Good question, Eric. And yeah, definitely tricky to reinforce non-existent behavior!

One of less glamorous implications of Differential Reinforcement is that, fundamentally, we can’t actually control other people or outcomes. We can only wait patiently for the right opportunity and hopefully respond to it intelligently.

If people not showing up is the problem, and getting them to “show up” more is the desired alternative, maybe try to start by rewarding very minor versions of “showing up”—e.g. any time they send an email or you run into them in the hall, make a point to mention how nice it is to see/hear from them.

Good luck!