I'd be interested in looking at child mortality in the Jamaicans studied in the 1920s. One way you could get oversampling of people with certain mental issues in the middle class is if it contributed to early childhood death among the poor, but not among the middle class.
All three groups (Whites, Blacks, Biracials) were selected from the same economic level:
"... it was decided that all three groups should belong to the prevailing agricultural class and that the Whites of the governing class and the white merchants of Kingston should be excluded. A difficulty arises in this, that just those Whites who are satisfied to work as agriculturalists in the midst of the island are hardly as representative of the more ambitious and intellectually endowed Whites as the agricultural Blacks are of the run of the Black population." (p. 9)
So I was incorrect in assuming that the biracial participants were middle-class. None of the participants were.
Even if the biracial participants had been disproportionately poorer, that wouldn't explain why they did less well on some of the psychological tests but not on most of them. On most of the tests, they performed midway been the Black participants and the White participants.
Thank you. I was thinking that the bi-racial were _not_ disproportionately poorer, but, compared to the Blacks wealthier. If you expected the outcome to be Blacks worst, Bi-racial middle, Whites best -- and instead saw the worst in the bi-racial category, one thing you would need to check is if the worst of the Blacks were dying before they were sampled.
How does hybrid vigor fit with this. I know first generation hybrid vigor doesn't continue to the second generation. And this might be a politically incorrect question, but what human populations if any, exhibit hybrid vigor when they do inter breed? Or are we too homogenized? For instance I've thought Jim Thorpe was the greatest athlete of the 20th century.
Hybrid vigor has not been demonstrated in the human species or, as far as I know, in any of the apes. It seems to occur in organisms that have less complex interactions between genes on the genome.
You may be referring to "rebound" from inbreeding depression. If, for example, your parents were first cousins, your children will likely be taller than you if you marry someone farther out.
According to his Wikipedia page, Thorpe could not be an example of first generation hybrid vigor because both his parents were already mixed (part Amerindian).
A great and insightful post as always Peter. Some questions I have: I remember in your 2022 post of how Europe pushed ahead; well over 1,000 years ago, was due to, in part, the broadening in the ninth century by church and state of banning cousin marriages to any couple who shared a common ancestor seven generations previously. As this expanded the Western European pattern of late marriage, celibacy and nuclear households, etc. was the reason this wasn't dysgenic and negative for population growth was that the European populations across the Hajnal line were more homogeneous than in modern times? As late marriage to people beyond third and forth cousins did not have the same effect on embryos in the past, as today, is the difference also between Medieval agricultural communities versus today's modern urban communities?
First, the reduction in fertility wouldn't have been a constraint on population growth. Most people have far fewer children than their biological limit, and this was especially true in medieval Western Europe, where the number of surviving children was around 3 to 5.
Second, take a look at the graph from the Danish study. The slope for outbreeding depression is a lot less steep than the slope for inbreeding depression. The dysgenic effects of a 1st-cousin marriage would therefore be equivalent to the dysgenic effects of an 18th-or 19th-cousin marriage. (I'm assuming that each 15 km of distance would be roughly equivalent to a degree of consanguinity).
I'd be interested in looking at child mortality in the Jamaicans studied in the 1920s. One way you could get oversampling of people with certain mental issues in the middle class is if it contributed to early childhood death among the poor, but not among the middle class.
All three groups (Whites, Blacks, Biracials) were selected from the same economic level:
"... it was decided that all three groups should belong to the prevailing agricultural class and that the Whites of the governing class and the white merchants of Kingston should be excluded. A difficulty arises in this, that just those Whites who are satisfied to work as agriculturalists in the midst of the island are hardly as representative of the more ambitious and intellectually endowed Whites as the agricultural Blacks are of the run of the Black population." (p. 9)
So I was incorrect in assuming that the biracial participants were middle-class. None of the participants were.
Even if the biracial participants had been disproportionately poorer, that wouldn't explain why they did less well on some of the psychological tests but not on most of them. On most of the tests, they performed midway been the Black participants and the White participants.
Thank you. I was thinking that the bi-racial were _not_ disproportionately poorer, but, compared to the Blacks wealthier. If you expected the outcome to be Blacks worst, Bi-racial middle, Whites best -- and instead saw the worst in the bi-racial category, one thing you would need to check is if the worst of the Blacks were dying before they were sampled.
How does hybrid vigor fit with this. I know first generation hybrid vigor doesn't continue to the second generation. And this might be a politically incorrect question, but what human populations if any, exhibit hybrid vigor when they do inter breed? Or are we too homogenized? For instance I've thought Jim Thorpe was the greatest athlete of the 20th century.
Hybrid vigor has not been demonstrated in the human species or, as far as I know, in any of the apes. It seems to occur in organisms that have less complex interactions between genes on the genome.
You may be referring to "rebound" from inbreeding depression. If, for example, your parents were first cousins, your children will likely be taller than you if you marry someone farther out.
According to his Wikipedia page, Thorpe could not be an example of first generation hybrid vigor because both his parents were already mixed (part Amerindian).
A great and insightful post as always Peter. Some questions I have: I remember in your 2022 post of how Europe pushed ahead; well over 1,000 years ago, was due to, in part, the broadening in the ninth century by church and state of banning cousin marriages to any couple who shared a common ancestor seven generations previously. As this expanded the Western European pattern of late marriage, celibacy and nuclear households, etc. was the reason this wasn't dysgenic and negative for population growth was that the European populations across the Hajnal line were more homogeneous than in modern times? As late marriage to people beyond third and forth cousins did not have the same effect on embryos in the past, as today, is the difference also between Medieval agricultural communities versus today's modern urban communities?
First, the reduction in fertility wouldn't have been a constraint on population growth. Most people have far fewer children than their biological limit, and this was especially true in medieval Western Europe, where the number of surviving children was around 3 to 5.
Second, take a look at the graph from the Danish study. The slope for outbreeding depression is a lot less steep than the slope for inbreeding depression. The dysgenic effects of a 1st-cousin marriage would therefore be equivalent to the dysgenic effects of an 18th-or 19th-cousin marriage. (I'm assuming that each 15 km of distance would be roughly equivalent to a degree of consanguinity).