The Birth of the Mind Quotes

“A major push is under way to figure out the molecular basis of those "critical" or "sensitive" periods, to figure out how the brain changes as certain learning abilities come and go. In some, if not all, of those mammals that have the alternating stripes in the visual cortex known as ocular dominance columns, those columns can be adjusted early in development, but not in adulthood. A juvenile monkey that has one eye covered for an extended period of time can gradually readjust its brain wiring to favor the open eye; an adult monkey cannot adjust its wiring. At the end of a critical period, a set of sticky sugar-protein hybrids known as proteoglycans condenses into a tight net around the dendrites and cell bodies of some of the relevant neurons, and in so doing those proteoglycans appear to impede axons that would otherwise be wriggling around as part of the process of readjusting the ocular dominance columns; no wriggling, no learning. In a 2002 study with rats, Italian neuroscientist Tommaso Pizzorusso and his colleagues dissolved the excess proteoglycans with an antiproteoglycan enzyme known as "chABC," and in so doing managed to reopen the critical period. After the chABC treatment, even adult rats could recalibrate their ocular dominance columns. ChABC probably won't help us learn second languages anytime soon, but its antiproteoglycan function may have important medical implications in the not-too-distant future. Another 2002 study, also with rats, showed that chABC can also promote functional recovery after spinal cord injury.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“How does the body push the comparatively tiny genome so far? Many researchers want to put the weight on learning and experience, apparently believing that the contribution of the genes is relatively unimportant. But though the ability to learn is clearly one of the genome's most important products, such views overemphasize learning and significantly underestimate the extent to which the genome can in fact guide the construction of enormous complexity. If the tools of biological self-assembly are powerful enough to build the intricacies of the circulatory system or the eye without requiring lessons from the outside world, they are also powerful enough to build the initial complexity of the nervous system without relying on external lessons.

The discrepancy melts away as we appreciate the true power of the genome. We could start by considering the fact that the currently accepted figure of 30,000 could well prove to be too low. Thirty thousand (or thereabouts) is, at press time, the best estimate for how many protein-coding genes are in the human genome. But not all genes code for proteins; some, not counted in the 30,000 estimate, code for small pieces of RNA that are not converted into proteins (called microRNA), of "pseudogenes," stretches of DNA, apparently relics of evolution, that do not properly encode proteins. Neither entity is fully understood, but recent reports (from 2002 and 2003) suggest that both may play some role in the all-important process of regulating the IFS that control whether or not genes are expressed. Since the "gene-finding" programs that search the human genome sequence for genes are not attuned to such things-we don't yet know how to identify them reliably-it is quite possible that the genome contains more buried treasure.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“What Jacob and Monod had discovered, in essence, was that each gene acts like a single line in a computer program.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Because genes work in combination, the incremental effect of adding a new gene to a genome may be not linear, but exponential.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“It is no exaggeration to say that genes are essential to nearly every aspect of memory and the process of learning; without them, learning itself would not exist.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Honey bees, too, use a highly specialized learning mechanism to help them figure out where they are going: the difference is that their system works based on the trajectory of a single star, our very own sun. Once again, part of the system is prewired, but part of it requires learning. The prewired bit is a mathematical function that relates the sun's position on the horizon to to a bee's orientation-but some of the values of the equation must be set, which is where learning comes in. What the bee learns is a highly specific bit of information about the sun's trajectory at the bee's particular latitude at a particular time of year. A five o'clock winter sun in Boston means something very different from a five o'clock summer sun in California, and a highly focused learning mechanism allows honeybees to take advantage of that information. We know that bees don't simply memorize a correspondence between particular places on the horizon and particular headings, because bees that have been raised in conditions in which they are exposed only to morning light can accurately use the sun as a guide during evening light.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“In universities and pharmaceutical labs around the world, computer scientists and computational biologists are designing algorithms to sift through billions of gene sequences, looking for links between certain genetic markers and diseases. The goal is to help us sidestep the diseases we're most likely to contract and to provide each one of us with a cabinet of personalized medicines. Each one should include just the right dosage and the ideal mix of molecules for our bodies. Between these two branches of research, genetic and behavioral, we're being parsed, inside and out. Even the language of the two fields is similar. In a nod to geneticists, Dishman and his team are working to catalog what they call our "behavioral markers." The math is also about the same. Whether they're scrutinizing our strands of DNA or our nightly trips to the bathroom, statisticians are searching for norms, correlations, and anomalies. Dishman prefers his behavioral approach, in part because the market's less crowded. "There are a zillion people looking at biology," he says, "and too few looking at behavior." His gadgets also have an edge because they can provide basic alerts from day one. The technology indicating whether a person gets out of bed, for example, isn't much more complicated than the sensor that automatically opens a supermarket door. But that nugget of information is valuable. Once we start installing these sensors, and the electronics companies get their foot in the door, the experts can start refining the analysis from simple alerts to sophisticated predictions-perhaps preparing us for the onset of Parkinson's disease or Alzheimer's.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“We should be far more worried about "genetic enhancement"- efforts to artificially construct "improved humans." Here I side with Fukuyama: Although the technology for improvement is close at hand, it comes with great risks, and some of the greatest risks stem from the complexity of the underlying biology. As we have seen, the basic logic by which genes operate-the regulatory IF conjoined with protein template THEN- is straightforward- which is why genetic enhancement might be possible, in principle. But the combined effects of 30,000 genes far exceed our comprehension; if we know the general principles, we don't know the details, and what we don't know really could hurt us.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“With continued progress in the rapidly growing field known as pharmacogenetics, it will become possible to prescribe drugs based on each patient's own unique biology.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“In the years to come, some of our best minds will try to dig deeper into that computer program, to figure out its individual lines of code (the IF-THENS that we call genes), the products of those lines (what we call proteins), how all those lines of biological code fit together, and how they make room for nurture.

In the long run, the effects on society will be profound. Take, for example, the advances that our increasing understanding of genes will lead to in medicine. Because, as we have seen, the brain is built like the rest of the body, it is also amenable to many of the same types of treatment. For example, stem cell therapies originally developed for leukemia are being adapted to treat Parkinson's disease and Huntington's disease. Gene therapies developed for cystic fibrosis may someday help treat brain tumors. Both work by harnessing the body's own toolkit for development.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“If there is not preformation, and no blueprint, there is also no getting away from the environment. Genes do not guarantee particular products; rather, they provide particular options: To every gene there is an IF, and with that IF comes an option. In many cases, those options are selected based on cues from the environment, and it is for that reason, more than any other, that the answer to the nature-nurture question is not one or the other, but both.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“In place of a view of the genome as a static blueprint that operates independently of experience and only up to the moment of birth, we have come to understand the genome as a complex, dynamic set of self-regulating recipes that actively modulate every step of life. Nature is not a dictator hell-bent on erecting the same building regardless of the environment, but a flexible Cub Scout prepared with contingency plans for many occasions.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Instead, in our world, nature's contribution to development comes not by providing a finely detailed sketch of a finished product, but by providing a complex system of self-regulating recipes. Those recipes provide for many different things-from the construction of enzymes and structural proteins to the construction of motors, transporters, receptors, and regulatory proteins-and thus there is no single, easily characterizable genetic contribution to the mind. In the ongoing, everyday functioning of the brain, genes supervise the construction of neurotransmitters, the metabolism of glucose, and the maintenance of synapses. In early development, they help to lay down a rough draft, guiding the specialization and migration of cells as well as the initial pattern of wiring. In synaptic strengthening, genes are a vital participant in a mechanism by which experience can alter the wiring of the brain (thereby influencing the way that an organism interprets and responds to the environment). There are at least as many different genetic contributions to the mind and brain as there are genes; each contributes by regulating a different process.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Dino-DNA injected into frog eggs would likely yield something different from dino-DNA in dinosaur eggs-because the micro-environment of the egg would inevitably influence which genetic cascades were expressed. (Fans of the environment shouldn't get too comfortable, either-implanting a frog's DNA into a dinosaur egg would be even less likely to yield a dinosaur.) Because the recipes that build the mind and brain are always sensitive to the environment, there is no guarantee that those recipes will converge on any particular outcome, and there will never be an easy answer to our questions about nature and nurture.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“The CD-ROM's worth of information in the genome really wouldn't be enough to paint a bitmapped picture of an embryo, but it is enough to describe a process for building one. An artist who only wants to paint a picture that looks like a kind of tree has much less to remember than an artist who wants to paint a particular Ponderosa Pine from memory; in a similar way, if some alien's genome had to encode every cell in a body, it would need much more information (many more nucleotides) than our genomes do, because ours specify a general way to build a creature rather than an exact picture of every detail of the finished product. Our genomes are lossy because they specify methods rather than pictures, but it is precisely that lossiness that allows them to so efficiently supervise the construction of complex biological structure.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“To the extent that genomes can be thought of as compressed encodings of biological structures, they are spectacularly efficient. All the trillions of cells in the human body-not just the tens of billions in the brain-are guided in one way or another by the information contained in 30,000 or so genes. The best high-quality set of pictures of the body- the National Institutes of Health Visible Human Project, a series of high-resolution digital photos of slices taken from volunteer Joseph Paul Jernigan (deceased)-takes up about 60 gigabytes, enough (if left uncompressed) to fill about 100 CD-ROMs-and still not enough detail to capture individual cells. The genome, in contrast, contains only about 3 billion nucleotides, the equivalent (at two bits per nucleotide) of less than two-thirds of a gigabyte, or a single CD-ROM.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Biology doesn't know in advance what the end product will be; there's no Stuffit Compressor to convert a human being into a genome. But the genome itself is very much akin to a compression scheme, a terrifically efficient description of how to build something of great complexity-perhaps more efficient than anything yet developed in the labs of computer scientists (never mind the complexities of the brain, there are trillions of cells in the rest of the body, and they are all supervised by the same 30,000-gene genome). And although there is no counterpart in nature to a program that compresses a picture into a compact description, there is a natural counterpart to the program that decompresses the compressed encoding, and that's the cell. Genome in, organism out. Through the logic of gene expression, cells are self-regulating factories that translate genomes into biological structure.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“To take one example, even a brief exposure to light in a newborn kitten, rat, or monkey can launch a complex cascade of gene expression. The light activates photoreceptors-which send signals-which trigger a pathway-which leads to the expression of neural growth factors and a set of genes known as "immediate early genes" or "early response genes"-each of which, in turn, triggers the expression of many more genes. One study of cichlid fish suggests that a change in social status (from submissive to dominant) is tied to changes in the expression levels of at least fifty-nine different genes-a phenomenon not entirely unrelated to the testosterone rush that Joe-six-pack gets when the home team wins.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“Cell differentiation can turn neurons into everything from clocks that control circadian rhythms to photoreceptors that convert light into electrical-chemical impulses or decision makers that tally votes and decide courses of action. In the retina (often used as a case study because it can be directly and naturally stimulated), there are at least fifty different kinds of neurons specialized to different tasks, such as looking for motion, recognizing colors, detecting objects in low light, and measuring brightness and contrast. In the brain as a whole, there may be as many as 10,000 different kinds of neurons, each contributing to a different aspect of mental life.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“What propels an embryo from one stage to the next-and makes one species different from another-is not a blueprint but rather an enormous autonomous library of the instructions contained within its genome. Each gene does double duty, specifying both a recipe for a protein and a set of regulatory conditions for when and where it should be built. Taken together suites of these IF-THEN genes give cells the power to act as parts of complicated improvisational orchestras. Like real musicians, what they play depends on both their own artistic impulses and what the other members of the orchestra are playing. As we will see in the next chapter, every bit of this process-from the Cellular Big 4 to the combination of regulatory cues-holds as much for development of the brain as it does for the body.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“In a 1957 experiment that helped launch the modern study of language acquisition, the late Roger Brown showed that children know that if you say, "Can you see a sib?" you probably have in mind an action or a process. No other mammal seems to be equipped to use such clues for word learning.

Even more dramatically, no other species seems to be able to make much of word order. The difference between the sentence "Dog bites man" and the sentence "Man bites dog" is largely lost on our nonhuman cousins. There is a bit of evidence that Kanzi can pay attention to word order to some tiny extent, but certainly not in anything like as rich a fashion as a three-year-old human child.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought

“In essence, the bee's azimuth system acts like a sundial run in reverse, and like a sundial, it has to be calibrated. A sundial, which must be oriented with respect to a known compass direction, calculates the time of day based on where the sun is; the navigational centers in the bee's brain calculate where the sun should be based on the time of day. As a consequence, the one thing that bees can't cope with is the discalibration that results from jet lag. In a famous 1960s experiment, Max Renner packed up a hive of bees in Long Island, New York, flew them to Davis, California, and tested their ability to navigate with the sun as a landmark. The jetlagged bees consistently misoriented themselves by 45 degrees, precisely as though they believed it was three hours later. The complex circuitry that allows the bee to use the sun as a guide is built in, but it is not that genes trump the environment (or the other way around). Instead, genes enable creatures to make sensible use of their particular environment. Learning is not the antithesis of innateness but one of its most important products.”
― Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates The Complexities of Human Thought