Vision Therapy is Messy

In his book Messy: How to be Creative and Resilient in a Tidy-Minded World, Tim Harford provides examples of how extreme organization and structure, reduced diversity, and oversimplification makes things easier but constrain and compromise outcomes.

Vision is complex and each person’s combinations of problems and circumstances is unique. Vision doesn’t function in isolation. It is represented in more areas of the brain than any other sense. It is involved in almost everything we do. How we see the world is an integral part of who we are. It follows that enhancing essential visual functions;

-eye alignment and movement,


-object perception, spatial perception, and guidance of movement

is messy and complex and that it is naïve to think that therapy is not influenced by the patient’s mindset, age, conflicts, and prior experiences.

All of this must be taken into consideration to treat patients. Computerized programs cannot do this but they can be useful to stimulate attention and motivation. It also requires more than a list of techniques. Doctors and therapists need to be ready and able to modify plans to match the patient’s current visual abilities. Optometric vision therapy is provided by doctors and therapists with specialty qualifications. Certified doctors are Fellows in the College of Optometrists in Vision Development (FCOVD). Certified therapists earn the title, Certified Optometric Vision Therapists (COVT). The College of Optometrists in Vision Development is the certifying body for this specialty.

Relationships between providers, patients, and their families are integral to the success of all healthcare, especially incremental care. Atul Gawande wrote about one of thirteen centers for treating patients with cystic fibrosis in the US in his book Better. One center had much better outcomes than all of the others even though the centers all followed the same protocol. The difference was that the director in one center got to know his patients personally. The better understanding and communication that resulted from these personal relationships fostered improved compliance. Atul Gawande also addresses this in his article on The Heroism of Incremental Care.

Therapy is an interplay between treatment and assessment as the patient progresses. The doctor and therapist continue to learn about patients from the way each patient responds. Dwight D. Eisenhower stated in reference to war that “Plans are useless, but planning is indispensable.” This also applies to other complex, messy situations.

Vision therapy is not easy and can be frustrating. Plasticity in Sensory Systems makes therapy possible. While neuroplasticity declines with age, it continues throughout life. Motivation can recruit surprising amounts of plasticity.  The Power of Habit balances our ability to change. Habit enables us to function without consciously thinking through everything we do, which is not possible, but it can also cause us to err when conditions change. Therapy develops new visual habits.  Focused rehearsal under a variety of circumstances facilitates supplanting existing habits with new skills and makes them more automatic than the dysfunctional patterns that they are replacing.

Optometric vision therapy takes advantage of neuroplasticity and the messiness in our visual system to make change possible. Therapy creates new visual patterns to be more efficient, more comfortable, and less taxing. Patients must achieve this for themselves, but appropriate feedback at the right time can be powerful, which is why doctors and therapists are indispensable in this process. Daniel Coyne provides example which demonstrate this in The Talent Code as does Norman Doidge in The Brain that Changes Itself. Humans are endowed with amazing abilities to learn and to adapt.


Hans Rosling

Hans Rosling was a professor of global health in Sweden. Astounded by the ignorance of his students on important issues, he toured around the world surveying his audiences with similar results. After studying the causes of the overly dramatic worldview held by most people, he made it his mission to educate people about how their instincts lead them to incorrect conclusions and to feeling overwhelmed. He demonstrates, in contradiction to our instincts, how the world is getting better in most ways. News is designed to capture these instincts and trap our attention, not to stimulate our more rational thinking. Developed in our evolutionary past, our primitive instincts do not consistently serve us as well in our larger and more complex world.  

The gap instinct: We tend to divide the world into them and us. This is one of the ways in which we simplify the world to make it easier to understand and easier to make decisions, but few important things are that simple.

The negativity instinct: We have a natural tendency to notice the bad more than the good. This instinct masks how things have been getting better and hinders our ability to see how they can continue to get better. It’s difficult to understand that things can be both bad and getting better at the same time.

The straight-line instinct: World population growth is an excellent example of the straight-line instinct. We all know that world population is increasing rapidly and this instinct causes us to predict a time when the earth is far too crowded. But the rate of growth has been slowing for decades and the UN predicts that the world’s population will level-off around 2100. The reason for this is that the birthrate has declined from 5 births per woman to less than 2.5 over the last 50 years. As women become more educated, have better health care and better income, and have access to contraceptives, they have less children.

The fear instinct: “If we are not careful, we come to believe that the unusual is usual.” The ability to stimulate fear is a significant factor in what gets presented as news. “The image of a dangerous world has never been broadcast more effectively than it is now while the world has never been safer.”

The size instinct: Large numbers shock us. The number of children who die each year is one of those horrible numbers; 4.2 million children in 2016. That was 3% of the number of children born that year. But 14.4 million children died in 1950, 15% of the total born in that year. These are bad numbers, but they are getting better.

The generalization instinct: Once again, generalizations help us to simplify and make decisions but averages tend to be very misleading (The End of Average). Knowing the majority misses many individual differences. Take Brexit for an example.

The destiny instinct: assumes that things never change. We tend to be change blind (The Invisible Gorilla). We were discussing a 1950s magazine this week which had an article about how a housewife should prepare for her husband coming home. That did not play out well in the next generation.

The single perspective instinct: A single perspective avoids cognitive dissonance, but few problems have a single cause or a single solution. Experts are particularly likely to fall into this trap because of the specificity of their training. “People who believe that democracy is the best way to run a country are often tempted to argue that democracy leads to or is even a requirement for other good things, like peace, social progress, health improvement and economic growth. But here’s the rub, and it is hard to accept: the evidence does not support their stance.”

The blame instinct: Placing blame is another simplification to find a clear, simple reason for why something happened which misses the more complex and incremental causes for most things – good and bad – and all of the associated people and events involved over time.

The fear instinct: Urgency is often used to cause us to make decisions without considering all of the options, not considering opposing positions, and not assessing possible unintended consequences. We usually have more time.

Hans Rosling was concerned that these traps are not being taught to children. They need to learn to be humble and to accept that being wrong is part of learning. This can reduce anxiety caused by the feeling that they always need to be right. They need to learn to critique information and to make comparisons, not just look at isolated numbers. They need to learn to find out about the author and the author’s perspectives, not to disqualify them, but to understand that it is important to know the person to enable you to interpret their thoughts. Data is much more available than in the past, but data without a humanistic perspective and history does not guarantee better decisions or a better quality of life.

For More:

The End of Average

The Invisible Gorilla

The Coddling of the American Mind: How Good Intentions and Bad Ideas are Setting up a Generation for Failure


David Epstein

In Range, David Epstein takes issue with the accepted belief that early specialization with concentrated study or practice are necessary to be successful. He starts with examples from sports and music and moves on to science, creativity, and problem-solving. Specialists tend to have difficulty communicating effectively with specialists from other fields. “Knowledge is a double-edged sword. It allows you to do some things, but is also makes you blind to other things that you could do.” Scientists with more range are able to synthesize information using analogical thinking to solve problems.

David Epstein draws information from many sources but relies heavily on the research of Daniel Kahneman and Amos Tversky (Thinking Fast and Slow) and also that of Philip Tetlock (Superforecasting). The intent of this book is to challenge the reader to think, question accepted wisdom, and to increase our range. How does this relate to our lives? How does this relate to sight and vision?

Sight is a narrow perspective, like that of the specialists. Sight presents data. Vision has range and interprets the data to give it meaning by combining it with other sensory input (from other specialties) and from prior experiences. The visual system has two parallel pathways. The focal pathway specializes in detail. The ambient pathway, which is subconscious, is responsible for aiming the focal pathway, guiding eye movements and body movements, spatial judgment, balance, peripheral warning combined with body image like we now have in cars, and stabilizing our perception of the environment despite our movement and the movement or our eyes (image stabilization). The importance of vision and therapy to develop vision can be overlooked with a simplistic model of vision which only considers focal system.

The following is an eleven-minute video which will change your appreciation of sight and vision: (previously discussed here)

Distortions in vision are not uncommon. While they are not as profound as those of Isaac Lidsky, they disrupt comfort and function. Also, since they are not as profound and the person, particularly if a child, may not have prior visual experience without distortions, they may be accepted as normal.  

Mr. Epstein shares research that applies to the challenges of vision therapy and the complexities of sight and vision. The analyses of Philip Tetlock and his distinction between “hedgehogs” and “foxes” applies to the differences between individuals who persist in taking a limited view of vision (sight) and those who appreciate the complexities.  “Beneath complexity, hedgehogs tend to see simple, deterministic rules of cause and effect framed by their areas of expertise, like repeating the patterns on a chessboard. Foxes see complexity in what others mistake for simple cause and effect. They understand that most cause-and-effect relationships are probabilistic, not deterministic.”

Vision is complex and it is critical to other complex tasks such as reading and sports. The women on the US World Cup Team are exceptional athletes. One factor in being an exceptional athlete is having exceptional vision. Wimbledon is being played as I am writing this. These athletes also have exceptional vision. Playing soccer, tennis, or reading well, all require good visual skills, not just visual acuity.

These skills cannot develop quickly without many errors along the way. Mr. Epstein discusses the importance of slow learning for knowledge and skills to be developed deeply so they are transferable and resilient to stress and fatigue. He also writes of “desirable difficulties” to enable learning to be mastered. The “generation effect, struggling to get an answer on your own, even a wrong one, enhances subsequent learning” is an example of a desirable difficulty. “For knowledge to be flexible, it should be learned under varied conditions, an approach called varied or mixed practice, or, to researchers, ‘interleaving’.” “Interleaving is a ‘desired difficulty’ that frequently holds for both physical and mental skills.”

These all apply to vision therapy. A hedgehog may say that watching a pencil as it comes close to your nose will cure eye teaming problems. Foxes understand that vision is complex to develop flexible, resilient, they must be developed slowly, under a variety of conditions to promote generalization, resilience, and automaticity. Expanding our range requires experience. Reading can enrich and broaden our range, but this is only possible after adequate experience.

“Learning stuff is less important than learning about yourself. Exploration is not just a whimsical luxury of education, it is a constant benefit.”

For More:

The Hidden Link Between Vision and Learning

Vision Therapy Changes in the Brain

The Coddling of the American Mind How Good Intentions and Bad Ideas are Setting Up a Generation for Failure

Greg Lukianoff and Jonathan Haidt

The book starts with three epigraphs which succinctly state the philosophy of the authors.

Prepare the child for the road, not the road for the child.
Folk Wisdom, origin unknown

Your worst enemy cannot harm you as much as your own thoughts, unguarded. But once mastered, no one can help you as much, not even your father or mother.
Buddha, Dhammapada

The line dividing good and evil cuts through the heart of every human being.
Aleksandr Solzhenitsyn, The Gulag Archipelago

While the authors support their arguments with science, they emphasize that their conclusions agree with the traditional teachings of cultures, religions, and philosophies which evolved to hold societies together. We evolved in tribes of approximately 200 individuals, but to survive and thrive in the future, we must expand our tribalism to include the entire population, current and future, not just the accidental state, culture, color, or religion of our birth. We need to resist and move beyond the easy and comfortable thinking of us versus them; good versus bad. We also need to protect ourselves against “groupthink” which is also part of our inheritance.


Lukianoff and Haidt are college professors who are watching how students act and the responses of the administrations. The authors are concerned about how “safetyism” is interfering with the ability of colleges to fulfill their mission. Safetyism shields young people from the experiences which will be uncomfortable in the short term but are necessary to develop the character and antifragility necessary to handle the challenges that life will present to them. The authors recognize that life is now more stressful for children than it was in the past and that true trauma can be disabling, but the definition of trauma cannot be allowed to creep until everything that someone doesn’t like is considered trauma.

An education should be preparation for the road; it is about opening and challenging minds, not submitting to the illusion that coddling students will develop the mental and physical resilience necessary to have a productive and satisfying life. It is about learning how to think, how to solve problems, how to handle opposing views, how to win, how to lose, and how to compromise. We delude young people if we lead them to assume that someone will always be there to assume responsibility. Prolonged education delays the full responsibilities of adulthood but does not eliminate them. The simple ethics of childhood is an important ideal to teach young children, but it becomes fuzzy in application. Rarely is one idea all good while another idea is all bad; one person all right and the other person all wrong; one culture good and others bad. Students need to be guided through these conflicts using historical examples and present manifestations to see that these problems have always existed and always will, even if their form has changed, but the lessons are sterile without experience.

The book is organized around the three Great Untruths.
1. The Untruth of Fragility: What doesn’t kill you makes you weaker. Children need to be challenged, take risks, fail and not quit. Children cannot become antifragile without these experiences.


2. The Untruth of Emotional Reasoning: Always trust your feelings. There is nothing objective about our feelings. Trusting your feelings has been shown to lead to anxiety and depression. The most successful treatment for these conditions and PTSD has been shown to be exposure to what upsets you and the gradual mastery of your rational thinking over your feelings. This is known as cognitive behavioral therapy.


3. The Untruth of Us Versus Them: Life is a battle between good people and evil people. “As a result of our long evolution for tribal competition, the human mind readily does dichotomous, us-versus-them thinking. If we want to create welcoming, inclusive communities, we should be doing everything we can to turn down the tribalism and turn up the sense of common humanity.”

When we dehumanize and demonize our opponents, we abandon the possibility of peacefully resolving our differences, and seek to justify violence against them.

Nelson Mandela


There are two ideas about safe spaces: One is a very good idea and one is a terrible idea. The idea of being physically safe on a campus – not being subjected to sexual harassment and physical abuse, or being targeted specifically, personally, for some kind of hate speech – “you are an n-word,” or whatever – I am perfectly fine with that. But there’s another view that is now I think ascendant, which I think is just a horrible view, which is that “I need to be safe ideologically. I need to be safe emotionally. I just need to feel good all the time, and if someone says something that I don’t like, that’s a problem for everybody else, including the university administration. I don’t want you to be safe ideologically. I don’t want you to be safe emotionally. I want you to be strong. That’s different. I’m not going to pave the jungle for you. Put on some boots and learn how to deal with adversity. I’m not going to take all the weights out of the gym; that’s the whole point of the gym. This is the gym.
Van Jones


The following is an excerpt from a commencement speech that Chief Justice John Roberts made at his son’s graduation from a prestigious, private middle school. He understands the concept of antifragility and what is necessary for it to be developed. While children can obviously be harmed by trauma, that are also at risk when they are coddled.

From time to time in the years to come, I hope you will be treated unfairly, so that you will come to know the value of justice. I hope that you will suffer betrayal because that will teach you the importance of loyalty. Sorry to say, but I hope you will be lonely from time to time so that you don’t take friends for granted. I wish you bad luck, again, from time to time so that you will be conscious of the role of chance in life and understand that your success is not completely deserved and that the failure of others is not completely deserved either. And when you lose, as you will from time to time, I hope every now and then, your opponent will gloat over your failure. It is a way for you to understand the importance of sportsmanship. I hope you’ll be ignored so you know the importance of listening to others, and I hope you will have just enough pain to learn compassion. Whether I wish these things or not, they’re going to happen. And whether you benefit from them or not will depend on your ability to see the message in your misfortune.

Risk Savvy: How to Make Good Decisions


Worried Sick


Visual Perception and Who We Are


In The Mind is Flat, Nick Chater uses our flawed intuitions about how we see to question the veracity of the intuition that we have a cognitive subconscious. My review will focus on what Mr. Chater calls “the grand illusion”; our belief that we see much more than we do. Our thoughts and actions are dependent on our perceptions. What we have perceived in the past influences our present perceptions as our current perceptions continue to create who we are and how we will perceive in the future. Illusions can cause us to believe that we are seeing what we know cannot be true. I cannot express this better than the author’s words.
Perceiving is a type of thinking. Indeed, it is perhaps the most important type; and all other types of thought are really just extensions of perception (though powerful extensions). We see far, far less that we think we do. Indeed, we see the world one snippet at a time; and we can tie snippets together, just as we can link together successive sentences in a story.

The following reference to “impossible objects” relates to drawings such as those by M. C. Escher which look real when you look at the whole scene, but you realize are impossible as you study the detail. The phenomenon of ‘impossible objects’ may seem to be no more than a momentarily entrancing party trick, but it provides deep insights into the nature of perception, and is a powerful metaphor for the nature of thought.


The limited visual ‘window’ depends, to some extent at least, on where we are looking. Yet we typically have only the vaguest sense of which part of an image or scene we are looking at directly – we have the impression that the entire visual scene is simultaneously ‘grasped’ in pretty much complete detail. These illusions enable you to experience this. The feeling created is that the picture is changing, not that we are moving our eyes.


How many black dots can you see?
It turns out that, as with so many convincing tricks, the grand illusion depends on misdirection. We point our fovea (we only see clearly within a 5-degree diameter of where our eyes are aimed) and concentrate our attention, on one aspect of the visual world, and notice scarcely anything of what is happening in all the rest. If we are suspicious, even for a moment, that our perceptual representations are rather vague and monochrome in the periphery of our vision, we swivel our eyes across to check, and, sure enough, all is detailed and colourful…. It is as if the visual system has a single metaphorical ‘hand’ that can reach out, select and manipulate just one pattern at any moment.
The grand illusion tricks us into believing that our focus of attention is far wider than it actually is…. We have little or no access to information that is not attended to…. If you don’t pay attention to a word, you just don’t read it. Indeed, from the brain’s point of view, it isn’t there.
Perception, then, is a process of incredibly rich and subtle inference – the brain is carefully piecing together the best story it can about how the world might be, to explain the agitations of its sense organs…. Perception is not merely inference – it is, of course, unconscious inference…. Consider, when deep in a novel, how our flow of the experience is taken over by the story – while we have no awareness at all of the mysterious process by which the brain transforms sequences of printed letters into images and emotions.
Scanning a perceptual scene or reading a text, our eyes jump, on average three to four times a second. During a typical eye movement, the eye will be in motion for between about 20 to 200 milliseconds, depending on the angle through which the eyes ‘jump’. During this period, we are in effect almost completely blind…. It is rather astonishing that we are, from the point of view of conscious experience, entirely oblivious to the highly discontinuous process by which our eyes gather information. (Also consider that we blink many times a second but do not perceive any interruption in our vision. This is also known as Saccadic Suppression.)
The brain’s goal is to inform us about the world around us, not about the workings of our own mechanisms…. This is not surprising: we can’t introspect how our lungs or stomachs work – why should it be any different from the brain?


Perception works by relating, often in the most flexible and creative fashion, our sensory input with our memory of past experience…. Perception and memory are therefore intricately entwined. Recognizing a friend, a word or a tune requires not merely linking together different aspects of the perceptual input, but connecting these fragments to stored memories of faces, words and melodies…. Today’s memories are yesterday’s perceptual interpretations…. As today’s thought or action is tomorrow’s precedent, we are, quite literally, reshaping and reinventing ourselves thought by thought.
We are programmed to develop from what we see and how we see. This is dependent on nature and nurture as are all areas of development. Undeveloped vision is not ready. Its development can be guided. Faulty perceptions lead to faulty thinking. Faulty development is more challenging but can also be improved. Enhancing our vision to enhance our potential is often overlooked.

The Invisible Gorilla: part 1

Stress and Mindset

How We Learn: The Surprising Truth About When, Where, and Why It Happens

The Knowledge Illusion Why We Never Think Alone

Have Smartphones Destroyed a Generation? by Jean M. Twenge

Stumbling on Happiness


Daniel Gilbert is a professor of psychology at Harvard who has an unlikely background. Stumbling on Happiness presents research with a commentary which makes it highly readable. Readable; but disappointing in what we discover about ourselves….

Gerard Ekdom looking confused

We are not as logical as we believe we are and we are more influenced by our emotions than we realize. As Gilbert states: “If the goal of science is to make us feel awkward and ignorant in the presence of things we once understood perfectly well, then psychology has succeeded above all others.” But, knowing more about how we make decisions and our pitfalls has the potential to enhance our lives, our happiness, and our interactions with others.

Gilbert starts with the evolution of our neuroanatomy. As our brains have expanded, our frontal lobes have developed disproportionately. Through evolution, we have become able to imagine which enables us to worry about and predict the future. The theme of the book is how we are generally not good at making those predictions, particularly about how we will feel in the future. The book is divided into six parts.


PROSPECTION: Gilbert discusses the “journey to elsewhen”. He presents research on how important it is for us to feel in control. “Being effective – changing things, influencing things, making things happen – is one of the fundamental needs with which human brains seem to be naturally endowed, and much of our behavior from infancy onward is simply an expression of this penchant for control.” He describes us as the ape that looks forward and states: “The greatest achievement of the human brain is its ability to imagine objects and episodes that do not exist in the realm of the real, and it is this ability that allows us to think about the future.”


SUBJECTIVITY: Gilbert presents “the science of happiness”. How can we compare experiences since we can’t have them both at the same time and, since everyone’s scales are different, we can’t easily compare the experiences of different individuals? Our memories of experiences are notoriously unreliable and “once we have had an experience, we cannot set it aside and see the world as we would have seen it had the experience never happened.”


REALISM: “the belief that things are in reality as they appear to be in the mind”, Gilbert presents the first of three shortcomings of imagination that give rise to the illusion of foresight. “Imagination works so quickly, quietly, and effectively that we are insufficiently skeptical of its products.” What Gilbert refers to as “the blind spot of the mind’s eye”. Of what can we be certain? “The elaborate tapestry of our experience is not stored in memory – at least not in its entirety. Rather, it is compressed for storage by first being reduced to a few critical threads or a small set of key features. Later, when we want to remember our experience, our brains quickly reweave the tapestry by fabricating – not by actually retrieving – the bulk of the information that we experience as memory.” In this section, Gilbert has a quote from George Miller. “The crowning intellectual achievement of the brain is the real world.”


Under the theme of “the hound of silence” (think Sherlock Holmes, not Simon and Garfunkel) Gilbert shares one of the most significant errors of our perception; our lack of awareness of what is missing.

PRESENTISM: Gilbert explains the second shortcoming of our imagination which is that it is not particularly imaginative. Our imagined future often looks like the present. “If the past is a wall with some holes, the future is a hole with no walls. Memory uses the filling-in trick, but imagination is the filling-in trick, and if the present lightly colors our remembered past, it thoroughly infuses our imagined futures. More simply said, most of us have a tough time imagining a tomorrow that is terribly different from today, and we find it particularly difficult to imagine that we will ever think, want, or feel differently than we do now.”


RATIONALIZATION: Gilbert demonstrates that our ability to predict how we will feel about future events when they happen is even worse than our ability to predict what the future might be. “The brain and the eye have a contractual relationship in which the brain has agreed to believe what the eye sees, but in return the eye has agreed to look for what the brain wants.” This bottom-up/top-down integration helps us function efficiently, but we can also deceive ourselves.


Lastly, under CORRIGIBILITY, Gilbert shares why it is so difficult for us to rise above these limitation. One way for us to make better predictions of how we will feel is to look at other people under similar circumstances. We reject this approach “Because, if you are like most people, then like most people, you don’t know that you are like most people.” “Ironically, the bias toward seeing ourselves as better than average causes us to see ourselves as less biased than average.”


The Influence of Evolution

Risk Savvy: How to Make Good Decisions

The American Spirit

Risk Savvy: How to Make Good Decisions

The End of Average

The Influence of Evolution

If you have any question about the influence of how we evolved on our health, I hope that the following information from The Story of the Human Body by Daniel E. Lieberman convinces you….


“Just because we evolved to eat certain foods or do certain activities doesn’t mean they are good for us, or that other foods and activities aren’t better.” p. 7 Statements in the press and certainly in advertising lose track of what drives natural selection. “The final and most important point about adaptation is really a crucial caveat: no organism is primarily adapted to be healthy, long-lived, happy, or to achieve many other goals for which people strive. As a reminder, adaptations are features shaped by natural selection that promote relative reproductive success.” p. 13
We are embodied creatures. We increasingly recognize “Descartes’ Error”. Our bodies and minds are not separate as Descartes stated and was accepted as axiomatic in the West for centuries. They evolved together as a continuum. It is important to recognize the conditions under which our bodies and minds evolved were very different from our current environments which create mismatches. “The evolution of hunting and gathering underlies the evolution of the human genus, Homo. Moreover, the key adaptations that were selected to make this ingenious way of life possible among the first humans were not big brains, but modern-shaped bodies. More than anything else, the evolution of hunting and gathering spurred your body to be the way it is.” p. 69
“Most often you think with your brain, but sometimes the digestive system seems to take over and makes decisions on behalf of the rest of the body. Gut instincts are actually more than just urges or intuitions. Both organs are expensive tissues that cost lots of energy to grow and maintain. In fact, brains and guts each consume about the same amount of energy per unit mass, each expends about 15 percent of the basal metabolic cost, and each requires similar amounts of blood supply to deliver oxygen and fuel and to remove wastes. Your guts also have about 100 million nerves, more than the number of nerves in your spinal cord or your entire peripheral nervous system.” p. 91 
Hunter gatherers not only had to work hard to find their food, they often had to dig it out of the ground and then process it in some way to make it edible and increase the available calories. The precursors to the fruits and vegetables that we have today were much different in their physical and chemical properties as was the meat. “Some foods, like potatoes, yield roughly twice as many calories or other nutrients if you eat them cooked versus raw.” p. 121
The news about the human genome study and on genetic engineering has skewed the perception of the role of genes. “Every organ in your body – your muscles, bones, brain, kidneys, and skin – is the product of how your genes were affected by signals from the environment during the period you developed, and their current functions continue to be influenced by aspects of your current environment.” p. 163 “You may have genes that predispose you to having flat feet, myopia, and type 2 diabetes, but the distant ancestors from whom you inherited the very same genes likely did not suffer from these problems.” p. 164
“Numerous cultural changes have altered interactions between our genes and our environments in ways that contribute to a wide variety of mismatch diseases. It is not possible to overemphasize just how important mismatch diseases are. You are most likely going to die from a mismatch disease. You are most likely to suffer from disabilities caused by mismatch diseases. Mismatch diseases contribute to the bulk of health-care spending throughout the world.” p. 168
While the incidence of diabetes has increased at a frightening rate, the development of oral medications for diabetes has dramatically decreased complications from type 2 diabetes. But, even as I praise the benefits of these medications, “A large study that compared the effectiveness of the most popular drug, metformin, with a lifestyle intervention in more than three thousand people found that changing diet and exercise was almost twice as effective and had more lasting effects.” p. 275 Before we praise those from just a generation or so ago, it is important to realize that calories are now less expensive than they were in the past and their acts of daily living involved more physical activity. Fewer of them had to go out of their way to exercise. “Osteoporosis causes more than one-third of elderly women in the United States to fracture bones, but the disease was rare among elderly until recently. Diseases of disuse account for considerable disability and illness in developed nations. Once they arise, they tend to be difficult to treat, but they are largely preventable if we pay attention to how our bodies evolved to grow and function.” p. 295 “Because bodies are not engineered but instead grow and evolve, your body expects and indeed requires certain stresses when you are maturing in order to develop appropriately.” p. 297
“A related reason not to sterilize everything in sight or overuse antibiotics is that certain microbes and worms appear to play a crucial role in helping to stress the immune system appropriately. Just as your bones need stress to grow, your immune system requires germs to mature properly. Like any other system of the body, the developing immune system needs to interact with the environment in order to match capacity appropriately with demand.” p. 310
“In the United States and Europe, nearly a third of children between the age of seven and seventeen become nearsighted (myopic) and need glasses to see properly; the percentage of myopic people is higher in some Asian countries.” “In late nineteenth century Denmark, the incidence of myopia among unskilled laborers, seamen, and farmers was less than 3 percent but was 12 percent for craftsmen and 32 percent for university students.” “Nearsightedness is a complex trait caused by many interactions among a large number of genes and multiple environmental factors. However, since people’s genes haven’t changed much in the last few centuries, the recent worldwide epidemic of myopia must result primarily from environmental shifts.” p. 330 

Book review: The Brain That Changes Itself