Dammit Pinker, you’re supposed to say “this research only applies to
large groups, not individuals. Judge people as individuals”. You can’t
just give away the game like this!
A truly enlightened observation my good gentlethem.
Your religion, nationality, and coat of arms, not to mention your Erdős number, history of familial rapid onset social justice warfare, or propensity to take unshakeable pride in the use of gas-powered leafblowers; all of the latter, after conducting manifolds experiments, dare I say courageously and at great risk to my réputation personnelle within the politically correct academic establishment, after, I say, carefully combing through exquisitely large datasets, and using the utmostly sophisticated Big Data analytics, I have, of my very own, discovered them to be very heritable and geneticy indeed.
I wonder why nobody corrected him.
"A conversation between @sapinker and people they follow or mentioned in this Tweet." Aha.
Well would be doubly ironic if he has weird stances on free speech/cancel culture, but im sure he isn't one of those.
E: Im also sure he is going to get so much flak from the rightwingers who are mad anytime somebody turns off the comments.
No, in academia, absolutely not. Heritability is strictly and explicitly a genetic reference. Anyone using it otherwise is using it colloquially, and the conflation is plausibly deliberately trojan'd to use as a motte. In this tweet, Pinker, certainly aware of the conventional scientific usage of "heritability", is absolutely asserting that personality is highly genetically determined, but can easily fall back to the false claim that he was *meaning*, environmental "inheritances" colloquially, knowing full well that the usual term for that is "influences" or "factors". Despicable.
Yeah, it can definitely be confusing, and you're both basically correct, just in different ways.
[Heritability](https://en.wikipedia.org/wiki/Heritability) is: 1) the degree of variation in 2) a particular trait found in 3) a specific population 4) that can be attributed to genetic variance. This is essentially always an estimate, though of course the degree of accuracy varies. Other causes of variation are considered "environmental factors."
Notice what that definition ends up doing, though: whatever degree of variation *cannot* be attributed to genetic variance *must necessarily be attributable to environmental factors instead*. In other words, "genetic variance" and "environmental factors" are both mutually exclusive and collectively exhaustive. Moreoever, we can't determine heritability in the first place without studying any environmental factors that may be involved.
So while it is entirely accurate to say that "heritability is strictly and explicitly a genetic reference," because the term specifically refers to the measurement regarding genetics, it would also be entirely accurate to say that "heritability is determined by environmental factors," because in quantifying one, you by definition quantify the other. Whatever is left once you've taken environmental factors into account is heritability, and vice versa.
> Notice what that definition ends up doing, though: whatever degree of variation cannot be attributed to genetic variance must necessarily be attributable to environmental factors instead.
There's some fascinating research on stochasticity during development which adds a third factor: A lot of what happens in our bodies isn't deterministic, but instead is more like weighted randomness (sometimes more heavily weighted so that it's close to deterministic, sometimes less heavily weighted so that it's closer to random). Some of those random decisions get locked in during development.
I put a bunch of links about it together here:
https://www.metafilter.com/185207/How-much-of-us-is-just-random
The stuff on brain development is extremely interesting. When the neurons in our brains are growing, the growth process is [stochastic](https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2011.2629) and [exuberant](http://web.mit.edu/~tkonkle/www/BrainEvolution/Meeting6/Innocenti%202005%20NRN.pdf). In other words, more neurons than are needed are given instructions to "grow in that general direction until you get this signal, then turn right, then keep going until you receive this other signal. If you don't get the correct signals, please kill yourself." The neurons grow by randomly pushing out a little bit in multiple directions and sniffing out where the signals they're looking for are strongest. It's not unlike the way that ants or termites build their nests, and the result is similar: Termite mounds from the same species have the same structure, but when you look closely you see lots of little differences because of the semi-stochastic method of construction.
Pinker's final offhand comment in the tweet ("Remaining variance in pers is largely random") is taking the extreme view of what's fairly preliminary research about this stuff at this point. We have no idea right now how big or important this effect is; we just know that it's happening.
We also know that the structure that's being set up is a structure *built for learning*, explicitly designed to be modified by experience. Part of what leads to statements like Pinker's is that when we're doing studies looking for the effect of genetics on personality traits, we're looking for *personality traits*, i.e. things that we've discovered don't change much over someone's lifespan. When you're looking for the cause of something that doesn't change much, you're likely to find causes that don't change much.
If we were doing more studies of the connection between genetics and things about us which we know change as we learn, we'd probably wouldn't find much of a connection between them and genetics, now, would we?
I've been thinking more about my last point.
Psychologists spent a century trying - and often failing - to find stable personality traits, stuff where people would give the same answer if you asked them twice. After throwing away a lot of traits that turned out to not be very stable (ask a research psychologist [what they think](https://www.vox.com/2014/7/15/5881947/myers-briggs-personality-test-meaningless) of Meyers-Briggs, for example), they're finally getting closer to finding a collection of traits which don't change much over time, which aren't much affected by learning and environment.
It's not surprising that the stable traits they've found would have a strong genetic component. Stable traits == stable causes. But: The many traits they've had to throw away in their search for stable traits are also important human traits. Thinking that "stable traits == genetics => genetics is the most important thing about us" ignores how hard it is to find stable traits that aren't affected by learning and experience. Unstable, learning-affected traits are also a very human thing.
Well whats about going through the “environment”? E.g. there are genes affecting muscle composition, and then there is being a couch potato which in Pinker’s world is genetic too.
>it would also be entirely accurate to say that "heritability is determined by environmental factors,"
No. No. Why would you do this. No one would say this, it is *extraordinarily confusing and inaccurate*. Only you have said this, and one would only say this in seriousness in order to piss off a biologist. I'll fix it for the sake of my mental health:
"heritability is statistically determined by **the exclusion of** environmental (and random) factors"
The issue is that the parent comment says:
>"doesn't heritable [...] include the [environment]?
no, heritability specifically excludes the environment, it is defined by this exclusion, as you (badly) and I have pointed out. There is no ambiguity here. So when Stinker says in the tweet that personality is highly heritable, and therefore, by definition, **not** highly environmentally determined, he can get away with it because confusion around the words 'heritability' and 'environment' leads people to think that "heritable" may as well just mean "exists for some non-random reason".
I appreciate the clarification, thank you, though "piss[ing] off a biologist" wasn't my intention in the slightest, and I apologize for doing so.
In my defense, the most common confusion I see specifically in the context of the "rationalsphere" is to (mis)interpret heritability as meaning "the ability to be genetically inherited," and then use that as the basis of racist pseudoscience (as I'm sure you're well aware), so I wanted to emphasize how heritability and environmental factors, though distinct, are related to each other, though clearly I didn't do so very well.
s'all good, I wasn't angry, just horrified by the potential
>one would only say this in seriousness
I was not referring to you, only some hypothetical one saying it for realsies.
I guess thes braincels are meaning to say heredity, but even that isn't the *ability* to genetically inherit, but rather fact of inheritance itself. Goddamn I hate these rigourless hucksters...
I would encourage you to have less surety in your tone while being schooled when your admitted qualification is reading an FAQ. Please read my username.
Anyway, yes, it is explicitly that. Another name for gene is "unit of [phenotypic] inheritance". The "mechanism that allows one to define a trait"? What? Traits are just that which we can measure. The mechanism of definition is just the question: 'can you measure it?'.
Every trait has a genetic component and a non-genetic component. For every trait, every individual differs from every other individual in ways that can be measured. Within a population, those differences will have a range that can be described. Some proportion of that range will be due to differences in environmental exposure and random chance. The remaining proportion will be due to genetic difference between individuals. This remaining proportion due to explicitly non-environmental and non-random and therefore genetic factors is called heritability, on the basis of genes being the mechanism of trait inheritance. You could have a trait that barely changes at all in a population (low variation), with none of the difference due to environmental factors (high heritability in a low variation trait). You can do the other thought experiments to work it out further.
Guesswise, you might have been referring to the binomial proportions of nature vs nurture **in a given individual**. Sample sizes of one are meaningless. Or you could be referring to the lazy ascription of definitional impotence from laypeople who decline to either do the work of understanding the ongoingly refined concept of a gene, or, admit the stagnation of their knowledge. Or you could be using "trait" in the psychological sense of meaning "disposition". Either way, throw that all out, the take-home message is: in the measuring of variation of a phenotypic trait in a population, the proportion of variation that is due to genetic variation in the population is called the heritability of the trait. It is only relevant when discussing changes in range of trait expression in a population, **a single** population, over time. Comparing heritabilities between populations is meaningless.
Yes, I thought that might have been the case, but I left my opening remark in anyway so as to have this brief aside. Rhetorical questions can be sneeringly passive-aggressive, and American culture encourages use of passive-aggression. I wanted to bring attention to the possible parse, while believing it to be most likely unintentional.
I think a lot of people tend to interpret "the heritability of personality trait X is 0.7" to mean "70% of your personality with regards to X is determined by your genes alone", which is clearly wrong.
I'm interested though, what would be the right way to interpret a finding like "nationalism has a heritability of 0.5"? (Obviously our genes don't know what nations are!)
This seems to be a confusion of Pinker’s between personality as
defined by psychometrics, and the ordinary-language meaning of the term,
which includes, e.g., propensities to behave in certain ways in certain
social contexts, and which obviously can include learned behaviors.
Gonna undertake a research program to identify and eliminate the racism gene
Dammit Pinker, you’re supposed to say “this research only applies to large groups, not individuals. Judge people as individuals”. You can’t just give away the game like this!
Doesnt heritable in humans include the household?
This seems to be a confusion of Pinker’s between personality as defined by psychometrics, and the ordinary-language meaning of the term, which includes, e.g., propensities to behave in certain ways in certain social contexts, and which obviously can include learned behaviors.