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Contrary to some other comments, heredity by definition excludes culture. Heredity can be measured via twin studies - if twins are adopted into two different f

Contrary to some other comments, heredity by definition excludes culture. Heredity can be measured via twin studies - if twins are adopted into two different families or cultures: what commonalities can we still find, beyond random variability. The goal is to take culture out of the consideration and look at the biology. (You may argue how successful this can be, but it is the goal, and it is what is meant by ‘heredity’) It’s reasonable to expect/have learned that all heredity must come through genes - which the headline illustrates - but we are starting to explore other mechanisms for heredity. The article makes no comment on cultural transmission, which is entirely an independent concept.

thelamest 9y ago
You can neither manipulate nor naturally observe the full range of possible cultural variation, though. And this problem will in fact inflate the additive genetic estimates. Ie. if we only observed plants in 21% oxygen, or never modified diets in phenylketonuria, we'd miss something important (in these simple cases, we knew it from other sources, but it's rarely this easy).
balance_factor 9y ago
> Heredity can be measured via twin studies - if twins are adopted into two different families or cultures: what commonalities can we still find, beyond random variability. And how often does this happen? It is about as common as a sighting of the Higgs boson - and you need a large sample group. Of "identical" twins separated at birth (identical twins are not genetically identical) and sent to two culturally/class-based different families, with little contact. The Pioneer Fund (you can read about them https://en.wikipedia.org/wiki/Pioneer_Fund https://en.wikipedia.org/wiki/Pioneer_Fund ) funded studies like the Minnesota Twin Family Study, but it was found to have many deficiencies, such as what I noted. Often twins in the cohort were only raised apart for a few years and so forth. On occasion I watch television, and see wealthy heirs like the Hilton heiresses or Kardashian heiresses, or watch documentaries like Born Rich with various heirs and heiresses, and it's quite obvious why such a class spends its money on endeavors that says nature rules over nurture. Like the heir Wickliffe Draper did with the Pioneer Fund. That they are born superior without having to work or do anything. For the past ten millennia they said the gods favored them, like Socrates noble lie ( https://en.wikipedia.org/wiki/Noble_lie#Plato's_Republic https://en.wikipedia.org/wiki/Noble_lie#Plato's_Republic ). The popes crowned them king. In our post-enlightened age this does not work so now they say their superiority comes from chains of amino acids. Of course, history tends to depose of them any how, the God-ordained superior genetics of the Romanovs were not as well adapted as the Bolshevik soldiers who rid the earth of them (tangential note - their inbreeding caused hemophilia which brought in Rasputin and hastened their downfall). It's an argument for laziness and parasitism - to not look at people by their work, but by the genetic superiority which they were supposedly born with. It's pathetic and parasitic.
thraway180306 9y ago
Heredity has no definition other than mathematical tools used to measure it. Do you say statistics has the power to exclude environment's influence just because you made up some definition on the label of the measured variable? Specifically about the twin studies this has been heavily criticized from their outset. Already Flynn (of the famous Flynn effect of IQ increase over time) put out the requirements for proper control of such studies in his 1980 book. Nevertheless in 30 years of conducting new ones it appears none improved the methodology to control more carefully for environment and for culture. Just one facet of their invalidity: adoptive families have been found to be exceedingly intelligent with IQ over 120 on average, which is obviously different than general average (Stoolmiller in Psychol. Bull. 125:392-409).
learnstats2 9y ago
Happy to accept the three critical comments here which have understood the point correctly.

thelamest 9y ago

You can neither manipulate nor naturally observe the full range of possible cultural variation, though. And this problem will in fact inflate the additive genetic estimates. Ie. if we only observed plants in 21% oxygen, or never modified diets in phenylketonuria, we'd miss something important (in these simple cases, we knew it from other sources, but it's rarely this easy).

balance_factor 9y ago

> Heredity can be measured via twin studies - if twins are adopted into two different families or cultures: what commonalities can we still find, beyond random variability. And how often does this happen? It is about as common as a sighting of the Higgs boson - and you need a large sample group. Of "identical" twins separated at birth (identical twins are not genetically identical) and sent to two culturally/class-based different families, with little contact. The Pioneer Fund (you can read about them https://en.wikipedia.org/wiki/Pioneer_Fund https://en.wikipedia.org/wiki/Pioneer_Fund ) funded studies like the Minnesota Twin Family Study, but it was found to have many deficiencies, such as what I noted. Often twins in the cohort were only raised apart for a few years and so forth. On occasion I watch television, and see wealthy heirs like the Hilton heiresses or Kardashian heiresses, or watch documentaries like Born Rich with various heirs and heiresses, and it's quite obvious why such a class spends its money on endeavors that says nature rules over nurture. Like the heir Wickliffe Draper did with the Pioneer Fund. That they are born superior without having to work or do anything. For the past ten millennia they said the gods favored them, like Socrates noble lie ( https://en.wikipedia.org/wiki/Noble_lie#Plato's_Republic https://en.wikipedia.org/wiki/Noble_lie#Plato's_Republic ). The popes crowned them king. In our post-enlightened age this does not work so now they say their superiority comes from chains of amino acids. Of course, history tends to depose of them any how, the God-ordained superior genetics of the Romanovs were not as well adapted as the Bolshevik soldiers who rid the earth of them (tangential note - their inbreeding caused hemophilia which brought in Rasputin and hastened their downfall). It's an argument for laziness and parasitism - to not look at people by their work, but by the genetic superiority which they were supposedly born with. It's pathetic and parasitic.

thraway180306 9y ago

Heredity has no definition other than mathematical tools used to measure it. Do you say statistics has the power to exclude environment's influence just because you made up some definition on the label of the measured variable? Specifically about the twin studies this has been heavily criticized from their outset. Already Flynn (of the famous Flynn effect of IQ increase over time) put out the requirements for proper control of such studies in his 1980 book. Nevertheless in 30 years of conducting new ones it appears none improved the methodology to control more carefully for environment and for culture. Just one facet of their invalidity: adoptive families have been found to be exceedingly intelligent with IQ over 120 on average, which is obviously different than general average (Stoolmiller in Psychol. Bull. 125:392-409).

learnstats2 9y ago

Happy to accept the three critical comments here which have understood the point correctly.