Wait, Then Go: The Strange Case of So-Called DRL Schedules

Ever see one of those u-tube videos where the dog has to sit there with a biscuit on its nose while some snarky owner says with pointed finger “Noooooo waaaaaaait” as the dog drools all over the owner’s shoes, in the best Pavolvian fashion? After what seems like an eternity, the snarky owner allows an “OK … NOW” and the dog obediently flips the biscuit in the air and down the hatch. Well, this is kinda close to something called a DRL schedule, which is a way to arrange reinforcers such that the responder has to wait for some period of time before making the response that will be reinforced. GO too soon and there is no reward, but delay too long and you just postpone what you could have had even earlier had you gone sooner.

There are, in fact, many situations in everyday life where responding is required, but not too much and when it occurs it needs to be well-timed. It’s a question of pacing of actions. But, laboratory examples of DRLs are easier, so here goes. Hungry pigeon pecking a response key. Timer running. Each peck resets the timer to start. Timer expires (no cue given that this happens other than time passing), next peck produces a food reward. Told you it was easier. But, so what? What’s really going on here?

Two things going on here. First the requirement for reinforcement is wait, then go, but go too early and you’ll never get the reward. That’s the actual requirement, but the effect is to generate low rates of responding, which is to say the response occurs infrequently. It is in essence a method for pacing responses. So, someone named this schedule with the longish handle of “Differential reinforcement of low-rate behavior,” abbreviated DRL, but don’t be put off by the longish name because all it means is wait, then go.  To be picky, the requirement really is on responses separated from one another by a specified time period. (Full disclosure: what I am describing here is one of three procedures that have been labeled “DRL.” The present one is called a “spaced responding DRL” by applied behavior analysts.)

Remember the old lyrics about “slow down you move too fast, you got to make the morning last” from Simon and Garfunkle’s “59th Street Bridge Song”? This is where DRL schedules come in. We don’t want to eliminate behavior, as is done with other kinds of arrangements like, say, a DRO schedule, where the reinforcer occurs only in the absence of the response for a specified time period.  No, we don’t want the behavior to stop, just to slow down.

Take eating, for example. Eating too fast can cause all kinds of problems, the most serious of which is choking and dying. Plus it looks bad if you have snarfed down the last morsel of dessert just as everyone else is starting on the main course. There are several case studies in which a DRL schedule was used to slow down inappropriately fast eating by reinforcing (with something other than food) taking a bite, but only after a short, say 5-s, pause since the last bite.  

Sometimes slowing down is part of the solution to a problem, but not the whole story.  With classroom work like doing math problems, reading, or writing, part of the problem is that children just work too fast with insufficient attention to quality. A DRL contingency can slow the pace, but other interventions may be necessary at the same time to improve the quality of the work.  

DRL is one of those seemingly esoteric schedules of reinforcement with potential but few actual examples of its use in everyday settings. Perhaps you, dear readers, have others you would like to share.