Reinforcement schedules and bar pressing: Some extensions of Zimmerman’s work

Two studies using Zimmerman’s 1959 paradigm for secondary reinforcement were performed. In Exp. 1 the effects of continuous vs. partial primary reinforcement, continuous vs. partial Sr, and buzzer and access to a runway after bar pressing vs. access only were studied. None of these factors or their interactions were significant sources of variation. In Exp. 2 the influence of a 1:5 FR schedule of Sr was compared to Zimmerman’s diminishing schedule. Two replications disclosed that the FR schedule led to significantly more bar pressing. While durable Sr was observed, the attribution of this to Zimmerman’s schedules was questioned. Two suggestions for further study of the Zimmerman phenomenon were offered.