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Top Replicated Findings from Behavioral Genetics (2016) (sagepub.com)
73 points by erentz 7 months ago | hide | past | web | favorite | 19 comments



While behavioral genetics is claiming victory in the replication crisis, it should not rest on it's laurels. Replicability is a sign that studies can be conducted consistently. However in the case of behavioral genetics, one fears that all they have managed to do is reproduce and scale up erroneous research designs.

Consider finding 3: "Heritability is caused by many genes of small effect"

This is exactly what you would expect to find if you do a regression with 1000s of variables: many effects, mostly small ones.

Of the 10 findings only 1 is clearly not a fact about statistics in settings where dimensionality is very high relative to sample size.

Finding 5. The heritability of intelligence increases throughout development

Observe that this finding is based not on associations between particular genes and traits, but instead on twin studies. Twin studies have their own problems when it comes to causal identification.

That said, the overall claims here make sense and have some empirical support. My point is that the field has long made outsized claims based on dubious science that is legitimized by it's appropriation of genetics (even though it is a branch of psychology, not biology).

Panofsky's book "Misbehaving Science: Controversy and the Development of Behavior Genetics" is excellent.


I don't think this paper was even about replication.

A replication is when one person/group does something, they write down instructions for someone else to do the same thing, and then the results are compared. Is there a single mention of this happening in that paper? I expected a table of such results.

Ie, replication is about doing some very specific thing, instead I see a bunch of vague stuff like "abnormal is normal"...


> This is exactly what you would expect to find if you do a regression with 1000s of variables: many effects, mostly small ones.

No, GWAS is smarter than that.


Wow, I didn't realize so much progress had been made in behavioral genetics in the last decade. Some of these findings are pretty mind-blowing.

The article mentions multivariate regression quite frequently—does anyone know if more recent machine learning techniques have made their way into the field?


| does anyone know if more recent machine learning techniques have made their way into the field?

Oh god I hope not.


The paper is written by behavioral geneticists and thus merits some skepticism. As another commenter notes, many of their “top 10 findings” are basically statements about statistics.


Machine learning is for identifying pictures of cats. Regression is for testing the statistical significance of the estimated effects of your variables. Right tool for the right job.


As someone with a background in neither genetics or psychology beyond a layman's interest, this was surprisingly readable and informative.


The research starts off with citing stats against psychological research, which I am fine with. What I don't understand is; how do governments and private companies appear to have such an absolute grip on human behavior? They can control your carreer, they can make you buy things you don't need, make you sick without you being aware of it and place every complaint under the labels of "fuss" and "conspiracy", those academics publishing unreplicatable papers look like fools in comparison, despite being the actual cited experts.


because while governments and companies do it all the time, they don't really know what exact part that they do is actually effective, while the academics job is to dissect and explain what exactly works and why.


Tweet sized: genes are everything, shared environment zero, and measurement error the rest.


From the paper:

> Finding 2. No traits are 100% heritable Although heritability estimates are significantly greater than 0%, they are also significantly less than 100%. As noted earlier, heritability estimates are substantial, typically between 30% and 50%, but this range of estimates is a long way from 100%.

Besides, some of the findings look significantly over generalized, and the ones that aren't don't seem very revolutionary or intetesting.


You are not going to be able to put this nuance in a tweet, but the major problem with estimating the heritability of phycological factors is the error bars are massive. You can’t even get near the same results when you measure the same person on different days.

While there is obviously a non-shared environmental component, it is really noise. The only factors that people care about are the factors that can be studied; shared environment (that is all the environmental factors that can in theory be measured) and genes. Non-shared environment is just what is left over once you account for measurable environmental factors and genes.


If I've understood correctly, what you're saying is that there's really too much noise is the results which can neither be explained by shared environment, or genetics?

I've browsed the paper, but must of missed it. How big are the error bars? Is it possible to get a sense of how much variation is explained by genetics alone?


There are three components to the variance: genetics, shared environment, and non-shared environment (noise basically). Shared environment is almost immeasurable for most of these traits (under 10%) while most is the variance is due to genetics or non-shared environment. The way non-shared environment is determined is by subtracting genetics and shared environment from the total varience. The worse the test the bigger the component that ends up in the non-shared environment factor.

The error bars depend on the trait being measured. Some are relatively small (like g), while others like "agreeableness" (just choosing a random trait) will be quite large as it is hard to measure this accurately and consistently.


Are you saying that patents don't matter any more than their genetic contribution? I would have a very difficult time believing that.


I think you might mean parents, but for most of the measurable general psychological traits then yes. As a parent it is in somewhat depressing, but on the other hand liberating. Provided you provide a basic level of love and support then your contribution to the basic personality of your children ends at conception.


The "environment depends on genes" part was pretty interesting.


If genetics determines behavior then we should be able to gene edit our way to perfect virtue.




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