absolute or relative, perfect or error-ridden, etc.

How would a naive view of information look like? Maybe like this.

The world is full of information. Or rather, the world is full of potential information, of which only a small part can be extracted and actually used by agents.

For example, the softness of a pillow could inform you of its resting qualities. This is potential information. To access this potential information, you could touch the pillow: the interaction between the environment (the pillow’s stuffing) and your sensors (touch sensors in your finger) allows you to extract some of the information on and maybe, use it. Your interaction with the pillow is a loop: you apply an increasing force on the pillow, the stuffing applies a resisting force on your finger, and a small part of the energy is dissipated into the environment.  It is really the interaction loop between the environment and you, the interplay of applied force and resisting force, that transforms the potential information into extracted information for you to use. The potential information in the whole world is absolute, infinite, and perfect. The information extracted from an interaction, on the other hand, is relative to the dynamics of your sensors, finite, and noisy.

Not all the information extracted by an agent is actually used by it. By « using information », I mean that the agent’s dynamics are changed by acquiring that information compared to the same agent without that information. If the behavior of an agent after extracting one type of information is exactly the same than the behavior of that agent without that information, we can conclude that the information is not used. If you act exactly the same (e.g. taking a nap) after touching a pillow than after merely waving your hand in direction of the pillow, I conclude that you don’t actually care about whether the pillow if soft of not. You take the nap anyway.

But say that you were actually been checking if you needed a new pillow or not, registered that information, and took a nap independently of your conclusions. This is information that is extracted and stored. It is expected to change your behavior (buying a pillow), albeit not immediately.

Stored information can change your behavior in very drastic ways. You could be a 1 year old child, touching the pillow because you don’t know that pillows are usually soft. Next time that you see a pillow, you might deduce that it is soft, without having to touch it. In short: learning. It is a form of deeply stored information. You don’t have to remind yourself that pillows are soft (like you have to remind yourself to buy a new pillow). It simply diffuses into all your future interactions with pillows.

The other day, a labmate’s talk made me aware of a deeper form of information storage: DNA. You won’t be surprised if I say that DNA stores information about you, but my labmate turned that around. DNA stores information about your environment. And you are just the storage… That really stuck with me!

A problem with artificial agents might be that they are often simulated in virtual worlds where there is not a lot of potential information. Potential information lies primarily in « hard laws »: the laws of physics (and chemistry, optics etc). Virtual worlds are typically poor in potential information, because it takes time and computational power to simulate in detail lots of hard laws and their interactions.
An artificial agent embodied in the real world, a robot, would have tons of potential information to extract, use, store, learn. But it is even more difficult to build real agents than virtual agents. A virtual agent needs one line of code to read an audio file; a robot need actual electric parts (microphones, cables, CPU), appropriate wiring and positioning of the microphones, plus the same line of code than its virtual counterpart.

When we build virtual agents, we usually decide what kind of laws they will use, simulate a simplified version of these laws and give the agents the sensors that we think are appropriate. This already takes time and effort, but imposes terrible limits on virtual Artificial Intelligence (AI).
Furthermore, there is little space for « soft laws ». These are laws that are often right, but sometimes wrong: they have limited validity in time, or in space, or can be changed by the agent itself. Soft laws may well be the reason why living beings must evolve learning abilities; if all events can easily be summed up with hard laws, then there is no need for adaptive behavior. Just store everything your agent will ever have to do inside its DNA. (This first approach is a very common approach in AI!)
But soft laws can often serve as heuristics for hard laws: simplifications that work well enough to be useful. That’s why it is very advantageous to store something like an « ability to learn » inside yous agent’s DNA, rather than use the first « hardwire everything! » approach.


Agents interact dynamically with their environment. These dynamics typically have attractors. An attractor is a state to which a system tends to be « attracted » to. Consider bipedal locomotion: there are a lot of possible things that we can do by moving our two legs, but we typically either walk or run. Walking and running are attractors in human locomotion. If you push a system out of one of its attractors, it can go back to this attractor state, fall into another, or just behave chaotically. In other words, an attractor represents a kind of balance in the dynamics in the system.

Imagine a simpler case: a ball rolling on an endless floor. This ball has infinite supply of energy and never stops rolling. Its state is defined by its position on the floor. If there is a bowl-shaped depression in the floor, the ball can fall into it and roll around without ever getting out. If you push the ball a little, it can keep rolling inside the depression or get out. The depression is an attractor for the dynamical system « ball rolling on uneven floor »: the coordinates of the ball tend to be always comprised in a small set of values. If the floor is completely flat, the ball will roll forever: there is no attractor.

What do attractors have to do with AI? Let’s go back to locomotion. Human babies start without the walking attractor. Adults can walk. Somewhere in between an attractor has appeared, or rather, was learned. How do humans, as dynamical systems, modify our dynamic landscape to create an attractor? Can learning be reduced to creating attractors where there were none? Humans and other animals are, in a very real sense, creatures of habits. The first years of our lives, we learn to associate the right behaviors to the right cues. Not only our brain, but the rest of our body as well. When you walk, your don’t have to think about how to move your legs: you mostly think about where to go and when to pause or stop. As adults, we can go entire days without doing anything completely new, simply by switching to the right habit at the right moment. And it is very hard to break an ingrained habit. There is actually hints that habits cannot be broken in the human brain, only replaces

So habits can be seen as attractors. The dynamical system they refer to is the system of our interactions with the environment. As we live, we extract information from our environment. If we find a particularly good way to extract a type of information, we’re likely to repeat it again and again, and build a habit. So one way to try to build powerful AIs is to look for ways to build useful attractors in artificial agents. Of course, when a baby learns to walk, it isn’t only the brain that changes. Newborn babies don’t walk, not only because they don’t know how, but also because their body simply can’t allow it. Learning to walk requires your body and brain to change on a medium-term scale (development) before you can actually work out the mechanics of walking on a short-term scale (learning).

So how to build attractors? They could be there from the very beginning (innate); they could be built by changes in your own body’s dynamics (development) or by changes into the way you extract information (learning). My opinion is that most attractors are a mix of these three influences. Walking certainly is. We have « innate » reflexes like kicking, we develop others like trying to stand and keep our balance, and after trial and error they combine into the right amount of kicking and balancing and off we go. An interesting path for AI would be to achieve integration of these three time scales to build attractors for locomotion, object manipulation, visual processing and everything that can be reduced to a combination of nicely steered habits.


I have been talking about attractors, but I did not really define the dynamical system they refer to. Ideally, we would take all possible inputs and outputs of the agent and as parameters to describe the system, but the sheer complexity of the task makes it virtually impossible. So let’s consider simple systems. We can for example, consider the values of one type of sensors (touch,vision..) and one corresponding motor output (contraction of muscles in your finger, eye..)

Until now, I mainly talked about interactions between one type of sensory input and the corresponding potential information sources in the environment. The values successively taken by the sensory input can be described as trajectories on an imaginary landscape. This landscape may have attractors; each attractor is a set of trajectories representing a state of balance in the system. Evolution, development and learning help us build attractors in our sensory landscapes. Extracting information then become much simpler: attractors guide our interactions so we extract the kind of information that we need.

Well, that was a rather strange and disorganized post, but I wanted to get rid of all those drafts. See you next time!

Stories #2 – Nail Polish and Liver Soup

Here comes the second episode of my series of translated travel posts. Initially I was planning to summarize them in only 4 parts, but it takes me more time than expected to translate so there’ll be 6 of them: Crossing Gazes, Nail Polish and Liver Soup, Fishing Party, The Sacred Bond of Marriage, There’s Worse Than Being a Foreigner, Tomorrow the Way Home Will Last Three Days.
The « TN » are notes that I added afterwards.


September 2nd, 2011

Today I finally could check my emails, and I also caught a cold the other day \o/

These days I feel like a mix between Tintin and an intern (TN: Tintin is an adventurer-reporter in a Belgian comics series). Every morning I go to the factory where Sandra is employed: she works in the international sales department. I sit down at my very own desk and surf on the web waiting for something fun to happen, which occurs about every two hours: an invitation to eat together, someone to help, or just a stranger who wants to have a chat… That’s for the « intern » part.

But there is also a feeling of self-education. I spend my days in a Chinese factory in a part of the city where there is literally no other foreigner. I explore a bit and realize that they use the same 3D modeling software that we have at my engineering school. I discover the hard life of the workers – those who make a living thanks to globalization.
I’m not here to play the sensationalist reporter, be horrified at the living conditions, play disgusted and criticize everything. I’m here because a young woman wanted to share her lunch with me, made me a liver soup to cure my cold and invited me to sit at her table. It touches me that people who don’t even know me propose to cook me a meal and invite me inside their houses without a sign of hesitation.

Just like the hotel’s reception clerk.
Sandra literally confided me to her, saying that she should take good care of me and help me improve my Mandarin skills. The clerk takes it very seriously, and sometimes reminds me of Chihiro (TN: a Japanese girl that I met while working in a factory in Japan, and who took care of me in pretty much the same way). She forces me to wear nail polish, criticizes my boyish pants, tells me about her not always happy life, and says that she « wouldn’t talk as freely to a fellow Chinese person, but since I’m a foreigner she doesn’t have to censor her thoughts ».
Today she got really angry because I got an access of fever, and instead of calling for her I stayed sweating in my bed. What the heck are you doing?! Take this medicine and drink hot water! Put the air conditioning on and eat something! And next time you call me, do you hear?! We’ll go to the hospital if it’s necessary!

She looked mortified (« Kids these days! ») but that was just my normal « caught a cold » state. Knocked out by the fever, runny nose and stupid with exhaustion: a cold! I just wanted to sleep forever but she looked so angry that I did everything she told me to. Apparently she even called Sandra, who brought me dinner in my bed (noodles and soup), as well as a stock of medicine and breakfast for the following day. Actually, it’s not so bad to be a kid…


In the next episode, even shorter than this one, there will be quite a lot delicious-looking pictures. I will also talk a bit more about Sandra’s present and future life. The episode after that will tell the story of how the hotel’s clerk arrived in Shenzhen; if you don’t already, after that you’ll want to give her a big hug. Bear with me.

Stories #1 – Crossing Gazes

Hello everyone.
Today I start a mini-series of 4 short posts, translated from French to English. These are posts form my older blog and my French readers already know about them.
But I chose to translate them today, because they are among the rare texts that I don’t feel ashamed of, even years after I wrote them. They speak to my heart and make me melancholic at the same time.

This series is about a short part of my 3rd trip to China, in summer 2011. I went to visit some friends, Sandra and Sunny (not their real names), near to the bustling giant industrial city of Shenzhen. At the time I could speak Mandarin, and spent some days in unofficial immersion in a plastic molds factory.

Some explanations: Except in some specific cases, all dialogues reported here happened in Mandarin. Also, I am a girl but I look (looked?) like a boy, and most people naturally assumed I was one. I usually do nothing to clear the misunderstanding. So don’t be confused by the pronouns: people in the text can talk about me with « he » or « she » depending on the situation.

Let us start softly with my arrival in Shenzhen, and progress in the future posts to the more serious talk. This is about people. This is about their stories, as they told it to me. But this is also about a black girl going to a place where foreigners don’t go. Don’t look for objectivity: this story is as biased as it comes.

September 1st, 2011

My 2 weeks long trip in China started with a 4 hour plane delay. The Tokyo-Beijing plane landed in the middle of the night on August 28th. It was so dark I couldn’t possibly find my way to the hotel, so I stopped a taxi. The driver was an old man. I showed him the printed address:

Me – Do you know this place?
Him – I can’t read these small wiggly lines (latin alphabet), little guy! How about you read it to me!

I read it, but it was a long time before we finally found the right place: there were no numbers on the houses. The hotel had received my train ticket for Shenzhen, courtesy of my friend Sandra. After resting for a full day, I left for the Beijing West train station. Those who know me will have guessed it: I got lost almost immediately. At some point, a strange looking bare-chested guy approached me. As a foreigner with the experience of visiting Vietnam’s biggest cities alone, I couldn’t help seeing everything with two wheels or two feet and asking too many questions as a potential enemy. Since I was stuck at a red light, I decided to play « stupid tourist », hoping to be quickly left alone.

Barechest – Hey! Hey! Where are you going? Heyyyy!
Me – *Smiles stupidly, shrugs*
Barechest – Where are you from?
Me – *shakes head*
Barechest – *turns towards a guy sitting on the ground nearby with a beer* Do you see that? This boy travels abroad, he can’t speak Mandarin AND he’s mute!
Beer guy – Hey you! Do you speak English?
Me – *Signs « a little » with hand*
Barechest – He’s mute I tell you!
Beer guy – *Hails a passing student-looking kid with a backpack* Hey little one, you study English at school, don’t you? Talk to this foreigner!
Kid – Errr! Hellow! Where you go?

At that point I decided to talk, because I didn’t want to wait for every passing person to be called by Barechested Guy, and why so much insistence towards a foreigner stupid and mute? In Mandarin, I said:

Me – West Station.
Kid – Train? You… Train?
Me – Yes.
Kid – It’s in the opposite direction, you’re going the wrong way…
Me – Er, really?
Kid – Yup, it’s *that* way.
Me – Oh… Thanks…
Kid – Bye bye!

And that’s how I noticed that my trip to Vietnam had made me paranoid, to the point of refusing to talk to people who were just genuinely trying to help me. Me and my big luggage that I was obstinately dragging in the wrong direction. I felt truly ashamed that I didn’t make the effort to speak in Mandarin to the guy who first talked to me. The young student really did his best to help me, even if he wasn’t confident in his spoken English. This is not an episode I am proud of. All of this to say, don’t be like me, don’t judge Beijing inhabitants on bad experiences that you’ve had elsewhere.

After that I rode the train for 38 hours nonstop, with two 8 years old kids as bed-neighbours. Everyone was so exasperated by the bratty behaviour of the two kids that we just gave up hope of getting to know each other and spent most of our time wide awake in bed. When the little family finally got off, after 32 hours, people exchanged a few polite banalities and we all fell into a deep, well deserved slumber.

On my arrival at Shenzhen, I met Sandra (« let’s eat something! You don’t eat enough, that’s why you’re so skinny! ») and we took the bus to my hotel, next to the town she lives in. It’s a « factory-town »: all the people who live here work in the little factories nearby, and most of them had never seen a foreigner.
There was a shy young man, hiding behind the bus curtains, who was too bashful to ask me directly if « I was born with my hair naturally like that (curly), or if I had it done by a hairdresser? ». It was a cute question that got me smiling all the way (but if your hairdresser does your hair like mine, please change to a different hairdresser).
There was an old man with very tan skin and small shiny teeth, who smiled to me almost without blinking for 10 min before I dared talk to him. He had a very soft voice, a huge smile, and seemed delighted to simply look at me. I told him I came from France, but I felt as if I could as well have said that I came straight from Mars.

It’s strange, nobody seemed to notice me when I was in the Chinese countryside or in the big cities, just like no one noticed cripples and homeless people. It was just normal that I was there and that I spoke Mandarin. But here, in this place stuck between a giant city and a deserted countryside, I wouldn’t look more bizarre if I suddenly grew horns and started hopping on my head.

At the hotel, the reception clerk (a young woman) asked me the usual questions then inquired about my age.
Clerk – What? 21 years old?! You are but a little child! A baby! 21 years old, oh gosh!
Sandra – Do you hear that Lana, she says you’re a little child! Hahaha, a baby! Ho ho ho!

Yes, I heard, Sandra. This is something that never changes, wherever I go…

Me – Do you know Sandra, there were 2 little kids in my train and…
Sandra – How nice. Did you talk to them?
Me – Well, no, they really were kids, 7 or 8 years old I guess, and…
Sandra – Good, you could have practiced your Mandarin!
Me – …

This post was meant as an introduction to the main characters. In the next, shorter episode, « Nail Polish and Liver Soup », I get a feeling of the town and the factory. In the 3rd and 4th episodes, we get to the core of things: Chinese lives in the big city as told by Chinese people.

Identity as a learning mechanism

Hi all. In two weeks I give a talk at the lab, but I’m supposed to keep it around 20 min long so I would like to put some order in my thoughts here first!
That way I can hopefully give a short, better organized talk.

Today’s topic is my latest reflections about identity (or personality) and why we need such a concept. What are the evolutionary advantages of having some specific tastes, preferences and personality traits? Why isn’t everyone a good natured, funny, easy going, broccoli-loving kind of person, for example? Diversity is often good to help a species adapt to new situations without having all its members wiped out, but in my opinion, this does not explain the diversity of personality traits in humans and other animals.

Another question is, why aren’t our personalities more stable, fixed in time? Why must part of our personality be reconstructed from cues in our environment, which can lead to errors and confusion as I mentioned in my previous post? Why must we reconstruct who we are based on outside hints, rather than take entirely reference on an inside « identity model »?

In this post I propose answers to these questions, and I hope to convince you that your identity is in fact a permanent reconstruction based on environmental cues, and not a fixed concept safely stored somewhere in your brain forever.


Let’s first talk about the dimension of spaces of choices. What are some differences between performing a successful golf swing, and performing a successful social interaction with a colleague?

Both must be learned: for the golf, you’ll do a few swings, get the feel of the club in your hands, the motion, the ball resistance. For the conversation, you’ll learn to approach people, read their face, their voice tone, the meaning of their words and phrasing, the appropriate reaction and timing to all these cues.

The number of possible movements you can do with a golf club in your hands is practically infinite. The number of physically acceptable movements is already much smaller. You can hit yourself on the head once, but not twice because you’ll most likely be dead or at the hospital. You must avoid every motion that could hurt you, break your equipment, or is too tiring. The number of movements that can be called « successful » is even smaller. You must avoid useless motions, hit the ball with the right part of the club, send it in the right direction with appropriate strength. All in all, you will most likely find one globally right class of movements that you’ll call « successful swing », and then add some small variations here and there to adapt to individual situations. « Successful swing » might be stored in your brain as a succession of touch and proprioception sensors activated in a determined order, at a determined timing, with a determined intensity, along with the muscles that must be used to reach this ideal flow.

The number of ways a conversation might possibly go is also infinite. Depending on what both of you say, how you say it, facial expressions, physical interactions, voice tone, the language you speak… But even when adding physical limitations like « don’t yell at the top of your voice » or « don’t put your finger in your eye », the number of possibilities is still endless. What is a « successful » interaction will depend on your goals, the person you’re dealing with, your current situation, your past interactions with this person and even past interactions with other people. Small changes in the interaction flow might change nothing at all to the output. Saying that joke now or in 2 min, talking louder or lower, smiling or being neutral, talking about the weather or rather about yesterday’s TV show… Of course, some choices might have a very big effect, but the point is that you have to make an infinite number of choices, many of which have very limited consequences. And once you have found a globally « successful » way to interact with that colleague, how and what is your brain supposed to store? Storing the complete string of choices you’ve made during that 5 mn conversation is virtually impossible. Did you stand at 50 or 60 cm? What words did you use? Did you smile first or did they? To learn from that interaction, you will have to store only a generalized part of what is relevant. But how will you store it? There is nothing as concrete as muscle memory or raw sensor data to keep somewhere. Instead you have vague abstract stuff like facial expressions, emotions and subjects of conversation to deal with. Each of which changes with the person you’re dealing with.

Of course, you do it every day since you were born, and effortlessly. But it does not mean that it is not difficult. We’re just really, really good at it: we’ve had lot of time to perfect the skill of interacting with each other, and it is crucial to an individual’s survival.

My theory is that identity as a noisy reconstructed signal is a way to deal with infinite spaces of choices. Whether it is social interactions, fashion sense or food preferences (only when food choice is unlimited can you be picky enough to have preferences…), it is more efficient to store information as being about you (« I’m a funny person. I like to make jokes. ») than as being about a set of specific situations (« I cracked a joke about food at John yesterday night and he smiled; I said a pun to Jenny last week and she laughed; I… » etc). Especially when the situations are difficult to summarize efficiently: just try to think about all the times you’ve interacted with someone with a positive outcome… since you were born. What made those interactions successful? What choices did you make, when? It is likely easier to store the fact that you’ve been a funny person, or a good listener, or a talkative/quiet person until now and that it seems to have worked well.

But not so easy after all. You must store quite a lot of these personality traits, and while they might be a good summary of what to do and what not to, in return they do not tell you exactly what to do. They’re rather vague concepts about yourself. You must apply dozens of such abstract concepts to specific situations in a single day.

So my second idea is that it is convenient to offload some of this information into your environment as practical examples (expressing your tastes via a funny t-shirt, classy shoes, an organic scent-free shampoo, or your social entourage), and then to pick up this information later, when necessary, by analyzing your past behaviour and current environment. If this two-step process uses less memory, or less processing power while still being reliable, then better use it than trying to hard-wire lots of hardly re-usable abstract information in your brain.

So my theory is that identity (personality traits, tastes) is mostly a way to insure behavioural coherence in an infinite space of equivalent choices. Research indicates that emotions help you actually make a choice between equivalent options. I think that identity is the way you store these choices to be re-used in the future. And I think that the easiest, most efficient way to implement this storage is to scaffold it in your immediate environment and rebuild the relevant parts when needed.

To end this post, here is a link about a person who suffered a very strange disorder: he systematically assumed that his own identity was whatever he knew about the person that was in front of him. Or following my hypothesis, he perpetually reconstructed his identity from the wrong cues…
The Man Whose Brain Borrowed Nearby Identities


PS: objections to this theory include the fact that even babies (who have limited impact on their immediate environment) have distinct personalities. But as most researchers, I do not believe in the opposition between « innate » and « learned »…

Stability, Short-term and Long-term memory

I got some positive comments on my previous post, so I decided to continue publishing in this format for a while. Now that I’m back in Tokyo, I might even post on the regular blog again: do not despair at this sudden change, French followers!

Today, I would like to talk about a theory of stability in the brain. In my previous post about the Chinese room experiment, I said that I have a problem with this: your brain is always changing, yet « something » seems to remain stable. This stability shows in the consistency of your behaviour, opinions,  tastes, ideas… These are part of your identity. Indeed, you probably feel as the same person waking up every morning and one year to the other, despite all the cellular changes in your brain and the rest of your body!

From here, I will give my own interpretation of existing research and explain my theory on the subject. Feel free to disagree and criticize it.

One hint about the stability of identity could be in recent research on behavioral economics. Several studies show that actually, our identity is not as well defined and fixed that we previously thought. In these experiments, they find that we take cues from our past behaviour to try to define what kind of person we are. When faced with a decision (« buying a drink »), you rely on what you did in the past (« I bought coffee from this shop last week ») to define your identity (« If I bought coffee there, it must mean that I like this shop ») and take a decision in the present (« I will go have a drink there, since I like the place so much »). Other example: you find yourself morally obligated to give to a charity, because all of your friends gave money to that same charity. You deduce that you’re a generous kind of guy, otherwise why would you give to charity? The following week you pass by a homeless person, and decide that giving them money is the obvious thing to do, because you’re a generous person. Note that the usual relation « I have this personality trait, therefore I act like this » is reversed into « I acted like this, therefore it must mean that I have this personality trait ».

Not convinced? There are lots of papers out there showing that this is actually what happens in our brains (I think the term is coherent arbitrariness, I recommend Dan Ariely’s books if you’re interested). The most compelling proof is that it works even when the decision in the past was *not* yours but you *believe* it was yours, and even if the past information has absolutely no link with the choice you must make in the present! I can actually think about some parents using this kind of tricks with their kids (« I know you will behave, because you’re a good boy »or »A nice boy like you does not hit his friends, does he? » can actually convince a rough kid to play nice), and some adults too. And it’s not just about the fear to disappoint.

We act as if we don’t know what kind of person we’re like, but instead have to guess it from our past choices. A series of psychology experiments also showed that if you can convince someone that they chose X over Y in whatever situation the past, and then ask them to justify that choice, they will come up with reasons why they absolutely prefer X and why X was obviously the rational choice for them and how they would totally choose X again if in the same situation… Even if in reality, what they had chosen was Y. We also use other hints from our environment to « guess who we are », like the opinion that others have of us, or what objects we own, but ultimately  it seems to be reduced to choices we made.

So identity is not a rock hard concept embedded in you, but rather something that your brain tries to reconstruct when necessary. And, oh look! Unsurprisingly, the same goes for memory. A long time ago, science thought that memories where stored in the brain and retrieved as a block when necessary. But all recent science paints a very different picture. Memories are reconstructed from diverse bits every time you need them, not retrieved intact from some storage place in your brain. And this reconstruction itself tends to modify the memories. This is partly the reason why it is possible to induce false memories of the past in people just by influencing their present environment (yes, science did it… and it worked).

To summarize, your image of yourself (memories, preferences, personality traits) is not fixed, but gets reconstructed by your brain in real time, using whatever is found in your memory. This memory itself tends to change when accessed. You then base your present and future behaviour on this reconstructed image of yourself. Therefore, the stability I was looking for in the last post emerges from a loop:

– You make choices that get summarized and partially stored in your memory

– You rely on these memory bricks to re-build memories of what you have done in the past

– You use these memories to build an reconstruction of your own identity

– You make new choices based on this identity

– Start again from the beginning of the loop.

If this is true, it shines a new light on the effects of a disease like Alzheimer. People with this condition start by losing their ability to build new memories. They become unable to remember what just happened, then forget events further and further in the past. Family members often say things like « this is not the person I knew » or report feeling like talking to a stranger. Well imagine what happens if you become unable to complete the loop above because your ability to form new memories is impaired. You make choices that you forget immediately. You are forced to rely on older and older memories for identity-building, but the memory-bricks of these memories change when you access them and fail to be re-stored, making even that part of you more fragile. At some point you’re left with only some disparate fragments of old things to build your identity with. Then it’s not surprising that you’re a total stranger for people who thought they knew you.

This also works for some forms of amnesia. People remembering abilities (speaking their mother tongue, riding a bicycle), but with no memories from their previous life. If tastes and preferences were hard wired in the brain somehow, you would expect these persons to still like the same food and appreciate the same hobbies. But it is not what happens. Instead, they end up with a brand new set of tastes and a whole new personality, an new identity. Which would not be very surprising if my stability loop really is what happens in their brain, in mine and in yours.


I would like to finish this post by a part on artificial intelligence, of course. I think the following network-based system would be able to exhibit a form of stability, despite underlying instability:

– First we need a short term memory, to store recent events quickly. Add a necessarily slower long term memory with a « summarizing system », to analyse the short term memory, store the bits that look important, and erase the rest. We also need a mechanism to re-build past events from bits found in the long term memory.

– Our system’s behaviour must be heavily based on rebuilt past events. By making choices, the system imprints it behaviour on the environment. These prints then go through the memory system.

Then my prediction is that even if the structure of the system changes drastically and completely over time, and even if storage errors tend to happen, and even if just about everything is unstable in the system, the behaviour of the system will be very stable. And if among stable systems this one is the minimally complicated, then the result of artificial evolution project I described in my previous post should look a lot like this one. This is important, because to be useful, a theory must be able to make predictions. Then if the prediction is correct, it is a good sign that there is some truth in the theory.  My theory is that the « stability loop » exists in humans and in just about every biological system in need of stable behaviour, and my prediction is that it emerges when there is selection pressure for stability applied on unstable systems.

This is the end of this post. I should definitely add the references to the papers I’m mentioning, but then writing these posts would take me as long as writing an actual paper!


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