Frances K. McSweeney is Regents Professor and ViceProvost for Faculty Affairs at Washington State University, USA.Cited as one of the most prolific contributors to behaviouranalysis journals, she holds both Masters and Ph.D. degrees fromHarvard University. The former Chair of WSU s Department ofPsychology and of the Association for Behavior AnalysisInternational (ABAI). Professor McSweeney is a fellow of ABAI, ofthe American Psychological Association (Divisions 3 and 25), and ofthe Association for Psychological Science. Her recent researchfocuses on short-term changes in reinforcereffectiveness. Eric S. Murphy is Associate Professor in the Departmentof Psychology at the University of Alaska Anchorage, USA, and holdsa doctorate in experimental psychology from Washington StateUniversity. He has published research in the Journal of theExperimental Analysis of Behavior and Journal of AppliedBehavior Analysis, and in 2010 received UAA s FacultyExemplar Award for enhancing undergraduate research opportunities.A specialist teacher and researcher in behavior analysis, Dr Murphyis currently leading a study of the variables regulating reinforcereffectiveness.