BSR can serve as a robust operant reinforcer. A single operant response triggers the dispense of a single dose of reinforcer. In operant conditioning, the function of the reinforcer is to influence "future behavior". If the removal of an event serves as a reinforcer, this is termed negative reinforcement. That is, a discriminative stimulus is also a "conditioned reinforcer". Any stimulus that increases the likelihood of a behavior increasing is a reinforcer. This stimulus may be a primary reinforcer or another conditioned reinforcer (such as money). In conditioning, contiguity refers to how associated a reinforcer is with behaviour. Assume praise is a positive reinforcer for a particular employee. But many mands have no correspondence to the reinforcer. The behavioral cusp, like the reinforcer, is apprehended by its effects. This is where a positive reinforcer is taken away to teach the behavior. A social reinforcer is an approval of a behavior. Planned ignoring is accomplished by removing the reinforcer that is maintaining the behavior. Also, the timing of the delivery of a reinforcer is crucial.