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1.
Pigeons were trained in a within-subjects design to discriminate empty intervals (bound by two 1-sec visual markers) and filled
intervals (a continuous visual signal). The intervals were signaled by different visual stimuli and they required responses
to different sets of comparison stimuli. In Experiment 1, empty intervals were judged longer than filled intervals. The difference
between the point of subjective equality (PSE) for the empty intervals and the PSE for filled intervals increased as the magnitude
of the anchor-duration pairs increased. Although there was more pecking during filled intervals than during empty intervals,
there was no significant correlation between pecking during filled intervals and the value of the PSE. In Experiment 2, empty
intervals continued to be judged longer than filled intervals, even when pigeons were required to refrain from pecking during
filled intervals. Keypecking per se does not appear to play an important role in the empty-filled timing difference. 相似文献
2.
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
3.
Cathie E. Alderks 《Learning & behavior》1986,14(3):331-335
Seventeen pigeons observed a model peck an illuminated key at either a high or a low rate and obtain a high or low percentage of possible reinforcement. Observers were subsequently placed on an automaintenance schedule. Although there was no difference among groups in the number of trials to the first peck, when the present data were compared with other researchers’ automaintenance-acquisition data, there was some indication that modeling reduced the number of trials to the first peck over nonmodeled birds. However, by the end of 20 sessions, the birds that had observed a model pecking at a high rate and with consistent reinforcement pecked significantly faster than those that had observed the model peck at a slow rate or obtain infrequent reinforcement. The conclusion is that two types of information are transferred via a model: first, a correlation between the stimulus and the reinforcer, and second, the specific or minute attributes of the schedule that may produce reinforcement. 相似文献
4.
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
5.
Two experiments were performed to investigate the relationship between excitatory stimulus control (number of responses to a training stimulus) and dimensional stimulus control (generalization gradient slope). In experiment 1, after being trained to peck a green key, pigeons received either 20, 40, or 80 brief (.5, 2, 4, or 8 sec) presentations of a 45-deg line followed by reinforcement (12 groups) or 20, 40, or 80 reinforcements for pecking a continuously presented 45-deg line (3 groups). Number of reinforcements determined the slope (percent of total responses to 45 deg) of a subsequent line-angle generalization gradient, but number of responses to the 45-deg line in the test was controlled by total experience with 45 deg as measured by either total exposure time or total responses to 45 deg in training. In a second experiment, it was shown that increasing the number of days of pretraining to green decreased the slope of the gradient (in subjects given 2-sec presentations), but had no effect on number of responses to 45 deg in the test. Furthermore, continuous presentation yielded flatter gradients but more responding to the 45-deg line in the test than did 2-sec presentations. It was concluded that the measures of dimensional stimulus control and excitatory stimulus control reflect different processes because they vary differentially (sometimes in different directions) in response to the same independent variable manipulations. 相似文献
6.
In Experiment 1, three food-deprived pigeons received trials that began with red or green illumination of the center pecking key. Two or four pecks on this sample key turned it off and initiated a 0- to 10-sec delay. Following the delay, the two outer comparison keys were illuminated, one with red and one with green light. In one condition, a single peck on either of these keys turned the other key off and produced either grain reinforcement (if the comparison that was pecked matched the preceding sample) or the intertrial interval (if it did not match). In other conditions, 3 or 15 additional pecks were required to produce reinforcement or the intertrial interval. The frequency of pecking the matching comparison stimulus (matching accuracy) decreased as the delay increased, increased as the sample ratio was increased, and decreased as the comparison ratio was increased. The results of Experiment 2 suggested that higher comparison ratios adversely affect matching accuracy primarily by delaying reinforcement for choosing the correct comparison. The results of Experiment 3, in which delay of reinforcement for choosing the matching comparison was manipulated, confirmed that delayed reinforcement decreases matching accuracy. 相似文献
7.
Cathryn P. Brown 《Learning & behavior》1978,6(1):94-97
White-Leghorn × Black-Orpington chicks were reared socially, in isolation, or were isolated and exposed to an artificial stimulus at 16 h. They were tested at 24, 48, or 72 h for pecking in the presence of another chick, of the artificial stimulus, or in isolation. Socially reared chicks pecked more during pair-testing than in isolation, and showed no increase in pecking with the artificial stimulus. Imprinted chicks pecked most with the artificial stimulus, but showed a slight increase in pecking during pair-testing compared with isolation. Isolates showed similarly low peck rates under all conditions. These results, showing the importance of familiarity with test conditions in facilitation, were interpreted as consistent with an arousal-reduction account of facilitation. The importance of stimulus movement was also discussed, both as a potential dimension of stimulus generalization and as a factor in maintaining a minimum level of arousal essential to responding. 相似文献
8.
After training with a variable-interval schedule of positive reinforcement, pigeons were tested for stimulus generalization along the hue dimension. For one group, the stimulus was located on the response key. For a second group, the stimulus was located on a surface adjacent to the response key. The stimulus-on-key group produced the typical steep gradients normally found with hue stimuli; the stimulus-off-key group produced flat gradients. After discrimination training between the presence and absence of the hue stimulus, both groups produced decremental gradients. In a second experiment, naive pigeons were trained to peck a transparent key with the stimulus surface located approximately 3.8 cm behind the key. When tested for generalization, the hue gradients were decremental. The results suggest that location of the stimulus in the line of sight with pecking is a necessary condition for stimulus control by hue after nondifferential training. 相似文献
9.
In each of two experiments, different groups of pigeons were required to discriminate between one of two basic kinds of stimulus differences: stimulus quality or stimulus location. For stimulus-quality groups, a key was illuminated by one of two colors on trials ending with food delivery and by the other color on trials ending with no food. For stimulus-location groups, a key was illuminated at one of two locations on trials ending with food delivery and at the other location on trials ending with no food. The birds began to respond differentially to the stimuli (i.e., peck the keys on food trials and not peck the keys on no-food trials) earlier in acquisiton if the stimulus qualities served as the signals for trial outcomes than if the stimulus locations served as those signals. The results from both experiments are consistent with predictions from a hypothesis regarding interactions among the qualities and locations of stimuli and responses (the “quality-location hypothesis”). Furthermore, the present results support other recent demonstrations of the important role that spatial relations among stimuli can play in classical conditioning. 相似文献
10.
Barry Schwartz 《Learning & behavior》1973,1(3):164-166
Response key illuminations were followed by food delivery or shock, and keypecks were programmed to prevent the occurrence of whichever stimulus was scheduled. At high shock intensity, pigeons did not peck: at low shock intensity, pigeons pecked in about half of the trials. When different key colors signaled food and shock trials, pigeons pecked on food trials, thus preventing food delivery, but not on shock trials, thus failing to avoid shock delivery. That pecks occurred despite the fact that they avoided food but did not occur when they avoided shock is taken as evidence that the keypeck is frequently governed by biological predispositions, and not by its consequences. 相似文献
11.
Donald M. Wilkie 《Learning & behavior》1987,15(1):35-39
Five 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. On half the trials, the light was bright; on the others, it was dim. Durations of 4, 6, and 8 sec of both dim and bright light were also presented; choices on these trials were not rewarded. The probability of the pigeons’ choosing the short alternative decreased in a graded manner as duration of both bright and dim light increased from 2, to 4, to 6, to 8, and to 10 sec. However, the pigeons were more likely to choose the short alternative with longer durations of the dim light than the bright light, a result that implies that the perceived duration of a dim light was shorter than that of a bright light of equal length. One interpretation of this effect is that stimulus intensity affects the rate of the pacemaker in an internal clock mechanism subserving timing of event duration. 相似文献
12.
In two experiments, behavioral stereotypies elicited by scheduled presentations of food and water were compared. In Experiment 1, pigeons were exposed to a fixed-time 30-sec (FT 30-sec) schedule of food or water deliveries with a brightening keylight stimulus signaling time to the unconditioned stimulus (UCS) on each trial. Food and water presentations both produced terminal autoshaped keypecking that was similarly distributed in the trial but differed in response topography and persistence. Locomotor interim behavior was different in the two motivational conditions: With food presentations, it consisted of a “retreat” to the rear of the chamber after UCS termination, followed by “pacing” in the midportion of trials. The water schedule produced very little locomotor activity with no regular distribution in the trial. Experiment 2, using a random-time 30-sec (RT 30-sec) schedule, showed that the differences in interim locomotor behavior persisted in the absence of temporal predictability of the UCS and the keypecking terminal response. The results are taken to support Timberlake’s (1983a) behavior-system theory. 相似文献
13.
The behavior of 77 pigeons maintained at 80% of their free-feeding weights in open-wire battery cages was monitored 16 times a day by observers for up to 285 days. Five distinct types of stereotyped behaviors were operationally defined. One of these behaviors, “spot pecking,” clearly predominated. Forty-nine of the 77 pigeons were observed spotpecking on at least 25% of the days they were observed, and several pigeons emitted more than 50,000 spot pecks per day. This occurred in spite of the total absence of any explicit reinforcer. A series of three experiments demonstrated that the great majority of spot pecks occurred in the hours immediately after feeding, that only food-deprived birds spot pecked, and that the behavior of adjacent birds influenced the rate of acquisition of stereotypes. Difficulties with labeling spot pecking as superstitious, respondent, or mediating are discussed. It is suggested that spot pecking be classed as an “adjunctive” behavior. 相似文献
14.
When the response of pigeons is maintained to a number of stimulus wavelengths, but extinguished to one (S?), the birds peck more rapidly at stimuli near the S? than at more distant stimuli. The present study explores this “dimensional contrast” effect as a function of the number and spacing of test wavelengths. A fixed portion of the wavelength continuum was spanned by 5, 9, 13, or 49 stimuli, which appeared in random sequence behind a standard pecking key. At the end of each 20-sec trial, pecks to test stimuli produced a conditioned reinforcer (sometimes followed by food), while pecks to the S? stimulus produced only darkness. Dimensional contrast “shoulders” developed to test stimuli on either side of the S?; these shoulders were of approximately the same height and wavelength position for all but the 5-stimulus (widely spaced) condition, and were comparable to the original contrast results with 25 stimuli. The results strongly suggest that the extent and locus of contrast shoulders are largely independent of the number and spacing of test stimuli. 相似文献
15.
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
16.
The relationship between the duration of stimuli and their conditioned reinforcing effect was investigated using a learning-tests procedure. In Experiment 1, stimuli were the same duration on training (stimulus → reward) and test (choice response → stimulus). Ten- and 30-sec stimuli provided effective differential conditioned reinforcement but 3-sec stimuli did not. In Experiment 2, different pigeons had each combination of the 3- and 30-sec stimuli on training and test trials. Evidence of conditioned reinforcement was obtained only for the birds with 30-sec stimuli on both training and test. The results were interpreted as indicating that stimuli become effective conditioned reinforcers on test trials only when their duration exceeds the duration of differential short-term memory cues resulting from a difference in the events that precede them on training and test trials. 相似文献
17.
Pigeons were trained in a forced choice task with four alternatives to categorize arrays consisting of 1, 3, 5, or 8 dots.
Before the pigeons chose a comparison stimulus, they were required to peck each dot sequentially. A single peck to a dot,
which was defined as an indicating response, changed the color of the dot so that it was differentiated from those that remained to be counted. The pigeons
successfully learned to categorize the numerical arrays and then displayed transfer to novel arrays consisting of two, four,
six, or seven dots, in a manner according to the order of 1 < 2 < 3 < 4 < 5 < 6 < 7 < 8. Subsequent tests revealed that the
pigeons discriminated the stimuli by relying on the number of indicating responses. They also utilized multiple information
(surface area, time, and other confounded events), but this was of minor significance, and after training, the pigeons were
able to disregard these cues. 相似文献
18.
If pigeons are trained on matching-to-sample with differential responding required to the two samples, there is evidence that
the differential responding can control comparison choice. We asked whether similar responding required at two different locations
could also serve as the basis for comparison choice. Pigeons were pretrained to report the location that they had pecked.
To reduce the likelihood that they could use the presence of differential proprioceptive cues at the time of their report,
a common response was required between the location response and the comparison choice. They were then given experience with
a conditional discrimination in which location of the comparison response varied randomly and was incidental to the choice
of comparison. On test trials, after the pigeons had made their comparison choice, they showed a significant tendency to choose
the appropriate test comparison when they were unexpectedly asked to report the location of their previous pecking response.
These results have implications for the demonstration of episodic-like memory in pigeons because they suggest that pigeons
have the capacity to recall, unexpectedly, specific details about their past experiences. 2007 Psychonomic Society, Inc. 相似文献
19.
William S. Maki 《Learning & behavior》1975,3(4):312-316
In a study of sustained attention (“vigilance”), pigeons performed a conditional discrimination in a 3-key operant chamber. Pecking a white center key initiated a 0.2- or 2.0-sec cue (a red or green disk). The side keys then displayed white disks, and a peck on the right or left key was reinforced depending on whether the preceding cue was red or green. Pecks on the white center key initiated the cue according to one of two schedules of cue production (FR 1 or VI 7.5 sec). Control of side key choices by 0.2-sec cues was disturbed by transition from FR 1 to VI 7.5, and recovered after the schedule of cue production changed from VI 7.5 back to FR 1. Control of choices by 2.0-sec cues was not affected by changing schedules of cue production. Rates of pecking the cue were higher than rates of cue-producing responses. 相似文献
20.
In Experiment 1, the development of autoshaped pecking to a keylight signaling food was blocked if the keylight was presented only in conjunction with another stimulus already established as a signal for food, even though the blocking stimulus (either an overhead light or a train of clicks) never elicited pecking itself. In Experiment 2, pigeons came to peck a white keylight which signaled the presentation of a red keylight which had earlier been established as a first-order signal for food, but this second-order autoshaping was blocked if the white keylight was presented only in conjunction with the houselight or clicker which had previously signaled the presentation of the first-order stimulus. Second-order autoshaping was thus blocked in the same way as was first-order autoshaping. 相似文献