Acquisition of observing responses with delayed conditioned reinforcement

Six pigeons were trained to key peck for 3-s access to mixed grain on a multiple variable-interval 60-s extinction schedule. The schedule then was changed to a mixed variable-interval 60-s extinction schedule. Simultaneously, a treadle was introduced into the chamber. For 3 pigeons, the stimulus correlated previously with the variable-interval schedule could be produced by treadle pressing (i.e., an observing response) on a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior 10-s schedule. For the other 3 pigeons, no contingency was implemented for treadle pressing. Treadle pressing was established equally in the presence and absence of the observing contingency. The results did not extend previous findings on response acquisition with delayed reinforcement to delayed conditioned reinforcement. Several aspects of the observing procedure are discussed, including the rate of food reinforcement, delays to food, and schedule preference