Preference for Signaled Versus Unsignaled Reinforcement Delay in Concurrent‐chain Schedules

Abstract

A concurrent-chain schedule was employed to examine pigeons' preferences for signaled versus unsignaled delay of reinforcement in which the delay durations ranged from zero to ten seconds. In general, pigeons preferred signaled delay over unsignaled delay especially when a variable-interval 30-second schedule operated in each initial link; when a variableinterval 90-second schedule operated in each initial link, these preferences tended toward indifference or were attenuated. In addition, prior training seemed to exert partial control over behavior. Responding in the terminal link was higher under signaled delay than unsignaled delay in a majority of the cases. Moreover, response rates under signaled delay remained fairly constant whereas responding under unsignaled delay was initially high, but decreased systematically with delay durations as short as 2.5 seconds. These results are consistent with a number of other studies demonstrating the significant role of a signal for impending positive stimuli.Key words: signaled reinforcement delay, unsignaled reinforcement delay, choice behavior, concurrent-chain schedules, key peck, pigeons Over the years, much attention has been allocated to the effects of delayed reinforcement on various aspects of behavior. Early studies by Grice (1948), Perin (1943), and Spence (1947) demonstrated how delayed reinforcement affects the acquisition of new behavior. More recent investigations have examined the effects of delayed reinforcement on maintained response rates (Dews, 1960;Ferster, 1953;Pierce, Hanford, & Zimmerman, 1972;Richards, 1972Richards, , 1981Sizemore & Lattal, 1977 Williams, 1976), and on postdiscrimination gradients of stimulus control (Richards, 1973;Richards & Hittesdorf, 1976Richards & Marcattilio, 1978). Still other inquiries have been concerned with defining a quantitative relationship between responding and the length of the delay interval in choice situations (Chung, 1965;Chung & Herrnstein, 1967;Fantino, 1969 (1970) found that rats learned to escape shock much faster when the negative reinforcement delay interval was signaled compared to when it was unsignaled. Results from two separate studies suggest that responding under conditions of signaled delay decreases as the delay interval increases (Pierce et al., 1972) and that similar results are found under conditions of unsignaled delay except that the latter procedure maintains lower response rates especially at shorter delay durations (as short as 3-sec; Williams, 1976). Recently, Richards (1981) confirmed these general findings in a within-subjects design. In addition, these studies also indicate that responding maintained by unsignaled delay procedures is more variable than responding maintained by signaled delay.Despite the wealth of information this research has contributed, no research to date has examined pigeons' preferences for signaled versus unsignaled reinforcement delay. Such was the purpose of the present investigation. 221 1981, 36,[221][222][223][224][225][226][227][228][229] NUMBER 2 (sE...

Preference for Less Segmented Fixed‐time Components in Concurrent‐chain Schedules of Reinforcement

“…Moreover, the delay in the chained schedule was signaled, whereas that in the tandem schedule was not. From such a perspective, our procedure is comparable to that employed by Marcattilio and Richards (1981), who presented pigeons with two VI 60-s schedules of delayed reinforcement in the terminal link. The delay, ranging from 0 to 10 s in different conditions, was unsignaled for one schedule, and was signaled (by simultaneously switching off the keylight and houselight and turning on a yellow pilot light) for the other.…”

Effects of Unsignaled Delay of Reinforcement on Preference and Resistance to Change

“…Only two prior studies have investigated unsignaled delay of reinforcement in concurrent chains. Marcattilio and Richards (1981) trained pigeons on a concurrent chain with equal VI 60-s terminal links, and studied various durations of signaled and unsignaled delays for those schedules. In general, subjects demonstrated a preference for the terminal link with the signaled delay, and this preference was greater when the initial links were short than when they were long.…”

Handling Time and Choice in Pigeons

“…It means that changes in relative times on the two sides are not simply a case of matching relative times to relative numbers of reinforcers obtained, but rather are an effect of delay per se. Studies of delayed reinforcement of key pecking on VI schedules (e.g., Chung, 1965;Chung & Herrnstein, 1967;Marcattilio & Richards, 1981;Richards, 1981) suggest that pigeons should display a preference for no delay over 4-or 8-s delays on concurrent VI schedules. However, variables like the lengths of the basic VI and the COD and the nature of the delay signal, if any, would all be expected to influence the degree to which preference for a shorter delay is exhibited on such schedules.…”

“…However, because the effects of even 8-s delay were quite small in some cases here, the basic VI schedule was changed to VI 60 s in the next experiment in the hope of enhancing the display of preference (cf. Marcattilio & Richards, 1981).…”