Inter‐response Time Distribution as a Function of Differential Reinforcement of Temporally Spaced Responses

Abstract

In his analysis of temporal discriminations, Skinner (1938) described an experiment in which the response rates of rats were decreased by reinforcing only interresponse times (IRT's) which exceeded 15 seconds (p. 306). Wilson and Keller (1953) confirmed and extended this finding by demonstrating that the rate of responding is inversely related to the duration of the minimum required IRT. This type of schedule of reinforcement is referred to as the "differential reinforcement of low response rates" (DRL). Recent investigations indicate that DRL schedules engender temporal discriminations which can be analyzed by means of the relativefrequency distribution of IRT's or the distribution of response probabilities (Anger, 1956; Sidman, 1956).On DRL schedules of reinforcement, each response starts the required delay interval. Responses which occur before the delay interval has elapsed not only are unreinforced but they also postpone reinforcement by starting a new delay interval. To the extent that the animal can discriminate the delay interval, these two contingencies should eliminate responding during the delay interval. Wilson and Keller (1953) reported that their rats adapted to the DRL schedule by developing varioua chains of overt behavior which persisted between lever presses and which occupied enough time so that the lever presses following the chains were reinforced.More recent investigations, which include detailed analyses of the temporal response patterns which develop on DRL, have consistently indicated that a large proportion of IRT's occur at about 0-3 seconds (Conrad, Sidman, & Herrnstein, 1958; Sidman, 1955;Sidman, 1956a;Sidman, 1956b). These short IRT's result from frequent "bursts" of responding, and they generate IRT relative-frequency distributions and probability distributions which are bi-modal. One mode occurs in the vicinity of the minimum IRT which is required for reinforcement; the second mode, which is a result of these bursts, occurs at about 0-3 seconds. Sidman presented evidence indicating that the probability of a burst was high near the minimum IRT required for reinforcement. le suggested that "late in the delay period, a single lever press often fails to reset the animal's 'clock,' with the result that several quick responses are emitted" (Sidman, 1956a, p. 472).A very precise control of the rate of responding can be developed by reinforcing only those IRT's which fall within a specified range (Ferster & Skinner, 1957, pp. 498-502); that is, a reinforced IRT must not only be longer than some minimum value (as in DRL) but also shorter than some maximum value. Thus, reinforcements are available for only a limited period of time. This type of schedule is referred to as DRL with a "limited hold" (DRL LH). For example, on DRL 20 LH 3, only responses which are emitted between 20 and 23 seconds after a preceding response will be reinforced; responses emitted at less than 20 seconds or more than 23 seconds after a preceding response start the timing interval again. On DRL LH 91

EFFECTS OF HUNGER AND VI VALUE ON VI PACING1

“…Bower (1961) also obtained such chains in rats by reinforcing runway responses immediately when the running time was relatively long and after a delay when it was short. Clocks apparently not involving collateral chains have been reported by Anger (1955) and Kelleher, Fry, and Cook (1959). (After the data reported here were obtained, the wattage of the houselight was increased to allow observation of the rats.…”

“…The VI 3 curve of A3-8 is based on 14 days, during each of which IRT/Op(6-8) was greater than IRT/Op(8-10); 2469 occurrences of band(6-8) and 1221 occurrences of band(8-10) were used. It seems unlikely that these peaks prior to the reinforced band are sampling errors, although previous experimentation involving DRL and DRL, limited hold (Anger, 1955;Sidman, 1956;Conrad, Sidman, and Herrnstein, 1958;Kelleher et al, 1959) has disclosed no instance of this peak failing to occur in the reinforced band during stabilized performance. (The reader should remember that we refer to the IRTs/Op, not the proportion of all IRTs.)…”

Temporal effects of reinforcement: A negative “frustration” effect

“…However response latency following reinforcement is usually longer than following a response, which accounts for the frequent finding that reinforcements tend to occur in runs on DRL schedules (cf. Farmer & Schoenfeld, 1964;Ferraro, Schoenfeld, & Snapper, 1965;Kelleher, Fry, & Cook, 1959). The finding of a modest omission/frustration effect in a DRL situation (Davenport, Flaherty, & Dyrud, 1966) is simply another way of expressing this difference in inhibitory after-effects between reinforcement and a response.…”

Food-based timing behavior sharpened by the selective punishment of short interresponse times

“…The frequency and probability distributions of interresponse times (IRTs) tend to peak near the time interval when reinforcement is available, particularly when a limited hold (LH) is also in force, i.e., when the availability of reinforcement expires after a predetermined time has elapsed. This finding has been demonstrated repeatedly in both animals (Anger, 1956;Kelleher, Fry, & Cook, 1959;Sidman, 1955;Wilson & Keller, 1953) andhumans (Bruner & Revusky, 1961).…”