Choice in a self-control paradigm: effects of reinforcer quality.

Pigeons were exposed to a self-control paradigm in which they chose between larger, more delayed and smaller, less delayed reinforcers. Reinforcer quality (i.e., the type of grain associated with each alternative) was varied across conditions. Choice behavior was influenced by grain quality; proportions of responses for the larger, more delayed alternative changed as a function of the grains associated with the response alternatives. Furthermore, the percentage deviation from mean baseline response proportions generally decreased as a function of the relative grain types associated with each response alternative. Manipulation of reinforcer quality can significantly influence the degree of self-control typically exhibited by pigeons.