When researchers estimate heritability from twin studies either longitudinally or cross-sectionally, one result almost always replicates: as individuals grow older, heritability estimates of behavior tend to increase, for some phentoypes like IQ by extreme amounts.
"Since they are genetically identical, if they share an environmental exposure, then their reaction to that cannot differ due to their genes, therefore their correlation remains stable" The reaction can still differ due to developmental noise, though, no? And how are compounded interactions from other prior, but still interrelated, environmental variables (i.e. higher dimensionality: Identical twins experience context x but with a different context y behind context x which will in turn affect how they process the experience of x?) partitioned--I understand that this would be 'captured' superficially under 'nonshared environment', but if nonshared environment specifically affects the latent nature of shared environment, then is it properly fair to conceptualize the environment as 'shared' to begin with, since the nature of its received experiences will therefore differ, and so, in effect, not really be *equivalently* 'shared'?
For example, are you familiar with Jay Joseph's argument against the EEA?
To give a super simple example for the sake of (hopefully) some elucidation: Consider a 'shared' environmental instance in which both twins see the same dog in the same setting/context, but a few days prior to seeing this dog one twin had a nonshared experience in which they were attacked by a different dog, and is now afraid of dogs as a result. Fast forward to the shared environmental instance and now the way in which that environment is received is no longer 'shared' despite the superficial factors appearing 'shared'.
(If there is an element to the match which emulates this precisely rather than crudely please let me know and I'll correct myself)
"Since they are genetically identical, if they share an environmental exposure, then their reaction to that cannot differ due to their genes, therefore their correlation remains stable" The reaction can still differ due to developmental noise, though, no? And how are compounded interactions from other prior, but still interrelated, environmental variables (i.e. higher dimensionality: Identical twins experience context x but with a different context y behind context x which will in turn affect how they process the experience of x?) partitioned--I understand that this would be 'captured' superficially under 'nonshared environment', but if nonshared environment specifically affects the latent nature of shared environment, then is it properly fair to conceptualize the environment as 'shared' to begin with, since the nature of its received experiences will therefore differ, and so, in effect, not really be *equivalently* 'shared'?
For example, are you familiar with Jay Joseph's argument against the EEA?
To give a super simple example for the sake of (hopefully) some elucidation: Consider a 'shared' environmental instance in which both twins see the same dog in the same setting/context, but a few days prior to seeing this dog one twin had a nonshared experience in which they were attacked by a different dog, and is now afraid of dogs as a result. Fast forward to the shared environmental instance and now the way in which that environment is received is no longer 'shared' despite the superficial factors appearing 'shared'.
(If there is an element to the match which emulates this precisely rather than crudely please let me know and I'll correct myself)