My SO is a Occupational Therapist, so she spent part of her master's degree studying pediatric development milestones. A LOT of those milestones (ability to han

My SO is a Occupational Therapist, so she spent part of her master's degree studying pediatric development milestones. A LOT of those milestones (ability to handle objects with hands, develop muscle strength, resolve conflict with others, etc) depend on playing with other kids in the real world. If a child is proportionally spending more time on a device than interacting with peers, they're going to have problems. Prime example: W-sitting. Lots of "iPad kids" have an unusual sit pose where they splay their legs out. Oftentimes it's because they're sitting on a device so often that their core muscles are underdeveloped.