SCHEDULE INTERACTIONS INVOLVING PUNISHMENT WITH PIGEONS AND HUMANS

The principal aim of the present experiments was to assess whether pun ishment increased or de creased the rate of unpunished behavior (contr ast and induction, respectively) for which reinforce ment rate was hel d constant, with physical and nonphysical punishers (electric shock an d response cost), pigeon and human subjects, signaled and unsignaled c omponents (multiple and mixed schedules), and the presence or absence of a blackout period between components. Across the three experiments there were 20 punishment conditions. Induction was found in nine of th ose, less consistent response-rate reduction was found in three, contr ast was found in four, and in four there was no change in responding f rom conditions without punishment. Contrast occurred consistently only with multiple schedules during the first exposure to electric-shock p unishment. Induction and no change, however, were found with every com bination of the independent variables studied. Four conclusions regard ing the interactions between punished and unpunished responding emerge d from the present results: (a) Both contrast and induction occurred w ith the reinforcement rate held constant and a blackout between compon ents, (b) induction was more common than contrast, (c) contrast occurr ed only in the presence of a stimulus different from that correlated d th the punisher, and (d) contrast diminished with prolonged exposure t o punishment. None of the current theoretical accounts of punishment c ontrast can explain the present results.