Rate-dependent effects of superimposed response-independent reinforcement on response rates maintained by FR schedules
The challenge was finding an analysis that accounts for both response rate increases and decreases which occur when response-independent reinforcers are superimposed on response-dependent reinforcers. This study was designed to determine whether superimposed VT schedules of reinforcement have a rate-dependent effect on response rates maintained by FR schedules. Three different baseline overall response rates were generated by FR 30, FR 60 and Fr 180 schedules. Two frequencies of response-independent reinforcers were provided by VT 40-s and VT 80-s schedules. Both VT schedules were superimposed on each FR schedule for each of six rats. The first two conditions were replicated for each rat. Results showed that both frequencies of superimposed VT reinforcers had rate-dependent effects on response rate. Linear regressions accounted well for the data both when overall response rate and when the inverse post reinforcement pause and running rate were used as dependent variables. However, different reinforcer frequencies did not have an effect analogous to that of drug-dose: Neither y-intercept nor slope were systematically affected by changes in VT-value. Nonlinear regression fits using Bugress & Wearden's (1986) modified version of Herrnstein's (1970) equation provided a comparatively inadequate account of the data. Based on the data collected, it is not possible to decide which is the preferable approach to account for response rate increases and decreases when response-independent reinforcers are superimposed on response-dependent schedules. It is suggested that a more fruitful approach might be one that considers both reinforcer frequency and baseline response rate as important response rate determining factors. The challenge is the exploration of their interaction.
Hemmerich, Dagmar, "Rate-dependent effects of superimposed response-independent reinforcement on response rates maintained by FR schedules" (1990). ETD Collection for Fordham University. AAI9025019.