C34 y0u r93d th18?
On our adaptable brain
Cogito ergo sum. I think, therefore I am. You almost have to begin an essay about the brain with the words of French philosopher René Descartes. The brain makes us think and remember. Makes us feel the breeze against the face and the smell of flowers in the wind. The brain makes us curious and wanting to explore the world. Maybe it made you want to read this text? In any case, it is thanks to your brain that you can distinguish the letters on this page and hopefully find meaning in the words these tiny letters form. And not least, the brain enables us to bring forth thoughts and ideas that change the world. Forever.
YOUR BRAIN CAN PREDICT THE FUTURE
The child in the cradle learns from its experiences. Slowly it manages to grab, crawl and then walk. Similarly, the child’s brain works at full throttle with the sensory perceptions that it collects, making use of the its experiences as it learns to navigate in the big world.
Let us take the faculty of sight as an example. As we explore the world, the retina transmits a large number of impulses through the optic nerve to the occipital lobe – the visual processing center of the brain. It is natural to believe that the visual cortex here uses all its computational power to interpret the visual impetus as they reach – we see everything that the retina sees.
The visual cortex, however, appears to be far more advanced than this. It is built up of multiple layers of brain cells, and instead of analysing visual impressions as it receives them, the outer layer of the optic cells work to predict what visual impressions the inner layer of the cerebral cortex receives via the optic nerve. The cerebral cortex thus forms its model of the world – and then uses the actual sensory impressions from the optic nerve to test whether the model corresponds to the reality.
But why does the visual cortex make these intricate calculations instead of just keeping track of what happens? To understand why the brain needs to be proactive, we will for a moment imagine that we are standing in a large square. There are no cars; shops and cafes surround the town square, and a constant flow of people passes across the square in different directions. Some are busy while others are walking and making stops along the way to observe what is happening across the square.
Three children play with a ball, which occasionally jumps in among the passers-by. If you decide to cross the square, you would – with an ‘observing brain’ – always need to be aware of the paving stones immediately in front of you to register pigeons, balls, benches, or fellow pedestrians that you risk bumping into with each step you take. If something gets in the way, you need to change your direction quickly, while keeping the course towards that cafe on the opposite side of the square.
With the ‘predictive brain’ you can, on the other hand, let the brain do the work for you: Your brain has already encountered thousands of pedestrians and balls jumping on a hard surface during your walks together – and based on these experiences it can rapidly estimate both their direction and speed. Therefore, the brain does not need to keep an eye on everything all the time. Instead, it may from time to time check that humans and balls are roughly in the position they were predicted to be. And it can also plan a route that avoids the area where the children are playing with the ball.
Your brain now functions as an advanced autopilot, which controls and adjusts your route across the square. Instead, you can direct your attention to the beautiful buildings surrounding the square, the flower pots and portrait artists’ drawings at the fountain. If nothing unforeseen happens, you will reach the cafe as you planned – your unconscious mind has completed the navigation while you enjoyed the stroll.
YOUR INNER FILM – AND ITS BLIND SPOTS
But, let us say that on your way across the square you suddenly see a magician with a crowd of spectators around him. With intricate movements, he gets balls and coins to disappear before the eyes of the wide-eyed crowd. Even if you concentrate on following the magician’s hands and his props all the time, you cannot discover his tricks. How does he do it?
This example reveals both the strength and the weakness of the brain guessing what you see – the mechanism brain researchers describe as predictive coding. Positively, it allows the brain to control our navigation from very few visual impressions, because the brain uses our past experiences to form a useful image of the world.
In practice, brain researchers believe that the outermost cell layer of the visual cortex makes predictions of how the world looks and how it behaves – while the deeper layers of the cortex compare these forecasts with the visual impression that it continually receives. If there is too much discrepancy between the prediction and the real world, the neurons at the bottom send a message about the difference to the neurons at the top, which then improves their model. In this way, the brain can form a kind of inner film that represents the surroundings – and regularly update with new details to make it more and more accurate.
You experience the downside of the mechanism when the magician snares your senses over and over again: Your brain will invariably concentrate on the places where the visual effects change quickly. The magician knows this and acts in ways to make sure that your attention is redirected away from the areas where his tricks actually take place. In this way, your brain is tricked to not update the image of the magician’s left hand as he cleverly gets a prop out of sight, because it is busy following the fast movement of the playing cards in the magician’s right hand. The trick just never pops up in the pictures of the event in your brain – even if you look very close.
UNUSUAL BEHAVIOUR REGISTERED
Continuing your stroll across the square, you are again interrupted in your sightseeing. Out of the corner of your eye, you have detected that some people stop in their tracks. At the same time, a small procession of people in colourful medieval costumes emerges from a side street. What just happened in your brain is remarkable.
While you are occupied by the beautiful facades of the square, your predictive brain detects something unusual: Firstly, some other pedestrians did not reach the place in your field of vision that your brain had predicted – but instead stood still. Secondly, in the flow of people, some suits and colours suddenly did not fit in on a summer day in 2018.
The Finnish brain researcher Risto Näätänen discovered in 1978 that the cerebral cortex emits a special failure signal if something in our environment suddenly changes. He studied how the auditory cortex reacts, if it analyses sounds where the pitch or beat changes slightly along the way.
If you have seen – or rather heard – the initial rounds of TV singing shows like The X Factor, you know that we immediately notice, if the pitch in “Livin ‘on a Prayer” does not precisely match Bon Jovi’s original version of the song. We are cringing, and unsurprisingly brain researchers can measure the discomfort in our minds. The surprising thing about Näätänen’s failure signal is that the auditory cortex unconsciously detects deviations in the sound image even if you have your attention focused on something completely different.
Both the auditory and the visual cortex thus continually calculates the difference between the sound and visual impressions it receives and its predictions. Näätänen’s failure signal measures this difference and can, if the signal is too powerful, activate your attention. Your unconscious mind invariably monitors the surroundings for you – and alerts you if something unexpected happens. Such as when the fashion style shifts with a few hundred of years.
ARE YOU ALBE TO RAED THIS?
The genius German physicist and physician Hermann von Helmholtz already suggested in the 19th century that our subconsciousness builds an inner model of the world to explain the sensory impressions we receive. British brain researcher Karl Friston has even pointed out that the brain might control and steer our movements via the sensational signals that the muscles and tendons send back to the brain. The brain thus sets the body in motion – and checks if everything feels right.
It is a great advantage that your unconscious mind predicts what is happening in the world around you – and only alerts your conscious mind when something in the sensed impressions seems wrong or unusual. The effect of this feature of the brain is that your unconscious mind can take control of an increasing number of functions as you learn them, which in turn releases computational resources so your conscious mind can learn even more – as the brain again automates and so on and so forth.
The brain keeps information that makes it better at predicting the world around it. When we learn to read in school, we first learn to recognise the letters, then how they form words and how we spell these words correctly. But for the brain, the task is not completed. It follows other rules than those you have consciously learned. Let us test this now.
In the next section, I have changed the text so it can not be read instantly. But try anyway. Maybe you can decode what I have written.
Can you raed waht I’m wtirnig now? In tihs prapargah, I hvae spawepd aonurd the ltertes idsnie the wrdos. The fsrit and lsat lrtetes are sltil in tiher ccreort pealcs, but the ltertes in beewetn are now in rodnam oredr. At frsit, it is hrad to get uesd to, but ocne you pitrcace a bit, yuor biran fdnis out the stesym in the txet. It fndis taht the stncneees mkae ssnee if it deos not rierque the mldide lrttees to be in the uausl and etexecpd oredr. Aetfr a wlhie, msot pploee can raed a txet taht is ‘enyrctepd’ in tihs way, aslomt whutiot pmelrobs. Yuor biran has lraeend to regnoicse qtiue a few wdros, and now it has bmoece so good taht it can furige out waht the wdors say, eevn if tehy hvae ireccornt sniellpg. It is sramt, rhgit?
BE PREPARED
Be prepared! The Scout motto fits well as a motto of the mind as well: One of its most important features is to gather information and develop skills so that we avoid standing in dangerous situations; situations where we do not know what to do.
For our ancestors, it could mean the difference between life and death being prepared for attacks by predators. They should be able to respond quickly and appropriately, if they suddenly found themselves at risk. It is exciting to study how the brain manages situations where we are in critical, life-threatening conditions, but such research obviously cannot be done by brain researchers. Instead, we can use tv and the internet to observe how people respond, if they think they are in danger.
Searching for “scare pranks” on the internet, you will find video clips where pranksters scare the living daylights out of friends and family. It is fascinating to observe the reactions: some of the victims are freezing and standing completely still. Other of the victims react either by instinctively attacking the prankster – or by surprisingly fast escape. On the videos, you can see how these fast instinctive reactions and high screams almost always take the attacker himself by surprise.
We do not even control the reflex that causes us to freeze, fight or flee for life, if put in critical situations. Our amygdala is in charge. We find this almond-shaped cluster of neurons inside the temporal lobe, and it activates when we discover an axeman behind the kitchen door a dark and rainy evening, or when at other times we feel fear or anger.
Amygdalas role as rescue catapult for dangerous situations has given it a special privilege: if it receives sufficiently hazardous visual impressions from its surroundings, it can instantly make us stop, strike and kick or run away in wild panic. It does not go through a time-consuming process in which our conscious mind first has to devise a rescue plan.
At the same time, the amygdala increases the pulse, blood pressure and blood flow to our muscles, so we are ready to exert such forceful outcomes. In other words, Amygdala initiates physical reactions at the very moment we feel fear but have not yet registered what triggered it.
But our amygdala not only instinctively reacts to dangerous situations – it also remembers them. When we see, hear or feel something that is reminiscent of the first time the danger appeared, amygdala can, therefore, initiate the emergency response again and improve our chances of coping with the situation, if it occurs again.
Amygdalas alarm function is not always appropriate: Sudden noise and lightning can, for example, activate the amygdala of a veteran soldier who has been exposed to traumatic experiences in a war zone. Amygdala not only recalls the mental images of explosions and dismemberments he or she has seen – it also reproduces the strong psychological and physical stress reaction experienced by the soldier at the time. But this time, being alert and prepared does not help the soldier.
I intentionally write “activate amygdala” because the cerebral cortex is not necessarily involved in the reaction. Amygdala, in other words, makes us feel fear, anger or sadness without being aware of what exactly triggered the feeling. Conversely and – in this case – unfortunately, the cortex cannot control the amygdala so the soldier cannot decide not to relive the stress condition again and again. Brain scientists are working on developing methods for erasing bad memories. But it is a difficult task: Many are worried that they accidentally also wipe out other parts of our memories or remove important skills.
Let us for a moment return to your stroll across the square and the moment before the “failure signal” caused you to pay attention to the people wearing medieval costumes. You unconsciously turned your head as something in your peripheral vision did not match.
Friston has suggested that our unconscious mind not only predicts what our senses capture. The brain also helps to gather better data into its predictions. As you turned your head towards that part of the place where something seemed wrong or mismatched, it was your predictive brain that made you think, that it could get better or at least supplementary image data to its predictions. Instead, if the data collection had revealed a cafe owner who was moving parasols out of the way in the square, your unconscious mind would not have disturbed your conscious sightseeing but left it undisturbed on the way to the cafe across the square.
The brain can thus match its model of the world and the real world by gathering more information. The next question is whether the brain will try to change the world of reality? Or change the model it has created from the world itself?
Imagine that you are attending a dinner party: The table is set with glasses, plates, and sets of cutlery. One of the knives is slightly out of position and touches another knife. Do you – without thinking about it – put the knife in place, so everything is parallel? Or is it allowed to stay until you need it for the main course? Many will instinctively put the knife in its “right” position. Create order in the world so that it fits our inner model.
C34 Y0U R93D TH18 38 W9LL?
Now we will test what happens if the brain cannot get its model to fit. Let us imagine that you are suddenly in a parallel universe. It looks very similar to ours, but there is a single, distinct difference: Alphabet letters look entirely different to what you are used to. The question is now whether your brain will stubbornly hold onto its model of the world – the standard alphabet – or will it form a new inner world and adapt to new rules? The next section almost implicitly answers that question.
C34 y0u r93d wh3t 1’m wr1t14g 40w 38 w9ll? 14 th18 89ct104 1t w1ll 59 3 l1ttl9 h3rd9r! 40w 1 h3v9 r9pl3c9d 80m9 0f th9 l9tt9r8 w1th 4um59r8 59tw994 z9r0 34d 4149. F0r 9x3mpl9, th9 4um59r thr99 r9pl3c98 th9 f1r8t l9tt9r 0f th9 3lph359t, 34d th9 4um59r 4149 r9pl3c98 th9 f1fth l9tt9r 0f th9 3lph359t. Y0u m3y 40t h3v9 34y pr10r 9xp9r194c9 14 r93d14g w0rd8 w1th 4um59r8 14 th9m, 80 1f y0u 49v9rth9l988 8ucc99d 14 r93d14g th18 t9xt, 1t m9348 th3t y0ur 5r314 gr3du3lly f1gur98 th3t th9 w0rd8 m3k9 89489 1f 1t ‘r93d8’ 80m9 0f th9 4um59r8 38 l9tt9r8. 1 h3v9 8w3pp9d 81x l9tt9r8 w1th 4um59r8. Th9 w0rd8 59c0m9 h3rd9r t0 r9c0g4189 1f y0u r9pl3c9 m0r9 l9tt9r8 w1th 4um59r8 0r 8ym50l8. Y0ur 5r314 18 5r1ll134t, 18 1t 40t?!
This simple play with numbers and letters raises a far greater question: Will the brain also ignore or re-calibrate our lessons learned about what is right and wrong if circumstances require it? In fact, Friston’s theory suggests that our brains will do anything to reduce discrepancies between its model of the world and the real world.
Numerous psychological experiments confirm that we are prepared to change our norms and behaviours quite a lot to avoid colliding with the expectations of the surroundings. When young people end up in crime, abuse or radicalisation, we often blame for example poor education. But if the environment is radically changed, the brain will most likely change the convictions and the model of the world that was formed in the childhood in order to adjust to the new environment in which it now operates.
In any case, the brain was ready to break with our idea of what an alphabet looks like, in order to not let us down in the parallel universe we just visited.
The article is an excerpt of “The Brain” by Leif Østergaard. A part of Aarhus University Press’s book series Tænkepauser (~ Breaks for thinking). The first Monday of each month (except July and August) a new book in the series is published. Since 2012, more than 50 different books have been published.
The basic premise of each book is, that a researcher from the University of Aarhus convey their knowledge of a given field on only 60 pages. Topics covered include everything from faith, hope and love to ants and monsters. The printed book costs $8. The digital editions can be purchased for $6.50 via the publisher’s website, www.unipress.au.dk, or at other online retailers.
Some releases in the series have already been published in English under the title “Reflections”, and several are under way, including “The Brain” by Leif Østergaard.
Leif Østergaard
M.D., M.Sc., Ph.D., Dr. Med. Sci
The author of the small book “Hjernen” (The Brain) that is forthcoming in an English translation, from which we here bring an excerpt. Østergaard holds a doctorate in Medical Science at the Faculty of Health Sciences at Aarhus University, Denmark. He is a Clinical Professor (tenured) in experimental neuroradiology, Department of Neuroradiology, Institute of Clinical Medicine and is the director of MINDLab at the National Experimental Core Facility for Neuroscience and Cognition Research, CFIN, at Aarhus University and Aarhus University Hospital.