Key pecking during extinction after intermittent or continuous reinforcement as a function of the number of reinforcers delivered during training.

Key pecking by 7 pigeons was established and maintained on a multiple variable-ratio variable-ratio (VR) schedule of food presentation. The schedule in one of the components was then changed to fixed-ratio (FR) 1 for a predetermined number of reinforcers. Both components were then changed to extinction (i.e., multiple extinction, extinction). This sequence was repeated a different number of times for each pigeon to determine the relation between the number of reinforcers delivered during each component of the multiple VR FR 1 schedule and the number of responses during extinction. For most pigeons, there were fewer responses during extinction in the presence of a stimulus recently correlated with FR 1, regardless of the number of reinforcers received. The ratio of the total responses in extinction in the former VR component to the total responses in the former FR 1 component increased as the number of reinforcers delivered during each component of the multiple schedule increased. Within-subject replications of the partial-reinforcement extinction effect generally occurred, and there were no overall reductions in the number of responses in extinction with repeated exposures to extinction.