Screens are far more interactive now. Perhaps that’s a component as well
Of course, a lack of interaction with humans could be a factor too but in our case we were literally playing with it alongside her and she would still get upset if it was taken away.
But if we want to keep the discussion on topic, we should talk about the age group being studied. Beyond that, we want to have a different study.
(edit, grammar because it's really too early in the morning for writing)