How The Mind Works

“And because this research can measure only the ways in which people differ, it says little about the design of the mind that all normal people share. But by showing how many ways the mind can vary in its innate structure, the discoveries open our eyes to how much structure the mind must have.” 

In discussing how the mind works, Pinker acknowledges that a lot of research has been conducted on people whose minds did not work typically. Either an injury or some genetic alteration produced a brain that behaved differently than what we see in most people. However, as he points out, it is not the ways that the human mind can differ that are important. The fact that we all share the same basic architecture and yet all have different minds is most fascinating. This theme of distilling the mind to what all humans share is crucial to understand how Pinker is approaching the study of the mind. As he points out, even given the aspects that are the same for everyone, the mind manages to develop differently in all seven billion people on this planet. Understanding how we produce such differences out of our similarities will only happen if we first understand what we all share.

“Artificial computer programs, from the Macintosh user interface to simulations of the weather to programs that recognize speech and answer questions in English, give us a hint of the finesse and power of which computation is capable. Human thought and behavior, no matter how subtle and flexible, could be the product of a very complicated program, and that program may have been our endowment from natural selection. The typical imperative from biology is not ‘Thou shalt…,’ but ‘If…then…else.’”

Pinker summarizes his argument that the computational theory of mind is a powerful and flexible way to approach researching the mind with this quote. In it, he highlights the theme that people have misunderstood the computational theory of mind and produced criticisms that display that misunderstanding. The quote also highlights the focus on logic statements (if…then…else) in examining the mind’s operations. Many people think that a divine being is needed to create something as elegant as the mind, but arguably, a set of rules and structure handed down by a divine being could never be as flexible and adaptive as the human mind: A “Thou shalt…” statement is static and risks becoming obsolete with changing environments, whereas “If…then…else” statements are flexible. Thus, treating the mind’s operations as logic statements, akin to computations, is both appropriate and productive.

“But consciousness or sentience, the raw sensation of toothaches and redness and saltiness and middle C, is still a riddle wrapped in a mystery inside an enigma. When asked what consciousness is, we have no better answer than Louis Armstrong's when a reporter asked him what jazz is: ‘Lady, if you have to ask, you'll never know.’” 

This quote introduces a core mystery of the human mind. In Chapter 8, Pinker expands on the idea of consciousness. This quote embodies the fundamental issue, which is that we just “know” what consciousness is. We can’t articulate how we know it, but we know it when we see it, and we do not hesitate to call something conscious or sentient. If we can’t ask about it easily, we can’t study it very easily either. To consider what it is to lack consciousness may require us to suspend our own consciousness or turn off what that consciousness gives us, which is impossible. 

“One, they have to have intelligent but impenetrable responses to situations. You have to be able to observe the alien's behavior and say, ‘I don't understand the rules by which the alien is making its decisions, but the alien is acting rationally by some set of rules.’ …The second requirement is that they have to care about something. They have to want something and pursue it in the face of obstacles.” 

David Alexander Smith is describing the key factors in deciding something is intelligent. Like consciousness, we tend to know intelligence when we see it. However, there are varying levels of intelligence, and it can be difficult to figure out where something is on that scale. The fundamental requirements, as Smith describes, include rationality and goals. Rationality means using a rule system, and using a rule system for behavior means behavior will be consistent in the same scenario and similar across similar scenarios. If someone is using rules for their behavior, you can predict their behavior as you learn the rule system. As Pinker points out in Chapter 6, unpredictable beings are distinctly unsettling. Either we don’t understand their rule system, or we wonder if there is one. 

“Conceptually speaking, a hidden-layer network is a way to compose a set of propositions, which can be true or false, into a complicated logical function held together by ands, ors, and nots—though with two twists. One is that the values can be continuous rather than on or off, and hence they can represent the degree of truth or the probability of truth of some statement rather than dealing only with statements that are absolutely true or absolutely false. The second twist is that the network can, in many cases, be trained to take on the right weights by being fed with inputs and their correct outputs. On top of these twists there is an attitude: to take inspiration from the many connections among neurons in the brain and feel no guilt about going crazy with the number of gates and connections put into a network. That ethic allows one to design networks that compute many probabilities and hence that exploit the statistical redundancies among the features of the world. And that, in turn, allows neural networks to generalize from one input to similar inputs without further training, as long as the problem is one in which similar inputs yield similar outputs.” 

This quote summarizes the iterative process by which the brain creates complex networks that can create complex thoughts, emotions, and experiences. This iterative building process from small and simple pieces is a major part of Pinker’s argument about how the mind works. In this quote, he highlights two key points that contribute to the unique human mind. The first is the ability to express the probability of a stimulus being in the environment instead of only having yes/no options. We can process gradations of similarity among objects instead of needing to decide something falls 100% into a category or doesn’t at all. Therefore, we can create categories with fuzzy boundaries or know that chimpanzees and gorillas are similar in some ways but not in others. The second point is the ability to exponentially expand the number of small pieces that connect. This key property allows us to expand our network and knowledge, it enables us to quickly categorize along many domains, and it expands the possible combinations of thoughts and actions we can create. We see this iterative process in larger concepts like emotion and relationships as well, using many elements to categorize people (family, friends, acquaintances, enemies) and simultaneously having more specific and fuzzy boundaries (brother by blood, brother as a close friend, best friend, work friends). 

“This dynamic processor, called a recursive transition network, is especially plausible for sentence understanding, because we hear and read words one at a time rather than inhaling an entire sentence at once. We also seem to chew our complex thoughts piece by piece rather swallowing or regurgitating them whole, and that suggests that the mind is equipped with a recursive proposition-cruncher for thoughts, not just for sentences.” 

Our iterative building process is fundamental to how the mind works. We receive, process, understand, and convey information in discrete chunks. We then connect these chunks and their meaning. Instead of having unique processors for every possible combination of words we may hear or images we may see, we have limitless options for bringing in new information and expanding our world because we don’t have to know all the possible options up front. 

“Our incomprehension of sentience does not impede our understanding of how the mind works in the least. Generally the parts of a scientific problem fit together like a crossword puzzle. To reconstruct human evolution, we need physical anthropology to find the bones, archeology to understand the tools, molecular biology to date the split from chimpanzees, and paleobotany to reconstruct the environment from fossil pollen. When any part of the puzzle is blank, such as a lack of chimpanzee fossils or an uncertainty about whether the climate was wet or dry, the gap is sorely felt and everyone waits impatiently for it to be filled. But in the study of the mind, sentience floats in its own plane, high above the causal chains of psychology and neuroscience.” 

It should not be surprising given how our brains use small pieces of information to build to larger concepts that humans also study the world this way. We divide knowledge of the world into categories and study the world from specific lenses or with a focus on specific phenomena. Then, we put those pieces together to understand something like how humans evolved or how the mind works. This process, as any scientist knows, both is useful and creates gaps in knowledge. Coordination among disciplines can be difficult. The mind can sometimes suffer from similar issues, with preplanned motor activities conflicting with a stimulus the cerebellum is processing, causing jerky, uncoordinated movements as we try to handle two situations. However, the mind suffers from lack of coordination far less than scientists in different disciplines. Pinker mentions an interesting aspect of the mind, which is that its most inner core, sentience, may be inscrutable. Looking at yourself is difficult, and sentience doesn’t seem to have discrete pieces we can process and try to connect.

“Life is a densely branching bush, not a scale or a ladder, and living organisms are at the tips of the branches, not on lower rungs. Every organism alive today has had the same amount of time to evolve since the origin of life—the amoeba, the platypus, the rhesus macaque, and, yes, Larry on the answering machine asking for another date.” 

This quote highlights Pinker’s main argument about why human intelligence is likely unique to humans. All organisms in the world today have had just as long to evolve as humans. We all started from the same single-celled organisms and have branched from there. Therefore, all the unique traits each species evolved are specific to that species’ environment and needs. Many other evolved organs are impressive, such as an elephant’s trunk. The trunk evolved from the unique pressures facing elephants and their ancestors. Human intelligence will not appear in elephants because of the very different pressures these species have faced.

“The major faculties of the mind, with their feats no robot can duplicate, show the handiwork of selection. That does not mean that every aspect of the mind is adaptive. From low-level features like the sluggishness and noisiness of neurons, to momentous activities like art, music, religion, and dreams, we should expect to find activities of the mind that are not adaptations in the biologists' sense. But it does mean that our understanding of how the mind works will be woefully incomplete or downright wrong unless it meshes with our understanding of how the mind evolved.”

Pinker brings up a subtle but important point about evolution, natural selection, and human existence. Genes that code for traits that are adaptive are more likely to be passed on. Over time, those traits will predominate in the species, but that does not mean they will be the only traits we see or that we won’t still see a lot of traits that aren’t adaptive in any particular way. Traits that are distinctly maladaptive are likely to die out, but some traits have no particular value one way or the other, and many versions of those traits can exist. Eye and hair color still exist even though no particular eye or hair color is better for survival. Similarly, traits that are adaptive can produce by-products as their adaptive value wanes or the environment changes. Our bodies still store fat as when we went long periods without eating, and yet in many modern societies hunger is not a serious threat. Obesity is partially a by-product of our adaptive responses to earlier dietary challenges. We can also use our adaptive features for things not related to our survival. Our eyes have adapted to distinguishing boundaries and environmental shapes, and we prefer art that depicts clear boundaries and common shapes in the environment. 

“Whatever is special about the human mind cannot be just more, or better, or more flexible animal intelligence, because there is no such thing as generic animal intelligence. Each animal has evolved information-processing machinery to solve its problems, and we evolved machinery to solve ours. The sophisticated algorithms found in even the tiniest dabs of nervous tissue serve as yet another eye-opener—joining the difficulty of building a robot, the circumscribed effects of brain damage, and the similarities between twins reared apart—for the hidden complexity we should expect to find in the human mind.”

This quote extends Pinker’s point about human intelligence being the result of specific pressures in human evolution and, therefore, unlikely to evolve in other creatures. Similarly, other animals have their own information-processing units that are perfectly adapted for their environment. There aren’t pressures on them to develop human-like intelligence. Many animals have some similar characteristics to human intelligence—different pieces that are also useful in their environments—but only creatures with the same pressures as humans across their evolution would find themselves in the same position as humans. 

“Experts are needed because expertise is needed: the mind's problems are too technical and specialized to be solved by a jack-of-all-trades. And most of the information needed by one expert is irrelevant to another and would only interfere with its job. But working in isolation, an expert can consider too many solutions or doggedly pursue an unlikely one; at some point the experts must confer. The many experts are trying to make sense of a single world, and that world is indifferent to their travails, neither offering easy solutions nor going out of its way to befuddle. So a supervisory scheme should aim to keep the experts within a budget in which improbable guesses are more expensive. That forces them to cooperate in assembling the most likely overall guess about the state of the world.” 

This quote builds even further on the iterative building process of the human brain and mind. In this case, at the highest level where we are choosing a course of action, we are combining information from “experts,” or simpler neurons that respond to specific stimuli, with information from other “experts” that respond to other stimuli. The “executive” interprets the information to come to a single, coherent understanding of the world. Just as with other aspects of how the mind works, these experts handle their own, smaller pieces of the puzzle and another layer that puts the pieces together for the larger concept or image or sentence. The executive uses processes such as constraint satisfaction to arrive at the most likely image, sentence meaning, or concept being discussed. 

“Jorge Luis Borges writes of a Chinese encyclopedia that divided animals into: (a) those that belong to the Emperor, (b) embalmed ones, (c) those that are trained, (d) suckling pigs, (e) mermaids, (f) fabulous ones, (g) stray dogs, (h) those that are included in this classification, (i) those that tremble as if they were mad, (j) innumerable ones, (k) those drawn with a very fine camel's hair brush, (1) others, (m) those that have just broken a flower vase, (n) those that resemble flies from a distance.” 

In this quote, Pinker highlights that humans do not categorize things for fun or because doing so makes processing information faster. Since we tend to remember individual examples of a category and the category itself, categorization is a cost to processing speed and adds to the amount of information to collect and maintain. Categories must serve a purpose, and their purpose is to quickly process information. Categories allow us to make inferences about the characteristics of an object that we can’t see or hear. Once we categorize a new animal, we make inferences about things like how it sounds or how it eats or moves, even if we have only seen a single picture of the animal. These inferences speed our learning and ability to work with information in the world because we don’t have to personally experience everything. They also allow us to make initial judgments of whether something is predator or prey, dangerous or harmless. 

“Even the most recondite scientific reasoning is an assembly of downhome mental metaphors. We pry our faculties loose from the domains they were designed to work in, and use their machinery to make sense of new domains that abstractly resemble the old ones. The metaphors we think in are lifted not only from basic scenarios like moving and bumping but from entire ways of knowing. To do academic biology, we take our way of understanding artifacts and apply it to organisms. To do chemistry, we treat the essence of a natural kind as a collection of tiny, bouncy, sticky objects. To do psychology, we treat the mind as a natural kind.” 

Pinker shows throughout Chapter 5 that humans build new understanding from old understanding. When we try to explain a new experience, we use words that evoke concrete and already known things. In many ways, we have not left our evolutionary ancestors as movement and spatial words still predominate our language. We explain things using spatial relations even when they are not physical objects or when they do not have a spatial relationship. This use of more concrete and well-known concepts to explain new concepts is another way humans build from simpler, smaller pieces to larger and more complex pieces. We use what is known and build to what is not yet known. Humans do not distinguish chemistry and physics and psychology from the world we have already described but instead use the world we have already described to learn chemistry, physics, and psychology.

“Educated understanding is an enormous contraption of parts within parts. Each part is built out of basic mental models or ways of knowing that are copied, bleached of their original content, connected to other models, and packaged into larger parts, which can be packaged into still larger parts without limit. Because human thoughts are combinatorial (simple parts combine) and recursive (parts can be embedded within parts), breathtaking expanses of knowledge can be explored with a finite inventory of mental tools.” 

To summarize the iterative process described throughout Chapter 5 and built in the preceding chapters, Pinker discusses higher-level education. He focuses on math, which, after basic number theory and spatial relationships, requires humans to learn abstract concepts. To do so, humans require practice and building blocks. We start with numbers and simple operations because those come most naturally. To build from numbers to abstract algebra, we must practice ideas that are difficult. We build small concepts into larger concepts and large concepts into even larger concepts. At each stage, we must practice using the new concepts or they won’t stick with us because they are not built into our standard, evolutionarily based functioning. Abstract algebra doesn’t have a survival purpose; it can be readily left behind to ensure we are using resources on survival needs. Therefore, we must practice and practice, but with that practice we can build to infinite levels of combinations of thought. 

“And here is the key to why we have emotions. An animal cannot pursue all its goals at once. If an animal is both hungry and thirsty, it should not stand halfway between a berry bush and a lake, as in the fable about the indecisive ass who starved between two haystacks. Nor should it nibble a berry, walk over and take a sip from the lake, walk back to nibble another berry, and so on. The animal must commit its body to one goal at a time, and the goals have to be matched with the best moments for achieving them.” 

Many people think of emotions as by-products of being social beings, as nuisances, or as reactions to experiences. Instead, emotions shape our experiences and are useful for determining what is happening around us and what we should do next. Humans can only engage in one line of behavior at a time. We can only be in one place at a time. Emotions help us decide what that place should be based on the information available. Here, Pinker introduces a very different way of thinking about a well-studied human concept. Emotions, art, humor, and relationships are all discussed over the last three chapters in ways that are not typical in the scientific literature. In each case, Pinker offers a plausible and highly logical explanation for the why behind each concept instead of just what we see. These three chapters are examples of the reverse-engineering that Pinker argues for in early chapters.  

“The body is the ultimate barrier to empathy. Your toothache simply does not hurt me the way it hurts you. But genes are not imprisoned in bodies; the same gene lives in the bodies of many family members at once. The dispersed copies of a gene call to one another by endowing bodies with emotions. Love, compassion, and empathy are invisible fibers that connect genes in different bodies. They are the closest we will ever come to feeling someone else's toothache.” 

Empathy is something we develop and show because we care about other humans. It makes sense to care about other humans because we are social beings who live with other humans to survive. However, we don’t experience empathy for everyone, and empathy is much stronger for family. Empathy could be linked to the knowledge that copies of our genes reside in people related to us. We feel a sense of connection that makes us hurt when they hurt and feel joy when they feel joy. That connection increases the likelihood we will help because we feel a shadow of the way they feel, and the best way to solve that pain is to help them get rid of it. 

“Once again I think it is unwise to confuse how the mind works with how it would be nice for the mind to work. But perhaps some comfort may be taken in a different way of looking at things. Perhaps we should rejoice that people's emotions aren't designed for the good of the group. Often the best way to benefit one's group is to displace, subjugate, or annihilate the group next door. Ants in a colony are closely related, and each is a paragon of unselfishness. That's why ants are one of the few kinds of animal that wage war and take slaves. When human leaders have manipulated or coerced people into submerging their interests into the group's, the outcomes are some of history's worst atrocities.” 

A running theme throughout the book is that misconceptions about natural selection and many arguments against it come from thinking that genes would be selected that are good for someone other than the replicator. Natural selection is often suggested to have goals, like developing intelligence. Natural selection doesn’t have a goal. We do not select for intelligence, but intelligence was helpful throughout our evolutionary history, so those who were more intelligent had more opportunities to reproduce and pass on their genes. The mind also did not evolve with a goal. Humans are as nice as is needed to live in groups, and this niceness sometimes confers other benefits in modern society or is used with people outside the group when appropriate. 

“It's logically possible but seems psychologically impossible; grief is the other side of love. And there may lie the answer. Perhaps grief is an internal doomsday machine, pointless once it goes off, useful only as a deterrent. What parents have not lain awake contemplating the horror of losing a child? Or worried themselves sick with awful images when a child is late or lost? These thoughts are powerful reminders to protect and cherish a loved one in the face of myriad other demands on one's time and thoughts. Like all deterrents, grief would be effective only if it is certain and terrible.” 

Emotions allow us to experience intensely negative or positive events in small, imagined circumstances. We can picture something happening and how we would handle it without having to go through it. We can plan how to handle strong emotions that come with some event by experiencing them safely first. Therefore, emotions can be, as Pinker puts it, an “internal doomsday machine.” They are not useful in and of themselves, but they teach us what has negative consequences, they let us picture negative events and learn to deal with them, and they reinforce what we care about and why (such as not wanting a loved one to die). 

“Wealth is not the only asset that people flaunt and covet. In a complicated society, people compete in many leagues, not all of them dominated by plutocrats. Bell added a fourth canon to Veblen's list: conspicuous outrage. Most of us depend on the approval of others. We need the favor of bosses, teachers, parents, clients, customers, or prospective in-laws, and that requires a certain measure of respect and unobtrusiveness. Aggressive nonconformity is an advertisement that one is so confident in one's station or abilities that one can jeopardize the good will of others without ending up ostracized and destitute. It says, ‘I'm so talented, wealthy, popular, or well-connected that I can afford to offend you.’” 

Pinker describes ways that people show their status. Conspicuous outrage is an addition to the original list of conspicuous consumption, conspicuous leisure, and conspicuous waste. The first three are only available to people with resources that come with status. Wealth, power, and skills are all linked such that having them will afford a person resources. Those resources can then reach a level at which one can “waste” money on goods, services, or experiences. Outrage does not require resources. However, strategically using conspicuous outrage could trick others into thinking one has status, and one could leverage that impression into actual status. 

“And despite the oppression of his people, he [Dalai Lama] remains an optimist and predicts that the twenty-first century will be more peaceful than the twentieth. Why? asked the interviewer. "Because I believe," he said, "that in the 20th century, humanity has learned something from many, many experiences. Some positive, and many negative. What misery, what destruction! The greatest number of human beings were killed in the two world wars of this century. But human nature is such that when we face a tremendous critical situation, the human mind can wake up and find some other alternative. That is a human capacity." 

Pinker often warns against explaining how the mind works by thinking about how it would be nice for the mind to work, and this quote ends a sequence in which he gives an example of the difference between how the mind really works and how people would like the mind to work. In this section, Pinker is discussing how humans are prone to conflict, but that doesn’t mean that humans are wantonly violent. Many people argue that the human mind is inherently kind. The human mind did not evolve with a goal of kindness, and it does not want anything. It is an information processor. It comes up with relevant solutions to puzzles presented to it. It can be directed as to the organism’s goal: to eat, to mate, to sleep, etc. It does not have goals on its own. Conflict is a natural part of there being many humans with similar goals and only so many resources for accomplishing those goals. However, even humans notice when conflict accomplishes little, and it should only occur when necessary. As the Dalai Lama points out, when facing a critical problem, the human mind gets to work on a solution. As the best information-processor ever developed, the human mind is in the best place to solve these critical problems, and we won’t necessarily choose conflict to do so. Many of the problems the Dalai Lama eludes to likely won’t be solved with fighting all over the planet, and his hope is that humans will use their superior information-processing units to develop peaceful solutions to these problems.

“Given that the mind is a product of natural selection, it should not have a miraculous ability to commune with all truths; it should have a mere ability to solve problems that are sufficiently similar to the mundane survival challenges of our ancestors. According to a saying, if you give a boy a hammer, the whole world becomes a nail. If you give a species an elementary grasp of mechanics, biology, and psychology, the whole world becomes a machine, a jungle, and a society. I will suggest that religion and philosophy are in part the application of mental tools to problems they were not designed to solve.” 

As also discussed in Chapter 5, Pinker returns in Chapter 8 to how humans have developed things like philosophy and religion despite their lack of survival value. How did a mind and body selected over millennia to maximize survival come to develop unnecessary past-times on which they often spend considerable time? Pinker argues that we build larger concepts from smaller pieces, building an infinite set of thoughts and rule systems. As humans have mastered the external environment, they can consider even larger questions that don’t have immediate relevance to survival. Our minds can plan ahead and visualize things that have not happened and how they may turn out. We can start to consider future potential survival problems, such as diseases that shorten lifespan, as both individuals and as a species. In doing so, we are still constrained by using a system designed to solve survival problems. We will focus on solutions closest to what we have already experienced. Therefore, in developing religion and philosophy, we have found accurate and interesting answers to perplexing questions and have also created fantastically inaccurate theories and ideas later shown to be false. 

“No account of the causal effects of the cingulate sulcus can explain how human choices are not caused at all, hence something we can be held responsible for. Theories of the evolution of the moral sense can explain why we condemn evil acts against ourselves and our kith and kin, but cannot explain the conviction, as unshakable as our grasp of geometry, that some acts are inherently wrong even if their net effects are neutral or beneficial to our overall well-being.” 

This quote summarizes Pinker’s argument in Chapter 8 that his book does not explain several aspects of the human mind. Natural selection and the computational theory of mind can explain many aspects of how the mind works, and Pinker is confident we will continue to explain ever more complex aspects of the human mind. However, we are nowhere near understanding free will. Humans debate whether we have free will because so many of our actions are linked to biological imperatives or feel like the only behavior for the given situation. However, we also do things, fairly ubiquitously, like condemn murder and set up laws that protect those with fewer resources or who are weaker. It is not clear why the human mind would have these convictions and rules, or at least obey those given by society, and more work is needed to explain these aspects of the human mind.

“The hypothesis does not imply that we have sighted the end of science or bumped into a barrier on how much we can ever learn about how the mind works. The computational aspect of consciousness (what information is available to which processes), the neurological aspect (what in the brain correlates with consciousness), and the evolutionary aspect (when and why did the neurocomputational aspects emerge) are perfectly tractable, and I see no reason that we should not have decades of progress and eventually a complete understanding—even if we never solve residual brain-teasers like whether your red is the same as my red or what it is like to be a bat.” 

In explaining the problems we face explaining some aspects of the mind, Pinker makes it clear that he believes we will explain most aspects of how the mind works. The fact that the way the mind works can produce things we don’t understand doesn’t mean we can’t or shouldn’t continue to research how the mind works. Pinker argues that some of the things we want to explain about the mind, like sentience and free will, involve considering ourselves in a way that may not be possible. However, there are still so many computational, neurological, and evolutionary aspects of the mind to understand, we are many decades from when sentience and free will are all that remain to explain.