Sean Parker and his Facebook buddies knew exactly how to hook users. Photo: Theo Wargo/Getty Images for Global Citizen

Facebook’s founding president Sean Parker — Justin Timberlake in The Social Network, if that’s how you keep track of the platform’s key players — sat down with Axios’s Mike Allen at an event in Philadelphia this week. Parker, who now chairs the Parker Institute for Cancer Immunotherapy, was there to discuss advances in cancer research — but nevertheless managed to squeeze in a few comments about building Facebook. What he had to say is not going to make Zuck happy.

Confirming what you basically know, but probably don’t want to think about too closely, Parker explained just how he and the other early Facebookers built the platform to “consume as much of your time and conscious attention as possible.” He described the system of users posting content and receiving likes as “a social-validation feedback loop … exploiting a vulnerability in human psychology.” “We need to sort of give you a little dopamine hit every once in a while, because someone liked or commented on a photo or a post or whatever,” Parker said. “And that’s going to get you to contribute more content, and that’s going to get you … more likes and comments.” He also noted that he and Zuckerberg, and later Instagram’s Kevin Systrom, were very much aware of this and “did it anyway.”

Parker also joked that his comments would probably prompt Mark Zuckerberg to block him on Facebook. We’ll see.