Michael MuthukrishnaNov 29, 2022

🚨 What's the cultural evolution of genetic heritability?

We got a lot of commentaries on our article. Here's a 🧵 summary of our reply "Integrating cultural evolution and behavioral genetics".

But first, in case you missed it, here's the target article summary. https://t.co/1tMb7vT9S0

Michael Muthukrishna on Twitter

“🚨New target article in @BBSJournal: "Cultural Evolution of Genetic Heritability" w/ @RyutaroUchiyama & @RachelASpicer Preprint: https://t.co/dwQZTj9UyW BBS: https://t.co/c9V7NLiONP Long thread, but important topic. Helps to resolve controversies such as IQ differences 1/”

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Show threadMichael MuthukrishnaNov 29, 2022
We wanted to start a conversation between cultural evolution & behavioral genetics. Both try to explain variation in human behavior yet haven't sufficiently engaged with one another. The response was overwhelming! 29 diverse commentaries were accepted: 1/ https://t.co/rGQq6T7lkZ
Michael Muthukrishna on Twitter

“After the 88 tweet long thread on our recent BBS paper - "Cultural evolution of genetic heritability" - I thought it was only fair to tweet each of the comments we received. Our response has taken us longer than expected, but we're almost done! 1/”

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Show threadMichael MuthukrishnaNov 29, 2022
A truly interdisciplinary group of scholars responded. Researchers in behavioral genetics & cultural evolution, but also evolutionary biology broadly, anthropology, psychology, psychiatry, education, philosophy. They pushed back, raised further points, and suggested extensions 2/
Show threadMichael MuthukrishnaNov 29, 2022
Interdisciplinary research needs a common language. We agonized over phrasing and definitions, but the commentaries revealed discrepancies and misconceptions in word use, particularly around the concepts of heritability, culture, and related terms. I'll save you the minutiae 3/ https://t.co/46jq7CPN4D
Michael Muthukrishna on Twitter

“Interdisciplinary research needs a common language. We agonized over phrasing and definitions, but the commentaries revealed discrepancies and misconceptions in word use, particularly around the concepts of heritability, culture, and related terms. I'll save you the minutiae 3/”

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Show threadMichael MuthukrishnaNov 29, 2022
On heritability, key take homes:
1. culture cannot simply be controlled to calculate heritability. Without modeling and measuring the cultural transmission, heritability tells us very little. These add more flesh to arguments made by @[email protected] over 2 decades ago. 4/ https://t.co/P2MVW8a2iT
Michael Muthukrishna on Twitter

“On heritability, key take homes: 1. culture cannot simply be controlled to calculate heritability. Without modeling and measuring the cultural transmission, heritability tells us very little. These add more flesh to arguments made by @ent3c over 2 decades ago. 4/”

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Show threadMichael MuthukrishnaNov 29, 2022

.@[email protected] & @[email protected] don't go far enough in our opinion, but represent a common view of culture in BG.

Cultural psychologists @[email protected] & @[email protected] make the strongest version of "why bother with heritability at all?" 5/ https://t.co/2OZRs8jfqG

Michael Muthukrishna on Twitter

“.@DavidMShuker & @BSL_MDX don't go far enough in our opinion, but represent a common view of culture in BG. Cultural psychologists @StevenHeine4 & @SCIDLab make the strongest version of "why bother with heritability at all?" 5/”

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Show threadMichael MuthukrishnaNov 29, 2022
.@[email protected] noted that within education research high heritability means an optimal educational environment. 6/ https://t.co/o3bMVewYkG
Michael Muthukrishna on Twitter

“.@SallyLars_27 noted that within education research high heritability means an optimal educational environment. 6/”

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Show threadMichael MuthukrishnaNov 29, 2022
The debate stems from priors for the stability of environments, convergence over time, and commonality between cultural clusters - are we swimming in the same water? To thread the needle, we need to spend as much time measuring culture as we do genes. We offer the framework: 7/
Show threadMichael MuthukrishnaNov 29, 2022
I encourage you to read the responses extending our arguments from @[email protected], @[email protected], @[email protected], @[email protected]. We directly addressed @[email protected] & @[email protected] points about the use of language, always important, but we explained why we disagreed. Your opinion? 8/
Show threadMichael MuthukrishnaNov 29, 2022
The response to @[email protected] needed its own section, which we'll get to in a moment. But first, a few notes about culture. 9/ https://t.co/B6mpH2iEmk
Michael Muthukrishna on Twitter

“The response to @timothycbates needed its own section, which we'll get to in a moment. But first, a few notes about culture. 9/”

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Show threadMichael MuthukrishnaNov 29, 2022
We should have been clearer - by culture we use the standard definition in cultural evolution following Boyd and Richerson and the way culture is modeled in the field as socially transmitted information that affects behavior, rather than a list-like approach. 10/
Show threadMichael MuthukrishnaNov 29, 2022
Can't emphasize this enough: the WEIRD backronym is not a list of traits and was never meant to be. To treat it as a list and try to measure each component would be like measuring the Big Bang by how much "big" and how much "bang". CFst offers a decent proxy scale. @[email protected] 11/
Show threadMichael MuthukrishnaNov 29, 2022
The heart of the disagreement between behavioral genetics and a dual inheritance perspective is laid bare by 3 key questions posed by @[email protected] (thanks!). Check out the back and forth. Here are the questions: 12/ https://t.co/JrsWTcXv41
Michael Muthukrishna on Twitter

“The heart of the disagreement between behavioral genetics and a dual inheritance perspective is laid bare by 3 key questions posed by @timothycbates (thanks!). Check out the back and forth. Here are the questions: 12/”

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Show threadMichael MuthukrishnaNov 29, 2022
1. For how long could a population thrive if furnished with all of today’s inventions and institutions, but shorn of ability-associated genetic polymorphisms? You might spot that this an inversion of the "lost European explorers" often invoked by Boyd & @[email protected]. Preview below:
Show threadMichael MuthukrishnaNov 29, 2022
2. Bates asks whether our theory works for more complex behavioral phenotypes like mental illness and education, which seem unyielding to interventions. Preview below: 14/
Show threadMichael MuthukrishnaNov 29, 2022
3. what fraction of DNA variants associated with traits such as cognition or reading skill we believe will reverse their effects under conditions that raise mean educational outcomes, given that such reversals in genetic main effects have not yet been found. 15/
Show threadMichael MuthukrishnaNov 29, 2022
Finally, there is the point about the distinction between learning machinery provided by genes and what is learned by the system. Lots to say on this, citing and amplifying commentaries by @[email protected] @[email protected] @[email protected] @[email protected] @[email protected] among others. 16/
Show threadMichael MuthukrishnaNov 29, 2022
In R3.3, we get into the weeds a little with @[email protected] @[email protected] on how to best model cultural evolutionary behavioral genetics and a response to @[email protected] &
@[email protected]. I'll let you read the details in the response. 17/
Show threadMichael Muthukrishna
In R4, we discuss proposed framework extensions for the notion of cultural clusters (e.g. @[email protected] @[email protected] @[email protected] @[email protected]@yoavram), development (e.g. @[email protected] @[email protected] @[email protected] @[email protected] @[email protected]), and power (@[email protected] @[email protected]). Power preview:
Nov 29, 2022 at 10:22amWeb
Show threadMichael MuthukrishnaNov 29, 2022

It was arduous but rewarding to bring behavioral genetics and cultural evolution into conversation through dual inheritance. We're grateful to all the amazing researchers who deeply engaged with our paper.

The conversation doesn't stop at @[email protected] – let's keep it going! 19/

Show threadMichael MuthukrishnaNov 29, 2022
Here's a summary of the reply by first author @[email protected]. 20/ https://t.co/wyvy4xyIOn
Ryutaro Uchiyama on Twitter

“Our @BBSJournal paper "Cultural evolution of genetic heritability" was recently published, more than a year after the initial call for commentaries Here I'll review our (@mmuthukrishna & @RachelASpicer) response to the 29 commentaries the paper: https://t.co/Htyeu0JDsE 1/🧵”

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