Operant learning theory in pain and chronic pain rehabilitation. 
The application of operant learning theory on chronic pain by Fordyce has had a huge impact on chronic pain research and management.  The operant model focuses on pain behaviors as a major component of the pain problem, and postulates that they are subject to environmental contingencies.  The role of operant learning in pain behaviors generally has been supported by experimental studies, which are reviewed in the present article.  Subsequently, the rationale, goals, and methods of operant behavioral treatment of chronic pain are outlined.  Special attention is paid to three therapeutic techniques (graded activity, activity pacing, and time-contingent medication management), which are discussed in detail with regard to their operationalization, effectiveness, and (possible) mechanisms of action.  Criticisms of the operant model are presented, as are suggestions for the optimization of (operant) behavioral treatment efficacy.