Comment by wycs | Hacker News Reader

Comment by wycs | Hacker News Reader

I don't think we can rule out an evolutionary explanation so quickly. We are starting to get firm genetic evidence that something like dysgenics is occurring in Iceland, for example:http://www.pnas.org/content/early/2017/01/10/1612113114

There is also a plausible mechanism of action, intelligent people tend to get an education proportionate to their intelligence. Educated people have ridiculously low birth rates. Intelligence is heritable.

Just like conservatives will have to overcome their global warming denial, those of the progressive tradition may well have to start accepting what cognitive genomics is making increasingly obvious: intelligence is hereditary and this has policy implications.

Should it prove to be a genetic decline, we have solutions, such as embryo selection, in the wings that can work now with little research. This will get us ~3-8 IQ points per generation:https://www.gwern.net/Embryo-selection

Iterated embryo selection and genetic engineering will be able to offer much more, several standard deviations in multiple traits simultaneously.

But we cannot repair problems we refuse to look in the face.

> Intelligence is heritable

I believe parent is getting downvotes because of this, but this isn't a matter of opinion or social science. It's hard quantitative genetics: https://en.wikipedia.org/wiki/Heritability_of_IQ

This is the crux of any inter-generational change in average intelligence in a population. Human assortative mating patterns and the inverse relationship between intelligence and fertility account for some of the effect and some is due to shifts in the gene pool. While we can't and shouldn't discount environmental effects (goodbye lead paint!), the latest genetics research tells us that only 15-25% of variation in intelligence can be attributed to the environment.

But how does assortative mating account for it? One would then expect at least neutral relationship between fertility and intelligence.

Smart people tend to reproduce with other smart people, but they reproduce an awful lot less. Interestingly, smart people having low fertility is a rather recent phenomenon. Lots of famous scientists came from huge broods.

famous scientists are probably exceptional enough to not be accounted into statistics. The questions is why they breed less.

>15-25%

Citation, please?

Click the wikipedia link I shared in the post you're replying to.

Heritability and genetic determinism aren't the same thing, at all, despite what you and the grandparent comment wrote.

We’re not talking about individuals, we’re talking about large groups.

> We have solutions, such as embryo selection , in the wings that can work now with little research. This will get us 3-8 IQ points per generation.

Can you provide some links to support this? I wasn't aware a trait as complex as intelligence was anywhere close to being selectable in embryos. You name a very specific "3-8 IQ points ours generation" though so I'm assuming you got this value from somewhere.

See gwern's write up: https://www.gwern.net/Embryo-selection

We can predict roughly 16% of the variance in IQ.

The article cites a recent study showing the IQ decline in pairs of siblings starting at the same time as the broader observed decline happened.

for every such study there are probably 10 twin studies showing that intelligence is heritable.

Heritable and genetically determined are not the same thing, and the findings of these kinds of studies are less clear-cut than you suggest:

> In all of these twin studies, however, researchers have rarely accounted for differences in the social context.

...

> Highlighting the insights of Kurt Lewin more than 70 years after his work, the researchers found that socioeconomic background had a major impact on genetic influences on intelligence: More specifically, when twins were reared in high socioeconomic status environments, genes accounted for approximately 72% of variance in intelligence scores between twins. When reared in low socioeconomic status environments, genes accounted for only about 8% of variance in intelligence within the twin pairs.

Source: https://www.psychologytoday.com/au/blog/under-the-influence/...

I used to subscribe to this kind of simple genetic determinism.

I've since had cause to pursue a path in life in which I've become deeply aware of the other influences on intellect, cognition and judgement, which include the emotional environment (trauma, abuse, chronic fear/anxiety) and the nutritional and chemical environments.

From researching this topic extensively over several years, I'm confident in the belief that even if embryo selection were to help at all, it won't help enough to overcome these other factors.

Conversely, there’s a lot than can be done to help people improve their cognitive ability, regardless of their genetics, by altering these environmental factors.

See:

https://www.researchgate.net/publication/325704105_Flynn_eff...

Although there is still one possible genetic cause, which is people (both women and men; in fact, some studies show the effect is stronger for men: https://www.nature.com/articles/gim200868) having children later in life.

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