Sally Kohn: We've been talking about due dates as it relates to library books. She says when she started thinking in the language of artificial scarcity, that I really started to see a lot of it in my own practice. Kohn: It's limiting the opportunity for the student to show you what you've learned,. And so student can still learn things. But on the other hand, deadlines are there for a reason, right? Why is there artificial scarcity? Well, because I got a great stuff sometime.