Two-Choice Conditional Discrimination Using Temporally-Defined Schedules

 Given experimental discrepancies regarding limited availability contingencies for reinforcement, and the development of  control stimuli,  this study exposed rats to a two-choice conditional discrimination procedure using temporally-defined schedules. Both tD and tΔ subcycles were 30 s long and signals added to the tD subcycle were auditory or visual. Within each tD subcycle the first response in either of the two available levers produced reinforcement, if and only if the signal-lever combination matched the experimental predefined arrangement. Except for one rat exposed to auditory stimuli, the percentage of correct responses progressively increased across sessions. Additionally, at the end of the experiment response frequency during the tD subcycle was higher than during the tΔ subcycle for all rats. In line with previous studies, results confirm that limited hold reinforcement does not prevent stimulus control.

Keywords: Conditional discrimination, limited-hold reinforcement, stimulus modality,