InfoQ Homepage Articles The Brain is Neither a Neural Network Nor a Computer: Book Review of The Biological Mind

The Brain is Neither a Neural Network Nor a Computer: Book Review of The Biological Mind


Key Takeaways

  • The brain is a biological organ, and not a digital computer.
  • Neuroscience has discovered that while the brain mediates between the body and the environment, it does not command the body.
  • Often brain problems can be traced to problems in the rest of the body, and not to a malfunctioning brain.
  • Many mental illness are a combination of genetics, culture, and environment, as well as brain function.
  • There is no essence of the brain that can be separated from its body and surrounding environment.

Underlying much of artificial intelligence research is what Alan Jasanoff calls the cerebral mystique— the idea that the essence of an individual resides in the brain. In The Biological Mind, he argues that this idea neglects the fundamental lesson of neuroscience. The brain is a biological organ embedded in a physical environment. A brain cannot function independently from the body and its surrounding world. Dismantling this myth will allow us to understand what is reasonable to expect from artificial intelligence, as well as technology designed to improve human life.

Although Jasanoff’s book argues from a neuroscience perspective, it supports the idea of embodied cognition—our cognition does not just come from the brain, but from the interaction of a particular being with its environment. Some refer to this as an “ecological approach.” The brain does not make a computation to process sensory input into actions. The brain uses perception and action to link the body to the environment.

 The first part of the book describes the four components of the cerebral mystique fallacy: abstraction, complexification, compartmentalization, and autonomy. The second part explains why a biological-based view of the brain is important especially in areas such as psychology, medicine, and technology.

The Cerebral Mystique

Jasanoff splits the cerebral mystique into four beliefs: the brain computes, the brain is complex beyond analysis, the brain pilots the body, the brain is always in control.


Abstraction is the idea that the brain engages in computations much as a computer does.

Computing analogies date to the earliest days of computing. John von Neumann wrote The Computer and the Brain in 1957. Von Neumann noted several differences between brains and computers. Nonetheless, many subsequent investigators went further. The ideas of electrical neural circuitry, Shannon’s theories about encoding information, and questions about how information is stored in the brain, led many people to believe that there is an isomorphism between how a computer operates and how a brain operates. The ultimate expression of this idea is that a merger between human and artificial intelligence is possible; repairing, remaking, or even storing brains to preserve them forever.

Jasanoff points out that only half of the brain's cells are neurons, the other half are glia cells. In the cerebral cortex, they outnumber neurons by a factor of up to 10 to 1. Glia cells also signal. Many brain diseases, such as multiple sclerosis, concussions, stroke, Alzheimer’s disease, and some cancers have little to do with neurons. Conceiving the brain without taking such facts into account seems problematic.

Neurotransmitters and related molecules called neuromodulators are essential to the proper function of the neurons. They are not support structures such as cooling fans and power supplies in a computer. There is some evidence that enzymes in the blood can alter the neuron’s electrical signals, as can the dilation of blood vessels from hyperemia. Selective activation of glia through optogenetic stimulation can alter the firing rates of neurons.

Given these facts, Jasanoff argues, you could build a chemistry-centric model of the brain with electrical signals of neurons facilitating the movement of chemical signals, instead of the other way around. The electrical signals could be viewed as part of a chemical process because of the ions they depend on. Glia cells affect the uptake of neurotransmitters which in turn affects neuron firing. From an evolutionary perspective, the chemical brain is no different than the chemical liver or kidneys.

An epigenetic understanding of dopamine, drug addiction, and depression focuses on the chemistry in the brain, not the electrical circuitry.

Our brains function just like the rest of our biological body, not as an abstraction of hardware and software components. To Jasanoff, there is no distinction between a mental event and a physical event in the body.


Complexification refers to the belief that the brain is so complicated that it defies analysis.  

What does it mean to say that the brain is complex?

Do you mean the number of neurons? If every neuron synapse was the equivalent of a bit, you could store almost all of Netflix in your brain. Your brain, however, is not a storage device so that is not possible. Beethoven’s Fifth symphony or a drawing of a dollar bill is not stored anywhere.

The complexity of the brain, for Jasanoff, comes not from the number of components, but the number of interactions between them. A bucket of water has more molecules than the brain, but clearly, it is not more complicated. Although it is a crude estimate based on incomplete studies, the number of connections in the brain could exceed the number of atoms in the universe.

Is there a minimum size to the brain?

While there have been no studies to indicate the minimal number of parts of the brain we need, there have been case studies of humans with major parts of the brain missing who have been able to function. Animal studies indicate that there is no minimum size. Corvids(crows, ravens, magpies) anticipate and prepare for the future, make and use tools, and recognize themselves or people in a mirror. Whales and elephants with much larger brains than humans are not as intelligent as humans.

Similar conclusions hold for focusing on brain size versus body size. Recent research seems to indicate that the complexity of the brain revolves around the different types of neuronal and glial cells in the brain. Human kidneys have more cells than the cerebral cortex, but they are almost all organized in the same type of structure, nephrons.

The brain has many functions, so understanding it is different from understanding something that has only one function such as a car. It is easy to relate the different parts of the car to the idea of transporting someone from one place to another. You can easily understand one part of the mechanism (brakes or engines) without knowing much about another part. On the other hand, the brain does many things, often contradictory things, at the same time. You could be talking to a friend on the telephone, looking out the window at the landscape, while you relax after a day of work. Functional decomposition of each part of the brain in isolation would not help you understand how the brain does all these things at the same time.

To Jasanoff, these arguments mean that brain complexity is no different from other products of nature, so it can be understood much as we have eventually understood other products of nature.


Compartmentalization refers to two ideas: mental functions are located in certain parts of the brain, and the brain pilots the body with minimal influence from biological processes in the rest of the body.

Brain imaging studies, such as fMRI offer a misleading and possibly contradictory view of the brain despite their enormous presence in popular presentations on the brain. At best, such tests indicate the tip of the iceberg of where brain abilities lie.

Brain maps based on fMRI, MRI, and other technologies are not fine enough to resolve at the level of individual neurons. In fact, these technologies are incapable of determining if the lack of brain activity might also be a signal. Even technologies that are capable of this, such as optical microscopy have found it impossible to explain behavior in simple organisms such as worms or zebrafish. Part of the reason for this is that the brain and nervous system do not perform cognition on their own. Cognition needs to be understood in the context provided by the body and its surrounding environment. 


Autonomy is the idea that the brain is self-governing, receptive to the environment, but always in control.

Somatic disorders ranging from improper sugar levels and hormone imbalances to diseases such as malaria or syphilis can cause mental dysfunction. Some individuals are placed in mental hospitals when correcting an underlying disorder would actually fix the problem.

At the simplest level, no amount of mental determination would make you a world-class athlete if you did not have the right type of muscle fibers or hand-eye coordination. You cannot flap your arms and fly—the aerodynamics does not allow it. Paganini could only be the legendary violinist he was because of his flexibility. No amount of musicianship could provide that ability.

Cognitive processes are embodied. They emerge from the interaction between physical organisms and their environment, not just their brains. For example, there is evidence that the nature of your gut bacteria can cause anxiety, stress, and even depression.

Replacing a diseased organ with a healthy one can increase mental functioning.  A kidney transplant will help remove poisons from the blood such as urea or ammonia which will increase brain health.

The caffeine in your cup of coffee blocks adenosine, a chemical-signaling molecule. Blocking adenosine in the ventrolateral preoptic area leads to arousal, resulting in increased blood pressure and cortisol levels as well as mild anxiety or stress. This promotes alertness and better mental and exercise performance.

The heat from very hot weather can increase our inclination for violence, just as the changing seasons can produce varying degrees of discomfort in some, and depression in others. Circadian rhythms show the interdependency between environmental factors and brain behavior, for example, jet lag. When darkness falls, melatonin is released and that generates a desire for sleep.

Signals to the brain about hunger and thirst affect us, as much as our attempts to ignore those signals in certain circumstances. Any athletic performance is a struggle between the signals to the brain of fatigue, hunger, or thirst, and the brain’s determination to finish the event.

The Biological Brain

After his discussion of the cerebral mystique, Jasanoff then discusses how this belief has distorted our understanding of several issues confronting us.

The Brain and Its Environment

Are we a victim of social forces, or are we ultimately responsible for our own behavior?

The brain is a mediator, neither a passive recipient of outside forces beyond its control nor a self-contained independent entity only stimulated by events. Neuroessentialism, the modern view of the brain as a controller, ignores the biochemistry that relates the brain and the body to the environment.

Consider the famous example of the sniper Charles Whitman who killed his wife and mother, and then killed 14 people and wounded 31. Was it the tumor near his hypothalamus and amygdala, (the areas of the brain that regulate emotional control), or was it his abusive father, repeated career rejection, substance abuse, or the ease with which he procured his weapon? Neuroessentialism ignores the role of environment and culture, but it is also true that behaviorist treating the mind as an irrelevant black box cannot be correct either. Environment does not explain everything.

Is it just that adolescent and young adult brains are different from mature brains? Or is it that today the cultural environment calls people adolescent when they would have been considered grownups in the past? Cognitive as well as cultural, economic, and educational factors affect the ability to engage in creative endeavors.

You cannot disentangle the brain from environmental factors.

Mental Illness and the Broken Brain

Understanding that mental illness, such as depression, is an organic disease can help people seek treatment. Accepting that you have a medical condition is easier than accepting that you have a moral defect. Nonetheless, the cerebral mystique can also cause people with mental illness to believe themselves broken people, incapable of recovery. Sometimes this self-stigmatization can be harder to fix than people who believe themselves morally flawed. Focusing on the brain ignores cultural and environmental factors, as well as non-physical therapies.

General paresis of the insane, a diagnosis which was once applied to a large fraction of the people admitted to an asylum, was treated as a mental disease until the early 20th century when it was shown to be caused by advanced syphilis. This is a clear example of a mental disease of biological origin outside of the brain acting through the brain by the degeneration of neurons, but not caused by the brain. It is a brain disease, a biological sickness, and an environmental condition simultaneously.

Some mental diseases such as schizophrenia have a large heritable component; others such as major depression do not. Other conditions such as bipolar disorder and anorexia nervosa have intermediate values. Often environmental factors are triggers or reinforce existing conditions. There seems to be a correlation between schizophrenia and urban living.

Jasanoff states that brain diseases are a combination of instantaneous brain function, genetic predispositions, and environmental and societal factors. They are more like a car accident than a broken car—a product of road conditions, driver, weather, and car defects. It is not all in the brain as the cerebral mystique would have it.

The most glaring example of the social context in mental disease was the Soviet Union declaring dissidents to be suffering from psychiatric disorders. Perhaps the Soviet doctors, given their belief in the Communist system really believed such people must be of unsound mind. The fact that you can argue this, even if the reality was they were just excuses for torture, shows how subjective the definition of mental disease can be. There are no bacteria, growths, or lesions to point to for a diagnosis, only the opinion of the professional within the standards established by the profession.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) has very vague boundaries for most mental illnesses. Diseases have been added and dropped over the years. The definition of mental illness is statistical, based on what the majority of people consider the limits of sanity.

 At the level of policy, this leads to a false dichotomy between drugs and psychological approaches such as cognitive behavioral therapy (CBT). Internet-based therapies, such as those using a smartphone to detect changes in voice or behavior, are based on CBT. Psychiatric epidemiology can also use internet-detectible signs of pathology related to the environment such as cultural niches or economic factors.

Brain Hacking

The idea that we can hack our brain to improve, or to preserve it for the future, is based on the cerebral mystique.

This idea has a long history starting with the frontal lobotomy. Today, deep brain stimulation for certain neurological conditions and brain-machine interfaces allow individuals to control limbs disabled by a stroke.

Such advances have lead people such as Raymond Kurzweil to predict the merging of brains and computers in the singularity, or Michio Kaku to predict an “Internet of the mind” where even dreams are videotaped and sent over the net. The Defense Advanced Research Projects Agency (DARPA) wants to leverage neuroscience to optimize human performance in battle.

All these ideas are motivated by the idea that the brain can overcome the constraints of the body. They contradict the facts of human biology. The brain is deeply connected to the body. The brain is not stronger or less limited than the body.

Transhumanism takes this to the ultimate extreme where some advocate using technology in various forms to re-engineer the human body. Nanobots going through the body would teach us literature or foreign languages, receiving signals from other humans. Imagine driving cars without using our hands and feet, or receiving information without reading or listening. Immortality would be achieved through transcending the body.

There are many philosophical, social, practical, and moral arguments about transhumanism. Imagine the mental manipulation at the level of neurons that this would require, and imagine the potential for abuse of this technology. What if your fellow students or business competitors started using nootropic drugs? Might you use them even though you do not fully know their side effects? Think of athletics who have doped themselves to win medals. What about other brain intervention methods? Would this not increase even more the inequities between rich and poor? What if this spread to society as a whole? Is this a world in which you would want to live?

All this, Jasanoff says, is rooted in the idea that the human body is something to overcome. As a biological entity, it seems both safer and easier to manipulate the brain from the outside, than trying to hack it from the inside. The fundamental lesson of neuroscience is that the brain is a biological organ embedded in a continuum of internal and external stimuli. The brain is not all there is. The brain is not our soul.

Relationship to Embodied Cognition

Current advances in artificial intelligence, buoyed by improvements in computing speed, big data, and neural networks, have demonstrated many achievements beyond human abilities, but they are far from demonstrating human understanding.

AI models may have gone beyond human performance on a language understanding benchmark, but could such a model pass a medical licensing exam? If it could, would you trust it to be a doctor? To be a doctor requires understanding a patient which means you need to have an implicit understanding of other people and the surrounding environment.

The human body evolved to deal with specific risks and opportunities in the world around it. A just born baby already has pre-existing reflexes such as sucking what comes into its mouth, or holding things in its hand. It is prepared to recognize faces. It directly differentiates sound and noise. It already has assumptions about a world of possible predators or nurturers. Babies are not born with rules on how to make representations of the world, or the ability to manipulate information. Their brains are not general-purpose computing engines.


Jasanoff’s book is more concerned with what the brain is, rather than how it works. The mind is what the brain does, and the brain is not separate from the body. We are not separate from nature, and therefore our brains are part of nature. We cannot learn about ourselves if we treat ourselves as something other than biological.

The brain mediates our experiences; it is not a substitute for those experiences.

While artificial intelligence might continue to make great strides, it is a domain to itself, not a way of understanding how the brain works. On the other hand, if artificial intelligence wants to achieve human like performance, it will have to take a different approach.

This book hints at questions such as what does it mean to be alive? Do current scientific models of the brain rule out free will? Perhaps if we do not have free will, the robots are already here.

About the Author

Michael Stiefel, principal of Reliable Software, Inc. is a consultant on software architecture and development and the alignment of information technology with business goals. As a member of an OASIS Technical Committee, he helped develop a core SOA Reference Model and related Reference Architectures. He was a Lecturer in the Aeronautics and Astronautics Department at the Massachusetts Institute of Technology where his research and teaching focus was understanding how people build mental models in order to solve problems. As Adjunct faculty, Stiefel has taught graduate and undergraduate software engineering courses at Northeastern University and Framingham State University. He explores his interest in the intersection between technology and art in the blog Art and Software.

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