 Hey! Brad here with resistance to extinction, which is the relative frequency with which behavior is emitted during the extinction process. So that directly relates to schedules of reinforcement and the effects all of those have dealing with extinction. You should go check those videos out to kind of give a deeper insight into what we're talking about here. But overall, when a behavior is put on extinction or reinforcement is never met, reinforcement is no longer met contingently for that behavior happening. All the variability and the duration with which we get variability is resistance to extinction.