Donahoe, John - Reinforcement: History and Current Status - The following topics will be among those discussed; (1) implications of Darwinian thinking (selectionism) for selection by reinforcement, (2) the problem of “circularity” and its treatment by the probability- differential (Premack) and response-deprivation (Timberlake & Allison) hypotheses, (3) the Rescorla- Wagner model of conditioning and its operant-respondent distinction as viewed by UPR, (6) implications of UPR for phenomena such as those identified in studies of behavioral momentum, conditioning of behavior-systems, and temporal coding, (7) issues in the experimental analysis of the free-operant procedure and their implications for the molar-molecular debate, (8) neural-networks as a means of interpreting the effects of reinforcement, and (9) the role of neuroscience in the formulation of the reinforcement principle.