An excellent and compelling reinterpretation that brings together several disciplines to argue that a key to human evolution was the taming of fire anAn excellent and compelling reinterpretation that brings together several disciplines to argue that a key to human evolution was the taming of fire and its use for cooking--which allowed us to get nutrition more efficiently, develop larger brains, lose the ability to climb trees, and develop a division of labor between men and women--with marriage based more on this economic division of labor than sexual relations and paternity. Note that this is cooking--not just "man as hunter" because cooking can make many foods more digestible (e.g., grains) and conversely meat with cooking is not nearly as efficiently nutritious.
At points the book is a bit too repetitive or takes longer than needed to make certain points (although it is still a relatively svelte 200 pages). And it is necessarily speculative, especially about the very early history of development of cooking, just how pivotal it was in human evolution, and also the ways in which it shaped gender. It would be nice if a wider array of evidence all lined up to support the speculation.
What follows is a brief summary of the key points of the chapters:
Quest for Raw Foodists: A completely convincing account of how it is basically impossible for humans to survive on raw food. Even sophisticated, modern high quality food with blenders and even low temperature cooking leads to tremendous weight loss and often loss of the ability to reproduce. And no known human society has ever just eaten raw food.
The Cook's Body: We have much smaller mouths and teeth than other primates and our digestive system (particularly the colon) is much smaller than you would predict from our size. We're also much more susceptible to food bacteria.
The Energy Theory of Cooking: Goes through the biological ways in which cooking "pre-digests" food, breaking it down into more digestible morsels. And how we have evolved to like the taste of that cooking.
When Cooking Began: This felt more speculative to me given the lack (or weakness) of archeological evidence and some of the limitations of what you can learn from the fossil record of humans. But Wrangham argues that fire was domesticated around the same time the Homo Erectus emerged and was a key to that emergence.
Brain Foods: A super interesting chapter whose main point is that there is an inverse correlation among primates between how much energy they use in digesting food and how much energy their brains use. This leads to the convincing speculation that we reduced the energy used in the digestive process (see the smaller colon, among other evolutionary developments) and our brains grew in proportion. And the brain growth was, of course, key to humans as social learners.
How Cookings Frees Men: Cooking frees up men to hunt or possibly even engage in leisure by being more calorie-intensive and also by enabling cooking/eating after dark because of the light provided by fires so can get more done during the day.
The Married Cook: Wrangham argues that in every known society women do the cooking, even as other aspects of gender roles have varied widely. He also points out that in all of them women specialize in collecting different foods than men do. And that husbands and wives share food. All of this is unique to humans--other animals do not specialize in types of food collection by gender and don't share food between adults, in fact generally eating it where they find it rather than brining it "home".
The Cook's Journey: Speculative on how fire developed and spread.
Epilogue: The Well-informed Cook: A fascinating account of how the modern version of calories were developed in the early 19th century by assigning an amount of energy per gram to the three major macronutrients (protein, carbohydrates and fat) and how this technique has been refined but in ways that change the numbers trivially since then. But that the amount of energy in food is very different than the amount of net energy your body gets from food because of the energy used in digesting it and because not all gets through. Wrangham advocates, or wishes, for a measure that would capture this but acknowledges the difficulties, including that it depends on how the food itself is prepared. But it left me wishing there was a simple summary statistic, like calories but more meaningful, we could label everything with....more
“T: The Story of Testosterone, the Hormone that Divides and Dominates Us” is a superb piece of science writing about the role that testosterone, or T,“T: The Story of Testosterone, the Hormone that Divides and Dominates Us” is a superb piece of science writing about the role that testosterone, or T, plays in the development of sex differences and their expression throughout life. Carole Hooven consistently acknowledges and highlights the importance of culture and conscious choices as shaping the way in which T is expressed but is scathing about those who deny a role for T at all. In telling this story Hooven draws mostly on endocrinology (a subject I have never really read about before) but also some more familiar ground in human evolutionary biology and other disciplines as well. She also includes some fascinating history of science from the 19th century discovery that T operated through the vascular system by transplanting testes into the wrong place in young male chickens through many more recent large-scale experiments.
Just reading about how animals have two systems that interact internally to shape development, behavior, and more—the neural system which sends targeted electrical signals and the hormonal system which sends broad communications that can only be received and interpreted by some cells—was very basic biology but still fascinating to me because it was explored with such detail and nuance in this one specific case.
Human males have three major surges of T: one around 20 weeks gestational, one a few months after birth, and one starting around age 12 and lasting for the rest of life. Hooven explains in detail how these surges play a role in the differentiation of primary sex characteristics (the first one) and secondary sex characteristics (the third one, which brings about puberty). She also acknowledges that scientists do not understand that second surge in babies, one of a handful of places throughout the book where she acknowledges and highlights what scientists do not (yet?) understand—which is also part of the never-ending excitement of science because it is a process of discovery not a full truth.
Hooven then has chapters that focus on issues like the role of sexual selection, different performance in sports, vastly different levels of violence, also differences in willingness to risk one’s life for a stranger (a trait heavily skewed towards males), and more. She also discusses the role of T in people transitioning, a very well done chapter that largely tells a set of stories through extended quotes from interviews with a number of people that have transitioned.
Hooven draws on animal studies to illustrate the continuity with humans but also the variety of evolutionary strategies. For example, part of a chapter is devoted to the extraordinary set of studies of red deer in the Isle of Rum off Scotland and the way in which some males maintain harems, fighting off the solitary males who are mateless. She then explains that red deer differ from human babies in that they can fend for themselves almost from birth and so require almost no parental input while paternal input—not just fathering lots of children—is a key input to evolutionary success in humans.
I had mixed feelings about how much of the T was devoted to arguing against a recent set of popular and in some cases scientific writings denying that T matters in humans, instead arguing that humans are a blank slate and that gender differences are entirely socially constructed. I sympathized with how frustrating the reach of these writings given the mountain of evidence against them: animal studies, human studies, examples of humans who had their T cut off (eunuchs and castrati), humans with different types of genes (e.g., XY’s that cannot process T), humans who have transitioned, and other evidence. You can sense Hooven’s frustration about some of the pseudo-science that gets amplified in the press, even on basic factual questions like one person arguing that T levels are not hugely different in men and women when in fact even the highest T women are below the lowest T men. But I did not always like it as a foil.
Hooven, however, is interesting in speculating about why there is this tendency to deny nature--arguing that for some it has become a proxy in the fight for feminism and equality. She is scathing about this view, arguing (correctly in my view—although she does not actually develop and prove the case) that if we downplay or ignore biology we will miss opportunities to improve women’s safety and equality. She also argues that the difference-deniers are making the mistake of implicitly accepting that what is “natural” is good and that instead it is better to argue that people and cultures can change and reshape the way people behave—while acknowledging there are natural differences and these differences themselves are often grounded in one particular chemical and the role it plays throughout our lives, T.
Overall, I learned a lot from this book and found the writing very engaging—highly recommended....more
The book is basically in three parts with somewhat different writing styles and levels of difficulty. The first is about the biology of CRISPR, a bit of the history that led to it, the sequence of discoveries, how it works, and how it was initially applied. This section is not always easy, it is dense with a decent amount of jargon. All of it is reasonably well explained and can be followed but it isn't always fun. It does, however, convey the excitement of discovery, the collaborative process and some of the competition too. But it is not quite science written on the level of Brian Greene or memoir on the level of James Watson. (Of course, Doudna didn't win her Nobel Prize for this book but for her pathbreaking discoveries.)
The next part of the book is about the applications of CRISPR for agriculture, health, and other areas. The reading got a lot easier and my only complaint--which is hardly the author's fault--is that it was published in 2017 so left me wanting to know more about even more recent years given how rapidly the technology is evolving.
The final part of the book was in many ways the most interesting where Doudna grapples with the ethics of CRISPR. She starts spending considerable time outside the lab talking to ethicists, stakeholders (like people with diseases) and others. What is interesting is that this process of engagement both reduces her confidence (in a good way) and changes her mind. She really listened, took in all sides, and sympathizes with them. She starts out with a harder line against using CRISPR for germ-line modification but ends up more sympathetic to finding ways to eventually do it safely given the tremendous toll of genetic diseases and various safeguards that may be possible.
Ultimately Doudna is a changed person--from helping make a breathtaking scientific breakthrough to then thinking hard and deep about its implications and the importance of scientists not just speaking to each other but also speaking to the public--and (in what is less common) listening to them to....more
This was a nice, breezy tour of everything from the formation of the earth, its early geologic history, to the emergence of life, the transformation oThis was a nice, breezy tour of everything from the formation of the earth, its early geologic history, to the emergence of life, the transformation of the atmosphere, mass extinctions, animals, and humans. It begins and ends with a plea on climate change and the environment. All of it felt up-to-date and reliable, nice pictures and tables, but more of a review than any sort of original argument or synthesis. Not a criticism, just makes it more workmanlike useful to read than especially memorable....more
A short book by a Nobel Prize winning biologist that examines five facets of life: cells, genes, evolution, chemistry and information. The chapters arA short book by a Nobel Prize winning biologist that examines five facets of life: cells, genes, evolution, chemistry and information. The chapters are a combination of going through fairly standard accounts (Mendel's discovery of genes, the double helix, a few pages on how epigenetics mostly does not change anything, Darwin, etc.) but gets a little more speculative and conceptual when it comes to chemistry and especially life as information. That last, of course, was the centerpiece of a book also called What Is Life? with Mind and Matter and Autobiographical Sketches by Erwin Schrödinger (I've also read a third book with the same title, What Is Life?: Investigating the Nature of Life in the Age of Synthetic Biology that was quite interesting albeit journalistic).
There are a lot more pop science books by Nobel Prize winning physicists than biologists. This book was perfectly good entry to the genre but most of it was not profoundly original. In some ways the parts that were the most interesting were describing his own research on yeast, how he pieced together various discoveries and the excitement and serendipity. I wish there had been more of that....more
I read a bit more than half of this book several years ago but set it aside. I originally read the parts about Henrietta Lacks, her disease, death, anI read a bit more than half of this book several years ago but set it aside. I originally read the parts about Henrietta Lacks, her disease, death, and the immortality of her cells. But I got a bit bogged down in the period after and her family's growing understanding of what had happened and participation in the story. I restarted it (on Audible) and ended up loving the second half, which could have been termed "The Mortal Life of Deborah Lacks" since it is about the author's teaming up with Henrietta's daughter Deborah to learn Henrietta's story and ultimately, through the author, tell it to the world. The portrayal of Deborah and other families members at times seems to have genuine depth and sympathy but at other times seems a little cartoonish and exploitative. Rebecca Skloot never engages with that tension, but she does engage very subtly with other tensions: research done without consent, whether tissues count as a person and should be subject to consent, the ways that Henrietta Lacks was abused by the system but also the tremendous gains in lives saved as a result of the research. At the end of the day, Skloot is also very sympathetic towards the scientists and does not minimize the scientific accomplishments.
An important book to have been written, a nice combination of science (although less than I personally would have wanted), family chronicle, discussion of medical ethics, and more. With some amazing characters and dramas--even more so for being real--to drive it all along....more
"The anthropologist Sarah Hrdy noted that to pack hundreds of chimpanzees into close quarters on an airplane would be to invite violent chaos, whereas"The anthropologist Sarah Hrdy noted that to pack hundreds of chimpanzees into close quarters on an airplane would be to invite violent chaos, whereas most human passengers behave sedately even when they are crowded. As Dale Peterson observed, however, intense screening is needed to ensure that a secret enemy will not carry a bomb on board."
This captures the phenomenon (or "paradox") the book is trying to explain: humans have very low reactive aggression, that is uncontrollably attacking someone in the anger of the moment. We can walk down the street, see strangers, they can even bump into us, and we'll virtually never hit them and usually won't even send a dirty look their way. Virtually no other wild animal is like that. But humans also have extraordinary levels of proactive aggression, we can plot wars, genocides, and much more that kill millions of humans in the process--something that no other animal could come remotely close to doing.
Richard Wrangham advances a bold thesis for how this came about: evolutionary changes driven by hundreds of thousands of years of capital punishment that effectively "self domesticated" humans, much like the process that turned reactively aggressive wolves into tame dogs and many other examples of domestication. Basically, language (a bit of a deus ex machina in this account, and given that it doesn't fossilize it may always be in every account) enabled humans to coordinate to kill overly aggressive people using gossip, plotting, and the like. Over hundreds of thousands of years--or about 12,000 generations--this led to genetic changes that separated from earlier humans not to mention chimpanzees.
The evidence Wrangham puts forward for this hypothesis is draws on evolutionary biology, animal behavior, genetics, neuroscience, anthropology and more. A lot of it draws on studies of the way the domestication changes animals, many of them in the direction of paedomorphic changes in which animals retain more juvenile features as adults, including reduced differences between males and females, certain aspects like bone density, and interesting things that have simultaneously evolved multiple times like floppy ears and white tufts. Wrangham looks at the fossil record and modern humans and sees many of these features diverging from our ancestors--and also differing from very recent relatives like neanderthals.
Wrangham contrasts his hypothesis to other explanations. One explanation he debunks (following a long-standing tradition of arguing against it) is group selection, because this generally cannot explain why individuals will not benefit from defecting--something that fear of execution can explain. He also criticizes cultural explanations for human aggressive behavior because of the strong evidence about how deeply rooted it is, observable in babies, in children even when given contrary instructions, etc.
He also applies this idea to a variety of areas. For example, he explains several moral puzzles about people's behavior (e.g., trolley-problem like issues around people not wanting to touch or directly engage in certain behavior that they would do indirectly) as humans evolving to be risk averse, trying to avoid being (unfairly) blamed when they were trying to help. He also analyzes war which is an example of "coalitionary proactive aggression," contrasting the primitive version which relied on voluntary consensus without leaders leading to raids with a very high probability of success with the modern version which entails leaders getting their followers to do things that are highly non-adaptive from an evolutionary perspective--requiring intense drilling, rules, and created camaraderie to make it work.
The above does not do justice to what is a very rich, dense, but highly readable book that draws on a lot of cutting-edge, peer-reviewed research. Although I am not 100 percent convinced of the execution hypothesis there is a rich set of evidence for it, not just an ex post just so story. Also, even if you do not agree with the hypothesis there is a lot to get out of the book, including a better understanding of aggression, some history of science (and particularly, some appalling politicalization that led scientists to resist admitting things like chimpanzee infanticide or hunter-gatherer warfare because they were afraid it would legitimize it in humans), and much much more.
Ultimately Wrangham is at pains to distance himself from the naturalistic fallacy that just because something is natural or evolved it is legitimate. He points out the ways that culture has changed over time to reduce violence--and that even nature itself builds in responses to incentives (e.g., the frequency of chimpanzee infanticide depends on factors that change the evolutionary rewards for engaging in it). Ultimately he agreed with Katherine Hepburn's character from The African Queen that "Nature... is what we are put in this world to rise above."
Very, very highly recommended.
P.S. Another image, like the opening quote, I cannot get out of my head is how humans have never really been led by alpha males, whether in hunter gathers or sophisticated societies. Our leaders are not obeyed because they could win a wrestling match with any other challenger but because they can organize a coalition to engage in violence to enforce the law. This means that humans have obedience in way that no wild animal does....more
One of the most amazing books I've read in recent years, The Secret of Our Success has a single thesis that sounds obvious but then it shows you how dOne of the most amazing books I've read in recent years, The Secret of Our Success has a single thesis that sounds obvious but then it shows you how different it is from what you might have thought before, how much it explains, and how we have learned all of this with a combination of genetics, social psychology, anthropological observation of different groups, studying primates, game theory, experimental economics, and many other disciplines all of which come together to form a richer, more complex understanding of what makes humans so unique.
Joseph Henrich's thesis is that humans are set apart because culture and genes have co-evolved. We’re not smarter, more social or more strategic than other animals but we’re much better at learning from each other. This cultural evolution is non-genetic and can make rapid progress, including adapting to different and changing environments. But it is not unrelated to genes, in fact genetic changes have made us better cultural learners--and made us worse at everything when we do not have that a cultural learning at our disposal. In a sense, humans domesticated themselves--just like they domesticated wolves into more docile and weaker dogs.
Henrich goes through reasons why some other explanations are wrong:
(1) Humans are not smarter than other animals. Infants score about the same as chimps on various cognitive tests, we're worse at getting to the Nash equilibrium of games like matching pennies than many chimps, we can be worse at numerical recall than chimps, etc. Where we excel is in our ability to learn from each other.
(2) Humans are not more successful because of our better evolved instincts. Take European explorers and drop them in the middle of an unfamiliar area like Australia, the Canadian north or even Florida and they will have no idea how to hunt for food, fashion weapons, make boats, make warm clothing, identify or prepare foods, etc. We don't have instincts, we have locally adapted cultural knowledge to survive in these contexts.
(3) Humans are not inherently more prosocial than other animals, it is learned not innate. For example, a variety of experimental games (like the "ultimatum" game) show more collaborative attitudes in larger scale societies than in smaller ones.
Instead his explanation is that culture is like a "collective brain" that enables ideas that are discovered by one person to be spread to others. He shows through a model that it less important to have geniuses than to have learners and collaborators. And that learning depends not just on population size but its interconnectedness. That is why larger populations come up with more complex inventions (e.g., the wheel was only invented in Eurasia) and more complex languages with more sounds and more words.
This ability to learn does depend on our brains but has also co-evolved with our brains. For example, we have smaller teeth and a weaker digestive system which forces us to pre-digest our food with tools, fire and many other treatments. We are capable long distance runners, which requires a system to sweat, which only works because we can carry water with us and rehydrate. Etc.
Cultural transmission has also made us respect and learn from people in our groups, those with greater age and more prestige.
Henrich has personally made important contributions to understanding in a number of these areas, but not everything in the book is completely original. And that is a strength of the book--it is conveying a cutting edge field but does not appear (to my admittedly layman views) to be idiosyncratic or pushing a thesis too far. Instead it is partly summarizing the state of the art.
In some cases the book is more speculative or has to extrapolate from lab experiments to complex dynamics that play out over hundreds of thousands or even millions of years. Henrich is generally honest about the limitations on our understanding and how they will be filled in over time. But does not let that detract from the bigger thesis.
Occasionally Henrich's arguments suffer a bit from the "just so" stories that rationalize any human behavior as an evolutionary adaptation. But his novel and creative use of just how hard it is to adapt to different environments (e.g., an extended discussion of what it takes to hunt/cook a seal in the arctic or prepare manioc in Africa without getting cyanide poisoning) make it clear that many of these adaptations really are that--adapative.
Henrich also takes a relatively conservative stance that places a lot of emphasis on hierarchy, prestige, age, and not thinking too much for oneself and instead accepting the culture we get because that culture is adaptive and adaptive in ways we don't fully comprehend so tampering with it can have serious downsides. In fact in the conclusion he is quite explicit about this: "Humans are bad at intentionally designing effective institutions and organizations, though I’m hoping that as we get deeper insights into human nature and cultural evolution this can improve. Until then, we should take a page from cultural evolution’s playbook and design 'variation and selection systems' that will allow alternative institutions or organizational forms to compete.”
There is nothing inherently wrong with being conservative in this sense, but it does have two risks: not explaining how we have innovated in part by challenging authority and asking questions (the enlightenment had that attitude and very rapid change) and a normative risk of lending too much credibility to existing institutions and practices.
These are small quibbles when set aside against contemplating one of the most impressive accomplishments of human cultural evolution, understanding ourselves would be high up on the list. And this book represents the accumulated ways we have better understood ourselves, many of which we have only learned in the last few decades. Imagine how much more we will learn in the coming years, decades, centuries and more....more
As someone that knew relatively about the topic, this was a good introduction to epigenetics. It is, however, very dense, does not provide much contexAs someone that knew relatively about the topic, this was a good introduction to epigenetics. It is, however, very dense, does not provide much context, and while about 20% of the pictures are useful the other 80% are mostly silly distractions. That said, it starts from all of the basic definitions, is comprehensive in covering the biology, evolutionary aspects, diseases, etc. And seems very balances in eschewing the hype that often surrounds this topic. But it did not seem like an easy introduction so I'm not sure exactly who it was for. But am glad I read it....more
A short graphic, group biography of Jane Goodall, Dian Fossey, and Biruté Galdikas by the author of the excellent Feynman. Conveys the sense of exciteA short graphic, group biography of Jane Goodall, Dian Fossey, and Biruté Galdikas by the author of the excellent Feynman. Conveys the sense of excitement and the commonalities and differences in the experience of these three women who were all sent by Richard Leakey to study different primates in order to both advance inherent knowledge but also learn more about humanity. Like Feynman, Primates also does not appear to whitewash his human subjects in an effort to pander to children, instead portraying (some) of what seems to be the philandering of Leakey, the complicated marriage of Galidikas, the tragedy of Fossey, and the like.
The Teenage Brain provides an up-to-date(ish, was published in 2015) study of the science of the teenage brain and its implications for a host of pracThe Teenage Brain provides an up-to-date(ish, was published in 2015) study of the science of the teenage brain and its implications for a host of practical issues like learning drinking, drugs, screens and sports. It was written by Frances Jensen, a neurologist, and it describes what it says are the major advances in the understanding of the teenage brain the last decade that resulted from a turning attention to it and new tools, like functional MRIs. Overall the argument is that there is something special and different about teenage brains, that much of their behavior is rooted in this, giving them a tremendous capacity to learn but also tremendously bad judgment and difficult problems to navigate. Much of the science feels relatively cutting edge, but most of it does little to change what are the many commonsense recommendations on many of the issues. Sometimes the link between the science and the specific issues even gets a bit more tenuous than it should be. And at times the book suffers from the awkward marriage of science and self help, with too much science for one type of reader and too much self help for another type.
The teenage brain has a lot of grey matter (neurons) but not as much white matter (the connectivity for these neurons). The neurons need to be cleared out a little to make paths and the connectivity proceeds from back of the brain to the front, with the frontal lobe that is responsible for judgement the last to get “myelinated” and thus able to function as quickly and effectively as it does in adult brains. The brain itself reaches physical maturity long after the body does, fooling us into thinking that older teens are adults when really they have substantial mental differences. The 20% of the brain that is underdeveloped is responsible for executive functioning, “prospective memory” of what you intend to do, judgment and the like. Often teenagers compensate by doing these tasks with other parts of the brain, but the result is they are less effective. At the same time, the abundance of grey matter makes the brain even more plastic, capable of rewiring itself through more learning.
This scientific overview is followed by specific chapters on specific topics. The sleep chapter explains that teenagers release of melatonin results in them going to sleep later than adults and they still have a substantial amount when they wake, making them groggy. As Matthew Walker argued in Why We Sleep: Unlocking the Power of Sleep and Dreams, the result of less than the recommended 9-1/2 hours of a sleep a night is less mental ability, more diseases, emotional problems, and more. A series of chapters focus on various types of addiction, arguing that the flip side of the superior capacity of the brain to learn is the greater capacity to become addicted, because both rely on plasticity. Much of the rest of these chapters is relatively commonsense.
Perhaps the most interesting chapter is on gender, documenting the substantial physical differences in male and female brains (e.g., men have less connections between hemispheres), the differences in the pace of development and the differences in how and which parts of the brain work on what problems by gender. Nevertheless, Jensen asserts that the functional differences are much smaller or even non-existent, just different physical ways to get to the same place. More explorations of this question would have been interesting.
I look forward to further rapid developments in neuroscience general, and for teenagers in particular. I am also interested in seeing whether any further developments challenge any more of our ideas rather than mostly just affirm them....more
This was exactly the book I was looking for: a rigorous guide to the cutting edge of the emerging genetic-based social science that explains the methoThis was exactly the book I was looking for: a rigorous guide to the cutting edge of the emerging genetic-based social science that explains the methodologies scientists are using and also their limitations. The book is both hopeful about the future of research but also appropriately critical of the limitations of the study so far. Could not recommend it more highly—and I would not skip any of the footnotes or appendices which contain a lot of important insights, elaborations, and background. Reading the book left me excited for the future of the field but also frustrated about our ability to overcome the many inevitable limitations that they are so careful in expositing.
Dalton Conley and Jason Fletcher are both sociologists (and Dalton is also got a Ph.D. in genetics). The main point of their book is that genetic analysis is giving social scientists a powerful new tool to better understand the causes of differential educational attainment, incomes, poverty and other social phenomenon. But that we are still having a hard time linking particular genes to social outcomes let alone understanding the biological pathways and there is a huge amount of complex intersection between different genes and genes and the environment. Much of the book is about the social outcome of educational attainment, both because it is important but also because it is easier to study because is often included in the genetic data.
Conley and Fletcher start out by going through the research that establishes the high degree of heredity in many traits, including physical ones like height (80%) but also social ones like educational attainment (40%). They explain the models used to assess heredity, like comparing identical twins and fraternal twins or other well measured genetic distances. They explain in detail the methodology of the ACE model, the assumptions underlying it, why they thought it might be wrong, and how they ended up confirming it in their own research.
They then go on from the overall measures of the hereditary component of different traits to linking these to actual genes. Their take on the attempts to link behavior to single genes is that it was also spurious data mining, caused by the fact that while medical outcomes are well defined social outcomes have numerous measures and you can always find one correlated with the genes. The single gene efforts have given way to genome wide association studies (GWAS) that look at millions of genes and correlate them with outcomes at very high levels of significance to avoid data mining. Taken together, GWAS can produce a “polygenic score” that predicts a particular outcome, like educational attainment. GWAS, however, has three shortcomings: (1) you need to be careful to avoid the “chopsticks problem” (i.e., mistakenly inferring there is a gene for chopsticks when really is just a correlation with East Asian genes); (2) it gives up most any hope of a biological pathway because so many genes; and (3) it suffers from the “missing heredibility” problem of not explaining as much hereditability as know is there from twin studies. This last problem, they suggest, is caused by not analyzing the full genome for cost reasons.
They then go through a series of topics. One is genetic sorting where they examine the arguments in The Bell Curve about the increasing salience of genes and increased marriage based on them and thus locked in genetic stratification. Contrary to this the evidence they produce shows: (1) some traits are more genetically determined now than in the past (like height or weight, because most people have access to enough food so environment matters less) but others are less genetically determined now than in the past (like education, because of compulsory schooling laws); (2) people do mate based on phenotypes but much less on genotypes; and (3) no strong correlation between polygenic score for education and number of children.
They then have a chapter on race where they make the (familiar) point that there is much more genetic distance between most any two African tribes than between Europeans and Asians—which undermines many genetic concepts of race. This is because of the bottleneck of only ~1,000 people leaving Africa for Europe and Asia. They rebut the standard Stephen Jay Gould arguments against important racial differences (e.g., small genetic differences can matter a lot and evolution can happen quickly), but they establish that much of genetic variation is due to random drift not natural selection and that there is no links, and not really much research that could find a link, between race-based genetics and important social outcomes.
The chapter on the genetics of economic growth and war is a good literature review on the non-genetic studies in these areas but thin on the actual genetic studies, really just one for each topic. And finally the book concludes with a discussion of future “designer babies” either through embryo selection or gene editing, raising many concerns including that often “bad” traits are associated with “good” ones and have a benefit for the ecosystem as a whole so we will be taking risks.
Overall, I really appreciated that the book was research-based, did not just list discoveries but explained their methodology, and also that it was critical and skeptical throughout—but used that as an argument for more research not less....more
This book is a testament to the marvel of human evolution. Particularly that humans could evolve to the point where they had the ability, motivation aThis book is a testament to the marvel of human evolution. Particularly that humans could evolve to the point where they had the ability, motivation and capability to undertake the research project that David Reich and his many collaborators and colleagues have done to understand tens of thousands of years of history by looking at the DNA of people today and extracting a few thousand samples of ancient DNA as well.
Who We Are and How We Got Here is by a leader in the field of ancient DNA and he describes much of his own research and excitement while amply sharing credit all around for our increased understanding of the past. Much of the book is based on cutting edge research in a field that is advancing so rapidly that some of it may be outdated already, but in addition to the specifics the book is also a good primer on the methods by which scientists can use genomic data to increasingly understand the deep past. This is not just questions like which people migrated where and mixed with whom but also questions like how large was the ancient population at different points in time and how large was the extent of inequality (hint: it fluctuated reaching a particularly unequal point with the advent of agriculture).
The first part of the book describes the science broadly and discusses the ancients mixes of humans, Neanderthals and Denisovans. The second is a tour of the world, going through Europe, the Americas, Asia, India, and elsewhere, with the broad emphasis on two broad facts: (1) the substantial mixing of populations at many stages of pre-history and (2) the substantial migrations so where a people is today is not necessarily where they were ten thousand years ago. In the course of this, Reich describes the updating of the "out of Africa" hypothesis to show the significant evolution that took place outside Africa and, in some cases, returned to it.
One of the most interesting ideas I had never heard before is the hypothesizing of distinct "ghost" populations that must have existed in the past to explain the mixtures people see today. Scientists predicted some of these and then went out and found them, a little like the discovery of Neptune which was predicted by the mathematics of gravity before it was seen (although, unlike ghost populations, the astronomers had an advantage in that mathematics also said precisely where to look for Neptune).
The final third of the book is on broader issues, including inequality and genetics and race. Someone impatient with all the details of the migratory shifts in India (and I sometimes found the book dragged slightly in that part), could skip from the first part to this to understand the increasing ways in which science is understanding how much genetics affects outcomes (e.g., the identification of genes that are associated with going to college--although not for reasons you might think, they seem to be related to delaying childbearing), how quickly evolution can still happen (e.g., these genes associated with college have evolved in just the last generation in Iceland), and how natural selection can result in differences in even complicated multi-gene systems (e.g., the evolution of genetic differences in height). I find Reich's handling of this sometimes controversial material fully persuasive that it is important to not shy away from the conversations, but also not to use them as a pseudo-scientific basis for racist discrimination.
Overall a real model of what a popular science book should be, well written with clear charts and figures that let you follow many of the major points....more
“Scientists have discovered a revolutionary new treatment that makes you live longer. It enhances your memory and makes you more creative. It makes yo“Scientists have discovered a revolutionary new treatment that makes you live longer. It enhances your memory and makes you more creative. It makes you look more attractive. It keeps you slim and lowers food cravings. It protects you from cancer and dementia. It wards off colds and the flu. It lowers your risk of heart attacks and stroke, not to mention diabetes. You’ll even feel happier, less depressed, and less anxious. Are you interested?”
Well, are you?
Matthew Walker is part scientist, part evangelist, part zealot, and part monomaniac. He is like a carpenter with his tool (sleep study) and for him everything looks like a nail (i.e., something that just needs sleep to fix it). At one point he even speculates that homo sapiens’ evolutionary takeoff was caused by our ability to get better sleep than other animals that were up in trees.
Walker is good at providing the evidence for his main conjectures. They include controlled experiments with humans in sleep labs (e.g., randomly assign people to different amounts of sleep and give them mental or physical tests the next day), controlled experiments in animals, epidemiological research, theoretical propositions and other methods.
But Walker bad at providing context, interpretation or qualification for his evidence. He just about never gives a contradictory study, never addresses the “file drawer” bias of studies finding no effects no being published, doesn’t discuss the limits of animal research for humans, and can be casual about correlation vs. causation (e.g., sick people not sleeping much, does that mean lack of sleep caused their sickness or vice versa)? In fact, just about the only time he does take reverse causation seriously is one of the only contrary pieces of evidence he even cites, which is that sleeping too much is associated with earlier death—something that he dismisses as caused by cancer patients being tired so sleeping a lot.
All of that said, the book does a marvelous job presenting the current state of sleep science, the different roles that REM and NREM play, how we have learned about these, etc. The section on PTSD is particularly interesting, basically most people suppress anxiety producing chemicals while dreaming, allowing them to process bad memories in a safe way. That doesn’t happen with people with PTSD, so they don’t overcome and process the traumas in a way that is more accommodated over time. Giving them a drug to suppress these chemicals while dreaming allows them to process their dreams better, leading to less repetitive nightmares and alleviating PTSD to some degree. This would be an example of a theory, controlled experiments, and also a biological understanding of the mechanisms linked to the psychology of dreams. As such, it seems like something remarkable for people to have figured out.
And all of that said, Walker’s main thesis—that we are sleeping too little—is persuasive. As is his condemanation of the macho culture that associates lack of sleep with success, he points out would you want a drunk CEO or surgeon making decisions? This is what you’re like when sleep deprived. (He also is a little giddy in pointing out that testoerone, sperm count and even testicule size all shrink when sleep deprived, all points he uses to rebut the macho culture around sleep deprivation.) His solutions are mostly familiar—keep that iPhone in a different room—but I wasn’t aware of some of the others, like the importance of a lower temperature when sleeping.
Walker is also persuasive on some public policy issues, like we do way little to raise awareness of drowsy driving relative to the efforts to combat drunken driving and the importance of later start times for high schoolers (he points out their circadian rhythm is pushed back, so is not that they’re lazy but that we’re trying to wake them up at what would seem like 3am for us). And completely persuasive on the insanity of the long hours we make medical residents work.
Overall, we spend nearly 33% of our life in a semi-coma like state swirling with partial paralysis, crazy dreams, and amnesia. It seems worth spending 0.001% of our life reading a book to help us better understand this weird state, why we do it, what it does, and how to make it better....more
One of the best books I read this year and not one I had been planning to read. I skimmed a few reviews, which were interesting but did not leave me tOne of the best books I read this year and not one I had been planning to read. I skimmed a few reviews, which were interesting but did not leave me thinking that I needed to read the full book. But then I started a sample on a whim and was swept away by the carefully observed descriptions of octopuses (and to a lesser degree cuttlefish) and the use of that as a springboard to discuss evolutionary biology and the philosophy of the mind.
Octopuses are a type of mollusk and, like all invertebrates, branched off from the stream of animals that led to humans enormously long ago--and well before the evolution of central nervous systems, eyes, or much else of any sophistication. But now octopuses have large collections of neurons, rivaling mammals, but they are evolved largely independently of ours. And they have important differences, for example most of their neurons are distributed in their arms rather than collected together in their brain. This leads Peter Godfrey-Smith to speculate about what this says about intelligence and whether we should think of body parts as having their own autonomous intelligences (in the form of reflexes or even higher order thought in octopuses). Some of the interesting speculations are about how humans benefited from the feedback loop between our sensing of our own actions (e.g., we can hear ourselves talk) while octopuses and cuttlefish can make impressive color displays but are themselves colorblind so they do not see their own displays nor do they use them to communicate with others.
Towards the end the book turns poignant as Godfrey-Smith relates how this highly curious and interactive animal, the closest thing to an alien we have on earth, only lives for about two years--much less than anything else its size and intellectual sophistication. This leads into both the evolutionary biology of aging and its link to reproduction and ultimately an homage to the ocean and conservation that is less original than much of the book but powerful for how much he learned about the human mind from swimming on the bottom of the ocean....more
A wide-ranging journalistic exploration of extinction, Elizabeth Kolbert takes you from her entree into the topic (an article about frogs dying out inA wide-ranging journalistic exploration of extinction, Elizabeth Kolbert takes you from her entree into the topic (an article about frogs dying out in Central America), to the "discovery" of extinction (through the realization that mastodon fossils were of an animal that no longer existed), through a wide range of continents and species to explore the impact of climate change induced ocean acidification on coral reefs to the impact of poaching on rhinos to the story of invasive species as told through the spread of a fungus that is killing off bats to prehistoric topics like the extinction of the dinosaurs and very large mammals and the extinction of Neanderthals. All of this is told through the ideas of the scientists she talks to, the places she visits, but in the course of it the book manages to cover a wide range of science, scientific history, and deploy it to tell what is actually a rather bleak and depressing story about the "sixth extinction" which is currently underway and eliminating a substantial chunk of the world's biodiversity. She briefly references some of the many organizations trying to push the other way, but mostly to dismiss them and instead try to understand why it is happening and what the consequences will be.
Overall it is well written, a broad-ranging tour, and my only complaint is with the journalistic genre that it exemplifies and the need to present so much of the first person reporting as opposed to just provide the facts/theories/analysis in a straighter fashion. But this was not a huge drawback and it was reasonably well done....more
My guess is I'm not the first person to use the term "magisterial" to describe this so-called "biography" of cancer. In fact I would be surprised if mMy guess is I'm not the first person to use the term "magisterial" to describe this so-called "biography" of cancer. In fact I would be surprised if many people had not used the term in their description. It begins with Imhotep's description/diagnosis of cancer and the stark statement that there is nothing that can be done about it. And then it moves forward charting our understanding of the disease, the evolution of the main types of treatment, how we think about the disease, all interspersed with a few stories of his own patients that illustrate many of the larger themes in the book.
I initially thought it was poorly organized and like any historical survey took too long to get to the modern understanding and in particular the molecular biological understanding of cancer. But it eventually got there, in a quite fullsome way, and looking back it was a coherent read and actually an exciting page turner. I just wish we knew how it ends--but that chapter has not been written yet....more
The Signal and the Noise was a really great read. It's one of those books that lets you annoy your friends by tediously repeating facts, many of whichThe Signal and the Noise was a really great read. It's one of those books that lets you annoy your friends by tediously repeating facts, many of which they already have picked up from reading the book, reading reviews, or other tedious friends. Like when the Weather Channel says it is a 30% chance of rain it rains 30% of the time, but that when it says a 10% chance of rain it really means a 3% chance of rain (they would rather people be pleasantly surprised). Or that earthquakes are unpredictable. Or that minor league baseballs players are difficult to predict and give a good advantage to very good scouts, while in the majors it is different. Or that a particularly great professional sports better will win 56 percent of the time. Or other examples drawn from the areas Nate focuses on: political predictions, elections, the macroeconomy, financial markets, epidemics, earthquakes, terrorism, baseball, chess, and poker.
There is a deeper and more important set of lessons in the book to anyone that has not been sufficiently exposed to Bayesian methods. None of that was new to me, but it is still interesting to read and should be mandatory reading for anyone who has not been exposed to it before.
I take some issue with the presentation of economics. Nate is completely right that macroeconomic forecasting has a terrible track record, and does not even appreciate how terrible its own record is. But he doesn't seem to recognize that there is a lot more to economics than macroeconomic forecasts. And, at least as much of the fault with those forecasts lies with the people demanding and using them as with the people providing them.
And I'm not quite as impressed with Nate's election forecasting--anyone relying just on public polls taken in the days before the election would have correctly picked 49 or 50 of the 50 states in both 2008 and 2012. Nate did not have any magic, but he did have much better perspective on the uncertainty in the forecasts and how to read/interpret the significance of movements well in advance of election day.
But those are quibbles, this book really deserves wide readership, probably starting with all of those who rushed out to buy it after the election and still have it sitting on their shelves....more
I cannot believe that I had not read this before. I had been carrying around my father's copy for twenty-five years but only just read it. It is a fasI cannot believe that I had not read this before. I had been carrying around my father's copy for twenty-five years but only just read it. It is a fascinating, exciting and sometimes even funny account of the race to unravel the structure of DNA. It is unflinchingly honest in describing not only the thrill of scientific discovery but also the more ordinary impulses including scientific rivlaries and everything from the desire to win the Nobel Prize to the desire to win over girls. It is also a great account of collaboration, not only with Francis Crick but also with Maurice Wilkins, Rosalind Franklin, and Linus Pauling -- in the case of the later three the collaboration was mixed with a fervent desire that they not beat Watson and Crick to the discovery of the strucure of DNA. Finally, it is also an excellent detective story as Watson and Crick follow fragmenatory and contradictory evidence along several false leads but eventually stumble on the extremely elegant answer.
The Double Helix is at the opposite extreme of Einstein's book Relativity which presents the pure science, derived from first principles, and explained to the lay reader. Instead in The Double Helix, the extensive descriptions of the science are all subsurvient to moving the story of the discovery forward. None of these scientific discsussions are derived from first principles or includes any explanation for the reader (and I, for one, started the book with no knowledge of x-ray crystallography or stereoscopic chemistry and only pieced together a dim understanding of them over the course of the book). And there is virtually no discussion of the implications of the discovery, what followed, or really much in the way of context. But it is hard to hold any of that against The Double Helix, especially when many, many other books have handled all of those topics, while this book uniquely and superlatively describes the process of discovery itself....more
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