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”…