Date of Award:


Document Type:


Degree Name:

Master of Science (MS)




Carl D. Cheney


California Quail were exposed to fixed-interval schedules whose values ranged from FI 90 to FI 180. Post-reinforcement pause lengths and terminal rates were recorded and grouped into relative frequency distributions. The relative post-reinforcement pause length was found to be an increasing function of FI value such that at larger FI values a proportionally greater period of time was taken up by the post-reinforcement pause. Terminal rate (rate during the final 20% of the interval) was a decreasing function of FI value. The large amounts of variability in terminal rates observed indicated that terminal rate in fixed-interval schedules is not constant from interval to interval as is often reported in the literature. For a given subject, when overall rate of response for a session was plotted as a function of mean pause length for that session, no consistent relationship was found. Among the subjects there were two to three-fold differences in overall rate on FI 90, the only value to which all subjects were exposed. Differences among subjects in mean overall rates were correlated with differences in mean pause lengths, however. Thus, a subject's performance on a fixed-interval schedule could be characterized in terms of pause length and overall rate although rate in any given session was not necessarily correlated with mean pause length for that session, Differences between subjects in mean overall rates were also correlated with differences in mean terminal rates.