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 little dopamine hit every once in awhile, 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 comments.

It's a social-validation feedback loop ... exactly the kind of thing that a hacker like myself would come up with, because you're exploiting a vulnerability in human psychology.

The inventors, creators -- it's me, it's Mark [Zuckerberg], it's Kevin Systrom on Instagram, it's all of these people -- understood this consciously. And we did it anyway.