Correlation vs Causation, revisited
I figured it is time for me to put the academician hat back on, and delve into the deeper realm of research. I recently read, thanks to the Language Log blog, and interesting dialectic from the blog “…In Different Voices” and I wanted to share it with you. Let me be painfully obvious, and lead you to the point of considering the difference between things being “highly correlated” and being caused by something. Also, note the resistance in the dialogue to even a hint of correlation!
Now, without any further ado, the excerpt:
Q: Very good. (It didn’t fit the rhythm, and anyway they get the picture.) How would you react to the idea that a psychological trait, one intimately linked to the higher mental functions, is highly heritable?
A: With suspicion and unease, naturally.
Q: It’s strongly correlated with educational achievement, class and race.
A: Worse and worse.
Q: Basically nothing that happens after early adolescence makes an impact on it; before that it’s also correlated with diet.
A: Do you work at the Heritage Foundation? Such things cannot be.
Q: What if I told you the trait was accent?
A: I’m sorry?
Q (in a transparently fake California accent): When you, like, say words differently than other people? who speak, like, the same language? because that’s how you, you know, learned to say them from people around you?
A: Do you have a point to make, or are you just yanking my chain?
Q: Would you agree that accent has all the characteristics I just described?
A: Higher cognitive functions — heritable — class and race — not plastic after adolesence — correlation with diet, hah! — I guess I must.
Q: But would you say that there is any genetic or even congenital component to accent?
A: Not really. Obviously, some congenital conditions, like deafness or defects of the vocal chords, make it hard to impossible to acquire any accent. And I can imagine, though I don’t know of anything, that there might be very specific mutations which make it hard to hear a distinction between a given pair of sounds, or easier to learn a specific distinction. But, in general, no, there is no non-trivial genetic component to accent.
Q: Then why were you worried that I was about to start channeling Arthur Jensen?
A: Because those are the sorts of claims usually trotted out by people who want to claim that something is innate, un-plastic, and usually invidiously distributed; sometimes there is a “sadly” to the claims of group inferiority, and sometimes, I think, that “sadly” is even genuine.