From Billionaire Sean Parker:

The thought process that went into building these applications, Facebook being the first of them, ... was all about: 'How do we consume as much of your time and conscious attention as possible?'

"And that means that we need to sort of give you a dopamine hit every once in a while, because someone liked or commented on a photo or a post or whatever. And that's going to get you to contribute more content, and that's going to get you more likes and more comments."

It's a social-validation feedback loop ... This is exactly the kind of thing that hacker like myself would come up with, because it's exploiting a vulnerability in human psychology. the inventors, creators — me, Mark, Kevin Systrom of Instagram, all of these people — we understood this consciously. And we did it anyway

God only knows what it's doing to our children's brains.

https://www.youtube.com/watch?v=R7jar4KgKxs