1) The DRO schedule refers to a procedure in which a reinforcer follows any performance the animal emits except a particular one. Thus, the DRO schedule specifies the performance which is to go unreinforced rather than the one which is increased in frequency. The result of such a schedule of reinforcement is a decrease in the frequency of the particular performance that is specified. This decrease in frequency usually results from an increase in frequency of an incompatible performance.

2) Reinforcement for any behavior other than a target operant.

3) A reductive procedure in which reinforcers are delivered contingent on the nonoccurrence of a response for a given time interval. Sometimes called omission training. See also Momentary DRO.