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Innate: How the Wiring of Our Brains Shapes Who We Are
A leading neuroscientist explains why your personal traits are more innate than you think What makes you the way you are--and what makes each of us different from everyone else? In Innate, leading neuroscientist and popular science blogger Kevin Mitchell traces human diversity and individual differences to their deepest level: in the wiring of our brains. Deftly guiding us through important new research, including his own groundbreaking work, he explains how variations in the way our brains develop before birth strongly influence our psychology and behavior throughout our lives, shaping our personality, intelligence, sexuality, and even the way we perceive the world. We all share a genetic program for making a human brain, and the program for making a brain like yours is specifically encoded in your DNA. But, as Mitchell explains, the way that program plays out is affected by random processes of development that manifest uniquely in each person, even identical twins. The key insight of Innate is that the combination of these developmental and genetic variations creates innate differences in how our brains are wired--differences that impact all aspects of our psychology--and this insight promises to transform the way we see the interplay of nature and nurture.
304 pages, Hardcover
Published October 16, 2018
About the author
Kevin J. Mitchell
6 books49 followersKevin J. Mitchell is associate professor at the Smurfit Institute of Genetics and the Institute of Neuroscience at Trinity College Dublin. He is a graduate of the Genetics Department, Trinity College Dublin and received his Ph.D. from the University of California at Berkeley.
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Displaying 1 - 30 of 74 reviews
January 30, 2020
I always really enjoy these science books but then at the same time I feel like the material is too introductory for me and so like it's useful to read to reinforce my knowledge but what I really want to know more about is the research and the papers. At the same time though am I really going to go try to pirate these scientific papers one by one on my own time when I would just prefer the convenience of a book. Someone publish like a meta-analysis for everything neuroscience but in book format which also breaks down methodology and the statistical analysis. That's truly all I want from the world. But outside of that this was enjoyable and I felt like it really cemented a lot things I had thought about neurophysiology already. I think its also left me quite unsure about the ethics of all that information and what it means for how we relate to one another/how much responsibility we should put on others and all the other myriad of issues brought up. I mean Mitchell doesn't claim to have answers to those questions either so. I will definitely be going through his blog next though. Really curious about the details of how one determines how connections between the brain are made etc. Some of it was covered but yeah I'd always love to know more.
June 6, 2021
After reading Kevin Mitchell’s Innate, the first reflection that comes to mind is....
Damn!
This mother f***er can write!!!
In point of fact.
He’s on FIRE 🔥
Despite the fact that he threw the entire contents of the proverbial ‘kitchen sink’ into this book.
It’s lucid and accessible.
The pace is LITERALLY nonstop.
Mitchell bombs you with well constructed argument after well constructed argument.
But somehow, you’re not shell shocked by the end.
BRILLIANT.
If you’re an educated reader, you may not walk away from Innate with a lot of “new” information.
But you’re all but guaranteed to have either a new more realistic outlook on human development, or at least have some of your old ideas challenged.
#FirmwareUpgrade
The basic premise of Innate is simple.
DNA encodes a genetic program for making human brains, and brains make us who we are (to an overwhelmingly large extent).
But the way that the genetic program ultimately plays out is far from deterministic in any simple sense.
It’s affected by obvious stuff like the environment, social milieu, and culture.
Yeah sure.
But a system as complex as a brain is also significantly effected by random processes, such that if you were to clone yourself 100 times, there will all but certainly be greatly different outcomes in important psychological traits, even if you controlled for all that other stuff (like environment, social milieu, and culture etc).
In other words, two identical twins 👯♂️ raised in the same or even completely different environments, will likely emerge with durable similarities (because DNA).
We all know this.
But... these same twins, also may emerge from identical environments with significant differences, purely by dint of stochastic (random) processes, occurring entirely in the frothy complexity of each individual brain 🧠.
And these differences may be quite significant.
One (genetically) identical twin may be gay, the other straight.
One identical twin may be schizophrenic, the other not.
All because of what essentially boils down to a roll of the dice.
Or rather, the roll of billions of tiny molecular dice, that are more like crazy complex little dungeons and dragons dice.
In other words, DNA makes people more or less likely to display certain traits (sometimes way way more or less likely), but dumb luck (probability) still plays a big role, even at the deepest level of our biology.
Other stuff that we commonly think of as having a durable effect, like parenting etc.
Well....
Not as big of a deal as you probably think.
It has a ginormous impact.
Yes.
But les durable than so called ‘innate’ shit.
This pokes a hole in a lot of the etiological claims of psychotherapy, and a lot of ‘change’ claims touted by the self help industry.
Yes you can change your life in important ways.
But if you quit doing the stuff that made the changes happen, like exercise, diet and meditation etc., you revert to a largely genetically determined baseline quickly.
So, yes you can change your ‘self’ but the change is constrained (i.e. WAY limited) and is dependent on effortful long term behavioral and environmental change.
In the end, Mitchell promotes a kind of radical self acceptance over endless self improvement strategies.
You can overcome stuff like anxiety, depression and addiction, absolutely.
And it’s worth it.
But some stuff, well...
Ya just can’t.
Cuz it’s innate.
So maybe it’s better to simply:
Accept the shit you can’t change. Change the shit you should (provided it’s worth the serious time and effort). And get your shit straight about which is which.
I LOVED this book.
Damn!
This mother f***er can write!!!
In point of fact.
He’s on FIRE 🔥
Despite the fact that he threw the entire contents of the proverbial ‘kitchen sink’ into this book.
It’s lucid and accessible.
The pace is LITERALLY nonstop.
Mitchell bombs you with well constructed argument after well constructed argument.
But somehow, you’re not shell shocked by the end.
BRILLIANT.
If you’re an educated reader, you may not walk away from Innate with a lot of “new” information.
But you’re all but guaranteed to have either a new more realistic outlook on human development, or at least have some of your old ideas challenged.
#FirmwareUpgrade
The basic premise of Innate is simple.
DNA encodes a genetic program for making human brains, and brains make us who we are (to an overwhelmingly large extent).
But the way that the genetic program ultimately plays out is far from deterministic in any simple sense.
It’s affected by obvious stuff like the environment, social milieu, and culture.
Yeah sure.
But a system as complex as a brain is also significantly effected by random processes, such that if you were to clone yourself 100 times, there will all but certainly be greatly different outcomes in important psychological traits, even if you controlled for all that other stuff (like environment, social milieu, and culture etc).
In other words, two identical twins 👯♂️ raised in the same or even completely different environments, will likely emerge with durable similarities (because DNA).
We all know this.
But... these same twins, also may emerge from identical environments with significant differences, purely by dint of stochastic (random) processes, occurring entirely in the frothy complexity of each individual brain 🧠.
And these differences may be quite significant.
One (genetically) identical twin may be gay, the other straight.
One identical twin may be schizophrenic, the other not.
All because of what essentially boils down to a roll of the dice.
Or rather, the roll of billions of tiny molecular dice, that are more like crazy complex little dungeons and dragons dice.
In other words, DNA makes people more or less likely to display certain traits (sometimes way way more or less likely), but dumb luck (probability) still plays a big role, even at the deepest level of our biology.
Other stuff that we commonly think of as having a durable effect, like parenting etc.
Well....
Not as big of a deal as you probably think.
It has a ginormous impact.
Yes.
But les durable than so called ‘innate’ shit.
This pokes a hole in a lot of the etiological claims of psychotherapy, and a lot of ‘change’ claims touted by the self help industry.
Yes you can change your life in important ways.
But if you quit doing the stuff that made the changes happen, like exercise, diet and meditation etc., you revert to a largely genetically determined baseline quickly.
So, yes you can change your ‘self’ but the change is constrained (i.e. WAY limited) and is dependent on effortful long term behavioral and environmental change.
In the end, Mitchell promotes a kind of radical self acceptance over endless self improvement strategies.
You can overcome stuff like anxiety, depression and addiction, absolutely.
And it’s worth it.
But some stuff, well...
Ya just can’t.
Cuz it’s innate.
So maybe it’s better to simply:
Accept the shit you can’t change. Change the shit you should (provided it’s worth the serious time and effort). And get your shit straight about which is which.
I LOVED this book.
April 26, 2020
Innate presents a lot of interesting findings on how genetic and developmental forces make who we are. The author argues that the wiring of our brain is more innate than you and I would think. The "innate" here refers not only to our genetic makeup, but also the developmental influences, i.e. the actual realization of the genes, the randomness in fetal or early childhood development, which is a part of the "nature" not "nurture".
The author draws from many studies, especially twin studies (monozygotic twins vs dizygotic twins, monozygotic twins reared apart), on personality traits, sexual preferences, intelligence and mental disorders. I find it intriguing that one's environment does not have a long lasting effect on these innate characteristics (the author does not mean the behavioral outcome, but the underline trait, although I find it may be hard to separate an actual outcome from the underline trait in real life situations). For example, "...these findings suggest that many reported correlations between parental behavior and offspring traits do not reflect direct causal link as often inferred, but instead, reflect the effect of shared genes. If, for example, we find overprotective parents have anxious children, this could be because overprotective parenting causes children to be anxious, but evidence described is not consistent with such interpretation, as it should affect monozygotic and dizygotic twins, or adopted and biological offsprings equally. Instead, the general finding suggests parental overprotectiveness and child anxiety are more likely both manifestations of the same genetic effect, acting in both parents and offspring. Similarly growing up in a household with more books is correlated with higher IQ. Does this mean reading raises your IQ? Well, I am all for reading, but this correlation is likely that parents with higher IQ tend to have more books in the house and tend to have children with higher IQ." What is the implication of such findings?
On randomness in brain development: you can't bake the same cake twice. Your genome is a set of coded instruction, not a blueprint. Randomness plays a part in the development from genes to the actual functioning human brain. Your clone is different from you in many ways, even as a baby.
The author makes excellent argument on why we can't use IQ test results between different populations to infer the group difference in intelligence.
Chapter 9 is dedicated to the differences between sexes. Again, a lot of interesting arguments. The explanation of why homosexuality is innate (may or may not be genetic) is fascinating. It seems the differences of various personality traits between sexes do exist. Although each trait has a wild spectrum overlapping between two sexes, there seems also an overall brain profile, a combination of several traits that can tell if it is a male brain or a female brain. IQ wise, although there is no overall difference between sexes, the distribution curve of IQ in male and female population is different. Are women better at language than men? Yes, several studies result in consistent findings. Are men better at math than women? No, the findings in different studies are inconsistent. The author argues that it is unscientific if all such discussion is branded as "neuro-sexism", and it is the interpretation of these findings that may cause issues, not the findings themselves. I agree. However, because of the existing gender discrimination, scientists need to be extra mindful when publishing such findings, as the misinterpretation, intentional or unintentional, is bound to happen. I believe scientists have moral responsibility, perhaps more so than the average citizens.
Other interesting points: we are born prewired--genetically and developmentally, but not hardwired; the role of serotonin in brain development and functioning is truly complex and fascinating; our mind is a not a thing, but a process, the brain at work; when it comes to mental disorders, having one or several gene mutations often does not infer one will surely develop certain symptoms, but only the propensity, the higher likelihood of such misfortune; higher general intelligence may be the result of less load of harmful mutations.
The last chapter, chapter 11, implications, is the fine prints of the main arguments made in the book, to avoid misinterpretation by the general public. It includes the discussion of the new eugenics.
The author is dismissive to epigenetics. As a layperson, I am not qualified to argue with Prof. Mitchell, but I'd love to see more discussions on this topic. This is the fun of science, isn't it?
The author is not a fan of self-help books, which he thinks often exaggerate the role of neuroplasticity and make nonsensical claims. I find his view too narrow. Neuroplasticity in adults is achievable, so what's the harm of making it known to the public? Also, has he looked into mindfulness meditation?
The author draws from many studies, especially twin studies (monozygotic twins vs dizygotic twins, monozygotic twins reared apart), on personality traits, sexual preferences, intelligence and mental disorders. I find it intriguing that one's environment does not have a long lasting effect on these innate characteristics (the author does not mean the behavioral outcome, but the underline trait, although I find it may be hard to separate an actual outcome from the underline trait in real life situations). For example, "...these findings suggest that many reported correlations between parental behavior and offspring traits do not reflect direct causal link as often inferred, but instead, reflect the effect of shared genes. If, for example, we find overprotective parents have anxious children, this could be because overprotective parenting causes children to be anxious, but evidence described is not consistent with such interpretation, as it should affect monozygotic and dizygotic twins, or adopted and biological offsprings equally. Instead, the general finding suggests parental overprotectiveness and child anxiety are more likely both manifestations of the same genetic effect, acting in both parents and offspring. Similarly growing up in a household with more books is correlated with higher IQ. Does this mean reading raises your IQ? Well, I am all for reading, but this correlation is likely that parents with higher IQ tend to have more books in the house and tend to have children with higher IQ." What is the implication of such findings?
On randomness in brain development: you can't bake the same cake twice. Your genome is a set of coded instruction, not a blueprint. Randomness plays a part in the development from genes to the actual functioning human brain. Your clone is different from you in many ways, even as a baby.
The author makes excellent argument on why we can't use IQ test results between different populations to infer the group difference in intelligence.
Chapter 9 is dedicated to the differences between sexes. Again, a lot of interesting arguments. The explanation of why homosexuality is innate (may or may not be genetic) is fascinating. It seems the differences of various personality traits between sexes do exist. Although each trait has a wild spectrum overlapping between two sexes, there seems also an overall brain profile, a combination of several traits that can tell if it is a male brain or a female brain. IQ wise, although there is no overall difference between sexes, the distribution curve of IQ in male and female population is different. Are women better at language than men? Yes, several studies result in consistent findings. Are men better at math than women? No, the findings in different studies are inconsistent. The author argues that it is unscientific if all such discussion is branded as "neuro-sexism", and it is the interpretation of these findings that may cause issues, not the findings themselves. I agree. However, because of the existing gender discrimination, scientists need to be extra mindful when publishing such findings, as the misinterpretation, intentional or unintentional, is bound to happen. I believe scientists have moral responsibility, perhaps more so than the average citizens.
Other interesting points: we are born prewired--genetically and developmentally, but not hardwired; the role of serotonin in brain development and functioning is truly complex and fascinating; our mind is a not a thing, but a process, the brain at work; when it comes to mental disorders, having one or several gene mutations often does not infer one will surely develop certain symptoms, but only the propensity, the higher likelihood of such misfortune; higher general intelligence may be the result of less load of harmful mutations.
The last chapter, chapter 11, implications, is the fine prints of the main arguments made in the book, to avoid misinterpretation by the general public. It includes the discussion of the new eugenics.
The author is dismissive to epigenetics. As a layperson, I am not qualified to argue with Prof. Mitchell, but I'd love to see more discussions on this topic. This is the fun of science, isn't it?
The author is not a fan of self-help books, which he thinks often exaggerate the role of neuroplasticity and make nonsensical claims. I find his view too narrow. Neuroplasticity in adults is achievable, so what's the harm of making it known to the public? Also, has he looked into mindfulness meditation?
June 20, 2019
There is a growing crisis in the fields of genetics and evolutionary psychology with mischaracterization and misinformation in their popular literature. There seems to be a reinforcing tradition of pushing the strength of biological reductionism beyond the actual scientific implications and actively erasing all research for other causal effects. Unfortunately, this book continues this tradition.
I've already had my Twitter exchange with Dr. Mitchell, and although there was some concession that some important mechanisms were missed it mostly ended up with that fallback that every geneticist says more as a platitude than a scientific assertion: well, overall it's an interplay of genetics and environment. And the overall weighting of the influences, which they've just asserted to be one very asymmetric way, they fall away from making quite such a definite assertion, but nothing comes of it. Their stronger assertion stays the position of record. There are no second editions to correct the record. And book by book it goes, misrepresentation and misinformation.
Despite the social media exchange, I think this review should still review in some detail the primary problems this book presents.
This is a book that looks to describe the innateness of neurological phenotype expression. For this book, innateness means more than just genetics, though that is the primary mechanism explored. It also means by innateness those other parts of expression outside our control, like the inherently stochastic dynamics of ontogeny and the processes in the environment also driven by innate expression.
And the book bends so much of the science dishonestly here for this goal. Let me go over the different processes with causal effects on the phenotypes and point to the problematic emphases, ommisions, and misstatements to give the fuller picture.
The genetic scale has a fair amount of description dedicated to it. You get the classic middle-school review of DNA, bases and their pairing, gene start/end markers, and an abridged description of transcription and translation. There isn't a lot of the detail about the transcription codons and their differential mutational neighborhoods, which would give some better awareness of the actual levels of robustness and mutation-sensitivity of the genome which gets played on a lot later. In fact, this book steers clear from numerical attributions of effect strength ecept in one telling (and misleading) exception: heritability.
The book gives a strange description of the measurement of heritability. It goes into the nature of correlations (giving a brief tour of Galton's wider contributions) and describes the genetic influence in monozygotic and dizygotic twins. But here it fails completely to describe the full diversity of effects that cannot be removed from the relative correlational adjustments which make up the (broad-sense) heritability function. At no point does he describe how all cultural biases against one inherited trait that act out to affect the expression of other phenotypes will measure as heritability in that latter phenotype despite having nothing to do with a mechanism of genetic expression of the latter phenotype. These kinds of examples that show where heritability may hide cultural controllability are never discussed around heritability.
The closest the book comes to such a conversation is this strange aside where the possibility that people may have innate traits (due to their genes) that may make them more likely to be abused, and that may reinforce traits that make them abusers when they grow up. This strange aside insists it is not intending to blame the victims of abuse (even though it really kind of is) and is completely concerned in it's description in pointing out how the development of one uncontrollable trait may influence other traits in innate ways through the environment. At no point is it pointed out that the environment can be controlled, or any of the research on intervention. It certainly does not discuss example like a child with minority racial traits having expression of some phenotype affected by social bigotries and what kinds of traits the research has shown such biases in.
The description of expression mentions in passing some pieces of expression, but doesn't really pull it together and connect it with a bogeyman word attacked throughout the book: epigenetics. We know that methylation can affect gene expression in a way to hide perfectly healthy variants from transcription. We know how the geometry of protein layout in the germ cells can affect the geometry of ontogeny. We know of metabolic millieu that can be inherited outside of the genes themselves. And we know that these kinds of things may be affected by environment through slow information-encoding processes that may have occurred in the parental lifetime and earlier.
In other words, we now have decades of research showing there are a variety of intermediate processes that can change the outcome of genetic causal paths, and that some of these are environmentally affected (though slowly, and typically most importantly through the parents before ontogeny).
So it is very telling that he makes fun of epigenetics. Apparently there are some who are selling epigenetics as some kind of self help and self-control panacaea, and he has taken it as an important point of this book to combat that belief. I personally have not read those kinds of books, and my exposure to epigenetics started in college with the Jablonka / Lamb book and has explored the journal literature from there. But he describes none of the actual research, and instead just makes some very demeaning comments about epigenetics as if it were simply his caricature he presents. This is the first major deception of the book.
When he describes the stochastic nature of development, he again focuses on the lack of control - this time in the source of randomness. An honest description that understood epigenetics would have pointed out the possible influence of epigenetic factors and maternal environment controls. During development, many chemicals are supplied the embryo from the mother, including nutritional (sugars, amino acids, fats, metabolic co-factors), as well as other chemicals affecting metabolic process (alkaloids, terpenoids, etc. from normal consumption or medications from intentionally directed consumption/injection/etc.).
He just repeatedly skips these environmental controls.
So when he gets to neuroplasticity - well that's just another caricature. Again, he gives none of the decades of research on how we are able to train different components of the nervous system. Again, he laughs at something he read in some really poorly researched self-help book somewhere and pretends that the professional study of neuroplasticity looks like it. So he talks about the possibility of developmental tendencies and their genetic influences, but does not go into the mechanisms of neuroplasticity and the research into their various scopes over different components.
In these ways, the book tilts it's uninformed readers into believing a biological reductionism that is not justified by the science.
It's not like this is an either-or proposition either. We have lots of very cool and important research on causal paths of genetic expression. And we have lots of cool information on epigenetics and it's realm of controls. And we have information on maternal controls on developmental environment. And we have tons of research on neuroplasticity and it's domains. And there is a lot still unknown. Telling that story, though, would not be done in a book titled "Innate".
I honestly don't know what to do about the dishonesty in these fields. I really don;t know why there is this concerted effort to make these misstatements and no concern shown about the misstatements. I pointed to Dr. Mitchell his misleading description of heritability and how every time he used a heritability number like 0.6 or 0.8, he would directly state (not even just imply) that that showed the variability of the trait was controlled 60 or 80% by genes (and let's not go into effects whose expression is not additive but multiplicative [likely most of them], which is a huge mistake in this view on a much more foundational level) - when I pointed out this - he didn't feel the need to change that message. Instead, he had some other revisions he would make but generally wasn't concerned about outright misstatements.
The same with Stuart Ritchie, who has never once responded to my pointing out the same heritability errors in his book.
The same with Richard Haier, whose journal Intelligence publishes papers all the time with the same misstaken view of heritability.
There is a lie that an entire field does not want to admit. That is not science. Something is making them _want_ to misrepresent. This is intentional. That is scary.
I've already had my Twitter exchange with Dr. Mitchell, and although there was some concession that some important mechanisms were missed it mostly ended up with that fallback that every geneticist says more as a platitude than a scientific assertion: well, overall it's an interplay of genetics and environment. And the overall weighting of the influences, which they've just asserted to be one very asymmetric way, they fall away from making quite such a definite assertion, but nothing comes of it. Their stronger assertion stays the position of record. There are no second editions to correct the record. And book by book it goes, misrepresentation and misinformation.
Despite the social media exchange, I think this review should still review in some detail the primary problems this book presents.
This is a book that looks to describe the innateness of neurological phenotype expression. For this book, innateness means more than just genetics, though that is the primary mechanism explored. It also means by innateness those other parts of expression outside our control, like the inherently stochastic dynamics of ontogeny and the processes in the environment also driven by innate expression.
And the book bends so much of the science dishonestly here for this goal. Let me go over the different processes with causal effects on the phenotypes and point to the problematic emphases, ommisions, and misstatements to give the fuller picture.
The genetic scale has a fair amount of description dedicated to it. You get the classic middle-school review of DNA, bases and their pairing, gene start/end markers, and an abridged description of transcription and translation. There isn't a lot of the detail about the transcription codons and their differential mutational neighborhoods, which would give some better awareness of the actual levels of robustness and mutation-sensitivity of the genome which gets played on a lot later. In fact, this book steers clear from numerical attributions of effect strength ecept in one telling (and misleading) exception: heritability.
The book gives a strange description of the measurement of heritability. It goes into the nature of correlations (giving a brief tour of Galton's wider contributions) and describes the genetic influence in monozygotic and dizygotic twins. But here it fails completely to describe the full diversity of effects that cannot be removed from the relative correlational adjustments which make up the (broad-sense) heritability function. At no point does he describe how all cultural biases against one inherited trait that act out to affect the expression of other phenotypes will measure as heritability in that latter phenotype despite having nothing to do with a mechanism of genetic expression of the latter phenotype. These kinds of examples that show where heritability may hide cultural controllability are never discussed around heritability.
The closest the book comes to such a conversation is this strange aside where the possibility that people may have innate traits (due to their genes) that may make them more likely to be abused, and that may reinforce traits that make them abusers when they grow up. This strange aside insists it is not intending to blame the victims of abuse (even though it really kind of is) and is completely concerned in it's description in pointing out how the development of one uncontrollable trait may influence other traits in innate ways through the environment. At no point is it pointed out that the environment can be controlled, or any of the research on intervention. It certainly does not discuss example like a child with minority racial traits having expression of some phenotype affected by social bigotries and what kinds of traits the research has shown such biases in.
The description of expression mentions in passing some pieces of expression, but doesn't really pull it together and connect it with a bogeyman word attacked throughout the book: epigenetics. We know that methylation can affect gene expression in a way to hide perfectly healthy variants from transcription. We know how the geometry of protein layout in the germ cells can affect the geometry of ontogeny. We know of metabolic millieu that can be inherited outside of the genes themselves. And we know that these kinds of things may be affected by environment through slow information-encoding processes that may have occurred in the parental lifetime and earlier.
In other words, we now have decades of research showing there are a variety of intermediate processes that can change the outcome of genetic causal paths, and that some of these are environmentally affected (though slowly, and typically most importantly through the parents before ontogeny).
So it is very telling that he makes fun of epigenetics. Apparently there are some who are selling epigenetics as some kind of self help and self-control panacaea, and he has taken it as an important point of this book to combat that belief. I personally have not read those kinds of books, and my exposure to epigenetics started in college with the Jablonka / Lamb book and has explored the journal literature from there. But he describes none of the actual research, and instead just makes some very demeaning comments about epigenetics as if it were simply his caricature he presents. This is the first major deception of the book.
When he describes the stochastic nature of development, he again focuses on the lack of control - this time in the source of randomness. An honest description that understood epigenetics would have pointed out the possible influence of epigenetic factors and maternal environment controls. During development, many chemicals are supplied the embryo from the mother, including nutritional (sugars, amino acids, fats, metabolic co-factors), as well as other chemicals affecting metabolic process (alkaloids, terpenoids, etc. from normal consumption or medications from intentionally directed consumption/injection/etc.).
He just repeatedly skips these environmental controls.
So when he gets to neuroplasticity - well that's just another caricature. Again, he gives none of the decades of research on how we are able to train different components of the nervous system. Again, he laughs at something he read in some really poorly researched self-help book somewhere and pretends that the professional study of neuroplasticity looks like it. So he talks about the possibility of developmental tendencies and their genetic influences, but does not go into the mechanisms of neuroplasticity and the research into their various scopes over different components.
In these ways, the book tilts it's uninformed readers into believing a biological reductionism that is not justified by the science.
It's not like this is an either-or proposition either. We have lots of very cool and important research on causal paths of genetic expression. And we have lots of cool information on epigenetics and it's realm of controls. And we have information on maternal controls on developmental environment. And we have tons of research on neuroplasticity and it's domains. And there is a lot still unknown. Telling that story, though, would not be done in a book titled "Innate".
I honestly don't know what to do about the dishonesty in these fields. I really don;t know why there is this concerted effort to make these misstatements and no concern shown about the misstatements. I pointed to Dr. Mitchell his misleading description of heritability and how every time he used a heritability number like 0.6 or 0.8, he would directly state (not even just imply) that that showed the variability of the trait was controlled 60 or 80% by genes (and let's not go into effects whose expression is not additive but multiplicative [likely most of them], which is a huge mistake in this view on a much more foundational level) - when I pointed out this - he didn't feel the need to change that message. Instead, he had some other revisions he would make but generally wasn't concerned about outright misstatements.
The same with Stuart Ritchie, who has never once responded to my pointing out the same heritability errors in his book.
The same with Richard Haier, whose journal Intelligence publishes papers all the time with the same misstaken view of heritability.
There is a lie that an entire field does not want to admit. That is not science. Something is making them _want_ to misrepresent. This is intentional. That is scary.
July 16, 2023
کتاب خوبیه برای سر درآوردن از کارکرد مغز و اثر عوامل گوناگون بر شخصیت انسان.
مثل بسیاری از کتابهای مشابهش، این کتاب هم قرار نیست زندگیتون رو متحول کنه یا کمک کنه تغییری در زندگی ایجاد کنید.
صرفا یک سری اطلاعات بهتون میده از چیزهایی که دست خودتون نیست ولی خیلی رو زندگیتون اثر داره.
اینجور کتابها بهشدت به درد کاهش خارش غدد کنجکاوی میخورن😅
مثل بسیاری از کتابهای مشابهش، این کتاب هم قرار نیست زندگیتون رو متحول کنه یا کمک کنه تغییری در زندگی ایجاد کنید.
صرفا یک سری اطلاعات بهتون میده از چیزهایی که دست خودتون نیست ولی خیلی رو زندگیتون اثر داره.
اینجور کتابها بهشدت به درد کاهش خارش غدد کنجکاوی میخورن😅
March 11, 2019
Excellent book. Everyone working in early child development should read this, including developmental paediatricians like me.
The author advances answers and explanations for many of the fundamental questions which vex clinicians such as myself. The difference from most such fare is that this guy knows what he’s talking about. He really really knows his stuff.
Two aspects make this book stand out. The author demonstrates the infallible sign of true mastery of the subject of discussion - the ability to use plain English, and explanations by analogy, to convey complex concepts to also-ran readers like me.
That feat is allowed in part by the author’s command of related contemporary psychology, and philosophy. The insight on show, in those areas, is deeper than that displayed by many current loudmouth professional psychologists and philosophers.
The most important concept expounded, the most important fact for any clinician reader to grasp, is that of the many-to-one and one-to-many relation between genetic variations on the one hand, and clinically defined entities such as autism and schizophrenia, on the other. Autism can be caused by many different genetic variations; because it is not really one disease/disorder. Whereas one genetic variation which causes autism in one individual will cause a different ‘condition’, or nothing at all, in another individual.
But there’s heaps of other important, interesting stuff too.
Complaints? Well, I could point out that the book does not contain any sophisticated examination of the construct of ‘ADHD’, only passing mentions. This is almost certainly because the author has spent no time in his academic life, examining the entity himself. This in turn indicates that the author isn’t stupid, since examination of the quasi-entity currently called ADHD is obviously a dead end which no amount of attempted sciencing will add to. So, fair enough.
Also, I listened to the audiobook. I understand the choice of a fairly posh sounding English narrator, who did an excellent job. Americans can’t understand most Strine (unadulterated Australian accent and vernacular); only an enlightened minority would make sense of Full Irish Narration.
But still it seems a shame - key observations, such as the following contained in Chapter 9, would have sounded even more compelling if uttered by the likes of Dylan Moran: “Men also have thicker skulls, especially in front, which may reflect the fact that we like to punch each other in the face a lot.”
I give this excellent book 5 STARS OUT OF FIVE.
The author advances answers and explanations for many of the fundamental questions which vex clinicians such as myself. The difference from most such fare is that this guy knows what he’s talking about. He really really knows his stuff.
Two aspects make this book stand out. The author demonstrates the infallible sign of true mastery of the subject of discussion - the ability to use plain English, and explanations by analogy, to convey complex concepts to also-ran readers like me.
That feat is allowed in part by the author’s command of related contemporary psychology, and philosophy. The insight on show, in those areas, is deeper than that displayed by many current loudmouth professional psychologists and philosophers.
The most important concept expounded, the most important fact for any clinician reader to grasp, is that of the many-to-one and one-to-many relation between genetic variations on the one hand, and clinically defined entities such as autism and schizophrenia, on the other. Autism can be caused by many different genetic variations; because it is not really one disease/disorder. Whereas one genetic variation which causes autism in one individual will cause a different ‘condition’, or nothing at all, in another individual.
But there’s heaps of other important, interesting stuff too.
Complaints? Well, I could point out that the book does not contain any sophisticated examination of the construct of ‘ADHD’, only passing mentions. This is almost certainly because the author has spent no time in his academic life, examining the entity himself. This in turn indicates that the author isn’t stupid, since examination of the quasi-entity currently called ADHD is obviously a dead end which no amount of attempted sciencing will add to. So, fair enough.
Also, I listened to the audiobook. I understand the choice of a fairly posh sounding English narrator, who did an excellent job. Americans can’t understand most Strine (unadulterated Australian accent and vernacular); only an enlightened minority would make sense of Full Irish Narration.
But still it seems a shame - key observations, such as the following contained in Chapter 9, would have sounded even more compelling if uttered by the likes of Dylan Moran: “Men also have thicker skulls, especially in front, which may reflect the fact that we like to punch each other in the face a lot.”
I give this excellent book 5 STARS OUT OF FIVE.
February 8, 2019
"Innate" is not synonymous with "genetic," as this book makes clear. Genes just code for the production of molecules (especially proteins), which then go to work building a body that works (or not). Along the way, a lot can happen -- especially when constructing something as complicated as a human brain. The brain has to wire itself as it develops, with many opportunities for randomness to affect the outcome. That means even monozygotic twins don't have identical brain architecture at birth.
So maybe you were planning to have yourself cloned? Don't bother. The result won't be another you. It will just be someone else with your genes. :-)
So maybe you were planning to have yourself cloned? Don't bother. The result won't be another you. It will just be someone else with your genes. :-)
October 12, 2019
Excellent primer for students of psychology (a student myself). It nicely sums up the essential concepts and the basic findings from developmental research. I judge it also easily accessible to the interested layperson.
The book adresses common misconceptions about the heritability of psychological traits, such as intelligence and personality. Genetic determinism is debunked in plain terms. How is it that identical twins most likely are extremely similar, but still in some cases might end up quite different? An important insight is that the role of environmental influences on development is unsystematic and random, contrary to commonly assumed. The book does an excellent job in unweaving the notorious concept of the heritability quotient.
An engaging read!
The book adresses common misconceptions about the heritability of psychological traits, such as intelligence and personality. Genetic determinism is debunked in plain terms. How is it that identical twins most likely are extremely similar, but still in some cases might end up quite different? An important insight is that the role of environmental influences on development is unsystematic and random, contrary to commonly assumed. The book does an excellent job in unweaving the notorious concept of the heritability quotient.
An engaging read!
December 20, 2019
A really fine book explaining how genetics affect our brains and minds. There are certain traits that are very strongly genetically associated, but in identical twins, with 100% identical DNA, if one twin has a trait the other twin only has 50% chance of having the same trait. How can that be?This book explains! A lot of who we are is “innate” in the sense that we are born that way, but our DNA has not precisely determined what we are, it has only prepared a situation where there are certain odds that we will be one way or the other. Well written and clear. I love it when a real scientist writes as well as a good science journalist!
May 29, 2019
Highly informative, and beautifully succinct resume of today's study of genetics.
The author manages to explain and teach the basics of genetics, neural pathways of the brain, the importance of mono-zygotic twin studies and much more.
I thoroughly enjoyed this book and learnt a lot.
The author manages to explain and teach the basics of genetics, neural pathways of the brain, the importance of mono-zygotic twin studies and much more.
I thoroughly enjoyed this book and learnt a lot.
September 5, 2020
I wanted to get a deeper dive into genetics, but I didn't want to deal with genetics on a level that was too abstract. And given that I'm very keen on psychology, the genetics of psychological traits tend to interest me the most. So when I saw this book it looked like the perfect opportunity. The book is written by Kevin Mitchell, a very successful neuroscientist, and it explores what causes human diversity and individual differences. How genetic processes end up writing our brains differently, and how that ends up as different traits such as a personality, intelligence, sexuality, and so forth.
The broad point is that psychological and behavioral traits are heavily genetic. Depending on the trait, it can anywhere from 30% to 80%. This largely comes from studies dealing with twins (monozygotic twins vs dizygotic twins and monozygotic twins reared apart). The author doesn't spend too much time on this point, rightfully so. Despite controversial, it is a rather basic and accepted fact, and the book is focused on exploring why this is the case rather than arguing it to death as some have done.
The first part of the book was a very general introduction. Not only to genetics but because we are dealing with how the brain is wired, the brain itself. This alone is well worth the book, and it was a fantastic introduction to cognitive and neuroscience. In the second part, it goes into more specific areas of innate differences and their mechanisms.
The book is somewhat similar to Pinker's Blank Slate, but I liked this one better. It much heavier on the science, and it doesn't go so much on philosophy or politics. I hate when these topics are full of apologetics and endless cautionary statements. I understand why they are required, but I feel like they detract from the science which should be the main point. I found the author balances this perfectly. It only dives into politics and controversies when absolutely required, and keeps it very succinct and brief. The rest is science.
Something else that I liked is that the book had a wide range of topics, some politically controversial (like IQ or sex differences), and some very benign (like personality traits). But they were dealt, for the most part, the same. I think they should. It wasn't trying to avoid controversy by skipping hot topics, but likewise, it wasn't focusing on them to make the book controversial or aggressive.
Something that really stuck with me was how much randomness there is for genetic mutations. There is often a debate between nature and nurture. That is often a false dichotomy, but beyond that, it is missing an important variable entirely: chance. When studies often find a high contribution from genetics, it seems to assume that left-over is the environment. But often it is not (because that's measured with the shared environment of twins). Some of the variations is completely random from the neurodevelopmental process of the brain. Random fluctuations in cellular components are unavoidable noise that accumulates and ends up affecting how the brain is wired. Meaning that a trait can be only partly genetic but still entirely innate with little influence from the environment.
I really liked the author's emphasis on how genetics also shape the environment, making the dichotomy even more problematic. If one is musically talented, they are more likely to pursue musical training. The training isn't genetic, it is part of the environment. Yet, that environment was chosen based on a genetic influence. Viewing as a purely environmental factor is misleading. Another example given that I liked is how a child with autism may have less interest in people's eyes. This will lead to missing social cues that will shape the development of language and communication. Where do these social deficits come from? They weren't purely genetic, but they certainly can't be attributed to the environment alone either. Another topic that covered often was that genetics isn't simply how you're born. It is a developmental process which includes maturation. Much like physical attributes, the genetics of brain wiring is a long process that isn't exclusive to neither gestation or even childhood.
And while this wasn't a big point in the book at all, the author articulated something I have been thinking for a good while about group differences. Stereotypes often have a grain of truth. While for example differences between men and women are certainly amplified and distorted by our culture, there are differences nevertheless. The stereotypes seem to coincidence (they aren't completely random), but very often in an exaggerated manner. They end up this way because they are oversimplified yet effective heuristics to make predictions with little information. But they end up very off when applied to specific individuals. Trying to claim the stereotypes are completely inaccurate is not helpful because it is untrue. Yet, adhering to such stereotypes is also counter-productive as they most certainly distort reality with oversimplified schemas. The goal should be to clarify why the stereotypes are oversimplifications and also to judge individuals by themselves without group labels.
Overall it's a very solid book. If you're interested in psychological traits or genetics, I think anyone would really enjoy it and finish it with a much better understanding of the underlying science. If you are interested in both, then I doubt there is a book better done than this. There is often a trade-off in many of these types of books. Not describing the science enough vs being too technical, or getting to dragged into political controversy vs not preventing unfair criticism and misinterpretation. I think Mitchell nailed these trade-offs perfectly and wrote a deeply educational and enjoyable book about a fascinating topic. If you're new to neuroscience or genetics, I would recommend getting the paperback and not the audiobook. While I chose the latter, many of the topics I was already familiar with. If I wasn't, I think the beginning of the book, which gives the required technical background, would be difficult to follow. If you're new, it's worth having the opportunity to read it instead of listening so you can take your time and have better retention.
The broad point is that psychological and behavioral traits are heavily genetic. Depending on the trait, it can anywhere from 30% to 80%. This largely comes from studies dealing with twins (monozygotic twins vs dizygotic twins and monozygotic twins reared apart). The author doesn't spend too much time on this point, rightfully so. Despite controversial, it is a rather basic and accepted fact, and the book is focused on exploring why this is the case rather than arguing it to death as some have done.
The first part of the book was a very general introduction. Not only to genetics but because we are dealing with how the brain is wired, the brain itself. This alone is well worth the book, and it was a fantastic introduction to cognitive and neuroscience. In the second part, it goes into more specific areas of innate differences and their mechanisms.
The book is somewhat similar to Pinker's Blank Slate, but I liked this one better. It much heavier on the science, and it doesn't go so much on philosophy or politics. I hate when these topics are full of apologetics and endless cautionary statements. I understand why they are required, but I feel like they detract from the science which should be the main point. I found the author balances this perfectly. It only dives into politics and controversies when absolutely required, and keeps it very succinct and brief. The rest is science.
Something else that I liked is that the book had a wide range of topics, some politically controversial (like IQ or sex differences), and some very benign (like personality traits). But they were dealt, for the most part, the same. I think they should. It wasn't trying to avoid controversy by skipping hot topics, but likewise, it wasn't focusing on them to make the book controversial or aggressive.
Something that really stuck with me was how much randomness there is for genetic mutations. There is often a debate between nature and nurture. That is often a false dichotomy, but beyond that, it is missing an important variable entirely: chance. When studies often find a high contribution from genetics, it seems to assume that left-over is the environment. But often it is not (because that's measured with the shared environment of twins). Some of the variations is completely random from the neurodevelopmental process of the brain. Random fluctuations in cellular components are unavoidable noise that accumulates and ends up affecting how the brain is wired. Meaning that a trait can be only partly genetic but still entirely innate with little influence from the environment.
I really liked the author's emphasis on how genetics also shape the environment, making the dichotomy even more problematic. If one is musically talented, they are more likely to pursue musical training. The training isn't genetic, it is part of the environment. Yet, that environment was chosen based on a genetic influence. Viewing as a purely environmental factor is misleading. Another example given that I liked is how a child with autism may have less interest in people's eyes. This will lead to missing social cues that will shape the development of language and communication. Where do these social deficits come from? They weren't purely genetic, but they certainly can't be attributed to the environment alone either. Another topic that covered often was that genetics isn't simply how you're born. It is a developmental process which includes maturation. Much like physical attributes, the genetics of brain wiring is a long process that isn't exclusive to neither gestation or even childhood.
And while this wasn't a big point in the book at all, the author articulated something I have been thinking for a good while about group differences. Stereotypes often have a grain of truth. While for example differences between men and women are certainly amplified and distorted by our culture, there are differences nevertheless. The stereotypes seem to coincidence (they aren't completely random), but very often in an exaggerated manner. They end up this way because they are oversimplified yet effective heuristics to make predictions with little information. But they end up very off when applied to specific individuals. Trying to claim the stereotypes are completely inaccurate is not helpful because it is untrue. Yet, adhering to such stereotypes is also counter-productive as they most certainly distort reality with oversimplified schemas. The goal should be to clarify why the stereotypes are oversimplifications and also to judge individuals by themselves without group labels.
Overall it's a very solid book. If you're interested in psychological traits or genetics, I think anyone would really enjoy it and finish it with a much better understanding of the underlying science. If you are interested in both, then I doubt there is a book better done than this. There is often a trade-off in many of these types of books. Not describing the science enough vs being too technical, or getting to dragged into political controversy vs not preventing unfair criticism and misinterpretation. I think Mitchell nailed these trade-offs perfectly and wrote a deeply educational and enjoyable book about a fascinating topic. If you're new to neuroscience or genetics, I would recommend getting the paperback and not the audiobook. While I chose the latter, many of the topics I was already familiar with. If I wasn't, I think the beginning of the book, which gives the required technical background, would be difficult to follow. If you're new, it's worth having the opportunity to read it instead of listening so you can take your time and have better retention.
January 7, 2021
It took me many months to read this book, and while for some time I considered that a strike against it, I now think that was due more just to my reignited interest in reading fiction in that same time. Reflecting now, I have to say that this is an impressive book in both the number of areas it covers and the depth but ease with which it explains complex topics to the reader.
One idea that will stick with me from this book is that of developmental randomness. The general idea is that the initial differences in psychological traits between people are due in part to the randomness of the process by which the brain is constructed in the womb. DNA does not lay out an exact plan for brain construction, but instead acts more like a set of guidelines. This creates variation in precisely how different regions of the brain are wired within themselves and with other parts of the brain. This variation contributes to people’s baselines in psychological traits. Of course, neuroplasticity allows for the brain to change through experience, but the initial differences set out by genes and developmental randomness play a key role in giving each of us our unique nature.
One idea that will stick with me from this book is that of developmental randomness. The general idea is that the initial differences in psychological traits between people are due in part to the randomness of the process by which the brain is constructed in the womb. DNA does not lay out an exact plan for brain construction, but instead acts more like a set of guidelines. This creates variation in precisely how different regions of the brain are wired within themselves and with other parts of the brain. This variation contributes to people’s baselines in psychological traits. Of course, neuroplasticity allows for the brain to change through experience, but the initial differences set out by genes and developmental randomness play a key role in giving each of us our unique nature.
February 12, 2022
This booked changed how I think about development and the interplay of nature and nurture.
April 14, 2019
People who study the classic scientific debate between nature and nurture tend to reach some version of this conclusion: It’s complicated, both sides make significant contributions to human behavior, and we should never be too quick to attribute a particular outcome solely to genetic or environmental factors. Kevin J. Mitchell’s Innate doesn’t completely overturn this paradigm, but it definitely modifies it in ways that feel fresh and exciting.
Innate is a dense but accessible analysis of cutting-edge findings from genetics, neuroscience and psychology. Mitchell has a true talent for condensing complex scientific concepts into graspable prose, and includes many well-designed visuals to complement his research. His thesis posits not only that the existence of innate personality traits is inarguable, but also that these traits appear to have a larger impact on our selection of behaviors and experiences than previously thought. He explains:
"The debate about the relative contributions of nature and nurture to our psychological makeup is classically framed as a battle between these two forces, rather than, say, a collaboration. In recent times, this has turned into a proxy war, with genetics on one side and brain plasticity on the other, lately allied with the shadowy forces of “epigenetics.” If the brain can change itself, and if we can turn our genes on or off by our own behavior (which is what some proponents of epigenetics rather nebulously claim), then it seems we could reverse the arrows of causation––our psychology could dictate our biology, rather than the other way around.
"Under this scheme, nurture––whether this refers to parenting, experiences, or our own conscious psychological practices––can trump nature. It can overwrite the innate differences in our brains that arise due to genetic and developmental variation. In fact, what tends to happen is just the opposite––initial differences tend to be amplified due to the self-organizing processes of brain development and the fact that individuals select and construct their own environments and experiences largely based on innate predispositions. This is a radically different conception, where the processes of brain plasticity––the supposed instruments of nurture––align with nature instead." (81)
I found the first component of Mitchell’s argument––that innate predispositions exist and obtain from an individual’s genetic makeup––to be neither controversial nor unfamiliar. The second component, however, was much more novel. Mitchell zooms in on the highly probabilistic and unpredictable nature of brain development, whereby each human body physically constructs its brain according to a person’s unique genome:
"The complex machinery of the brain emerges from instructions encoded in the genome, but it is not mapped out like a blueprint––there is no one part of the genome that corresponds to one part of the brain or one type of nerve cell. It is more like a recipe, or a series of protocols, which, when carried out faithfully, result in a human being with a human brain. And, just like a recipe, no matter how detailed and precise it is, there will inevitably be some differences in the outcome from run to run––you can’t bake the same cake twice." (54)
This process, which Mitchell helpfully refers to as “prewiring” (as opposed to “hardwiring,” which implies genetic determinism), exerts a massive impact on a person’s way of seeing and interacting with the world. The descriptions of prewiring in Innate are quite intricate for a popular science book, but Mitchell does a commendable job of leading the reader through the major self-organizing layers of brain development, revealing a vast and impressive array of pathways through which each person’s genetic program builds a brand new and completely unique brain. Mitchell gathers these factors under an umbrella concept called “robustness,” with each person thrown into a genetic lottery that can increase or decrease chances of efficacious development:
"There is an unexpected consequence of the way developmental systems are designed, which is a paradoxical fragility to certain kinds of perturbations, especially mutations in developmental genes. The robustness that evolved to buffer noise and environmental variables means the system can also absorb the effects of many mutations affecting the components of the developmental programs. But not all of them…We all carry thousands of minor genetic variants and typically 100-200 major mutations. So none of us has a developmental program that is as robust as it could be. If you or I were cloned 100 times, the result would be 100 new individuals, each one of a kind." (77-8)
Importantly, although the development of each individual brain is subject to a wide range of variability (each recipe can bake many potential cakes), which brain ultimately gets “baked” appears to be either minimally affected or completely unaffected by factors outside the body––the traditional forces of nurture. This means that the “world outside” the body has little to no impact on the development of our innate predispositions, at least when a person undergoes normal, healthy development (the effects of adverse childhood experiences may represent a categorical exception). Furthermore, as stated above, it is Mitchell’s view that these same predispositions tend to be reinforced and compounded by our environments and experiences, rather than challenged or subverted by them. Whether this assertion will stand the tests of time and scientific scrutiny remains to be seen, but as a first stab Mitchell’s case is compelling and well-supported.
Assuming Mitchell’s thesis is correct, what are the implications of shifting the nature/nurture debate in this direction? First, it is critical to point out that Mitchell is not a genetic determinist who believes that nature is the only game in town:
"The claim is far more modest. It is simply this: that variation in our genes and the way our brains develop causes differences in innate behavioral predispositions––variation in our behavioral tendencies and capacities. Those predispositions certainly influence how we behave in any given circumstance but do not by themselves determine it––they just generate a baseline on top of which other processes act. We learn from experiences, we adapt to our environments, we develop habitual ways of acting that are in part driven by our personality traits, but that are also appropriately context dependent." (264, emphasis his)
So, we shouldn’t interpret these findings as nullifications of the traditional forces of nurture, but we also shouldn’t downplay the powerful role of nature. By and large, innate differences between people are not the products of conscious human choices; they are not particularly sensitive to our intellectual discoveries, cultural traditions, or ethical convictions, and instead are received from the statistical crapshoot of developmental robustness and the contingent whims of our biological history. The fact that we are a sexually dimorphic species is the starkest example of this, and Mitchell includes an entire chapter addressing the significant and undeniable differences between men and women. He also explores the nature of variations in human perception, intelligence and mental illness, putting forth his own spin on how innateness operates in each field of study.
I think Innate is a good and worthwhile book, but I would like to point out one area where Mitchell’s intellectual consistency seems to falter. In his last chapter, he claims that his point of view does not align with determinism––that his research shouldn’t lead readers to conclude that people don’t have free will. I think Mitchell does a fine job of avoiding genetic determinism and neuroscientific reductionism, but I think he fails to refute determinism in the more general sense. In fact, Innate contains some of the strongest arguments I’ve encountered that support the determinist position and undermine the commonplace concept of free will.
Mitchell tries to split the difference by acknowledging that our freedom is constrained by biology and that “free will doesn’t mean doing things for no reason, it means doing them for your reasons” (266, emphasis his). However, the entire rest of his book could be interpreted as an extremely detailed and convincing explanation of exactly how little “choice” people get in shaping their motivations and reasons for action. It seems unclear, then, how we are supposed to feel the kind of personal ownership over our motivations and actions that would confer a legitimate sense of self-determined freedom. It would be better to admit that there’s no scientific evidence to support free will, and to point out that this reality doesn’t require us to completely surrender our notions of personal and social accountability. Rather, we ought to utilize the nonexistence of free will as a bedrock motivation for a compassion-based overhaul of our institutional responses to aberrant and violent behaviors. Mitchell’s failure to make this move constitutes a lost opportunity.
I don’t need to agree with Mitchell about everything in order to appreciate his valuable contribution to these fascinating and consequential subjects. The best of these is perhaps the intellectual tools Mitchell provides for “reality-proofing” our expectations of ourselves and others. Since people arrive on Earth with well-developed and wide-ranging predispositional palettes, we must accept that human communities are a mosaic of profoundly variable perceptions, preferences and reactions to our ever-changing world. There is a strong limit to how moldable people can become, and we must adapt our models of growth and learning to promote achievable progress while also rejecting the project of human perfectibility:
"There is a power in accepting people the way they are––our friends, partners, workmates, children, siblings, and especially ourselves. People really are born different from each other and those differences persist…Denying those differences or constantly telling people they should change is not helpful to anyone. We should recognize the diversity of our human natures, accept it, embrace it, and even celebrate it." (269)
This review was originally published on my blog, words&dirt.
Innate is a dense but accessible analysis of cutting-edge findings from genetics, neuroscience and psychology. Mitchell has a true talent for condensing complex scientific concepts into graspable prose, and includes many well-designed visuals to complement his research. His thesis posits not only that the existence of innate personality traits is inarguable, but also that these traits appear to have a larger impact on our selection of behaviors and experiences than previously thought. He explains:
"The debate about the relative contributions of nature and nurture to our psychological makeup is classically framed as a battle between these two forces, rather than, say, a collaboration. In recent times, this has turned into a proxy war, with genetics on one side and brain plasticity on the other, lately allied with the shadowy forces of “epigenetics.” If the brain can change itself, and if we can turn our genes on or off by our own behavior (which is what some proponents of epigenetics rather nebulously claim), then it seems we could reverse the arrows of causation––our psychology could dictate our biology, rather than the other way around.
"Under this scheme, nurture––whether this refers to parenting, experiences, or our own conscious psychological practices––can trump nature. It can overwrite the innate differences in our brains that arise due to genetic and developmental variation. In fact, what tends to happen is just the opposite––initial differences tend to be amplified due to the self-organizing processes of brain development and the fact that individuals select and construct their own environments and experiences largely based on innate predispositions. This is a radically different conception, where the processes of brain plasticity––the supposed instruments of nurture––align with nature instead." (81)
I found the first component of Mitchell’s argument––that innate predispositions exist and obtain from an individual’s genetic makeup––to be neither controversial nor unfamiliar. The second component, however, was much more novel. Mitchell zooms in on the highly probabilistic and unpredictable nature of brain development, whereby each human body physically constructs its brain according to a person’s unique genome:
"The complex machinery of the brain emerges from instructions encoded in the genome, but it is not mapped out like a blueprint––there is no one part of the genome that corresponds to one part of the brain or one type of nerve cell. It is more like a recipe, or a series of protocols, which, when carried out faithfully, result in a human being with a human brain. And, just like a recipe, no matter how detailed and precise it is, there will inevitably be some differences in the outcome from run to run––you can’t bake the same cake twice." (54)
This process, which Mitchell helpfully refers to as “prewiring” (as opposed to “hardwiring,” which implies genetic determinism), exerts a massive impact on a person’s way of seeing and interacting with the world. The descriptions of prewiring in Innate are quite intricate for a popular science book, but Mitchell does a commendable job of leading the reader through the major self-organizing layers of brain development, revealing a vast and impressive array of pathways through which each person’s genetic program builds a brand new and completely unique brain. Mitchell gathers these factors under an umbrella concept called “robustness,” with each person thrown into a genetic lottery that can increase or decrease chances of efficacious development:
"There is an unexpected consequence of the way developmental systems are designed, which is a paradoxical fragility to certain kinds of perturbations, especially mutations in developmental genes. The robustness that evolved to buffer noise and environmental variables means the system can also absorb the effects of many mutations affecting the components of the developmental programs. But not all of them…We all carry thousands of minor genetic variants and typically 100-200 major mutations. So none of us has a developmental program that is as robust as it could be. If you or I were cloned 100 times, the result would be 100 new individuals, each one of a kind." (77-8)
Importantly, although the development of each individual brain is subject to a wide range of variability (each recipe can bake many potential cakes), which brain ultimately gets “baked” appears to be either minimally affected or completely unaffected by factors outside the body––the traditional forces of nurture. This means that the “world outside” the body has little to no impact on the development of our innate predispositions, at least when a person undergoes normal, healthy development (the effects of adverse childhood experiences may represent a categorical exception). Furthermore, as stated above, it is Mitchell’s view that these same predispositions tend to be reinforced and compounded by our environments and experiences, rather than challenged or subverted by them. Whether this assertion will stand the tests of time and scientific scrutiny remains to be seen, but as a first stab Mitchell’s case is compelling and well-supported.
Assuming Mitchell’s thesis is correct, what are the implications of shifting the nature/nurture debate in this direction? First, it is critical to point out that Mitchell is not a genetic determinist who believes that nature is the only game in town:
"The claim is far more modest. It is simply this: that variation in our genes and the way our brains develop causes differences in innate behavioral predispositions––variation in our behavioral tendencies and capacities. Those predispositions certainly influence how we behave in any given circumstance but do not by themselves determine it––they just generate a baseline on top of which other processes act. We learn from experiences, we adapt to our environments, we develop habitual ways of acting that are in part driven by our personality traits, but that are also appropriately context dependent." (264, emphasis his)
So, we shouldn’t interpret these findings as nullifications of the traditional forces of nurture, but we also shouldn’t downplay the powerful role of nature. By and large, innate differences between people are not the products of conscious human choices; they are not particularly sensitive to our intellectual discoveries, cultural traditions, or ethical convictions, and instead are received from the statistical crapshoot of developmental robustness and the contingent whims of our biological history. The fact that we are a sexually dimorphic species is the starkest example of this, and Mitchell includes an entire chapter addressing the significant and undeniable differences between men and women. He also explores the nature of variations in human perception, intelligence and mental illness, putting forth his own spin on how innateness operates in each field of study.
I think Innate is a good and worthwhile book, but I would like to point out one area where Mitchell’s intellectual consistency seems to falter. In his last chapter, he claims that his point of view does not align with determinism––that his research shouldn’t lead readers to conclude that people don’t have free will. I think Mitchell does a fine job of avoiding genetic determinism and neuroscientific reductionism, but I think he fails to refute determinism in the more general sense. In fact, Innate contains some of the strongest arguments I’ve encountered that support the determinist position and undermine the commonplace concept of free will.
Mitchell tries to split the difference by acknowledging that our freedom is constrained by biology and that “free will doesn’t mean doing things for no reason, it means doing them for your reasons” (266, emphasis his). However, the entire rest of his book could be interpreted as an extremely detailed and convincing explanation of exactly how little “choice” people get in shaping their motivations and reasons for action. It seems unclear, then, how we are supposed to feel the kind of personal ownership over our motivations and actions that would confer a legitimate sense of self-determined freedom. It would be better to admit that there’s no scientific evidence to support free will, and to point out that this reality doesn’t require us to completely surrender our notions of personal and social accountability. Rather, we ought to utilize the nonexistence of free will as a bedrock motivation for a compassion-based overhaul of our institutional responses to aberrant and violent behaviors. Mitchell’s failure to make this move constitutes a lost opportunity.
I don’t need to agree with Mitchell about everything in order to appreciate his valuable contribution to these fascinating and consequential subjects. The best of these is perhaps the intellectual tools Mitchell provides for “reality-proofing” our expectations of ourselves and others. Since people arrive on Earth with well-developed and wide-ranging predispositional palettes, we must accept that human communities are a mosaic of profoundly variable perceptions, preferences and reactions to our ever-changing world. There is a strong limit to how moldable people can become, and we must adapt our models of growth and learning to promote achievable progress while also rejecting the project of human perfectibility:
"There is a power in accepting people the way they are––our friends, partners, workmates, children, siblings, and especially ourselves. People really are born different from each other and those differences persist…Denying those differences or constantly telling people they should change is not helpful to anyone. We should recognize the diversity of our human natures, accept it, embrace it, and even celebrate it." (269)
This review was originally published on my blog, words&dirt.
January 24, 2021
Quite interesting book which looks not only at how a lot of our behaviour is innate but explains how this doesn't always mean something is genetic but also isn't always the product of our environment as we consider it.
I'm a big fan of The Blank Slate and this book really elaborates on those ideas. In that book it's argued that while many trades are largely genetic the "environmental" component is mostly random, not due to parenting and such, but doesn't really go as far to explain how. This book really gets into the weeds and details of how genes lead to behaviours, personality traits, intelligence and illness in ways that are not guaranteed by one's genetics but also not influenced by things like parenting.
Very thorough. Well explained. Some great ideas and powerful concepts.
I'm a big fan of The Blank Slate and this book really elaborates on those ideas. In that book it's argued that while many trades are largely genetic the "environmental" component is mostly random, not due to parenting and such, but doesn't really go as far to explain how. This book really gets into the weeds and details of how genes lead to behaviours, personality traits, intelligence and illness in ways that are not guaranteed by one's genetics but also not influenced by things like parenting.
Very thorough. Well explained. Some great ideas and powerful concepts.
December 8, 2021
Accessible account of the interplay between genetics, brain and behaviour. Good philosophical final chapter. Recommended! Full review in Dutch: https://zijstraatjes.wordpress.com/20...
November 28, 2023
Good book.
October 17, 2021
這是一本說明基因如何影響大腦，大腦如何影響個性的一本書。這本書給的知識很紮實，讓人可以了解人類的個性如何被大腦所影響。同時也可以了解大腦的各種機制是如何在運作，比如男女差異、智商、特質，遺傳與後天經驗的影響等等。我最喜歡的是書中最後結語所說的，各式各樣的大腦產生了各種不同的人格特質，這是自然的一部分，所以我們不必總是追求某種性格上的完美，而應該接受人們性格的多樣性。 頗有啟發。
January 3, 2021
This is a really excellent book. I attended a public lecture by this author a couple of years ago on the subject and was very impressed. I'm even more impressed after reading this book. His writing style is clear, engaging and very accessible. He discusses what behaviours are innate, what innate itself really means, he backs all the information with evidence and discusses the implications of what we know. One major discovery for me was that innate includes not only genetic variation between people but also a part that is due to random developmental variation. I would have to say this is one of the best science books I have ever read.
May 18, 2022
This is a clear and well-structured discussion of the current state of knowledge about what makes a human mind. It carefully describes from where differences between humans arise, and how genetic and environmental variation can play out in different ways. The main message is that genes provide a set of potentials, or propensities, for how the organism can develop depending on the environment. Sometimes the genes limit the possible panorama of outcomes very tightly, sometimes only slightly, and sometimes a small set of possible outcomes are available. Importantly, in the latter case, the effects of pure chance can become crucial: if a system is set up to allow a divergence in development - a fork in the road, as it were - then the final result cannot be said to be neither "in" the genes nor determined by the environment. And yet it is innate.
I have a minor quibble: In a few paragraphs, the language has a few too many bio-jargon terms, which ought to have been edited away.
In the last pages, Mitchell makes a brief visit in the philosophical mine-field of determinism. He states that his view does not undermine free will, but he rejects dualism (the view that brain and mind are different). But he also writes "The mind is not a thing at all - at least, it is not an object. It is a process, or a set of processes - it is, simply put, the brain at work."
This seems to me to beg the issue. When he continues to affirm that the logical content of a thought - its meaning - can have a casual power in and of itself, by being an emergent phenomenon, then he seems to me to be much more of a dualist than he wants to admit. Now, I have absolutely no problem with this at all. The notion that the content of thoughts can have a causal power seems to me to contradict material determinism. The dualism (or rather theory of Worlds 1, 2 and 3) that Karl Popper espoused in "The Self and Its Brain" (with John Eccles) is, in my mind (!), a highly fascinating attempt at solving the mind-body problem.
I have a minor quibble: In a few paragraphs, the language has a few too many bio-jargon terms, which ought to have been edited away.
In the last pages, Mitchell makes a brief visit in the philosophical mine-field of determinism. He states that his view does not undermine free will, but he rejects dualism (the view that brain and mind are different). But he also writes "The mind is not a thing at all - at least, it is not an object. It is a process, or a set of processes - it is, simply put, the brain at work."
This seems to me to beg the issue. When he continues to affirm that the logical content of a thought - its meaning - can have a casual power in and of itself, by being an emergent phenomenon, then he seems to me to be much more of a dualist than he wants to admit. Now, I have absolutely no problem with this at all. The notion that the content of thoughts can have a causal power seems to me to contradict material determinism. The dualism (or rather theory of Worlds 1, 2 and 3) that Karl Popper espoused in "The Self and Its Brain" (with John Eccles) is, in my mind (!), a highly fascinating attempt at solving the mind-body problem.
April 7, 2022
This book very clearly explains the relationship of innate characteristics as genetically stablished framework modified by the complexity of experience laid down on the coded framework. The obvious nature of differences between people, peoples, and genders causes some people a great deal of angst. It shouldn’t. This text helps explain the differences without suggesting determinism or eugenics. There are no claims of value hierarchy, but instead a call to relish and celebrate the variances in the human innate. Quick read.
April 11, 2021
Kevin Mitchell, an associate professor at the Smurfit Institute of Genetics at Dublin's Trinity College, has written, in my view, the definitive text on the question of Nature versus Nurture. Supported by research and science, Mitchell expertly lays out the case for the power of innate traits and the degree to which we can or cannot overcome those predispositions. He explores how traits lead us to seek out environments that reinforce the traits and the degree to which parenting influences behaviors. Brilliantly done.
January 1, 2019
Excellent overview of the modern consensus on how genetics influences behavior and individuality. Written in a way that does not condescend to the reader, it is technical and enjoyable while also being readable by anyone interested in the material. Very much worth reading whether you are a new to the ideas or a scientist working in the field.
August 28, 2020
I enjoyed this. Some parts were underwhelming, while others were really good. There was a discussion on geniuses and IQ but not creativity - which I would have liked. I was familiar with some of the information in the book.
I recommend watching this interview by the Dissenter:
https://www.youtube.com/watch?v=VBc9A...
I recommend watching this interview by the Dissenter:
https://www.youtube.com/watch?v=VBc9A...
April 21, 2021
review is on blog
August 21, 2021
How is human nature genetically encoded in the human genome? Humans have species-general tendencies because they have human DNA. What is actually encoded is a program, or a series of developmental algorithms, mediated by mindless biochemical machines that, when carried out faithfully, will result in the emergence of a human being. The natures of individuals will differ due to differences in the genetic program. This means that even if the genetic instructions are identical between two people, the outcome will still differ! The way our individual brains get wired depends not just on our genetic makeup, but also on how the program of development happens to play out.
- BASIC TERMS: What evidence can we use to determine whether genetic differences contribute to differences in psychological traits? Twin and adoption studies: monozygotic twins should be more similar to one another than dizygotic twins. Genetic differences between people make a big contribution to differences in psychological traits across the population; differences in family environments make a much smaller contribution. If we measure traits in a population, we will frequently find a bell curve, or normal distribution. The amount of variability seen in a distribution of values is called the variance. We can calculate the percentage of the variance accounted for by various factors, and the amount of variance in a trait that can be attributed to genetic variation is known as the heritability of a trait. Heritability tells us about the sources of variance within a population and nothing about why the mean is what it is, and about the sources of differences in mean values between populations.
ALL ABOUT GENES: When we say that genes influence behaviour, what we really mean is that genetic differences contribute to differences in behavioural traits. What are genes? There are two main ways of understanding genes. The first is of some physical thing that gets passed on from parent to offspring, which determines the trait in question. The second is a stretch of DNA that codes for a specific protein; each successive three-letter stretch of DNA sequence corresponds to a different amino acid. DNA is inert; in order for the information encoded within to be acted upon, it must be read out by the cell and decoded. The machinery that does that is itself composed of other proteins in the cell. Each different type of cell in the body expresses a different subset of the 20,000 proteins encoded in the genome. The DNA therefore has to encode much more than instructions on how to make the protein, but also information on when, where, and how much to make too. We don’t all have exactly the same genes; where do these differences come from? Mutation. Those mutations which have a net positive effect on the chances of survival for the organism get selected for; the rest die off. Complex psychological traits are rarely encoded in one simple stretch of DNA; the relationship between specific genetic variants and specific traits is rarely as discrete as for the traits studied by Mendel. Extraversion, for example, cannot be ‘reduced’ in any simple way to a couple of strands of DNA. It’s the complex interplay of an astonishing array of genetic and cultural factors that influence this highly complex label of ‘extraversion’.
YOU CAN’T BAKE THE SAME CAKE TWICE: Monozygotic twins aren’t exactly the same. What other factor accounts for this difference? The final factor that contributes to the difference between identical twins is intrinsic to each person; the inherent randomness in the process of brain development. While your genotype encodes the program to build a human being like you, it doesn’t encode the instructions to build the ‘you’ that you are presently. Just like a recipe, no matter how detailed and precise it is, there will inevitably be some differences in the outcome from run to run - you can’t step foot twice into the same river. Both the river will have changed, and so will you. A new egg has a new genome. As the fertilised egg splits for the first time, the two new cells are already different because they are expressing a different profile of genes. Each cell carries all the information to make the whole organism but none of them sees it. Each cell is an actor in a play, all of whom know their lines and cues, but who cannot see the script in its entirety. The final one who sees the final production is the ultimate critic: natural selection. Good scripts survive; bad scripts die. Because the processes of development operate at a molecular level, they are susceptible to noise in the system. This means that there is variation from moment to moment in the precise numbers and positions and states of all of the millions of individual protein molecules that carry out the neurodevelopmental processes. All of the processes of neural development rely on differential gene expression and on interactions between proteins. This means that each of these processes is subject to noise as multiple levels, and that none of the processes in the developing embryo are fatalistic. (He uses the word deterministic, but that wouldn’t make any sense. What he means to say is that there is no fixed outcome that can be predicted in advance, i.e. fatalistic. A chaotic system can still be deterministic.)
NATURE AND NURTURE: it’s not nature vs nurture; what happens is initial differences are amplified due to the self-organising processes of brain development and the fact that individuals select and construct their own environments and experiences largely based on innate predispositions. Brain circuitry is highly plastic, and learning from experience obviously affects our behaviour, but there’s little evidence that learning affects our behavioural traits, i.e. those characteristics which lead us to learn in one way rather than another. However, extreme experiences in childhood can have a long-lasting effect on people’s psyches. We learn from our experiences and adapt to our environments but we don’t all experience the world in the same way! People don’t only react to situations that they find themselves in, but are proactively making decisions that will put them in certain situations over others. (If you take a group of genetically identical mice and place them in an environment to live together, then those mice that were ever so slightly more dominant at the outset were much more likely to be more dominant down the line as they encountered other mice; a tiny initial difference was amplified by repeated encounters.)
PERSONALITY TRAITS: Personality traits, like the Big Five, really are heritable and really do reflect some biological differences. However, they don’t necessarily reflect distinct biological modules, as they could emerge as composites measures from statistical analyses without necessarily mapping onto dedicated genes or neural circuits. Imagine you’re building a robot; in order to survive in the world, we need to program in some sensors so that it can detect things in the outside environment; the robot needs to assess situations and make competing evaluative judgments on what it should do. There isn’t only one set of parameters that can ensure survival, since different robots will behave differently based on their different parameters. Across many situations, these differences would manifest as global tendencies in ways that would be fairly stable and predictable. In short, our robots would have personalities. And something similar seems to underlie human personalities. The things we recognise and classify as personality traits may be built up from variation in a large number of more basal decision-making parameters. Variation in neuromodulatory systems may underlie the differential tuning of these parameters across individuals. The ongoing self-organising nature of postnatal brain development will tend to reinforce innate differences by affecting the experiences we have and the way we respond to them. We really are born different and we get more so over time. This means that we don’t all see the world in the same way; there is a rich diversity of perceptual experience, across all the senses. These differences affect not just what we sense or how we sense it, but also what meaning different stimuli have for us and, at a deep level, how we all think about various things in our world.
Intelligence: while differences in intellectual potential may be innate, actual intelligence increases over time, with maturation and education. However, this doesn’t mean that everyone will reach the same point; while absolute intelligence increases over childhood in each of us, our relative ranking remains remarkably stable. Children who had higher IQ at 5 will tend to have higher IQ’s at 20 too.
Men and Women: the brains of males and females are literally wired differently, both in neuroanatomy and neurochemistry. Men are more aggressive than women; they have increased body mass, bone density, etc. Big Five: women tend to score higher on agreeableness and neuroticism, and slightly higher on conscientiousness, while men tend to score higher on openness to new ideas. Extraversion isn’t higher in men or women, but men are higher on assertiveness and sensation seeking, while women score higher on sociability and gregariousness.
CONCLUSIONS: Twin, family, and population studies have all shown that psychological traits are partly heritable, but the relationship between genes and traits is far from simple. That fact that a given trait is heritable seems to suggest that there must be genes for that trait. It implies that genes exist that are dedicated to that function, but the fact that a trait is heritable means only that there are genetic variants that affect that trait. There are no genes for complex pschological functions - there are neural systems for such functions and genes that build them. A lot of the variation in mature function stems from differences in how the neural systems develop; the program encoded in the genome can only specify developmental rules, not precise outcomes. And the genetic architecture is not as modular as often thought; any given neural system can be affected by variation in probably hundreds of genes. Innate differences in psychological traits arise from two sources: differences in the program specifying brain development and function, and random variation in how that program plays out in an actual individual.
- BASIC TERMS: What evidence can we use to determine whether genetic differences contribute to differences in psychological traits? Twin and adoption studies: monozygotic twins should be more similar to one another than dizygotic twins. Genetic differences between people make a big contribution to differences in psychological traits across the population; differences in family environments make a much smaller contribution. If we measure traits in a population, we will frequently find a bell curve, or normal distribution. The amount of variability seen in a distribution of values is called the variance. We can calculate the percentage of the variance accounted for by various factors, and the amount of variance in a trait that can be attributed to genetic variation is known as the heritability of a trait. Heritability tells us about the sources of variance within a population and nothing about why the mean is what it is, and about the sources of differences in mean values between populations.
ALL ABOUT GENES: When we say that genes influence behaviour, what we really mean is that genetic differences contribute to differences in behavioural traits. What are genes? There are two main ways of understanding genes. The first is of some physical thing that gets passed on from parent to offspring, which determines the trait in question. The second is a stretch of DNA that codes for a specific protein; each successive three-letter stretch of DNA sequence corresponds to a different amino acid. DNA is inert; in order for the information encoded within to be acted upon, it must be read out by the cell and decoded. The machinery that does that is itself composed of other proteins in the cell. Each different type of cell in the body expresses a different subset of the 20,000 proteins encoded in the genome. The DNA therefore has to encode much more than instructions on how to make the protein, but also information on when, where, and how much to make too. We don’t all have exactly the same genes; where do these differences come from? Mutation. Those mutations which have a net positive effect on the chances of survival for the organism get selected for; the rest die off. Complex psychological traits are rarely encoded in one simple stretch of DNA; the relationship between specific genetic variants and specific traits is rarely as discrete as for the traits studied by Mendel. Extraversion, for example, cannot be ‘reduced’ in any simple way to a couple of strands of DNA. It’s the complex interplay of an astonishing array of genetic and cultural factors that influence this highly complex label of ‘extraversion’.
YOU CAN’T BAKE THE SAME CAKE TWICE: Monozygotic twins aren’t exactly the same. What other factor accounts for this difference? The final factor that contributes to the difference between identical twins is intrinsic to each person; the inherent randomness in the process of brain development. While your genotype encodes the program to build a human being like you, it doesn’t encode the instructions to build the ‘you’ that you are presently. Just like a recipe, no matter how detailed and precise it is, there will inevitably be some differences in the outcome from run to run - you can’t step foot twice into the same river. Both the river will have changed, and so will you. A new egg has a new genome. As the fertilised egg splits for the first time, the two new cells are already different because they are expressing a different profile of genes. Each cell carries all the information to make the whole organism but none of them sees it. Each cell is an actor in a play, all of whom know their lines and cues, but who cannot see the script in its entirety. The final one who sees the final production is the ultimate critic: natural selection. Good scripts survive; bad scripts die. Because the processes of development operate at a molecular level, they are susceptible to noise in the system. This means that there is variation from moment to moment in the precise numbers and positions and states of all of the millions of individual protein molecules that carry out the neurodevelopmental processes. All of the processes of neural development rely on differential gene expression and on interactions between proteins. This means that each of these processes is subject to noise as multiple levels, and that none of the processes in the developing embryo are fatalistic. (He uses the word deterministic, but that wouldn’t make any sense. What he means to say is that there is no fixed outcome that can be predicted in advance, i.e. fatalistic. A chaotic system can still be deterministic.)
NATURE AND NURTURE: it’s not nature vs nurture; what happens is initial differences are amplified due to the self-organising processes of brain development and the fact that individuals select and construct their own environments and experiences largely based on innate predispositions. Brain circuitry is highly plastic, and learning from experience obviously affects our behaviour, but there’s little evidence that learning affects our behavioural traits, i.e. those characteristics which lead us to learn in one way rather than another. However, extreme experiences in childhood can have a long-lasting effect on people’s psyches. We learn from our experiences and adapt to our environments but we don’t all experience the world in the same way! People don’t only react to situations that they find themselves in, but are proactively making decisions that will put them in certain situations over others. (If you take a group of genetically identical mice and place them in an environment to live together, then those mice that were ever so slightly more dominant at the outset were much more likely to be more dominant down the line as they encountered other mice; a tiny initial difference was amplified by repeated encounters.)
PERSONALITY TRAITS: Personality traits, like the Big Five, really are heritable and really do reflect some biological differences. However, they don’t necessarily reflect distinct biological modules, as they could emerge as composites measures from statistical analyses without necessarily mapping onto dedicated genes or neural circuits. Imagine you’re building a robot; in order to survive in the world, we need to program in some sensors so that it can detect things in the outside environment; the robot needs to assess situations and make competing evaluative judgments on what it should do. There isn’t only one set of parameters that can ensure survival, since different robots will behave differently based on their different parameters. Across many situations, these differences would manifest as global tendencies in ways that would be fairly stable and predictable. In short, our robots would have personalities. And something similar seems to underlie human personalities. The things we recognise and classify as personality traits may be built up from variation in a large number of more basal decision-making parameters. Variation in neuromodulatory systems may underlie the differential tuning of these parameters across individuals. The ongoing self-organising nature of postnatal brain development will tend to reinforce innate differences by affecting the experiences we have and the way we respond to them. We really are born different and we get more so over time. This means that we don’t all see the world in the same way; there is a rich diversity of perceptual experience, across all the senses. These differences affect not just what we sense or how we sense it, but also what meaning different stimuli have for us and, at a deep level, how we all think about various things in our world.
Intelligence: while differences in intellectual potential may be innate, actual intelligence increases over time, with maturation and education. However, this doesn’t mean that everyone will reach the same point; while absolute intelligence increases over childhood in each of us, our relative ranking remains remarkably stable. Children who had higher IQ at 5 will tend to have higher IQ’s at 20 too.
Men and Women: the brains of males and females are literally wired differently, both in neuroanatomy and neurochemistry. Men are more aggressive than women; they have increased body mass, bone density, etc. Big Five: women tend to score higher on agreeableness and neuroticism, and slightly higher on conscientiousness, while men tend to score higher on openness to new ideas. Extraversion isn’t higher in men or women, but men are higher on assertiveness and sensation seeking, while women score higher on sociability and gregariousness.
CONCLUSIONS: Twin, family, and population studies have all shown that psychological traits are partly heritable, but the relationship between genes and traits is far from simple. That fact that a given trait is heritable seems to suggest that there must be genes for that trait. It implies that genes exist that are dedicated to that function, but the fact that a trait is heritable means only that there are genetic variants that affect that trait. There are no genes for complex pschological functions - there are neural systems for such functions and genes that build them. A lot of the variation in mature function stems from differences in how the neural systems develop; the program encoded in the genome can only specify developmental rules, not precise outcomes. And the genetic architecture is not as modular as often thought; any given neural system can be affected by variation in probably hundreds of genes. Innate differences in psychological traits arise from two sources: differences in the program specifying brain development and function, and random variation in how that program plays out in an actual individual.
December 27, 2023
I was pleasantly surprised by how much I liked this, given how much less I liked other modern neuroscience books also published recently (How Emotions Are Made, Projections, The Disordered Mind). Rather than sprawl across other subfields of neuroscience that are only tangentially related, or dabble into philosophical conjecture, Dr. Kevin Mitchell keeps the chapters tight and orderly, focusing specifically on what he promises in the intro – the sources and effects of genetic variation driving individual differences in people's nature. He provides examples of landmark studies that observe the impact of shared genes and shared family environments that drove differences in observable psychology, the historical and modern techniques used that can be used to come to conclusions, and, importantly, summarizes the main points neatly for us to comprehend in full.
As a spoiler, his conclusion is that “Many aspects of the structure of the brain are very highly heritable—that is, most of the variation is due to genetic differences across individuals. Heritability estimates for various measures are: total brain volume, 82%; gray matter volume, 72%; white matter volume, 85%...Twin, family, and population studies have all conclusively shown that psychological traits are at least partly, and sometimes largely, heritable—that is, a sizable portion of the variation that we see in these traits across the population is attributable to genetic variation. However...for psychological traits, the link between gene action at a molecular level and expression of traits at a behavioral level is far too indirect, nonspecific, and combinatorial for [turning genes on and off equates to turning traits on and off]...variation in our genes and the way our brains develop cause differences in innate behavioral predispositions—variation in our behavioral tendencies and capacities. Those predispositions certainly influence how we behave in any given circumstance but do not by themselves determine it—they just generate a baseline on top of which other processes act. We learn from our experiences, we adapt to our environments, we develop habitual ways of acting that are in part driven by our personality traits, but that are also appropriately context dependent."
Or rather said, there is a large aspect of our brain structure and wiring that is highly heritable, but heritability as a measure is proportional to the population being measured. There is constant interplay between genetics and the external influence of upbringing on behavioral development, and separating the two into nature and nurture is a false dichotomy, as controlling for either – through a Brave New World program of fertilization, or a deliberately prescribed environment – will not uniquely determine outcomes, but only probabilities, of behavioral predisposition that are far too fast and complex for us to actually predict given the complexity of the question.
Overall, I would recommend reading if you are moderately interested in the field and enjoy/enjoyed science (even at the high school level), but it is probably too specific and too jargon-y to be labeled a "popular science" book for the broader audience. As a litmus test, go on Youtube and search for his debate with Robert Saplosky on free will vs. determinism. If the water feels like the right temperature, dive right into this! If that's boring for you, you'll probably not enjoy this either.
As a spoiler, his conclusion is that “Many aspects of the structure of the brain are very highly heritable—that is, most of the variation is due to genetic differences across individuals. Heritability estimates for various measures are: total brain volume, 82%; gray matter volume, 72%; white matter volume, 85%...Twin, family, and population studies have all conclusively shown that psychological traits are at least partly, and sometimes largely, heritable—that is, a sizable portion of the variation that we see in these traits across the population is attributable to genetic variation. However...for psychological traits, the link between gene action at a molecular level and expression of traits at a behavioral level is far too indirect, nonspecific, and combinatorial for [turning genes on and off equates to turning traits on and off]...variation in our genes and the way our brains develop cause differences in innate behavioral predispositions—variation in our behavioral tendencies and capacities. Those predispositions certainly influence how we behave in any given circumstance but do not by themselves determine it—they just generate a baseline on top of which other processes act. We learn from our experiences, we adapt to our environments, we develop habitual ways of acting that are in part driven by our personality traits, but that are also appropriately context dependent."
Or rather said, there is a large aspect of our brain structure and wiring that is highly heritable, but heritability as a measure is proportional to the population being measured. There is constant interplay between genetics and the external influence of upbringing on behavioral development, and separating the two into nature and nurture is a false dichotomy, as controlling for either – through a Brave New World program of fertilization, or a deliberately prescribed environment – will not uniquely determine outcomes, but only probabilities, of behavioral predisposition that are far too fast and complex for us to actually predict given the complexity of the question.
Overall, I would recommend reading if you are moderately interested in the field and enjoy/enjoyed science (even at the high school level), but it is probably too specific and too jargon-y to be labeled a "popular science" book for the broader audience. As a litmus test, go on Youtube and search for his debate with Robert Saplosky on free will vs. determinism. If the water feels like the right temperature, dive right into this! If that's boring for you, you'll probably not enjoy this either.
November 3, 2022
decent info dump, twin study was interesting and my favorite part, also the idea that low intelligence is just the number of small mistakes rather than a lack of a smart person gene was convincing, and that very high and low being not very hereditary is prob not very genetic.
Was hoping it defined personality better and at the beginning. the 5 traits thing was insightful. to make this book more interesting it could have shown if there was correlation between genes and wealth, monogamy, or creativeness (since divergent thinking is a predictor of success but IQ is not, at least after college), and if that correlation holds up across different countries or cultures. Also on the other end would have been interesting to see if there was a gene that most orphans, or criminals shared. Knee jerk reaction would be that this would be an almost cruel correlation to shed light on but this book was completely on the side of determinism and was a wink or elbow rub away from eugenics, and oh sure he covered his butt by saying it definitely wasn't eugenics, but eye roll to that haha he should have just said what he wanted to say and got put on the bad boy shelf next to the bell curve.
I did my own research and there is negligible correlation between genes and wealth. some correlation between genes (2 specifically that mostly controlled for how much dopamine one gets from drugs...interesting) and highly violent, and repeat criminals and rest of population including one time offending criminals. Also creativity in one of those insightful twin studies showed 25% determination for creativity which is less than it determines for personality. anyhow interesting but im a little distrustful of recent statistics given the Repeatability Crisis (https://en.wikipedia.org/wiki/Replica...) in science.
though differences in people seems difficult to show in small studies there is strong evidence of our species long term decline in aggressiveness and intelligence, and increase in agreeableness because of our lack of predators and abundance of resources. basically with such a low bar for survivability, reducing offspring amounts by taking time to find a good partner or reducing brood size is a loosing strategy (see r/K). with these conditions and a loooong time (unlikely with tech and CRISPR on the way) then our gene pool can afford more variably/general decline in intelligence and other survivability traits. We are already less 'fit' (and have much smaller brains) than people 3k years ago, however im sure my lack of success is not a representation of my intellect.... or maybe...“No one is satisfied with his fortune, and everyone is satisfied with his wit.”― Leo Tolstoy, Anna Karenina
:D
Was hoping it defined personality better and at the beginning. the 5 traits thing was insightful. to make this book more interesting it could have shown if there was correlation between genes and wealth, monogamy, or creativeness (since divergent thinking is a predictor of success but IQ is not, at least after college), and if that correlation holds up across different countries or cultures. Also on the other end would have been interesting to see if there was a gene that most orphans, or criminals shared. Knee jerk reaction would be that this would be an almost cruel correlation to shed light on but this book was completely on the side of determinism and was a wink or elbow rub away from eugenics, and oh sure he covered his butt by saying it definitely wasn't eugenics, but eye roll to that haha he should have just said what he wanted to say and got put on the bad boy shelf next to the bell curve.
I did my own research and there is negligible correlation between genes and wealth. some correlation between genes (2 specifically that mostly controlled for how much dopamine one gets from drugs...interesting) and highly violent, and repeat criminals and rest of population including one time offending criminals. Also creativity in one of those insightful twin studies showed 25% determination for creativity which is less than it determines for personality. anyhow interesting but im a little distrustful of recent statistics given the Repeatability Crisis (https://en.wikipedia.org/wiki/Replica...) in science.
though differences in people seems difficult to show in small studies there is strong evidence of our species long term decline in aggressiveness and intelligence, and increase in agreeableness because of our lack of predators and abundance of resources. basically with such a low bar for survivability, reducing offspring amounts by taking time to find a good partner or reducing brood size is a loosing strategy (see r/K). with these conditions and a loooong time (unlikely with tech and CRISPR on the way) then our gene pool can afford more variably/general decline in intelligence and other survivability traits. We are already less 'fit' (and have much smaller brains) than people 3k years ago, however im sure my lack of success is not a representation of my intellect.... or maybe...“No one is satisfied with his fortune, and everyone is satisfied with his wit.”― Leo Tolstoy, Anna Karenina
:D
June 7, 2019
The author advances answers and explanations for many of the fundamental questions which vex clinicians such as myself. The difference from most such fare is that this guy knows what he’s talking about. He really really knows his stuff.
Two aspects make this book stand out. The author demonstrates the infallible sign of true mastery of the subject of discussion - the ability to use plain English, and explanations by analogy, to convey complex concepts to also-ran readers like me.
That feat is allowed in part by the author’s command of related contemporary psychology, and philosophy. The insight on show, in those areas, is deeper than that displayed by many current loudmouth professional psychologists and philosophers.
The most important concept expounded, the most important fact for any clinician reader to grasp, is that of the many-to-one and one-to-many relation between genetic variations on the one hand, and clinically defined entities such as autism and schizophrenia, on the other. Autism can be caused by many different genetic variations; because it is not really one disease/disorder. Whereas one genetic variation which causes autism in one individual will cause a different ‘condition’, or nothing at all, in another individual.
But there’s heaps of other important, interesting stuff too.
Complaints? Well, I could point out that the book does not contain any sophisticated examination of the construct of ‘ADHD’, only passing mentions. This is almost certainly because the author has spent no time in his academic life, examining the entity himself. This in turn indicates that the author isn’t stupid, since examination of the quasi-entity currently called ADHD is obviously a dead end which no amount of attempted sciencing will add to. But I would have enjoyed the book even more if the author had wasted a year or two of his academic life before he realised that, and written of his revelation - see above about his not being stupid, however.
Also, I listened to the audiobook. I understand the choice of a fairly posh sounding English narrator; he does an excellent job. Americans can’t understand most Strine (unadulterated Australian accent and vernacular); only an enlightened minority would make sense of Full Irish Narration.
But still it seems a shame - key observations, such as the following contained in Chapter 9, would have sounded even more compelling if uttered by the likes of Dylan Moran: “Men also have thicker skulls, especially in front, which may reflect the fact that we like to punch each other in the face a lot.”
Two aspects make this book stand out. The author demonstrates the infallible sign of true mastery of the subject of discussion - the ability to use plain English, and explanations by analogy, to convey complex concepts to also-ran readers like me.
That feat is allowed in part by the author’s command of related contemporary psychology, and philosophy. The insight on show, in those areas, is deeper than that displayed by many current loudmouth professional psychologists and philosophers.
The most important concept expounded, the most important fact for any clinician reader to grasp, is that of the many-to-one and one-to-many relation between genetic variations on the one hand, and clinically defined entities such as autism and schizophrenia, on the other. Autism can be caused by many different genetic variations; because it is not really one disease/disorder. Whereas one genetic variation which causes autism in one individual will cause a different ‘condition’, or nothing at all, in another individual.
But there’s heaps of other important, interesting stuff too.
Complaints? Well, I could point out that the book does not contain any sophisticated examination of the construct of ‘ADHD’, only passing mentions. This is almost certainly because the author has spent no time in his academic life, examining the entity himself. This in turn indicates that the author isn’t stupid, since examination of the quasi-entity currently called ADHD is obviously a dead end which no amount of attempted sciencing will add to. But I would have enjoyed the book even more if the author had wasted a year or two of his academic life before he realised that, and written of his revelation - see above about his not being stupid, however.
Also, I listened to the audiobook. I understand the choice of a fairly posh sounding English narrator; he does an excellent job. Americans can’t understand most Strine (unadulterated Australian accent and vernacular); only an enlightened minority would make sense of Full Irish Narration.
But still it seems a shame - key observations, such as the following contained in Chapter 9, would have sounded even more compelling if uttered by the likes of Dylan Moran: “Men also have thicker skulls, especially in front, which may reflect the fact that we like to punch each other in the face a lot.”
July 19, 2023
This book is a good overview of genetic studies. The author aims to show how both genetic and developmental variation contribute to innate differences in people’s natures.
He covers the following:
- a conceptual overview of the origins of innate differences in human faculties looking at the evidence from twin and adoption studies of genetic effects on human psychological traits, brain anatomy, and brain function.
- genetic variation, where it comes from and the kinds of effects it can have.
- how differences in the DNA sequence ultimately impact the kinds of traits we are interested in through effects on development.
- the role of nurture in shaping people’s psyches.
- the environments and experiences we each have and how the way our brains react to them are largely driven by our innate traits.
- personality, perception, intelligence, and sexuality.
- genetics of common neurodevelopmental disorders, such as autism, epilepsy, and schizophrenia.
- social, ethical, and philosophical implications answering the following questions:
* If people really have large innate differences in the way their brains and minds work, what does that mean for education and employment policies?
* What does it mean for free will and legal responsibility?
* Does it necessarily imply that our traits are fixed and immutable?
* What are the prospects for genetic prediction of psychological traits?
* What limits does developmental variation place on such predictions?
* How does this view of the inherent diversity of our minds and our subjective experiences influence our understanding of the human condition?
He covers the following:
- a conceptual overview of the origins of innate differences in human faculties looking at the evidence from twin and adoption studies of genetic effects on human psychological traits, brain anatomy, and brain function.
- genetic variation, where it comes from and the kinds of effects it can have.
- how differences in the DNA sequence ultimately impact the kinds of traits we are interested in through effects on development.
- the role of nurture in shaping people’s psyches.
- the environments and experiences we each have and how the way our brains react to them are largely driven by our innate traits.
- personality, perception, intelligence, and sexuality.
- genetics of common neurodevelopmental disorders, such as autism, epilepsy, and schizophrenia.
- social, ethical, and philosophical implications answering the following questions:
* If people really have large innate differences in the way their brains and minds work, what does that mean for education and employment policies?
* What does it mean for free will and legal responsibility?
* Does it necessarily imply that our traits are fixed and immutable?
* What are the prospects for genetic prediction of psychological traits?
* What limits does developmental variation place on such predictions?
* How does this view of the inherent diversity of our minds and our subjective experiences influence our understanding of the human condition?
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