DISCRIMINATIVE FUNCTIONS BASED ON A DELAY IN THE REINFORCEMENT RELATION 1

Pigeons were shown to come under discrimination control when the S D and S Δ were temporally separated from reinforcement and non‐reinforcement. S D and S Δ consisted of distinctive key illuminations presented separately. Responding on an FR 5 in the presence of S D or S Δ produced a third stimulus containing a schedule requirement. If this third (or interpolated) stimulus was preceded by S D , responding in its presence produced reinforcement followed by a time‐out (TO). If, on the other hand, the third stimulus was preceded by S Δ , responding produced TO alone. In this fashion, the same stimulus and the same response requirement were imposed between S D and the reinforcement as between S Δ and the TO. In Experiment I, the schedule employed during the interpolated stimulus was FR; in Experiment II, FI. Discrimination reversal was accomplished in both experiments.