Meaning and its patterns in the brain

October 26, 2021

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Many ideas that come to us are unbidden and automatic. The shape of a house. The wheels of a car. These things can be left unsaid. This is one of primary roles of the brain---to weave a web of meaning. But just as they help us make sense of the world, they trap us.

This article's ideology: The brain primarily links chunks of meaning into patterns of neural pathways. Pathways and patterns of meaning help us intuitively solve the problems of everyday life. But they also trap us in those patterns, and stop us from seeing beyond them. Scroll to Summary

This old paper on automatic processing is a brilliant illustration of the most important function of the brain. It starts off with a three line story:

Toby wanted to get Chris a present for his birthday.
He went to his piggy bank.
He shook it. There was no sound.

We understand a great deal that's left unsaid here. We know, primarily, that Toby has no money to buy Chris a present. At least, not in his piggy bank. And yet, there's nothing in the passage that indicates what Toby's piggy bank has to do with Chris' present. Nothing, even, about Toby looking for money, nor that he was planning to buy something. There's nothing to indicate what was being shaken, nor why a lack of sound would be so illuminating.

Taken individually, each line bears no particular relationship to the last but together they weave a narrative that's much more involved that the sum of the parts.

The ideas that come to us, on reading Toby's story, are unbidden and automatic. More poignantly, as the authors say, there is:

a sense that comprehension occurs outside of our control.

Let's explore all the things the brain had to do to weave Toby's story together for us.

image A representation of the mental work involved in interpreting the reading passage. From Thurlow and Broek, 2006.

We infer that to get a present for Chris he probably has to buy it. We infer that Toby keeps money in a piggy bank, because that's what you use those for. We know, specifically, that Toby keeps coins in his piggy bank because bank notes don't really make noise when they're shaken. A lack of sound means there were probably no coins, because coins are heavy objects. And so on.

This illustration is a fabulous case study of the known properties of the brain.

Brains which are not brains.

There are features of the brain that are largely mysterious to us. Most features in fact. But the basic feature of brains is to link information together into 'chunks' of inter-related meaning.

It makes sense to first step back a little bit, and consider where information comes from. We have the information available in the world around us. Sounds, smells, sights, and so on. This much is obvious. But we also have the information available in parts of our body that are not the brain. Our eyes are a source of information about what we can see, and our fingers hold information about what we can feel. Etcetera.

This might seem trivial, but is in fact hugely important. Many animals have no need for a brain whatsoever because of this very fact.

Plants do not need a brain to track the sun across the sky. The plant can capture enough information in its cells to execute this operation completely locally—at the site of the sunlight striking the plant.

Bacteria do not need a brain to avoid toxic chemicals. This more complicated process requires merely that the molecules entering the cell are passed along to its flagella—little tentacle-like things that will then wiggle wildly for a bit until the bacterium is pointed in a different direction.

The 'chunks' of meaning for these very simple creatures are just the concentration of some kind of stuff in the cell. So long as there is a way for the world to interact with the stuff, it can be used to produce a response.

This same basic, autopoeitic function is realised in the brain, just in a much more complicated way.

Links and chunks, pathways and patterns

For humans, chunks of meaning have to be much more complicated. Our world consists of many more stimuli than the amount of light in the world or the concentration of certain chemicals.

For example, coloured light arranged into a particular shape hitting our eyes, and a pleasant smell entering our nose indicates that that we might have a flower in front of us. The same visual stimulus, but no pleasant smell might indicate that we only have a picture of a flower in front of us.

So we must have a chunk of meaning about the flowery-ness of certain shapes, which overlaps with a chunk of meaning about actual flowers and another chunk of meaning related to pictures of things.

The way the brain produces these chunks is pretty well understood, as theories about the brain go.

A tiny bit of neuroscience

Our bodily organs 'plug in' to our brain at various points. The eyes plug into the back. The ears into the side. Our faculties of touch and movement at the top and side. And so on.

At these sites of connection between brain and body, we have beautiful 'maps' of features of the world. At the sides of the brain, where the ear is connected, we have small clusters of cells that fire for specific frequencies of sound. At the back, where the eyes plug in, we have clusters of cells that respond to the very basic features of the visual world—colours, specific orientations, changes in contrast and so on. And where our bodily organs plug in, we have a map of of the body—a map of what we feel and a map of how we move:

image A representation of the 'map' of our body in our brain. On the left is what we feel. On the right is how we move. Two strips of the brain that have an almost 1-to-1 correspondence to our body parts. From Wilder Penfield, c. 1940.

The picture gets more complicated as we move away from these primary sensory regions, but what the cortex appears to be doing is storing information related to the interaction of those more primary sensory regions nearby---about less specific and more general features of the world that relate to multiple kinds of information.

For example, as you move away from the region of the brain that codes for body parts we move and toward the vision part and you start to see clusters of cells that enthusiastically respond to things like motion perception—something that is both about moving and seeing movement. Move away from the vision part and towards the hearing part and we see regions of the brain that frenetically respond to things in the world that are both audio and visual, like a barking dog. Move away from the hearing part and towards the body part and you find the language centres of the brain—something that is both about hearing speech and producing speech with our body.

image A representation of the information streams in our brain. As we move from primary sensory areas to places in between, we get cells that activate in response to combinations of information. Adapted from Kandel et al. 2013 Principles of Neural Science.

Essentially, things that are related to one another, the brain tries to put very close together, constrained in large part by where our senses are plugged into the brain.

This is a sensible strategy of course. The only reason storing chunks of meaning about the world would be useful is if we could link them to one another to make more complex meanings. The shape of a flower at the eye combined with the smell of a flower at the nose helps us understand that this is a flower and not just a picture of it.

The more related such things are to one another, the closer the brain puts them together. There could be any number of reasons for this, but in all likelihood it's simply because doing so is cheaper. You save on wiring and the energy required to pass messages from one place to another.

From links and chunks to pathways and patterns

So, the brain seems to represent all these 'chunks' of information, and those 'chunks' that are related to one another it needs to link together. The more related, the closer they are, all the better for the linking.

We can return now to Toby and his penniless state. Let me remind you:

Toby wanted to get Chris a present for his birthday. He went to his piggy bank. He shook it. There was no sound.

image The chunks and the links. From Thurlow and Broek, 2006.

The fact that the brain is optimising for the linking of chunks means that the organisation of the brain can tell us something about what we find important about the world.

If the brain needs to put chunks that are most inter-linked closest together, then the locations of all these chunks will tell us about how we put the world together.

This might sound a little trivial, but it's not quite. The example of the classic psychology test, the Stroop task, can tell us a little about why. I'd get you to read a list like this:

red

green

blue

Then I'd ask you to name the colour of the ink, as opposed to reading the words. You're going to find that latter task much more difficult. This is probably because you read words all the time, and similarly because you hardly ever name colours. So you want to read the words, but I've told you to name colours and you must somehow overpower the automaticity of reading to do that.

This particular task has fascinated researchers for the last 90-odd years, because we really aren't quite sure how the brain does that overpowering. But we're pretty clear on what's happening up until that point.

The general idea is that, in this task, the brain has two pathways from input to output. One pathway for word reading, and another pathway for colour naming. You can imagine that these two pathways run from the eyes to our brain, squiggle around for a bit, then eventually come out and end up at the muscles controlling the mouth. All along this route, these pathways overlap. At the places they overlap, there might be conflict. For example, you can't read words and name colours at the same time, because you only have one mouth. Conflict: one must win.

You can imagine similar kinds of interference happening in the brain in more abstract ways. And each time this happens, the word reading pathway is stronger and more dominant than the colour naming.

And thus, the effortful feeling of trying to force the colour pathway to 'win'.

These pathways, from input to output, seem most often to describe routes from perception to action. Our brain acts, in large part, as a connector, linking perceptions with the actions that are most sensible in the context.

James J. Gibson took this idea to it's limit, describing affordances: the environment offers us certain action possibilities. Our perceptions are tuned to these possibilities, and our brain creates routes, pathways, or links from these perceptual inputs to those action possibilities that might be related. Michael Graziano calls these action maps

This, then, explains some of the automaticity that we explored earlier. Remember the authors of Toby's story mentioned that there is:

a sense that comprehension occurs outside of our control.

We automatically generate this rich picture of Toby's circumstances because we have a rich network of pathways from input to output, each overlapping on the other, all describing the affordances; the action possibilities; the action maps of the world that we live in. Put another way, our brain describes the statistical structure of our interactions with the environment.

We are more than action maps

But of course, our brain must describe not just our perception-action maps. It must also have some relationship to emotions and value. Our gratification and desire. Our ability to do more than simply read words or name colours, but to force one pathway to win when another is easier. And so on.

Indeed, the vast majority of energy consumed by the brain appears to be used, not for processing links and chunks in the moment, or obtaining information about emotions and value, but rather some mysterious activity we call 'resting state' or 'spontaneous' activity.

These are tales for another time.

But what we take away from these ideas---links and chunks, pathways and patterns---is that the ideas we have are all related. In the world, as in our minds. Chunks of meaning scattered allong functionally connected trails of firing neurons that reflect the ways those meaning are connected for us in the world.

These pathways and patterns are the thing that allow us to so quickly understand Toby's story.

But these pathways and patterns aren't just helping link meaning in the world together. They are also ways of being in the world we occupy. It wouldn't occur to blow on Toby's piggy bank. We would only shake it. Blowing a piggy bank would be futile, particularly when it was full of coins.

Our perception-action maps help us navigate the world faster, but they also trap us. They make us see only the meaning we have learned to see.

This is why, to gain new kinds of insight, all the evidence suggests we must let these patterns go. It might very well explain why the most creative among us so often think quite differently.

Our patterns are the limits of the meaning we make of the world, unless we can free ourselves from them.

It's not all bad though. Toby's story might not be very interesting. But many things we find beautiful in the world are unveiled by these same processes. It's the reason we can see Morisot's bath at Mesnil:

image Berthe Morisot's Bath at Mesnil.

Our brain can draw the meaning that Berthe left unpainted.

And if that's true, just think what kinds of beautiful things we might find when we let those patterns go.

This article's ideology

Ideology: The brain primarily links chunks of meaning into patterns of neural pathways. Pathways and patterns of meaning help us intuitively solve the problems of everyday life. But they also trap us in those patterns, and stop us from seeing beyond them.

Summary:
Where our perceptions plug into the brain, beautiful maps of features of the world emerge. These maps start very concretely---specific sounds, or the orientation of a line. As we move further into the brain they become more abstract---maps of whole objects, or the marriage of an object and a sound as in a barking dog. The brain is mapping chunks of meaning about the world into intricate pathways of meaning. Patterns that reflect the way we think about the world and act in it. These patterns help us effortless solve the problems of day to day life. But they trap us from discovering new patterns, new ways of thinking, and new ways of being in the world. Only by understanding the brain can we really understand quite why that is.

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