SOME VARIABLES AFFECTING RATE OF KEY PECKING DURING RESPONSE‐INDEPENDENT PROCEDURES (AUTOSHAPING) 1

Animals exposed to schedules of partial reinforcement are typically more resistant to extinction than are animals trained with continuous reinforcement. This is the partial reinforcement effect (PRE). Animals experienced with both partial and continuous schedules are often more persistent on the continuous schedule, yielding a reversed PRE. Both conventional and reversed PREs have been elusive with classical conditioning paradigms. The present experiment attempted to demonstrate between-and within-subject PREs using 50% and 100% autoshaping schedules. Presence or absence of a PRE depended on the behavioral measures used. Marked terminal group differences in acquisition produced a between-subjects PRE with absolute response levels but not with rate-of-change measures. Within subjects, only choice trial comparisons were sensitive enough to differentiate the two schedules. Acquisition data were inconsistent with most of the classical conditioning PRE literature, but consistent with results reported in the autoshaping literature. These discrepancies may reflect the operant-classical interaction in autoshaping.Brown and Jenkins (1968) signaled upcoming noncontingent food presentations with a keylight and found that their pigeons pecked reliably at the key, even though responding had no scheduled effect. This training procedure, known as autoshaping, was devised originally as a method of training pigeons to keypeck, a response widely regarded (at the time) as an operant. Subsequent research has caused the autoshaped response to be regarded as largely the result of classical conditioning, with operant conditioning playing a less important role in both acquisition and maintenance (e

Section: Phasementioning

confidence: 90%

mentioning

confidence: 98%

Within- and between-subjects partial reinforcement effects with an autoshaped response using Japanese quail (Coturnix coturnix japonica)

Crawford

Steirn

Pavlik

1985

“…However, a more traditional measure of strength of keypeck responding-rate of maintained responding-shows less sensitivity to these variables (Balsam & Payne, 1979;Crawford, Steirn, & Pavlik, 1985;Gonzalez, 1974;Kay, Hemmes, & Brown, 1984;Lucas, Deich, & Wasserman, 1981; Newlin & LoLordo, 1976;O'Connell & Rashotte, 1982;Perkins et al, 1975).…”

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confidence: 99%

Effects of trial duration on overall and momentary rates of maintained autoshaped keypecking: Choice and single-stimulus trials

Hemmes

Brown

Vaca

1990

Pigeons were exposed to differentially cued autoshaping trials in which conditioned stimuli were followed by food after 6 or 14 sec. Average and momentary rates of keypecking were examined on two types of unreinforced test trials: single-stimulus probe trials and simultaneous choice trials, each 40 sec in duration. Rates averaged over the 40-sec test trials did not favor the cue associated with the shorter delay to food (the short-delay cue) on either type of test trial; however, average rates prior to the scheduled time of food delivery were reliably higher for the short-delay cue on choice trials. Momentary rates of keypecking during choice trials varied as a function of both cue and elapsed time from trial onset. At short elapsed trial times, rate ofpecking was higher for the short-delay cue, with this difference reversing at longer times. A reversal of the programmed relation between key color and delay to food presentation for 5 birds confirmed the generality of these findings. Implications of these data for models of Pavlovian conditioning and for methods of assessing conditioned response strength are discussed.As with other Pavlovian preparations, speed of acquisition under autoshaping procedures shows strong dependence upon parameters of reinforcement (Balsam, 1984; Gibbon, Baldock, Locurto, Gold, & Terrace, 1977; Gibbon, Farrell, Locurto, Duncan, & Terrace, 1980;Jenkins, Barnes, & Barerra, 1981). However, a more traditional measure of strength of keypeck responding-rate of maintained responding-shows less sensitivity to these variables (Balsam & Payne, 1979;Crawford, Steirn, & Pavlik, 1985;Gonzalez, 1974;Kay, Hemmes, & Brown, 1984;Lucas, Deich, & Wasserman, 1981; Newlin & LoLordo, 1976;O'Connell & Rashotte, 1982;Perkins et al., 1975).These findings challenge the comparability of autoshaped keypecking with other indexes of Pavlovian conditioning. Gibbon et al. (1980) addressed this issue, noting that measures of keypecking pertaining to the first peck of a trial generally behave similarly to more traditional preparations, whereas measures that include all of the pecks in a trial may not. In their study of autoshaped responding, strength of the first response (latency) in a trial increased with increasing probability of reinforceThis research was supported in part by Grant MH 39950-01 from the NationalInstituteof Mental Health, and by PSC/CUNY Grant 6-64350. We gratefully acknowledge the assistance of David Kay in the developmentof this project.Requests for reprintsmay be sent to NancyHemmes, Department of Psychology, Queens College-CUNY, Flushing, NY 11367. ment, while strength of subsequent responses (rate) varied inversely with reinforcement probability. Similar effects were reported by Picker and Poling (1982), who used a within-subjects design. Overall rates of responding on single-stimulus trials favored the partially reinforced cue; however, the locus of the first peck on choice trials revealed a clear preference for a cue associated with a 100% probability of reinforcement. This effect has also ...

“…The present experiment is addressed to another traditional variable in classical conditioning, partial reinforcement. There is evidence that partial reinforcement exerts effects on maintained responding (Gonzalez, 1973(Gonzalez, , 1974Perkins, Beavers, Hancock, Hemmendinger, Hemmendinger, & Ricci, 1975;Schwartz & Williams, 1972;Wasserman, 1974;Wasserman, Hunter, Gutowski, & Bader, 1975). The effect of partial reinforcement on acquisition of autoshaped responding has received less parametric study.…”

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confidence: 99%

Partial reinforcement in autoshaping with pigeons

Gibbon

Farrell

Locurto

et al. 1980

147

160

The acquisition, maintenance, and extinction of autoshaped responding in pigeons were studied under partial and continuous reinforcement. Five values of probability of reinforcement, ranging from .1 to 1.0, were combined factorially with five values of intertrial interval ranging from 15 to 250 sec for different groups. The number of trials required before autoshaped responding emerged varied inversely with the duration of the intertrial interval and probability of reinforcment, but partial reinforcement did not increase the number of reinforcers before acquisition. During maintained training, partial reinforcement increased the overall rate of responding. A temporal gradient of accelerated responding over the trial duration emerged during maintenance training for partial reinforcement groups, and was evident for all groups in extinction. Partial reinforcement groups responded more than continuous reinforcement groups over an equivalent number of trials in extinction. However, this partialreinforcment extinction effect disappeared when examined in terms of the omission of "expected" reinforcers.