Really? What studies have you done to back up this claim?
Absolutely none, and that is exactly my point.
Unfortunately, Humans are unfortunately by design pretty stupid. We tend to do something and see what happens, or think what's best for today and not worry about 5 or 20 years time.
For the majority of us here, we were born for the most part away from instant gratification computers and Internet. We played with physical toys, read books, used our minds and imagination, as humans babies/young children have done for hundreds of thousands of years.
Now, without any knowledge whatsoever, we have parents who think it's cool to give an iPad to a baby who'd brain is being wired together by nature in the early years, and these parents don't have a clue what effect it's going to have on their child as it grows up.
But hey, let's just do it anyway, we'll worry about that if things go wrong. Perhaps we can always label our child as having some social interaction disorder in another 5 or 10 years.
I've no idea what effect an iPad at 18 months is going to have at age 10.
And the problem is, no-one else does.
Naturally it's going to depend greatly on how the parents (and let's be honest, we all know some really dumb parents) use such things.
Do they spend lots and lots of real quality time with their child, helping them to read, write, make things, play imaginary games with them. Build things, paint things. And perhaps fit an iPad in as a small part of it. Which I'd guess would be great.
Or, more lightly do they just let the kid spend too much time with a device like the iPad, which will become more and more time, as over the months/years the child starts to get stroppy and cry when you take the device away from them.
And just leave them to it, whilst the parents get on with things they want to do, rather than spending quality time with their child.
In the same way, do you let your young child have 1 hour of TV, or do you just dump the kid in front of cartoon network all day as it's easier for you as a parent and it keeps them quiet.