Interaction effects in a multiple schedule of signaled and unsignaled reinforcement

Abstract

Pigeons received baseline training on an equal-valued multiple unsignaled variable-interval/signaled variable-interval schedule. This procedure resulted in high and low response rates during the unsignaled and signaled components, respectively. Behavior during each component was then separately extinguished. Extinction of the unsignaled component resulted in positive contrast in the signaled variable-interval component. When reinforcement was withheld during the signaled component, marked increases in responding during this component occurred, and responding in the presence of the signal was very resistant to extinction. Accompanying the breakdown of the discrimination during the signaled component was an increase in the rate of responding in the unsignaled variable-interval component (i.e., positive induction). The implications of these results for several theories of behavioral contrast are considered.