How the Brain Creates the Mind
Introduction
For thousands of years, probably since the proverbial Garden of Eden, humans have wondered about the link between the body, mind, and spirit. All those eons of devotion to this problem can be reduced down to two essential concepts. First, until the mid-20th century, virtually all study of the mind was done by introspection rather than experimentation. Philosophers speculated on how their own minds worked. They had no knowledge of how nerves and brains actually functioned. It was not until the mid-20th century that scientists discovered how nerve cells work.
Second, the main question entertained by philosophers was whether the mind and body are two different entities. Mind-body dualism states that they are separate things. The brain is a physical entity while the mind/soul/spirit/self is a separate non-physical entity with an existence independent of the brain. Dualism allows for the existence of a soul or spirit that persists after the brain dies. It is compatible with an afterlife.
Materialism, on the other hand, states that everything, including mental states and consciousness, arises from interactions of matter. The mind and spirit are just manifestations of the workings of the brain, in the same way that the image on a monitor screen is created by the computer. That is to say, they are illusions. When the body dies, the mind ceases to exist.
The mind-body dilemma is not just an ancient academic exercise. It is important in current politics and religion. If materialism is correct and the mind is just a manifestation of the physical operations of the brain, then it can be argued that there is no separate soul, no afterlife, no heaven or hell, and no divine source of moral guidance.
This impacts religions and theocracies all over the world, who rule by interpreting the desires of various deities for the benefit of their flocks. If the spirit is merely a manifestation of the brain, then the parishioners are all reasoning machines who can make up their own minds and rule their own lives, without fear of consequences in the afterlife.
Neuroscience has advanced tremendously since the mid-20th century. Today we know enough about the brain to meaningfully speculate on how it creates thought, memory, consciousness, and the sense of self. The quest for the mind is no longer in the domain of philosophers. It has been taken up by physicians, linguists, neurobiologists, psychologists, and computer scientists.
So now, in what I admit is an act of hubris, I will explain how the brain gives rise to the mind. When provided with knowledge of how a brain functions, the human mind is capable of understanding how the human mind works. What we perceive as thoughts and ideas are in fact patterns of electrical activity in the micro-circuitry inside our heads.
Chapter 1. The Brain
The Effects of Scale
Neurophysiology requires a clear understanding of the effects of scale. One cannot understand how the brain works without first knowing how many molecules are present in a glass of water. We will begin very small and work our way up to neurons, thoughts, awareness, and spirituality. First we must know what is happening in the devices of the brain at tiny distances and in huge numbers.
Humans tend to be unaware of things they cannot see. This is especially true of very small things that occur in very large numbers. If I ask you to visualize ten thousand snow geese in a rice field, or a million black birds in one of those huge writhing flocks that stretch on for miles on a winter day, you can probably do so. You may even be able to comprehend a swarm of a billion mayflies on the shores of the Tennessee River on a summer day.
However, consider the number of molecules in a glass of water. There are more molecules in a glass of water than there are glasses of water in all the oceans on earth. The number of molecules in a glass of water is about 10 to the 24th power (1 followed by 24 zeros), while the number of glasses in the oceans is about 10 to the 21st power. There are a thousand times more molecules in the glass of water than there are glasses of water in all the oceans on Earth. So, if the water in your glass contains only one part per billion of Sodium, then there are a million billion (1,000,000,000,000,000) atoms of Sodium in your glass. A tiny amount of a substance is a huge number of molecules.
The Basic Components
If we want to understand our own minds, we must first grasp the scale of the physical devices that create that mind. The human brain is made up of about 86 billion neurons. Each of them has between one thousand and ten thousand connections to other neurons. Those connections are so small that they can only be seen with an electron microscope. Each connection stores millions of molecules of chemicals and replaces them hundreds of times per second. There are a hundred trillion connections in the brain and a hundred times that many transactions every second.
Things are happening in the brain much faster than you can see, and the structures are much smaller than you can visualize. This only makes sense, because a single thought is the result of millions of events in the brain, recurring at hundreds of times per second. Moreover, the numbers of molecules involved in each tiny information exchange is enormous.
The neuron is the basic working unit of the brain. All nervous systems, from the most primitive flatworms to the most intelligent mammals, are made of these cells. They have changed very little in the past three hundred million years. The basic neuron has a cell body with two types of extensions, axons and dendrites. A neuron usually has several dendrites, and each of them has thousands of branches. There is only one axon per neuron, and it also branches thousands of times. Dendrites receive incoming signals to the neuron, and axons carry outgoing signals.
Nerve fibers carry electrical signals, but not in the way that wires do. No actual electrical current moves along the fiber. The signal is carried by a moving charge wave. The inside of the cell has a higher concentration of Potassium ions and lower concentration of Sodium ions than the outside of the cell. The cell membrane is said to be polarized.
A disturbance at a point on the cell membrane causes the delicate balance of ions there to flip over, changing the electrical charge across the membrane. This is called depolarization.
Enzymes quickly pump the ions back to their resting positions. However, before the disturbance can be corrected, it spreads to the surrounding membrane.
The flipped charge wave spreads from the starting point, causing an outgoing wave, much like the ripple caused by a pebble thrown into a pond. Unlike the concentric circles on a pond, though, there is only one outgoing ripple on the membrane, because the ion pumps quickly stabilize the balance of electrical charge across the membrane after the wave passes. This traveling wave of inverted ions is called an action potential. It moves along the membrane at about one hundred meters per second.
The connections between axons and dendrites are called synapses. There is a very narrow space between the synaptic membranes, called the synaptic cleft. Every neuron has thousands of synapses on both its dendrites and its axon. The synapse is the fundamental building block of thought and memory. Yet it is too small to be seen with anything except an electron microscope.
The synaptic cleft is another example of the effects of scale. Chemicals must cross the cleft by diffusion. That is to say, they simply drift across to the other side. However, the cleft is unimaginably tiny. More than a thousand clefts would fit inside the diameter of a human hair. Compared to the drawing above, a human hair would be forty feet wide. The distance across the cleft is so small that diffusion of chemicals across the cleft takes only microseconds.
The Mechanics of Memory
The axon side of the synapse has pre-positioned vesicles, tiny packets of chemicals, lined up along its membrane. Each vesicle is about 50 nanometers wide and contains about one million molecules of water and about ten thousand molecules of dissolved chemicals.
When an action potential on an axon reaches a synapse, it opens some of these vesicles, releasing chemicals into the narrow gap in the synaptic cleft. There are many different kinds of chemicals, but for this discussion they can be categorized as immediate-acting, short-acting, and long-acting.
Immediate-acting chemicals cause the membrane on the dendrite side of the cleft to flip its ion layer, starting an action potential on the other side of the synapse. These are the neurotransmitters, and they start the nerve signal on the next neuron. It is like the pebble thrown into the pond, creating a ripple that spreads out from the synapse. Enzymes in the membrane destroy these immediate-acting molecules very quickly, in microseconds, after the action potential leaves the synapse.
The short-acting chemicals in the packets cause the dendrite side of the synapse to become more sensitive to the next packet of chemicals. Each time the synapse fires it gets a little bit better at receiving a signal. It becomes more alert and responsive. Short acting chemicals persist in the synapse for a few minutes or hours. They make the connection stronger. This is the basis of short-term memory. Synapses become more sensitive with repeated use. However, this effect fades over time.
The long-acting chemicals remain on the dendrite side of the synapse for many hours. These are pumped back across the synapse during sleep and stimulate the synapse to grow. Those synapses which have had the most use during the day accumulate the most long-acting chemicals. In response to those chemicals, the synapses become larger at night during sleep. The actual physical dimensions of the synapse increase. Larger synapses have larger effects on the dendrite action potential. This is the basis of long-term memory.
Imagine you are learning to play a musical instrument, practicing a new chord on a guitar or a piano. At first you clumsily attempt the chord. You improve over time and, after an hour, your fingers begin to know their way. This is because all the synapses involved in the process, from your cerebral cortex to the muscles in your hands, have become more receptive and responsive during the hour of practice. Those synapses have accumulated short-acting chemicals, which makes it easier for them to sustain positive feedback loops through the involved neurons.
The active synapses have also been accumulating long-acting chemicals while you practiced. They are stored on the dendrite side of the synapse until you sleep. So you go to bed and sleep the night away, thinking your brain is resting. It is not. The brain consumes the same amount of energy while you sleep as it does when you are awake. It is busy remodeling your synapses under the control of those long-acting chemicals that accumulated during the day.
You think your brain sleeps because you do not remember what happened during the night. The machinery that creates your memories during the day is involved in other processes during sleep. You are still aware of your surroundings during sleep. You will awaken in response to a strange noise or smell. But you do not recall being aware, because your mind was occupied with things that were not being retained in memory. During sleep, the short-acting and long-acting chemicals are being replenished on the axon side of the synapses and removed from the dendrite side. You are not conscious during sleep because your memory is not working the way it does during wakefulness. We will return later to this relationship between consciousness and memory.
The next day, you have to relearn the chords, but it only takes a few minutes to do so. You are not able to simply pick up where you left off, but you are also not back to ground zero. Instead, you struggle a little at first, then get up to the level of the previous day in only a few minutes. During the night the neurons in your brain increased the size of the most heavily used synapses from the previous day. Those synapses that worked so hard the day before are now larger and stronger. This is how long-term memory works.
Axons and dendrites propagate action potentials differently. On dendrite membranes a signal fades as it spreads out from a synapse. It will not travel very far. The signals on dendrites need constant reinforcement from other synapses along their branches to sustain and build the signal strength. The creation of a strong action potential on a dendrite requires input from many synapses.
Not all of the synapses are positive. Some are negative or inhibitory and decrease the action potential. Neurons compete with each other for your mind’s attention. They may suppress the activity of their neighbors. The membrane of a dendrite is constantly adding and subtracting small action potentials initiated by synapses all along its length. It takes a lot of positive input from a lot of synapses to create an action potential with enough strength to reach the base of the dendrite and depolarize the body of the neuron. Once it does, though, everything changes.
When the body of the neuron depolarizes, the action potential travels to the axon. It does not fade over distance and time. Unlike dendrites, the neuronal body and axon sustain the signal. It spreads over the whole body of the neuron and out the axon all the way to the tips of all the axonal branches. When it arrives at the tips, it releases vesicles from every synapse on the axon.
Dendrites are analog devices. They add and subtract small amounts of depolarization all along their lengths, collecting input from many synapses, until the action potential reaches a certain threshold at the base of the dendrite where it connects to the body of the neuron. Once that threshold is reached, the action potential depolarizes the membrane on the body of the neuron. The body and axon then switch from “off” to “on,” sending out a single action potential.
The neuronal body and axon are digital devices. Unlike the dendrites, they only respond if a certain charge threshold has been exceeded. Then they respond all the way. If the action potential is triggered in the axon, then the axon is switched on, and the action potential travels out to all the synapses on all the branches of the axon. They all release their packets of chemicals into synaptic clefts.
For the benefit of those who wish to make the comparison, the human brain is a massively parallel computer with 86 billion individual processors. The processors are nothing more than analog adding machines. Each processor receives analog input from thousands of channels and produces a digital output of one or zero. Each processor independently adjusts the gain on its input channels during a nightly downtime, based on the volume of input the previous day.
Brain tissue is a compact mass of neurons and support cells. Each neuron is connected by thousands of synapses to thousands of other neurons. They are all constantly receiving signals, but at any instant in time only a small portion are receiving enough input to initiate an output. Each neuron sends a signal only when it gets enough input on its dendrites to reach the threshold on the neuron body. Whether an axon produces output depends upon the number of synapses connecting to the dendrites, their activity, their size, and whether the input is positive or negative.
Chapter 2. The Mind
Thoughts
Let us begin with a neuron that sends signals out along an axon with many branches, which connect with the dendrites of other neurons, which also have axons with many branches. A few of those branches connect back with the dendrites of the initial neuron. Most will connect to other neurons, which will also have branches feeding back to prior neurons in the network. Those will send signals to others with branches feeding back, and add on infinitum. This interconnectivity allows for feedback loops. These loops may pass through two neurons, or ten, or a hundred, before returning the signal to the original neuron.
The neurons in the loops may be stimulated repeatedly by each other and by neurons outside the loops. Input comes from sensory neurons like vision, hearing, and touch, and from other areas of the brain such as spatial recognition and math processing regions. Sensory inputs do not receive feedback and so are not in the recursive loops, but they do add to the signals and support the loops.
When enough positive feedback occurs, the loops become self-sustaining. All the neurons in the loops are re-stimulated many times a second. The action potential keeps cycling back around to the same neurons. The signal loop becomes recursive. These loops may persist over several seconds or minutes and involve millions of neurons. The pattern changes as different neurons enter or leave the loops. It is these sustained positive feedback loops, these recursive signals, which make up the substance of our thoughts. When we observe our thoughts, this is what we are observing. This is thinking.
(Note to neurophysiologists. These recursive loops may account for spike trains.)
(Note to psychologists: Inhibitory synapses decrease the likelihood of recursive signal loops, and reduce long-term chemical deposition. They reduce learning. This is how we learn what not to do.)
As an example, let us speculate that our original neuron is associated with the color blue. Of course there are many shades and hues of blue. This is a particular sky blue, and it receives input on its dendrites from many thousands of neurons related to this color, as well as other shades and hues of blue. It also has a single axon that branches out and connects to thousands of neurons related to blue in other ways.
Some of those neurons are also associated with shapes and images. There are active synapses connecting to neurons representing shapes of triangles, semi-circles, and the number three. Others are related to certain words and names and their spelling, or to odors, or to the concepts associated with flowers, and others are related to ideas such as delicate, ephemeral, and pleasing, but also to weeds and invasive species. All these neurons are interacting in sustained feedback loops.
The total number of neurons involved may be in the millions. Together they create what we perceive as a thought. In this case, it is the thought of a Virginia dayflower, a small triangular sky blue flower, invasive in many areas, but native to Virginia. It is delicate and pretty. The blossoms last only for a few hours in the morning before wilting.
As you look at the image of a dayflower, try to imagine how the neurons in your brain go through this process. The thought that comes into your awareness is composed of recursive signals connecting together a network of concepts with this flower. That is how our thoughts form. The flower that is in your mind is a fusion of thousands of concepts linked by a dynamic network of recursive signaling. The neocortex merges sets of concepts into ideas and thoughts.
The next question: where is this happening in the brain? The answer: in many places at once. The neurons associated with color are in the visual cortex. Shapes are probably there too, along with memories of images. Mathematical shapes are processed by neurons in the spatial reasoning area of the prefrontal cortex, while numbers use yet another set of neurons in the parietal lobes.
Any words associated with the image require participation by the speech areas of the brain. The words themselves are in Broca’s area, in the left parietal lobe of the brain where we keep our words. Association of those words with the image is handled by neurons in Wernicke’s area, where we construct speech. If you make an attempt to articulate the name of the flower (move your lips) as you read, you will need neurons in the area controlling movement of the muscles of the mouth and larynx.
Neurons related to memories of that particular type of flower would be in the temporal lobes. Higher level concepts such as “delicate” and “ephemeral” are in the frontal lobes. Odors are handled by the olfactory bulb, but if they illicit strong emotions, then neurons from the hippocampus and amygdala would be in the loop.
There are millions of neurons from many areas of the brain involved in the simple thought of a flower, and they generate thousands of sustained positive feedback loops. The network of recursive signal loops between the concepts of images, shapes, colors, sensations, emotions, and memories related to this flower is what you perceive as a thought.
Connected Concepts
Consider a population of concepts in the brain as shown in the box below. The human brain contains hundreds of millions of individual concepts. Reiterative loops between these concepts can form widely divergent thoughts according to the selection of sets of concepts.
Below is a very simplified diagram of a thought, in this case a particular blue flower. It consists of a unique population of sustained feedback loops through neurons representing concepts related to the flower. As long as these loops are sustained, the thought persists. These reiterative signal loops are the thought. In actuality, the involved neurons would number in the millions, and include images, language, and motor functions.
The diagram shows active feedback loops. Each of these concepts resides in a functional memory unit that is receiving stimulation from some other part of the brain. The colors and forms are being triggered by vision centers. The numbers are being stimulated by math centers. Esthetic concepts such as ephemeral and delicate are receiving input from frontal lobes. All that input combines to generate a population of sustained feedback loops that we interpret as a thought. These sustained loops pass through a collection of concepts. The Gestalt of those concepts is the thought of the flower.
It may be helpful to think of each concept as residing in a single neuron, but the brain organization is not that simple and straightforward. Does every idea and concept have its own neuron? No. It is more complicated than that.
The thinking part of the brain is called the neocortex. It is made up of about 500,000 cortical columns, each of which is organized into about 600 separate functional units, which Ray Kurzweil calls pattern recognizers. These highly organized collections of neurons are information processors. It is them, not the individual neurons, which are the functional units that represent concepts.
Kurzweil’s pattern recognizers are the concept units of the brain. Each of them represents a single concept or idea. There is one (or more) of these units for each word, phrase, color, sensation, action, odor, emotion, concept, event, person, and guitar chord in a person’s life experience. The human neocortex contains about 300,000,000 of these functional units. The concept stored in each device is defined by the synaptic connections within the unit and between that unit and the other three hundred million units in the brain.
Different people will have vastly different populations of concepts associated with any one species of flower. For instance, I once took a photograph of a Virginia dayflower refracted in a dew drop on the tip of a blade of grass. When I think of a Virginia dayflower, my mind recruits additional concepts such as water, dew drops, refraction, inversion, crystal balls, chromatic aberration, and the rewards of stubborn determination. It took two days and six rolls of film to get this image. Now that you have seen the photo, your mind will also recruit those concepts when you think of this flower.
Let us return to the box of concepts that allowed us to diagram the thought of a flower. Here is the same field of concepts with an entirely different set of sustained feedback loops. This is a simplified representation of the loops that might form the thought of a black widow spider.
In the brain, all these neurons are physically connected all the time by synapses. The diagram above shows only those connections that are currently conducting signals in sustained positive feedback loops. Our thoughts are nothing more than combinations of these active recursive signal loops.
Here is one more example. This again uses the same library of concepts. It represents the thought of a pretty woman. Note that some of the same concepts are recruited that were active for the flower and the spider. In particular, both the woman and the black widow spider recruit the concepts of hourglass and female. To some men (and some women), the pretty woman might also recruit concepts of dangerous and scary, depending on their circumstances and personal experiences.
In each scenario, the active iterations sustained by positive feedback loops make up a thought. It is the combination of concepts, connected by active loops, that constitutes thinking. When we are conscious of our thoughts, this is what we are observing. This floating, ever-changing set of reiterative signal loops is who we are.
Flow of thought
Our thoughts are constantly changing. Sometimes they meander and wander. New neurons join the loops as we think about a topic. Sometimes our thoughts drift. More often they are under the control of memorized sequences. After enough practice, as when learning the guitar or piano chords, the synapses involved in one action develop strong connections to the group of neurons responsible for the next action, and those feed forward to the next group, and so on.
It may take several seconds or minutes for the sequence to complete itself. Instead of the signal looping back on itself and reiterating, it feeds forward to new groups of neurons in a learned sequence. The entire collection of reiterating signals moves along a cascade of concepts in orderly fashion. If this process has an intended result, like putting on your shirt, it stops when you are finished. But if it is a music sequence, it can loop back around to the original set and just keep going. This is how a song gets stuck in your head.
The memorization of sequences may be the most important function of memory. It provides animals the ability to follow a consistent path, whether physically, from the home shelter to a water source, or mentally, from a rough stone to a formed tool. It enables structured language and procedural planning. Everything we do routinely is done in structured sequences, and is unidirectional. Each group of neurons in a thought feed forward to the next group in the cascade.
It is instructive to note that we do not have the ability to recall sequences backward. You must circle back by a different route in your brain. Recite your social security number. Now recite your phone number backwards. They are two entirely different process in the brain. The first is just a well-rehearsed task, probably housed in its own memory unit, which triggers the sequence. The second requires a complex conscious effort. You must visualize the number, then read it backward, one number at a time. You use the same process to spell your name backward, or to say the alphabet backward. For a greater challenge, explain tying a shoelace, backwards.
Memory Storage
I began this discussion by suggesting that our original neuron is associated with the color blue. But what, exactly, does that mean? It means that this particular functional unit in the neocortex has many strong synaptic connections with visual cortex neurons that in turn have connections with the retinal cone cells that respond to light with a wavelength of about 420 nm. It also has connections to functional units associated with the word “blue,” the spelling of that word, and its pronunciation. It is also heavily linked to things we think of as blue, such as a clear blue sky, lapis lazuli, a robin’s egg, Cobalt pigments, and now, of course, a Virginia dayflower.
Ultimately, all assignments of meaning to functional units in the brain are based on context and circular reasoning. There is nothing special about the pattern recognition unit that stores the concept blue. There is no blue neuron. It is the synaptic connections to and from the functional unit that give it meaning.
Chapter 3. The Self
Working memory
Thoughts are not static. They change constantly. They move and shift as new concepts enter the loops. We rarely have a single simple image in our minds. Rather we think about something in the context of other stuff going on about us. As you were looking at the picture of the dayflower, you were also thinking about the process of thinking, and about reading and processing the words on the page. You probably considered counter-arguments to my proposed definition of thought, or you may have questioned my sanity. Your mind was exploring pathways through additional concepts, checking to see if they fit well enough to reiterate. You were looking for others avenues of positive feedback. You were thinking.
The population of neurons involved in the sustained loops is constantly changing and drifting. Think of this as a reiterative memory process, constantly shifting in a sea of concepts. A chain of thought sometimes seems like a separate organism that takes on a life of its own. Minds wander, usually just off the intended path, but sometimes to forbidden or uncomfortable places. We often have difficulty controlling our thoughts.
Change may flow gently from one concept to the next, in a train of thought, or it may change suddenly in response to an interruption. As you are reading a Wikipedia article about a Virginia dayflower, your doorbell rings. This activates an entirely new set of neurons about sounds, annoying interruptions, visitors, curiosity, UPS deliveries, recent online shopping, neighbors, religious missionaries, strangers, and possible danger. The thought of the flower is gone. However, once you have dealt with the distraction, you are able to recover the thoughts of the flower.
Stop for a moment and think about how we got to this point. What was the train of thought that brought us here? Can you recall? Of course you can. Your mind holds a running record of your thoughts. It keeps track of where you have been, how you got here, and where you are going. This is called working memory. It is the map of the immediate past, the present, and the immediate future. It is your current recursive memory combined with your recent short-term memory. It is what you access when someone asks, “Whatcha doin?”
You are able to answer this question because the synapses you have been using recently are more alert than others. As your thoughts moved on, they left behind a trail of short-acting chemicals hanging out in the synapses. Those chemicals make it easier to recruit that set of neurons back into the reiterative loops. The details fade with time, but they last long enough for you to know how you got to where you are.
Working memory is an ancient process. Everything needs it. Limpets need to return to their homes when the tide goes out. Animals who climb trees need to find their way back down. Youngsters who wander away need to remember where they left their mothers. Mother squirrels need to remember which way is back to the nest. All vertebrates and many invertebrates have a working memory. It is necessary for survival. An earthworm uses a rudimentary working memory to navigate your lawn and avoid being eaten by a robin. Working memory is certainly not unique to humans.
However, humans use working memory in different ways than most other animals. Of course we remember how we got to work this morning, and where we parked the car, but we also remember the sequence of tasks we performed in order to repair an engine, cook a meal, or solve an equation. The human repertoire of concepts is very different than that of other animals.
Human memory is not necessarily larger or better, just different. We do not recognize 20,000 different odors, or know the sonar reflections of 1000 different flying insects. Instead we know vocabularies that range to tens of thousands of words. We know numbers and math. Humans have different things to remember and use memory for different tasks than animals, but the underlying neurophysiology is the same. We keep a running memory of how we got to where we are. It is maintained by short-acting chemicals in the synapses, which in turn are constantly resupplied by the repetitive firing of the synapses engaged in our active thoughts.
The trail of thoughts marked by short-acting chemicals is also marked by long-acting chemicals, but the long-acting chemical trail does not fade. During sleep, the synapses that were active in the day increase in size, stimulated by the long-acting chemicals accumulated in the day. Those synapses that had short-term memories during the day are remodeled. The short term memories become archived. They are converted to long-term memory by increasing the influence of the involved synapses.
In the process, details are lost. I can reconstruct what I was thinking two minutes ago, but probably not two hours ago, and certainly not two days ago. I can, however, recall where I was two days ago, and who I was with. Probably not two years ago though. I certainly recall where I lived two years ago, and what my house looked like. But how about twenty-two years ago. “Hmmm. Was I still living in the house on Mobile Street then, or had I moved to St. Georges Avenue? Was I even married then? Let me think. What year was my first divorce?” Our memory fades with time.
What does not fade is the sense of continuity. I have a personal history, an identity, a collection of memories that defines me. I know where I was and what I was doing with some degree of detail throughout all the years of my life. I feel strongly that when I awoke this morning, I was the same person who fell asleep in my bed last night. To paraphrase Descartes, I remember me, therefore, I am. My memories of myself are stored in the patterns of synaptic connections between the 86,000,000,000 neurons in my brain.
When I summon up thoughts of myself, I am generating reiterative feedback loops among neurons representing the details of all those memories, and I know who I am. When I say that I am self-aware, this is the self that I am aware of. It is that collection of memories that is unique to me, that concept I call my identity, the person who fell asleep in my bed last night, and it is a manifestation of the synaptic connections in my brain. This is what I perceive as a non-physical self. It is a population of self-sustaining positive feedback loops passing through neurons that are associated with memories of personal history, friends, events, desires, beliefs, plans, ancestors, and descendants. This is who I am. We will return to this subject later.
While you were looking at the image of the flower, there were millions of other active neurons in your brain and body that did not rise to the level of your attention. They were sending signals, but did not generate sustained feedback loops. Your ears and nose were receiving input and your brain was processing that information, comparing it to thousands of memories, watching constantly for patterns that warranted action. Your skin was alert to sensations, watching for biting insects, excessive heat or cold, or an unexpected touch that might warrant the attention of your mind. Your vestibular apparatus, the organ in your head that detects movement, was monitoring for any sudden change in position or acceleration that might need your attention.
You, the thinking you, were not conscious of any of this. None of these systems were sending enough input to your brain to generate sustained positive feedback loops and enter your thoughts. None of them distracted your mind from the flower. They did not stimulate recursive signaling. They were all in your subconscious.
Consider how things would suddenly change in your working memory if you heard a creak in the floor behind you, smelled alcohol, felt a hand on your right shoulder, and felt your chair suddenly begin to fall backward. Everything in your working memory would instantly change. Sensory neurons would send huge numbers of action potentials, overriding any current activity in your brain and replacing it with a whole new set of sustained loops involving danger, fear, and a variety of expletives. You would dismiss any thoughts of blue flowers and give your complete attention to your eyes, ears, nose, balance, and self-preservation.
It is important to note that you form memories of things even when you are not conscious of them. All those sensory synapses trying to get your attention may not be in your active thoughts, but they are still accumulating short-acting and long-acting chemicals. All active synapses do this. They are doing so at a slower rate, because they are not reiterating, but they are still part of your memory.
That is why you can recall things that happened when you were not paying attention to them. The memory does not last long, but it is there for your review. Your wife speaks to you while you are reading, and you hear her speak, but do not listen to what she is saying until you finish reading your sentence. Then you shift your attention to what she just said and listen to the content. You can recall her sentence even though you were paying attention to something else at the time.
You look at a diagram in a book and then go on to read about the diagram. You are able to look back at the image of the diagram in your mind and pick out details you did not notice before. You saw and can recall things that did not enter your stream of thought when you first viewed it. In extreme cases, this is the mechanism underlying photographic memory.
Awareness
We humans are very proud of our awareness, but we are not as aware as you may think. I recall my father telling me as a young man, “You don’t know what you don’t know.” Six decades later, I understand what he meant and can expand upon his advice. You cannot see what you cannot see, and you are not aware of what you are not aware of.
The most often cited example of this is the blind spot in human visual fields. There is a place on the retina where the optic nerve enters the back wall of the eye. That spot has no vision. However, you are totally unaware of this blind spot.
Place two dots on a piece of paper two inches apart. Hold the paper in front of your right eye and cover your left eye. Stare at the left dot on the paper while slowly moving the paper away from your face. When the paper is about six to eight inches from your face, the right dot will disappear. At that distance, the image of the right dot falls on the blind spot. You do not see the blind spot. You do not perceive it as a black area or a hole in your field of vision. It is simply not there. The blind spot, and the dot on the paper are not visible. You cannot see what you cannot see. You are not aware of what you are not aware of.
The list of things we humans are not aware of is astounding: the opening and closing of our heart valves, the constant movement in our stomach and intestines, the odors in our homes, ultraviolet and infrared light, and the pheromones produced by the people around us. The most outlandish lack of human awareness involves reproduction. Human males are unaware of female receptivity. The rest of the animal world would be astounded if they knew. All other animals have ways to synchronize reproductive efforts. Clams, corals, frogs, fish, eagles, hedgehogs, and deer all have this covered. Yet we humans are oblivious.
As I type this sentence, my body is aware of its surroundings, monitoring sounds and smells, but my mind is distracted by my thoughts. I am not “mindful” of those sensations unless something unusual or alarming occurs. My mind is occupied by writing. In this context, I am probably less aware than the average earthworm, who is never distracted by grammar, diction, and spelling.
Consider driving a car on Interstate 40 through the city of Nashville, Tennessee. You are aware of your surroundings and the immediate area around your car with respect to the other vehicles. You are attentive to the acceleration and centrifugal forces on your body. You are monitoring the sounds of the car and the vibrations made by the tires on the pavement.
You are also aware of a map, stored in collections of neurons in the spatial processing area of your brain, and your location on that map. You are aware of some of the components of your vehicle, such as the steering wheel and the speedometer. Your spare neurons may be listening to music on the radio. These are the thoughts occupying your working memory. These are the concepts currently connected by reiterating loops.
It is insightful to note what you are not aware of as you navigate through Nashville at 70 MPH between two 18-wheelers. You are not aware of your “self.” You are not concerned with your appearance, your relationships with others, your rightful place in the universe, or where you grew up. You are focused on getting to the other side of Nashville, alive, on your way to Knoxville. Like the earthworm in the lawn, your working memory, your consciousness, is focused on survival and purpose. (Unless you are me, thinking about this book while driving through Nashville toward Knoxville, in which case you find yourself lost in Chattanooga.)
Let us look closely at a tiny time interval of your awareness as you drive through Nashville. Your forward vision is focused on a large grey rectangle. It is slightly taller than wide. It has two black rectangles under the lower corners, also taller than wide. There are three small red circles on each lower corner. This is all being processed by neurons in the retina, in various ganglia in the brain, and in the visual cortex at the back of the brain. It is not currently in your active thoughts, though, because, at this instant, you are thinking about the lyrics to the song playing on your radio.
Then, the grey rectangular image abruptly begins to increase in size. The light coming from the red circles becomes brighter. Your visual cortex sends out impulses to neurons that sense range, alerting them that the grey rectangle is moving toward you. This stimulates neurons related to caution, warning, danger, and evasion.
By the time your frontal cortex establishes recursive loops related to the idea that the truck in front of you is braking and has slowed down, the motor neurons controlling your lower extremities have already moved your foot to the brake pedal. The truck has now entered your working memory, and your frontal lobe neurons are directing your head, neck, and eye muscles to search your mirrors for escape avenues if needed. The song lyrics are gone from your working memory. The population of sustained feedback loops in your brain has changed completely.
This little exercise in the neocortex involved millions of neurons and billions of synapses, yet it lasted only a fraction of a second and engaged a tiny portion of your brain. Our brains are aware of a great deal more than just what we are thinking about at the moment, and our minds make decisions outside of our narrow realm of conscious thought. Our active thoughts are composed of concepts connected by self-sustaining positive feedback loops. That is consciousness. There is also a huge background of awareness that is not in our thoughts but is constantly vying for admission. That is what we call the subconscious.
The distinction between conscious and subconscious is whether the signals are recursive. Have the engaged functional units, the concepts, been recruited into the recursive network and remained there long enough to lay down short term memory trails? Can we recall them?
We can sometimes summon up those subconscious fragments of thought if needed. They are recorded as accumulations in the synapses of short-acting chemicals we discussed earlier. We have a window of time in which to “review the video” or to “think about what was said” after the fact. You recognized the truck was braking only after your foot touched your own brake pedal. Short-term memory lets us go back and look again at things that did not have our full attention at the time. It allows us to answer the question, “What just happened?”
You may have done this if you ever found yourself lost while driving because you were listening to the radio and missed a turn. You think back over the route you took when you were not paying attention. In my case, I asked myself, “How did I get here? Why am I in Chattanooga?” I thought back over the turns I made and figured out my mistake, like Bugs Bunny saying, “I knew I should have made that left turn in Albuquerque.” This is short-term memory at work. It summons up those synapses that are still “warmed up” by their recent activity, and recruits them into active thoughts.
Of course, the example we are all so terribly familiar with is, “What did I come into this room for?” We find ourselves reviewing our recent activities in the previous room, trying to recall the stream of thought that led us to our current location. Something briefly entered our active thoughts and initiated an action, but then was displaced by other matters and forgotten. Usually we have to return to the other room and start over. This happens because your collection of active reiterative loops has moved on to other concepts and left the original thought behind.
Subconscious input to thoughts
The subconscious is not limited to sensory perception. Long-term memory provides a great deal of input to our thoughts. You have “baggage” from your personal history, subliminal associations from old experiences, ethnic bigotry from your racist grandfather, embarrassing incidents with past romantic partners, and a thousand other memories. These are ever-present inputs to our thoughts. Most of them are not strong enough to enter our consciousness. We do not recognize their input unless they generate enough feedback to secure a spot in our active thoughts. However, they are still being counted by the analog adding machines in our billions of dendrites. They influence our decisions.
As a hypothetical example, imagine you once picked a bouquet of wildflowers for your grandmother when you were 4 years old. Specifically, you picked the Virginia dayflowers from her flower garden. Instead of thanking you, she unexpectedly scolded you. You no longer recall this episode in enough detail to visualize it. However, your thoughts of this flower recruit bad feelings, and you do not know why. It is because your recursive signal loops on this subject include neurons associated with humiliation, shame, and regret.
The bouquet example illustrates another limit on our self-awareness. There are many things in our surroundings and our memories that influence our thoughts and behaviors but do not rise to the level of awareness. They are not intense enough to enter our active thoughts, and so we are not aware of their influence. There are ghosts in our memories, the past events in our lives that we cannot quite recall. It takes work to reveal the subconscious influences on our thoughts and behaviors. This is how therapists make their livings.
With every decision you make, every thought you form, there are tens of thousands of inputs, and most of them are under the radar, so to speak. They come from your sensory systems and your memories. They are tabulated by dendrites in the neurons in a cascade containing hundreds of levels, until they become focused on a relatively small group of concepts that have enough positive feedback loops to form an active thought. You are not aware of most of the input that led to your decision. This is how subliminal messaging works. The message is too low in amplitude to be included in your thoughts, but is still included in the input channels to the dendrites.
First impressions are a good example. They are formed in a fraction of a second. In that first observation, tens of thousands of sensory neurons are activated at once. They input to tens of thousands of other neurons in a sudden flood of signals. Those neurons send positive and negative feedback to each other and to thousands of others, comparing what you are sensing to memories in your past. All these neurons are competing for your attention. In a fraction of a second, a small group of neurons comes out on top and a set of concepts merge to form a thought. It happens too fast to leave a trail of short-acting chemicals. Most of the time you are unable to trace the input that got you there. The impression just seems to come from nowhere.
Years ago, in an ER where I worked, I was leaning against a counter, chatting with a psychiatry resident. We happened to be in view of the ambulance entrance about 140 feet away. As we were talking, we heard the pneumatic doors open, and two EMTs rolled a stretcher into the ER with a young man sitting up on the stretcher.
The psych tech glanced at him and said, “Yep, he’s mine.”
I answered, “He looks like he just got out of rehab.”
A few minutes later the EMTs reported to us that the patient had checked himself out of an alcohol detox unit that morning, gone on a binge, and then called 911 and said he was suicidal. The psych tech and I had both correctly diagnosed this patient in a fraction of a second from a distance of 140 feet. We did so based only on a split second of visual input and thousands of memories of patients. It is important to note that neither of us knew this patient. We had never seen him before.
I can make some educated guesses on how our brains made the decisions they made. The patient was sitting up on the stretcher. He was young and appeared healthy. He did not look like an ill person. He was fully dressed in clean street clothes and looked affluent. He had an angry, perhaps defiant expression. However, the speculations are irrelevant. We did not engage in any of those thoughts. The process was completely subconscious. Cascades occurred in both our brains simultaneously, too fast for us to see. Our neurons processed a huge number of sensory inputs, compared them to a huge number of memories, and formulated impressions, all in a fraction of a second.
This type of impression is very common in our lives. When the psych tech and I saw the patient on the stretcher we “recognized” him as a psych/rehab patient. When you see a friend at a restaurant, you recognize them as your friend. When you look at a menu, you recognize your favorite meals. If you have read this far, you are now able to recognize a Virginia dayflower. In every case, a cascade of non-recursive signaling occurs in your sensory organs and processing ganglia, your visual cortex, and your temporal lobe memories before the idea forms in your neocortex and you become aware of who or what you see. You do not recall and are not aware of all this prior processing. It is subconscious.
An epiphany works in a similar way. Occasionally, in all the cacophony of synaptic events in the brain, all those billions of transmissions occurring constantly, it happens by chance that a single neuron gets just enough input from a thousand other seemingly unrelated neurons at the same time, and an idea pops into your consciousness. You do not know where it came from. You just suddenly know: another way to fold a paper crane; a perfect gift for your great aunt; what it would be like to ride on a beam of light; or how intuition works. The idea came from thousands of inputs, each too small to be recognized, but your dendrites did the math, and found the answer for you.
“At times I feel certain I am right while not knowing the reason.”
Albert Einstein
Individual Recognition and Self Awareness
The standard test for self-awareness is the mark test. An odorless mark is placed on an animal at a location they cannot see without a mirror. For example, this would be on the forehead of a chimpanzee or on the breast of a crow. The animal is placed in front of a mirror. The investigator watches to see how the subject reacts to the spot. If they are only interested in the image in the mirror, or completely disinterested, they are not self-aware.
However some species will look in the mirror and then attempt to remove the mark from themselves. They recognize that the living thing they see in the mirror is themselves. They pass the mark test and are said to be self-aware.
The test subject must first become accustomed to a mirror. All animals, including humans, who have never before seen a mirror react the same way. They first interpret the image in the mirror as another individual. Later, they look behind the mirror. Eventually they ignore the mirror. Most species stay at one of those levels. A very few species eventually recognize that they are looking at a reflection of themselves. They use the mirror to look at parts of themselves they cannot see. They practice movements in front of the mirror.
Animals that pass the mark test are a diverse group, including humans, chimpanzees, bonobos, pilot whales, bottlenose dolphins, crows, ravens, and elephants; an enigmatic collection. Why do crows have self-awareness when grackles do not? They have very similar lives. Why do chimpanzees have self-awareness and capuchin monkeys do not? Why an elephant and not a rhinoceros. Furthermore, what do elephants have in common with crows?
As is often the case with behavioral sciences, the confusion arises in part from the test itself. The mark test is too rigid. It implies that an animal either has awareness or it does not; a one or a zero, with nothing in between. This is not realistic. Biological systems generally have gradual transitions. Where are the intermediate stages of development?
Self-awareness does not occur in nature as an isolated ability. It is one of several traits associated with the ability to recognize individuals. Some animals can, to variable degrees, recognize other animals as individuals, with unique sets of attributes. These might include smell, appearance, voice, behaviors, and anything else animals can detect. Individual recognition is a gradual development in evolution.
Most animals do not see each other as individuals. Invertebrates, fish, amphibians, reptiles, and most birds and mammals view all other members of their species the same. With rare exceptions, they do not form personal friendships and do not distinguish their kin from other members of their species. Their interactions and reproductive behaviors are completely impersonal.
Consider the whitetail deer. A male deer does not see female deer as individuals. During the fall rut, every female with that certain odor is an opportunity to breed. There is no personal history or previous relationship. There have been no prior good dates or bad dates. Outside the rutting period, any other deer is just a deer. It is simply a “not-predator.” This is called class recognition. It is not individual recognition. Adult deer do not have personal relationships. (Bambi is not real.)
While adult deer do not seem to recognize individuals, many birds and mammals do. A mother deer knows which fawn is hers. An eagle knows its mate. Cats know which humans belong in their homes. Horses know which people usually have carrots in their pockets. This is rote memory, based on smells, appearances, or voices. It is presumed to be a mixture of instinct and Pavlovian conditioning. It relies on a small set of long-term memories.
Animals identify each other as individuals in many different ways. Canines and most carnivores use smell, marking their territories and recognizing each other by the mix of chemicals produced by their anal scent glands. Those few fish that have a mate recognize them by color patterns. Many birds, including crows and penguins, recognize individuals by their voices. This is how penguins find their mates in their breeding colonies, and how the chicks recognize their parents.
Crows use voices and also use visual cues and can recognize individual human faces. This is advancing beyond class recognition to individual recognition. Crows can distinguish one individual animal from another outside their species. Humans and other primates do this too, primarily relying on visual cues and physical features, especially faces.
Humans, like crows and penguins, are extremely sensitive to voices. If you have ever lost your spouse in a crowd or a store, you may have found them by the unique sound of their voice. You can recognize your child’s voice in a herd of children on a soccer field or volleyball court. You can recognize a familiar voice even when it is speaking a foreign language, or when it is too distant to discern the words. Many people can instantly identify a vocalist on the radio by voice, choosing from thousands of celebrities, even when they have not heard the song before.
A dog’s mind links its master to an orchestra of chemical odors, and an assortment of sounds and visual cues. This is individual recognition, and the dog is able to apply the process to a large number of creatures in its environment. It is not just limited to the owner of the dog. A dog keeps memories of other people in the household, other animals in the home or on a farm, other dogs, neighbors, and frequent visitors. A dog can retain a huge library of recognized individuals and knows immediately when an unfamiliar human or animal approaches. Yet a dog does not pass the mark test.
A dog has memories that define its environment and the creatures that belong there, but it does not separate itself or them from that environment. It merely knows its surroundings well. Familiar animals and people are just normal on the farm. An unfamiliar person or animal is an intrusion on the normalcy, a disruption of the familiarity.
The dog recognizes the cow as belonging on the farm. However, it does not retain a personal history of the cow, or have any expectations of the cow. It does not know the wants, desires, and beliefs of the cow. It does not conceptualize the cow as an entity separate from the barnyard, or think about the cow when the cow is not there. It just knows that this cow is the cow that belongs in the barnyard.
Of course, there are some exceptions, particularly with very intelligent dogs such as border collies. Some dogs have truly remarkable memories, and can recognize people or other animals after years of separation. There are dogs that display complex emotions and recognize the emotions of their human companions. Some dogs seem to know what their masters want without being told. Some dogs are fascinated by mirrors. Dogs clearly show evidence of shame and embarrassment. Even those dogs, though, do not pass the mark test. I suspect this is a short-coming of the test.
Animals that pass the mark test are those that can separate an individual from its environment. Crows are a good example. Crows know which cats in the neighborhood are dangerous. They use different warning calls for the old lazy fat cat and a young cat that hunts birds. They recognize individual cats, independent of the cats’ locations. Crows know individual humans and can identify faces. They are well known to hold grudges against people who treated them badly, and to bring trinkets and gifts to their favorite people.
Chimpanzees know each other as individuals. They engage in complex social interactions, cooperating with some members of their community and cheating or deceiving others. They remember favors and hold grudges. They retain personal histories on the members of their social group, independent of location.
Humans retain personal histories on family, friends, and acquaintances. Cousin George is still George whether you see him in the barnyard, in church, or in the local supermarket. He is an entity separate from his environment. He is a unique person with defining traits and a history.
Now we can answer the question asked earlier. The commonality between self-aware species lies in their social skills. Bottlenose dolphins, crows, humans, and other self-aware animals interact with each other as individuals. Unlike eusocial insects and class-aware species, these animals are able to form relationships based on unique histories and social parameters. They know each other personally. They have memory units in their brains that represent individuals and link them to a wide variety of personal attributes.
Individual recognition is intimately related to self-awareness. Once a species has acquired the ability to recognize individuals as unique entities, separate from their surroundings, it is a short cognitive jump to self-awareness. A creature who recognizes others as separate individuals, can also recognize itself as a separate individual, especially when aided by a mirror. In fact, the mirror may play a major role in the self-recognition process in self-aware animals. Perhaps a dog could pass the mirror test if the mirror smelled like the dog.
The evolution of individual recognition follows a clear progression. Invertebrates other than cephalopods have none. Most fish, reptiles, and amphibians have some degree of class recognition. A few fish can recognize their mates. Most birds and mammals have class recognition, and many can recognize individuals based on rote memory. A few birds and mammals have true individual recognition, relying on a broad range of traits and cues.
Development in human children mirrors the evolutionary progression. Newborn human babies do not distinguish between their mother’s face and any others. They begin to respond differently to the mother at about 3 months of age. At that point they have class recognition, the ability to distinguish between mother and non-mother. Infants develop stranger anxiety at about 8 months of age. They are frightened by unfamiliar people. They begin to recognize individual faces and know that some people are not their family members.
Children become self-aware at about 18 months of age. It is at this age that they pass the mark test. They begin to refer to themselves by their own name and recognize that they are unique individuals. A few months later, they will begin to substitute “I” and “me” for their names.
Consciousness
What we call consciousness is the act of looking back at what we were just recently doing or thinking. It is the ability to recall our most recent thoughts. When my mind is engaged in thinking about the blue flower, I am not really conscious of those thoughts in the moment. I am thinking about the flower. If someone asks me what I am thinking about, I can answer by using the short term memory stored in recently active synapses. By the time I have formulated an answer, though, I have shifted my reiterative signal patterns to include the concepts of self, brain, and thinking. These are reflective concepts, like a mirror in the mind. I am no longer focused on the blue flower, but rather on my thinking process and its recent subject.
Trying to think about your actions while performing a task is difficult and distracting. To demonstrate, try to tie your shoelace while telling someone how you are doing it. You can tell someone else how you did it, but you cannot perform the task and narrate it at the same time. You will resort to performing the first step, observing what you did, and then narrating. You will go on the next step and repeat the process. This is because tying a shoelace is a memorized sequence that, once begun, runs by itself. You are not conscious of the individual steps in the sequence. (Physicians run into this problem when teaching medical students how to tie surgical knots.)
It is important to note that consciousness is really a function of short term memory. The absence of memory in a time interval is interpreted as loss of consciousness. A person who receives a blow to the head and has a lapse in memory, a period of amnesia, believes he was unconscious. I have seen many cases in which a patient thought he had been unconscious, when witnesses reported he was awake and talking the whole time. The patient believed he was unconscious because he recalled becoming aware again under circumstances different than those in which he was injured. “I must have gotten knocked out. I remember being in a fight at the bar, and the next thing I remember is being here in the ER.”
Light anesthesia is called “conscious sedation” because patients are awake enough to follow commands and report sensations. They appear to be conscious. However, they are not recording memories. These patients believe they were unconscious because they have no recall of the procedure. Many readers may recall an anesthesiologist telling them before a procedure, “You might be awake some, but you won’t remember it.”
Consciousness is not so much about being aware of what you are doing at the moment. Rather it is the ability to recall and think about what you were doing an instant ago. It is the act of forming new reiterative loops that include your recently experienced thoughts combined with reflective concepts like self, thoughts, mind, memory, and purpose. Observing a black widow spider, and observing your thoughts about the spider are two different activities separated by a very short interval in time.
Those self-reflective concepts are learned in childhood. Just as we are born with the ability to see the color blue, we have an innate ability to see the self. At a certain age, we spontaneously recognize individuals and reflect that back on ourselves. However, it takes time to learn what that means. Just as we have to learn about the color blue, we have to learn what this self is and what it means. We have to develop and nurture all the synapses required to form sustained positive feedback loops between the self and related concepts like family, purpose, history, and abilities, just as we learned all the associations for the color blue.
Summarizing memory
Memory can be classified into three separate processes: active thoughts, short-term memory, and long-term memory.
Active thoughts are not stored. Rather, they are refreshed hundreds of times per second by recursive signal loops engaging networks of neocortical functional units. The population of units engaged in those loops changes constantly during the process of thinking. Active thoughts are fleeting and ephemeral. However, with each iteration short-acting chemicals are deposited at the synapses, leaving traces of the thoughts. At the same time, there are millions of other neurons sending signals in the brain. They only enter the active thoughts if they get enough positive feedback to sustain reiterative loops. They also leave traces in the form of short-acting chemicals, but not as much as the reiterating synapses.
Short-term memory is stored as accumulations of short-acting chemicals in recently active synapses. These synapses are warmed up, so to speak. They are primed to depolarize and to enter or re-enter the active working memory at a lower threshold. They can be summoned into reiterative loops more easily than inactive synapses. Short-term memory fades over minutes to hours. It allows us to retrace and monitor our thoughts.
Long-term memory is stored in the patterns, sizes, numbers, and locations of synapses between the billions of neurons in the brain (and body). These develop over a lifetime, very rapidly in youth, and more slowly later in life. Synapses are the storage medium for our knowledge. This is how we archive language, culture, education, skills, coordination, emotions, personal history, and sense of self. Synapses continue to remodel as we learn throughout life.
Summarizing Consciousness
As a brain goes about its business, moment to moment, it leaves behind trails of short-term chemicals in the synaptic connections. All those recently active connections between concepts are still “warmed up” and are easily recruited back into active memory. That collection of connections and concepts is working memory, and it is the physical entity we call consciousness.
The human neocortex has hundreds of millions of functional units, each of which maps to a concept or body site. There are units connected to all sensory cells on surface of the body, every nerve for pain, light touch, pressure, and vibration. There are units for every group of fibers in every muscle in the body. There are units mapped to every point on the visual fields and every movement in those fields. Units represent colors, shapes, and numbers, and (literally) every conceivable idea and concept. Every memory unit is a concept, a single discrete meme`.
Among those we would find the concept of “blue.” It is defined by synaptic connections to a thousand other functional units related to the idea of blue. It is a sensory meme, a concept related to a sensation. We learned about blue in early childhood, and are still learning about it late in life, further refining the synaptic connections to that functional unit.
Among those ideas, we would also find functional units for concepts like “self,” and “me.” These are also ideas that we learned about in early childhood. We trained functional units in our brains to house these concepts. We developed synaptic connections between these functional units and a thousand others related to self. You are still refining those connections as you read this passage.
Consciousness is loosely divided into physical awareness and self-awareness. Physical awareness is the ability to sense your surroundings and respond to them. You have this ability and share it with the earthworm in your lawn. It links behavior to sensation, and is present in all Animalia.
Self-awareness is the ability to recognize yourself as a unique, discrete individual, separate from your surroundings. This is an extension of your capacity to recognize others as individuals. Your neocortex has functional units that represent you. They are linked by strong synaptic connections to other units that represent the physical components of your body, and to the historical components of your personal history. When active, they initiate recursive signal networks that define your uniqueness. They merge all those concepts into the thought that you call yourself.
