“Stereotypical nerd appearance, often lampooned in caricatures, can include very large glasses, braces, buck teeth, severe acne and pants worn high at the waist.”
"This surprised me - the conclusion is that most of the connection between myopia and intelligence is explained by genes and not environment (i.e. reading)."
That's because you incorrectly assume that variation in reading habits has non-genetic causes. A genetic correlation between two such things might simply result from a shared cause from equally genetic basis with interest in reading or something. In real life, things are more complicated, but you get the idea.
I wonder if both of these traits might be linked to insulin system sensitivity to refined carbohydrates in the diet. Some Inuit villages went from zero percent myopia to near universal appearance of the condition in their children when they shifted to an industrial diet as a result in changes in growth patterns of the eye in response to higher and unstable blood sugar during development. Similar linkages are known for adolescent acne.
That suggests that the nerd phenotype might represent the pre-agricultural phenotype (at least in European populations) and this is also consistent with brain size decreasing a bit during the spread of agriculture. Therefore I suggest nerds represent an echo of our European forager ancestors, while the jocks are more representative of the early farmers.
Do similar phenotypic stereotypes exist in Asian and African cultures?
"This surprised me - the conclusion is that most of the connection between myopia and intelligence is explained by genes and not environment (i.e. reading)."
That's because you incorrectly assume that variation in reading habits has non-genetic causes. A genetic correlation between two such things might simply result from a shared cause from equally genetic basis with interest in reading or something. In real life, things are more complicated, but you get the idea.
Thank you for this - editing to add a reference to your comment down here.
I wonder if both of these traits might be linked to insulin system sensitivity to refined carbohydrates in the diet. Some Inuit villages went from zero percent myopia to near universal appearance of the condition in their children when they shifted to an industrial diet as a result in changes in growth patterns of the eye in response to higher and unstable blood sugar during development. Similar linkages are known for adolescent acne.
That suggests that the nerd phenotype might represent the pre-agricultural phenotype (at least in European populations) and this is also consistent with brain size decreasing a bit during the spread of agriculture. Therefore I suggest nerds represent an echo of our European forager ancestors, while the jocks are more representative of the early farmers.
Do similar phenotypic stereotypes exist in Asian and African cultures?