Acquisition of schedule-induced polydipsia by rats in proximity to upcoming food delivery     

López-Crespo G  Rodríguez M  Pellón R  Flores P 《Learning & behavior》2004,32(4):491-499

Food-deprived rats that receive intermittent delivery of small amounts of food develop excessive drinking--specifically, schedule-induced polydipsia (SIP). A main characteristic of SIP is its occurrence at the beginning of interfood intervals. The purpose of this study was to demonstrate that SIP can be developed toward the end of interfood intervals, in closer proximity to upcoming than to preceding food delivery. In Experiment 1, two groups were exposed to a fixed-time (FT) 30-sec food schedule with water available during the first or the last 15 sec of each interfood interval. Two additional groups, which had access to water throughout, were exposed to FT 30-sec or FT 15-sec schedules of food presentation. The FT 30-sec group with free access to water developed the highest level of intake; similar and intermediate levels were induced in all the remaining groups. In Experiment 2, three groups of rats were exposed to an FT 90-sec food schedule with water available during the first, the second, or the last 30 sec of each interfood interval. One additional group with access to water throughout was exposed to the FT 90-sec schedule of food presentation. The group with free access to water developed a higher level of consumption than did the other groups, but by the end of training none of the four groups showed statistical differences in polydipsic drinking. Results show that adjunctive drinking can be developed in proximity to upcoming food delivery even with long interfood intervals.  相似文献   

Flexible coding of temporal information by pigeons: Event durations as remember and forget cues for temporal samples     

Angelo Santi  Maetin Mielke 《Learning & behavior》1991,19(2):171-176

The ability of pigeons to use event durations as remember (R) and forget (F) cues for temporal samples was examined. Pigeons were required to indicate whether a houselight sample stimulus was short (2 sec) or long (6 sec) by pecking a red or a green comparison stimulus. After training with a constant 10-sec delay interval, temporal cues (illumination of the center key) were presented 2 sec after the offset of the temporal samples. For one group, a short (2-sec) temporal cue served as the R cue and a long (6-3ec) temporal cue served as the F cue. This was reversed for a second group of birds. During training, comparison stimuli were always presented following the temporal R cue, but never following the temporal F cue. Tests for the effectiveness of the temporal R and F cues showed that F cues were equally effective in reducing matching accuracy in both groups of birds. It was concluded that pigeons used the duration of the cue to determine whether or not to rehearse the memory code for the temporal sample.  相似文献   

Pigeons’ memory for event duration: Intertrial interval and delay effects     

Marcia L. Spetch  Benjamin Rusak 《Learning & behavior》1989,17(2):147-156

The effects of within-session variations in the intertriai interval (ITI) and delay on pigeons’ memory for event duration were studied in delayed symbolic matching-to-sample tasks. Pigeons were trained to peck one color following a long (8 sec) sample and another color following a short (2 sec) sample. In the first three experiments, the baseline conditions included a 10-sec delay (retention interval) and a 45-sec ITI. During testing, the delay was varied from 0 to 20 sec, and the ITI that preceded the trial was varied from 5 to 90 sec. When the ITI and delay were manipulated separately (Experiments 1 and 2), the pigeons displayed a choose-short tendency when the delay was longer than 10 sec or when the ITI was longer than 45 sec, and a choose-long tendency when either the delay or the ITI was shorter than these baseline values. These effects occurred whether the sample was food access or light. When the ITI and delay were manipulated together, the pigeons showed a large choose-long error tendency when the short delay was tested together with a short ITI, and no systematic error tendency when the short delay was tested together with a longer ITI. A very large choose-short error tendency emerged on trials with a long delay and a long ITI; a reduced choose-short tendency was present when the long delay was presented together with a short ITI. In Experiment 4, the baseline conditions were a 0-sec delay and a 45-sec ITI. In this case variations in the ITI had a smaller and unidirectional effect: the pigeons showed a choose-long error tendency when the ITI was decreased, but no effect of ITI increases. Two hypotheses were proposed and discussed: (1) that pigeons judge sample durations relative to a background time composed of the ITI and delay, and (2) that the delay and ITI effects might arise from a combination of subjective shortening and proactive effects of samples from previous trials.  相似文献   

Initial-link duration and acquisition of preference in concurrent chains     

Berg ME  Grace RC 《Learning & behavior》2006,34(1):50-60

Initial-link response allocation in concurrent chains becomes less extreme as the absolute duration of the initial links increases (Fantino, 1969). The present study asked whether initial-link duration affected how quickly response allocation reached asymptote (i.e., acquisition of preference). Six pigeons were trained on a concurrent-chains procedure in which the terminal links were fixed-interval (FI) 8 sec FI 16 sec or FI 16 sec FI 8 sec and were reversed every 20 sessions. Across conditions, all possible combinations of transitions between variable-interval (VI) 8-sec (short) and VI 24-sec (long) initial-link schedules were studied. Overall, the rate of acquisition was faster when the durations of the initial links preceding the reversal were short rather than long, and when the durations of the initial links following the reversal were long rather than short. By contrast, initial-link duration had no effect on acquisition or asymptotic measures of temporal control of terminal-link responding. These results support the core principle of delay-reduction theory (Fantino, 1969) that the impact of a conditioned reinforcer varies directly with initial-link duration, but also suggest that temporal learning during the terminal links proceeds independently of initial-link duration. nt]mis|These data were presented at the annual meeting of the Association for Behavior Analysis, Boston, May 2004.  相似文献   

The psychophysics of remembered duration     

J. Gregor Fetterman 《Learning & behavior》1995,23(1):49-62

Pigeons were trained on a psychophysical choice task to make one response after a 2-sec signal and a different response after a 10-sec signal. Delayed dimensional control was assessed by presenting durations intermediate to the short and long signals and by introducing delays between the signals and choice opportunities. In Experiment 1, choices after intermediate durations were not reinforced; in Experiment 2, one choice was reinforced after the three shortest durations and another was reinforced after the three longest durations. In Experiment 1, the slopes of the psychophysical functions decreased with increases in delays, but the decrease in stimulus control was not unbiased; choice probabilities decreased for longer durations, but did not increase for shorter durations. Experiment 2 revealed the same generalized loss of stimulus control on the temporal dimension, but not the same pattern of bias; temporal control was relinquished equally for shorter and longer durations. These results are evaluated in the context of the subjective shortening model of remembered duration (Spetch & Wilkie, 1983) and Staddon’s theory of timing and remembering (Staddon, 1984).  相似文献   

Memory for duration in pigeons: Dissociation of choose-short and temporal-summation effects     

Douglas S. Grant  Marcia L. Spetch 《Learning & behavior》1993,21(4):384-390

Five groups of pigeons were trained in a symbolic choice-matching feast involving short (2-sec) and long (10-sec) durations of houselight as samples. Four groups also received training with a second set of samples: line orientations or 2- and 10-sec presentations of keylight. The type of sample-to-comparison mapping varied across groups. Although only two of the five groups demonstrated a choose-short effect (a tendency to choose the comparison associated with a short sample at longer delays), all groups demonstrated temporal summation (a tendency to respond on the basis of the combined duration of two successively presented samples). Moreover, the magnitude of temporal summation was equivalent in groups that did and did not-demonstrate a choose-short effect. The results suggest that the processes underlying the perception of sample duration remain invariant across different sample-to-comparison mapping arrangements, but that the memory code used to retain temporal information varies.  相似文献   

Concurrent schedules of wheel-running reinforcement: Choice between different durations of opportunity to run in rats     

Belke TW 《Learning & behavior》2006,34(1):61-70

How do animals choose between opportunities to run of different durations? Are longer durations preferred over shorter durations because they permit a greater number of revolutions? Are shorter durations preferred because they engender higher rates of running? Will longer durations be chosen because running is less constrained? The present study reports on three experiments that attempted to address these questions. In the first experiment, five male Wistar rats chose between 10-sec and 50-sec opportunities to run on modified concurrent variable-interval (VI) schedules. Across conditions, the durations associated with the alternatives were reversed. Response, time, and reinforcer proportions did not vary from indifference. In a second experiment, eight female Long-Evans rats chose between opportunities to run of equal (30 sec) and unequal durations (10 sec and 50 sec) on concurrent variable-ratio (VR) schedules. As in Experiment 1, between presentations of equal duration conditions, 10-sec and 50-sec durations were reversed. Results showed that response, time, and reinforcer proportions on an alternative did not vary with reinforcer duration. In a third experiment, using concurrent VR schedules, durations were systematically varied to decrease the shorter duration toward 0 sec. As the shorter duration decreased, response, time, and reinforcer proportions shifted toward the longer duration. In summary, differences in durations of opportunities to run did not affect choice behavior in a manner consistent with the assumption that a longer reinforcer is a larger reinforcer.  相似文献   

Observing behavior: Redundant stimuli and time since information     

Bruce A. Wald  Thomas D. Dukich 《Learning & behavior》1978,6(4):380-384

Pigeons were allowed to observe a stimulus signaling food (S+) by pecking one side key of a three-key chamber, or a stimulus signaling extinction (S?) by pecking the opposite side key. Components were 30 sec long and separated by 3-sec blackouts (after extinction periods) or 3-sec access to an illuminated food hopper (terminating food periods). Pigeons came to peck the S+ key almost exclusively. When food and extinction periods were presented in random order, the S+ key was pecked in nearly every component. But when the components alternated in abab fashion, the probability of an S+ keypeck during extinction decreased (after 3-sec access to food) while remaining high in food components (after 3-sec blackout). This suggested the development of trace stimulus control by the stimuli separating the components and that redundant stimuli would maintain observing when they signaled food. Results were discussed in terms of traditional notions of conditioned reinforcement and were not seen as supporting information theory explanations of observing behavior.  相似文献   

One-trial simultaneous and backward fear conditioning as reflected in conditioned suppression of licking in rats     

William J. Mahoney  John J. B. Ayres 《Learning & behavior》1976,4(4):357-362

In three experiments, groups of albino rats received one strictly simultaneous pairing of a 4-sec auditory conditioned stimulus (CS) and a 4-sec 1-mA shock unconditioned stimulus (US). Other groups received a backward pairing, in which the US began before the CS, or a forward pairing, in which the CS began before the US. Control groups received only the US or received both the CS and the US but widely separated in time. Later, the CS was presented while the rats licked a drinking tube for water, and CS-elicited suppression of licking was taken as an index of the Pavlovian conditioned response (CR). It was found that groups receiving a single forward or a single simultaneous pairing suppressed more than groups that had received a backward pairing; and the backward groups, in turn, suppressed more than the control groups. It appears, then, that excitatory fear conditioning, as reflected in conditioned suppression of licking in rats, can be produced in a single trial by both backward and simultaneous conditioning procedures.  相似文献   

Proactive effects in pigeons’ timing behavior: Implications for an internal-clock model     

Donald M. Wilkie 《Learning & behavior》1988,16(2):132-136

We have found proactive effects in pigeons’ timing behavior, a finding inconsistent with internal-clock models of timing that assume a resetable working-memory component. Six pigeons were trained to discriminate between 2- and 10-sec illuminations of a white light; choice of a red pecking key was correct and rewarded after presentation of the short stimulus whereas choice of a green key was correct and rewarded after presentation of the long stimulus. During training sessions, there were 60 trials separated by a 20-sec intertriai interval; short and long light occurred in a randomized order and correct choices were reinforced with 5-sec access to grain on a partial (75%) schedule. During test sessions, there were 120 trials separated by a 2-sec intertrial inter val. Light presentations occurred in a fixed order throughout these sessions: 2, 6, 10, 10, 6, 2 2, 6, 10 sec, and so forth. Choice of either red or green after 6 sec was not reinforced. However, red continued to be correct after 2 sec and green continued to be correct after 10 sec. Of central interest was how the subjects classified 6 sec of light in ascending (2, 6, 10) and descending (10. 6, 2) sequences of durations: Subjects chose the short alternative on 42% of the 6-sec trials in ascending series but only 29% in descending series, a result most plausibly interpreted as show ing that duration information from a preceding trial affects duration classifications on the cur rent trial. Such proactive effects should not occur according to working-memory models that as sume that stored information is cleared at the end of a trial.  相似文献   

Pigeons exhibit higher accuracy for chosen memory tests than for forced memory tests in duration matching-to-sample     

Adams A  Santi A 《Learning & behavior》2011,39(1):1-11

Following training to match 2- and 8-sec durations of feederlight to red and green comparisons with a 0-sec baseline delay, pigeons were allowed to choose to take a memory test or to escape the memory test. The effects of sample omission, increases in retention interval, and variation in trial spacing on selection of the escape option and accuracy were studied. During initial testing, escaping the test did not increase as the task became more difficult, and there was no difference in accuracy between chosen and forced memory tests. However, with extended training, accuracy for chosen tests was significantly greater than for forced tests. In addition, two pigeons exhibited higher accuracy on chosen tests than on forced tests at the short retention interval and greater escape rates at the long retention interval. These results have not been obtained in previous studies with pigeons when the choice to take the test or to escape the test is given before test stimuli are presented. It appears that task-specific methodological factors may determine whether a particular species will exhibit the two behavioral effects that were initially proposed as potentially indicative of metacognition.  相似文献   

Required pecking and refraining from pecking alter judgments of time by pigeons     

Zentall TR  Singer RA 《Learning & behavior》2008,36(1):55-61

There is evidence that humans' perception of time is affected by the activity in which they are engaged while they are timing. The more demanding the task, the faster time appears to pass. A similar effect has been found in pigeons. Pigeons trained to discriminate between a short-duration (2-sec) and a long-duration (10-sec) stimulus were required to peck when the stimulus was one color and to refrain from pecking when it was a different color. On probe trials of intermediate durations, the bisection point (50% choice of the stimulus associated with both long and short stimuli) for trials in which the pigeons were required to peck was almost 1 sec longer than on trials in which the pigeons were required to refrain from pecking (Zentall, Friedrich, & Clement, 2006). In the present research, we replicated this effect and determined the relation between this effect and the typical bisection point that occurs when pecking is permitted but not required. Results indicated that the typical procedure results in a bisection point that is between required pecking and refraining from pecking. Furthermore, the rate of pecking when pecking is allowed but not required also falls between the rate of pecking for the required-pecking and refrain-from-pecking conditions. This result suggests that, similar to humans, pigeons underestimate the passage of time when they are active or when attention to time-related cues has to be shared with attention to satisfying the response requirement.  相似文献   

Effect of intertrial interval on variable-interval discrete-trial barpressing     

Mark D. Holder  Seth Roberts 《Learning & behavior》1988,16(3):340-353

In seven experiments, an effect of the intertriai interval (ITI) duration on barpressing by rats was studied. A stimulus signaled a 15-sec variable-interval trial. The first response after the interval elapsed turned the stimulus off and was rewarded with food. Trials were separated by long (about 300 sec) or short (about 10 sec) ITIs. A within-subjects design established that response rate on trials after long ITIs was lower than that after short ITIs (Experiments 1 and 3–7). The effect was not cumulative (the effect of one and five consecutive short ITIs was the same). Response rate after short and long ITIs was the same when a between-subjects design was used (Experiment 2). Response rate was higher after 160-sec ITIs than after 300-sec ITIs, suggesting that the ITI duration at which all longer ITIs are treated the same (i.e., the upper limit) is greater than 160 sec (Experiment 3). When food, the trial stimulus, a novel stimulus, or a familiar stimulus never paired with food, was presented 10 sec before the next trial during some of the long ITIs, response rate on the next trial was similar to that found after 10-sec ITIs (Experiments 4–6). This similarity suggested that these events could mark the start of the ITI. However, the familiar stimulus did so only when it reliably predicted that the next trial would occur after a short interval. The effect of ITI duration on responding was apparently attributable to response latency. Response latency was greater after long ITIs, but once responding began, it was similar after long and short ITIs (Experiment 7).  相似文献   

Microanalysis of variable-interval performance during stimulus compounding     

M. Catherine Bushnell  Stanley J. Weiss 《Learning & behavior》1978,6(1):66-71

Additive summation is observed when more responses are emitted to the simultaneous presentation (tone-plus-light) of independently conditioned stimuli (tone and light) than to either stimulus presented alone. The current experiment sought to determine if this increased rate during tone-plus-light was a function of a new modal interresponse time (IRT) or a differential mixing of pauses with a modal IRT characteristic of the responding in tone and light alone. Three rats were trained on a three-component multiple schedule where tone and light were each associated with a variable-interval 30-sec schedule while a variable-interval 100-sec operated in the simultaneous absence of these stimuli, tone-off and light-out. Baseline response rates were 2–4 times as high in tone or light as in their absence. In testing, more responses were emitted to tone-plus-light than to tone or light by all animals, but the modal IRT was in the 0.2–0.4-sec IRT bin for all test conditions. Tone-plus-light controlled fewer long IRT values and more responses in the short modal category than tone or light alone. These results support the response mixing hypothesis of stimulus control; i.e., no “new” behavior was observed during the novel combination of stimulus elements, only a mixture of previously reinforced behavior patterns in different proportions.  相似文献   

A reevaluation of the CS− hypothesis for schedule-induced polydipsia under intermittent schedules of pellet delivery     

David Shurtleff  Andrew R. Delamater  Anthony L. Riley 《Learning & behavior》1983,11(2):247-254

Lashley and Rosellini (1980) have recently suggested that schedule-induced polydipsia (SIP) is determined by the occurrence of absolute periods within schedules of periodic food delivery which are associated with a low probability of food delivery, that is, CS? periods. To assess this hypothesis, SIP was examined in the present experiments under three schedules—fixed time, variable time, and random time (RT)—which differed in probability of occurrence and/or duration (Experiment 1), and under a range of RT schedules in which the CS? period was systematically varied by changing the interpellet interval (Experiment 2). In both experiments, the level and temporal distribution of SIP did not seem to be related to the absolute period associated with the absence of food. Instead, SIP was more systematically related to the average length of the interpellet interval and, therefore, to the average period associated with no food. It was suggested that drinking under intermittent schedules of pellet delivery, that is, SIP, is determined by an average CS? period and not by an absolute period associated with the unavailability of food.  相似文献   

Operant response topographies of rats receiving food or water reinforcers on FR or FI reinforcement schedules     

John H. Hull  Timothy J. Bartlett  Robert C. Hill 《Learning & behavior》1981,9(3):406-410

Separate groups of food- and water-deprived rats pressed a lever for food or water, respectively, on continuous reinforcement and various fixed-ratio and fixed-interval reinforcement schedules. Food-reinforced rats on continuous, FR 2-, or FI 10-sec schedules showed consistently longer mean lever contact durations per leverpress than did water-reinforced rats on the same schedules. Mean lever-contact-duration differences between food- and water-reinforced rats were greatly attenuated or disappeared under FR 4-, FR 8-, FI 20-sec, and FI 30-sec schedules of reinforcement. These results are interpreted as supporting earlier hypotheses that there are respondent components of operantly conditioned and autoshaped leverpresses, but that these respondent components weaken with partial reinforcement and the leverpress topography comes under the control of operant contingencies.  相似文献   

Schedule-induced wood-chewing in rats and its dependence on body weight     

T. J. Roper  G. Crossland 《Learning & behavior》1982,10(1):65-71

In Experiment 1, 12 rats were exposed to an FT 60 schedule of food reinforcement, followed either by extinction or by a massed-food control condition, in the presence of a wood block. In 9 rats, wood-chewing behavior increased systematically during the FT 60 condition and declined again during extinction or massed food, while the other 3 rats showed virtually no chewing behavior at any stage of the experiment. In Experiment 2, frequency and bout duration of wood-chewing under an FT 60 schedule of food reinforcement declined as body weight increased, in 7 rats. We conclude that wood-chewing qualifies as a schedule-induced behavior, and that it resembles schedule-induced drinking in its dependence on body weight. Unlike drinking, however, induced chewing occupied the middle region of the 60-sec interreinforcement interval, declined markedly within the session, and showed considerable within- and between-subject variability.  相似文献   

Transfer of a taste aversion from food to water under various states of deprivation     

Katy Gillette  W. P. Bellingham  Gerard M. Martin 《Learning & behavior》1979,7(4):441-446

The importance of ingestive contexts (feeding and drinking) and deprivation states to rats’ transfer of a taste aversion were examined, In Experiments 1 and 2, rats were trained with novel saccharin-treated foods while either food deprived or food and water deprived, They were then tested with a 1,0% saccharin solution while either water deprived or food and water deprived, Comparable aversions to the solution were displayed regardless of deprivation states, Two further experiments examined transfer to a .1% saccharin solution in conjunction with deprivation state change, When both stimulus properties and deprivation were widely discrepant from training to test, reduced transfer was noted. The results suggest that stimulus similarity was a stronger controlling variable than deprivation state similarity in facilitating the transfer of an aversion from a feeding context to a drinking context, The results were viewed as being consistent with the known parameters affecting generalization gradients.  相似文献   

Alterations in the memory code for temporal events induced by differential outcome expectancies in pigeons     

Mary Jo Ducharme  Angelo Santi 《Learning & behavior》1993,21(1):73-81

The effect of differential outcome expectancies on memory for temporal and nontemporal information was examined. Pigeons were trained to match short (2-sec) and long (8-sec) sample durations to red and green comparison stimuli, and vertical and horizontal lines to vertical and horizontal comparison stimuli. In Experiment 1, one differential outcome (DO) group received food for correct choices on short-sample trials, whereas another received food for correct choices on long-sample trials. On line-orientation trials, half of each DO group received food for correct responses following vertical samples, whereas the other half received food for correct responses following horizontal samples. Overall retention was greater in the DO groups than in a nondifferential (NDO) group that received either food or no food for correct responses on a random half of all trials. Furthermore, although the NDO group displayed a choose-short bias for temporal samples, both DO groups displayed equivalent biases to select the comparison stimulus associated with food. In Experiment 2, differential outcome expectancies were extinguished off-baseline. Subsequently, in the first nondifferential outcome test session, the. DO groups performed less, accurately than the NDO group. These findings indicate that temporal samples are not retrospectively and analogically coded when they are differentially associated with food and no food. Instead, they are remembered in terms of the corresponding outcome expectancies.  相似文献   

Pigeons’ memory for event duration: Differences between visual and auditory signals     

Angelo Santi  Lianne Stanford  James Coyle 《Learning & behavior》1998,26(2):163-171

In Experiment 1, pigeons were trained to discriminate short (2 sec) and long (8 sec) durations of tone by responding to red and green comparison stimuli. During delay testing, a systematic response bias to the comparison stimulus correct for the long duration occurred. Tests of responding without the tone reduced accuracy on long-sample trials but not on short-sample trials suggesting that the pigeons were attending to the tone and not simply timing the total trial duration. The pigeons were then trained to match short (2 sec) and long (8 sec) durations of light to blue/yellow comparisons. During delay testing, “choose-long errors” occurred following tone durations, but “choose-short errors” occurred following light durations. In Experiment 2, accuracy was assessed on test trials in which the tone and the light signals were simultaneously presented for the same duration or for different durations. Pigeons responded accurately to durations of light, but were unable to accurately respond to durations of tone simultaneously presented with the light. The data from Experiment 1 suggest that there are important differences between light and tone signals with respect to the events that control the termination of timing. The data from Experiment 2 indicate that pigeons cannot simultaneously time visual and auditory signals independently and without interference. Consequently, they are inconsistent with the idea that there is a single internal clock that times both tone and light durations.  相似文献