Stimulus control of foodcup approach following fixed ratio reinforcement

Rats were trained on fixed ratio (FR) schedules requiring either 5 or 10 leverpresses to produce reinforcement and an intertrial interval (ITI). Half of the Ss at each ratio requirement were extinguished on an FR 5 and half on an FR 10 schedule of ITI presentation. Fewer foodcup approaches were made on the FR 10 than on the FR 5 extinction schedule, regardless of acquisition FR. Leverpresses per approach were fewer on the FR 5 than on the FR 10 extinction schedule and were fewer following FR 5 than following FR 10 acquisition. Data suggested the existence of interoceptive as well as exteroceptive stimulus control of foodcup approach and were discussed in terms of their implications for a response-unit account of extinction.