Warning: long thread. I just finished listening to @WiringTheBrain's (Kevin Mitchell's) new book, Innate, based on a tweeted rec by @carlzimmer. I loved it - excellent book. It is VERY powerful in pointing out all the ways things can be "innate" w/o having been parents' DNA.
2/ These include notably the often overlooked effects random variations in humans & our development. Mutations in egg/sperm, somatic mutations, & the chance outcomes of much of embryonic development (esp in the brain). It argues powerfully (& somewhat against my own preferences)
3/ that many/most psychological traits are STRONGLY innate - not 100% but strongly. Esp good chapters on perceptual differences (wh/I kind of knew about but greater than I thought), sex differences & mental illnesses.
4/ I esp liked his point that nurture often reinforces, doesn't counter, nature. If you have some innate traits that make you an unlikeable baby, people's reactions to you may reinforce that. If you have some innate traits that make more likely to be good at school, people's
5/ positive reactions will reinforce those traits, incl/by physically changing the brain. Great point I'd not considered. I also liked his point that bigger brain regions in some people (or sexes) may not mean "better" - might mean "less efficient so must be bigger to be as good"
6/ There were some times when I thought it could have used another hard edit to make it more internally consistent. He early stresses importance of regulatory DNA but later talks of mutations only being important if they are in the "3%" of important DNA. I know he knows better.
7/ Similarly he focuses more on DNA as the book goes on. He stresses early that chance in development (say 70/30 odds on neurons going the right place) are important but later proclaims all mental illness is genetic (before qualifying that a bit late in that chapter).
8/ Then there are things I wish he had discussed more. I'd love more discussion than I recall in the book about mosaicism, esp the apparently high level of it in brain neurons, And I wish he had paid a bit more attention to pleiotropy. He considers it at points but not always.
9/ (I think.) E.g., he says small IQ boosting alleles are likely to be fixed in pops but IQ lowering ones won't be but should be under selection pressure. But what if IQ+ has, in some environments (external or genetic) non IQ effects that outweigh their benefits (& vice versa)
10/ I do have another IQ question. He argues strongly that it is largely innate & heavily genetic. But he does discuss the Flynn effect (pop mean IQs increasing over time). And he has an eg that makes this descendant of East Galway (Mc)Grealy's happy - the Irish.
11/ He says mean Irish IQ was ca 85 in '70s but ca 100 in late '90s. Attributes to change from rural, poor, unhealthy, poorly educated lives to urban, wealthier, healthier, & better educated ones. Very plausible. BUT isn't that nonfamily environment, wh/he thinks is minor in IQ?
12/ If we separate MZ twins at birth and sent one to the Fanad (poor peninsula in Donegal - I've got Fealty's from there) and one to Dublin, would he expect big IQ difference? I think he wouldn't, but why not? MAYBE rural/urban works thru prenatal development effects only. Maybe.
/13 I like that he ended w/an ethics discussion - & one that even referred to embryo selection w/stem cell derived gametes (my Easy PGD from End of Sex). Not only did I like that he discussed ethics issues, I liked his discussion.
/14 This thread is so long not bec/I didn't like the book but bec/i did. Taught me new stuff AND made me think. One "small world" point - after a Berkeley PhD (good school says this Stanford grad) he did a Stanford postdoc - w/my current next door neighbor, Marc Tessier Lavigne.
/15 (and last - I promise) Anyway, I strongly recommend Innate. It's written a good level for interested nonspecialists. He does basic intros to brain and to genes that should be helpful & he keeps jargon to a minimum. Three (I'm a mutant) thumbs up!
