> For babies research has shown that screen time is undifferentiated.
The research is largely undifferentiated, and overwhelmingly (maybe even entirely, for good ethical reasons) is observational studies that, even if they were able to distinguish between a differentiated relationship and an undifferentiated one would be unable to distinguish between, in <1 year olds, screen time causing developmental delays and conditions which cause developmental delays also causing behavioral differences which lead parents who respond to how things affect their children's behavior to be less likely to curtail screen time.
> Whether research is generally undifferentiated, as you claim, is not the same as specific research that proves that screen time is undifferentiated.
They are directly opposed: you have to have differentiation in the research to distinguish between a differentiated and undifferentiated effect.
> In other words, are you saying there are no such evidence as parent asserted?
I am stating a basis for my skepticism that there is sufficient basis for what he claims the research clearly shows, in that AFAICT the research is weak on both whether there is a differentiated association and not of the type that would be able to make strong statements about the causality of any association, differentiated by type of screen time or not, that it discovered.
The research is largely undifferentiated, and overwhelmingly (maybe even entirely, for good ethical reasons) is observational studies that, even if they were able to distinguish between a differentiated relationship and an undifferentiated one would be unable to distinguish between, in <1 year olds, screen time causing developmental delays and conditions which cause developmental delays also causing behavioral differences which lead parents who respond to how things affect their children's behavior to be less likely to curtail screen time.