Key Points
- Reinforcement flows to the behavior the team wants more of while the behavior targeted for reduction stops producing it - both halves are needed to shift the balance.
- The variants differ in what earns reinforcement: a functionally equivalent alternative (DRA), an incompatible behavior (DRI), the absence of the behavior (DRO), or lower rates of it (DRL).
- Plans fail in practice most often because the replacement sits on a leaner schedule than the problem behavior ever was.
Differential Reinforcement Explained
Differential reinforcement is how ABA replaces rather than merely suppresses. Reinforcement flows to the behavior the team wants more of; the behavior targeted for reduction stops producing it. The two halves work together - the withholding alone is extinction, the reinforcing alone just adds noise; differential application is what shifts the balance.
The common variants differ in what earns the reinforcement. Reinforcing a specific alternative that serves the same function as the problem behavior - asking for help instead of tearing up the worksheet - is differential reinforcement of alternative behavior (DRA). Reinforcing a behavior physically incompatible with the target - hands in lap when the target is grabbing - is DRI. Reinforcing the absence of the behavior for an interval is DRO, and reinforcing lower rates of a behavior that is acceptable but excessive - raising a hand, just not forty times an hour - is DRL.
Choosing among them is a function-and-practicality decision. DRA with a functionally equivalent replacement is the workhorse, especially as functional communication training. DRO suits behaviors with no obvious replacement, though it demands vigilant timing. DRL fits social behaviors where zero would be the wrong goal.
The details that make or break these plans are reinforcement quality and effort. The replacement has to work better than the problem behavior - faster, more reliably, at lower cost to the learner - or the old form remains the rational choice. Plans fail in practice most often because the replacement is on a leaner schedule than the problem behavior ever was.
Progress reads as two lines moving in opposite directions: the reinforced alternative rising, the target declining. Tracking both is the only way to distinguish genuine replacement from coincidental quiet - and it is why reduction goals and acquisition goals ship together in a well-written plan.