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Everything you said was incorrect. There isn't a single trait ever examined in which the impact of shared environment is larger than the genetic impact. In othe

by sadris 8y ago

Everything you said was incorrect. There isn't a single trait ever examined in which the impact of shared environment is larger than the genetic impact. In other words, the heritability of every trait ever examined is vastly larger than the effect of the shared environment (nurture). It's literally the second law of behavioral genetics: The effect of being raised in the same family is smaller than the effect of the genes. And about evolution, also wrong. We have evolved 100x faster in the past 5000 years than in the Pleistocene. https://en.wikipedia.org/wiki/The_10,000_Year_Explosion https://en.wikipedia.org/wiki/The_10,000_Year_Explosion People like to believe in falsities like yours because they don't want to admit than ability is mostly innate and there's nothing we can do about it.

belorn 8y ago
Most people misunderstand heritability, but there is an excellent video I can recommend by professor Robert Sapolsky: https://youtu.be/RG5fN6KrDJE?t=2427 https://youtu.be/RG5fN6KrDJE?t=2427 A common finding is that if you want to explain data around a trait and you can only know the environment or the gene, the environment is usually the better choice. The interaction between genes and traits is very counter intuitive for most people. As an example from the lecture, if we asked people how heritabile the number of fingers a person has we would expect the answer would be 100% since it is very rare for a person to be born with 4 fingers. But if we asked if genes or environment is the best method to explain why some people have 4 fingers, genes are a very proof explanation since finger amputation are caused very rarely from genes. The variation of fingers among humans has thus a very low (almost 0%) heritability. Heritability == the observed variation in the data set that can be explained from genes.
- sadris 8y ago
  Correct. That's why I explicitly said shared environment (the "nurture") and not all environment (which includes non shared environment). When comparing nature vs nurture it's going to be always nature. When comparing total trait variance, the genetically explained variance is on average 50% (averaged across all traits). A fraction of the remaining 50% is non shared environment (randomness) and a minute/neglible amount is shared environment (nurture).
speedplane 8y ago
> the heritability of every trait ever examined is vastly larger than the effect of the shared environment You're entirely misunderstanding heritability. Heritability is just the passing of traits to offspring, genetics may play a part in it, but likely a small part. Do children that read lots of books do so because their parents gave them good "book reading genes", or because they nurtured them in an environment where that was encouraged? Dawson illustrates this well with the heritability of tattoos. People are far more likely to get tattoos if their parents did, thus it is a heritable trait. According to your reasoning, the parents must have passed down a tattoo gene. Heritibility has as much (or more) to do with nurture than it has to do with nature.

by sadris 8y ago

belorn 8y ago

Most people misunderstand heritability, but there is an excellent video I can recommend by professor Robert Sapolsky: https://youtu.be/RG5fN6KrDJE?t=2427 https://youtu.be/RG5fN6KrDJE?t=2427 A common finding is that if you want to explain data around a trait and you can only know the environment or the gene, the environment is usually the better choice. The interaction between genes and traits is very counter intuitive for most people. As an example from the lecture, if we asked people how heritabile the number of fingers a person has we would expect the answer would be 100% since it is very rare for a person to be born with 4 fingers. But if we asked if genes or environment is the best method to explain why some people have 4 fingers, genes are a very proof explanation since finger amputation are caused very rarely from genes. The variation of fingers among humans has thus a very low (almost 0%) heritability. Heritability == the observed variation in the data set that can be explained from genes.

sadris 8y ago
Correct. That's why I explicitly said shared environment (the "nurture") and not all environment (which includes non shared environment). When comparing nature vs nurture it's going to be always nature. When comparing total trait variance, the genetically explained variance is on average 50% (averaged across all traits). A fraction of the remaining 50% is non shared environment (randomness) and a minute/neglible amount is shared environment (nurture).

speedplane 8y ago

> the heritability of every trait ever examined is vastly larger than the effect of the shared environment You're entirely misunderstanding heritability. Heritability is just the passing of traits to offspring, genetics may play a part in it, but likely a small part. Do children that read lots of books do so because their parents gave them good "book reading genes", or because they nurtured them in an environment where that was encouraged? Dawson illustrates this well with the heritability of tattoos. People are far more likely to get tattoos if their parents did, thus it is a heritable trait. According to your reasoning, the parents must have passed down a tattoo gene. Heritibility has as much (or more) to do with nurture than it has to do with nature.