Replies

“It tells us that poor nutrition and lack of stimulation lead to smaller brains.”

Actually, this study does not tell us that: your statement is but one possible explanation for the brain size data, as is the possibility that less intelligent small-brained people mate with less intelligent small-brained people, have small-brained children who are also less intelligent and who consequently earn less money.

This is an observational study and cannot show causation.

Also, since it is not controlled for nutritional patterns, educational level of parents, access to cultural enrichment, access to education, 1 or 2 parent homes, and many other variables, one cannot make many conclusions beyond an unexplained (by this study) association of small brains and low incomes.

The authors of the original article rightly say that further research needs to be done to clarify these questions, but such research is extremely hard to do well.

Personally, I believe that both explanations have merit, and probably, both are operational.

By way of example, I grew up in a lower middle class family in the Bronx, NY in the 1950’s. My father was a fireman, my mother a homemaker. Neither went beyond high school. All 4 of their children completed through graduate level of university and are quite successful. However, as kids, my low-salary father made sure that we went to museums, concerts, did our homework and ate as well as possible on his salary. I should say that although lacking in formal education, my parents both spoke three languages, my mother was a trained musician, and my father was extremely well-read. I doubt that even in view of their low income, that they had small brains.

Fast forward to the late 1990’s: a friend taught at a neighborhood parochial school in my old Bronx neighborhood, now somewhat lower in socioeconomic terms. He soon found out that although only a short subway ride away, none of his 5th graders had ever been to Manhattan to experience the cultural enrichment of the city, much of which is free. To his shock, these kids had no aspirations of anything outside their lives in one of the “Outer Boroughs.”

He became the first person to open their eyes to the possibilities by taking them on a field trip!

So, as you say, lack of stimulation and nutrition may indeed be part of the problem, but being the child of two less intelligent people cannot be an advantage in development of financial success.