Pauek's face
Pau Fernández

The available space for mental representations

The background is as follows:

  1. The brain contains an internal representation for everything we can think about. It's like an immense tree of tiny little lights, detectors that fire in extremely specific situations.

  2. The brain places those detectors by spreading them across small areas of the neocortex, which is a large but finite surface.

  3. Each area is connected in a particular way to the others, and has a specific size. For example, the area that detects faces uses the areas that detect eyes, noses, and mouths as inputs. (Incidentally, this circuit is genetically determined.)

  4. Each person has a different network of connections and therefore different sizes for each area.

  5. Some people have specific deficits in very particular domains. Two cases are well known: a) prosopagnosia, which is the difficulty in recognizing people's faces1, and b) dyslexia, which is the difficulty in recognizing words. Besides these, other similar kinds of deficits have also been catalogued.

The easy conclusion for me is that you struggle with the things for which your brain has a representation area smaller than normal. A small area means that few detectors "fit" in it, and so you won't have good discrimination. In the case of prosopagnosia, your detectors classify only a few types of faces, and large groups of faces that look alike (but are different) are treated as the same one.

On the other hand, certain things may seem "invisible" to you, because your brain barely registers them, simply because it has no detectors for them (your representation area is practically nonexistent).

There are two factors that muddy this analysis: plasticity and motivation.

Plasticity means that areas can keep expanding with use, so something you use very frequently will fight for representation space in the neocortex, and will win out over areas that get used less2. But the initial circuit matters quite a bit, because it can mean there are things that come easily to you from childhood with a facility that others find astonishing, or the other way around.

Then motivation moves mountains, and you can become passionate about things you aren't good at and end up doing them well, or be unmotivated about things you have great capacity for, which then fade away through disuse. I know people who are living examples of both.

I say all this because, aside from the scientific side, which holds an interest for me that's hard to describe, I tend to apply these ideas to make sense of what I see around me. In myself, for example, I see two well-endowed areas: vision, and three-dimensional vision in particular, and, in music, melodies (but not harmonies, which I find harder). I like these two things because they come to me effortlessly, but I don't pursue them out of intrinsic motivation or for work.

By contrast, I always get it wrong when I try to remember who was there with me in each situation I've lived through, and if you give me a year, I find it really hard to tell you what I was doing back then; I have to reconstruct it using clues. And yet there are people who seem to have a mental map of time3 and move through it as if they could see it (the way I do with three-dimensional objects).

The effect motivation can have is clear, but the upshot is that our "radar" has holes, frequencies where it receives no signal. Our brain is like a pair of glasses with a lens that filters reality in a very particular way. And that hugely affects our perception and, ultimately, partly determines who we are.

Footnotes

  1. 1.There are many degrees of prosopagnosia, from people who have simple difficulty to people who don't recognize the members of their own family (they recognize them in other ways: by smell, by voice, etc.). On the other hand, there are people who are incredibly good at recognizing others (the super-recognizers).

  2. 2.Blind people have a large part of the brain set up for processing visual information, but it ends up being used for other things, such as language.

  3. 3.There are people who remember, in perfect detail, every single day of their lives. (Although in this case other factors besides the size of the area that represents moments in time probably contribute too.)