Some of the 87 Twins Raised Apart pairs for which we have biographical detail went to the same schools for awhile, and other pairs went to schools not far apart where they might have been introduced.
Probably the most valuable datapoints are the two sets of Colombian twins described by Nancy Segal who got switched in the maternity award and each pair grew up thinking they were fraternal twins. One inadvertently mixed pair grew up in a rural town while the other mixed pair grew up in the big city. Neither knew of the existence of their identical twins. As young adults the four were reunited. The capital city mixed pair each got 16 years of schooling and the the village mixed pair got only 5 years. It looks like one City Mouse outscored his Country Mouse twin by 22 points and the other by 7 for an average difference of 14.5 points.
Granted, that's a tiny sample size, but it's an incredibly elegant experimental design (except for not being designed at all and happening only through hospital incompetence).
It's fascinating to read through the 87 identical twins raised (sort of) apart. What's missing is which ones were raised by a biological parent (or two) and which ones were adopted. That seems like a fascinating question. For example, in Nancy Segal's pair of identical twins who were incompetently switched in the maternity ward in Colombia, I'd be interested in which ones, adopted or biological, were raised by their biological parents and what their IQ scores were.
I have not read the study but that difference is well within the standard deviation of an IQ test. I mean that is the difference you can see between examiners, time of day or even a cold.
D'après mes notions sur le développement du cerveau des chercheurs des neurosciences et pedopsyhiatrie ( Piaget , Dan Siegel et plein d'autres), ont bien démontré que l'expérience de vie dans la petite enfance influence la manière donc le cerveau se développe ,l'école faisant partie de ce type d'expérience .
IQ est vu comme trop simpliste voir dépassé en tant que mesure de l'intelligence ..(d'ailleurs quelle type d'intelligence ?)
Bref ,le débat nature versus nurture n'es pas prêt d'être clos ,visiblement !!
This is a difficult one: If the 10 twins had "dissimilar" education, does this also mean that their socio- economic backgrounds were different? Then there could be multiple intervening variables. And, as even " similar" schools and families are never the same, I remain surprised by the strong evidence for genetics.
"A major limitation is that they were only able to find 10 twins reared apart in the “very dissimilar education” group."
I've been thinking about practical reasons why identical twins might get split up, and I suspect it's often because of constrained resources: each pair of adoptive parents can only afford to raise one child. Hence, we don't see that many Prince and Pauper splitting apart adoptions of identical twins into highly different classes.
For example, consider the case of identical twins who are orphaned when their parents die in a car crash and the extended families get together to decide who will adopt the children. If one volunteer is rich and the other is poor, often the extended family might suggest that the rich couple should take both twins.
It's only when the pairs of adoptive parents are _both_ financially constrained that we would see cases of both couples saying: "I can only afford one." If my assumption is right, then both split-up twins are likely to grow up attending similarly basic schooling rather than one going to Phillips Exeter Academy boarding school.
Similarly, there was a French adoption study of the impact of big class differences on IQ where they wanted to have 40 adoptees from four quadrants:
rich biological parents and rich adoptive parents
poor bio parents and poor adoptive parents
poor biological parents and rich adoptive parents
rich biological parents and poor adoptive parents.
But for the last quadrant (rich bio parents, poor adoptive parents) they could only find eight adoptees.
Still, for their N=38 they estimated IQ was 58% nature and 42% nurture.
Some of the 87 Twins Raised Apart pairs for which we have biographical detail went to the same schools for awhile, and other pairs went to schools not far apart where they might have been introduced.
Probably the most valuable datapoints are the two sets of Colombian twins described by Nancy Segal who got switched in the maternity award and each pair grew up thinking they were fraternal twins. One inadvertently mixed pair grew up in a rural town while the other mixed pair grew up in the big city. Neither knew of the existence of their identical twins. As young adults the four were reunited. The capital city mixed pair each got 16 years of schooling and the the village mixed pair got only 5 years. It looks like one City Mouse outscored his Country Mouse twin by 22 points and the other by 7 for an average difference of 14.5 points.
Granted, that's a tiny sample size, but it's an incredibly elegant experimental design (except for not being designed at all and happening only through hospital incompetence).
It's fascinating to read through the 87 identical twins raised (sort of) apart. What's missing is which ones were raised by a biological parent (or two) and which ones were adopted. That seems like a fascinating question. For example, in Nancy Segal's pair of identical twins who were incompetently switched in the maternity ward in Colombia, I'd be interested in which ones, adopted or biological, were raised by their biological parents and what their IQ scores were.
I have not read the study but that difference is well within the standard deviation of an IQ test. I mean that is the difference you can see between examiners, time of day or even a cold.
Ιnteresting especially for all these who need data to claim that "the obvious" may not be that obvious......
Talk about stating the obvious…
D'après mes notions sur le développement du cerveau des chercheurs des neurosciences et pedopsyhiatrie ( Piaget , Dan Siegel et plein d'autres), ont bien démontré que l'expérience de vie dans la petite enfance influence la manière donc le cerveau se développe ,l'école faisant partie de ce type d'expérience .
IQ est vu comme trop simpliste voir dépassé en tant que mesure de l'intelligence ..(d'ailleurs quelle type d'intelligence ?)
Bref ,le débat nature versus nurture n'es pas prêt d'être clos ,visiblement !!
This is a difficult one: If the 10 twins had "dissimilar" education, does this also mean that their socio- economic backgrounds were different? Then there could be multiple intervening variables. And, as even " similar" schools and families are never the same, I remain surprised by the strong evidence for genetics.
"A major limitation is that they were only able to find 10 twins reared apart in the “very dissimilar education” group."
I've been thinking about practical reasons why identical twins might get split up, and I suspect it's often because of constrained resources: each pair of adoptive parents can only afford to raise one child. Hence, we don't see that many Prince and Pauper splitting apart adoptions of identical twins into highly different classes.
For example, consider the case of identical twins who are orphaned when their parents die in a car crash and the extended families get together to decide who will adopt the children. If one volunteer is rich and the other is poor, often the extended family might suggest that the rich couple should take both twins.
It's only when the pairs of adoptive parents are _both_ financially constrained that we would see cases of both couples saying: "I can only afford one." If my assumption is right, then both split-up twins are likely to grow up attending similarly basic schooling rather than one going to Phillips Exeter Academy boarding school.
Similarly, there was a French adoption study of the impact of big class differences on IQ where they wanted to have 40 adoptees from four quadrants:
rich biological parents and rich adoptive parents
poor bio parents and poor adoptive parents
poor biological parents and rich adoptive parents
rich biological parents and poor adoptive parents.
But for the last quadrant (rich bio parents, poor adoptive parents) they could only find eight adoptees.
Still, for their N=38 they estimated IQ was 58% nature and 42% nurture.