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1.
Each of four pigeons was exposed to a single random-ratio schedule of reinforcement in which the probability of reinforcement
for a peck on either of two keys was 1/25. Reinforcer amounts were determined by an iterated prisoner’s dilemma (IPD) matrix
in which the “other player” (a computer) playedtit-for-tat. One key served as thecooperation(C) key; the other served as thedefection(D) key. If a peck was scheduled to be reinforced and the D-key was pecked, the immediate reinforcer of that peck was always
higher than it would have been had the C-key been pecked. However, if the C-key was pecked and thefollowing peck was scheduled to be reinforced, reinforcement amount for pecks on either key were higher than they would have been if
the previous peck had been on the D-key. Although immediate reinforcement was always higher for D-pecks, the overall reinforcement
rate increased linearly with the proportion of C-pecks. C-pecks thus constituted a form of self-control. All the pigeons initially
defected with this procedure. However, when feedback signals were introduced that indicated which key had last been pecked,cooperation (relative rate of C-pecks)—hence, self-control—increased for all the pigeons. 相似文献
2.
The effects of identical context on pattern recognition by pigeons for outline drawings of faces were investigated by training
pigeons to identify (Experiment 1) and categorize (Experiment 2) these stimuli according to the orientation of the mouth—an
upright U shape representing a smiling mouth or an inverted U shape representing a sad mouth. These target stimuli were presented
alone (Pair 1), with three dots in a triangular orientation to represent a nose and eyes (Pair 2), and with the face pattern
surrounded by an oval (Pair 3). In Experiment 1, the pigeons trained with Pair 1 were most accurate, those trained with Pair
2 were less so, and those trained with Pair 3 failed to acquire the discrimination within eighty 100-trial sessions. The same
ordering was found in Experiment 2 for pigeons trained on the three pairs simultaneously. The authors suggest that a contrasting
finding in humans, the face superiority effect, might be due to a gain in discriminability resulting from recognition of the
pattern as a face. An exemplar model of information processing that excludes linguistic coding accounts for the present results. 相似文献
3.
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
4.
In the present experiment, we investigated whether pigeons rely exclusively on elemental information or whether they are also able to exploit configural information in apeople-present/people-absent discrimination task. Six pigeons were trained in a go/no-go procedure to discriminate between 800 color photographs characterized by the presence or absence of people. Thepeople-present stimuli were designated as positive, and thepeople-absent stimuli were designated as negative. After training and a subsequent generalization test, the pigeons were presented with both familiar and novel people-present stimuli containing human figures that were distorted in one of seven different ways. All the pigeons learned the initial discrimination and also showed generalization to novel stimuli. In the subsequent test, performance on all types of distorted stimuli was diminished in comparison with that on the intact original pictures from which they had been derived. At the same time, however, peck rates clearly exceeded the level of responding found for regular people-absent stimuli. This result strongly suggests that responding was controlled by both the constituting target components and their spatial relations and, therefore, points to the dual importance of elemental and configural information. 相似文献
5.
Jacky Emmerton 《Learning & behavior》1998,26(3):243-256
Two experiments are described in which pigeons were trained in a simultaneous conditioning procedure to discriminate small arrays of dots that differed in numerosity. The birds successfully learned to choose the array of each pair that contained fewer dots when these choices were reinforced and choices of the array with more dots led to timeout. For the majority of numerosity values tested, discrimination performance for a fixed S+ value was better when the numerical difference between S+ and S-values was larger rather than smaller. This effect was seen in the first experiment when the numerical difference value was shifted between training trials and novel test trials. In the second experiment, too, performance level depended on the size of the numerosity difference when the birds were concurrently trained with two difference values that varied across trials within sessions. However, discrimination accuracy was influenced secondarily by variations in the density, or interdot spacing, of the stimulus arrays. In order to explain the latter finding, it is suggested that a tendency to “scan” a lowdensity array incompletely might alter the probability of accepting it as the smaller numerosity (S+) stimulus. This would increase error rates with S? arrays in which the dots are more widely spaced. 相似文献
6.
Pigeons were trained in a duration-comparison procedure to peck one key if the comparison duration (c) was 1 sec shorter than a standard duration (s), and another key if c was 1 sec longer than s. During training, the s-c delay was 1 sec, and the total duration of an s-c pair was not predictive of the correct choice. In Experiment 1, during equal-duration pair test trials, pigeons increasingly
responded long (i.e., c τ s) as the s-c delay was lengthened. In Experiment 2, we demonstrated that s affected long responding on equal-duration test trials, even at the 8-sec s-c delay. In Experiment 3, long responding increased as the s-c delay was lengthened, even when stimulus conditions during the s-c delay differed from those during the intertrial interval (ITI). Additional analyses indicated that it was unlikely that the
increase in long responding was due to the pigeons’ adding the s-c delay to c and comparing the total against the duration of s. The increase in long responding with an increase in s-c delay is more consistent with subjective shortening of s than with confusion between the s-c delay and the ITI. 相似文献
7.
When pigeons are trained on a discrete-trial simultaneous discrimination, some of the value associated with the positive stimulus appears to transfer to the negative stimulus (Zentall & Sherburne, 1994). Pigeons preferred a negative stimulus that had been discriminated from an always-positive stimulus (S+) over a negative stimulus that had been discriminated from a sometimes-positive stimulus (S±). A very different finding (suggestive of transitivity of preference or contrast) was reported by Belke (1992). On concurrent probe tests of stimuli associated with equal variable interval (VI) schedules but originally trained in alternative concurrent pairs (one with a richer schedule, the other with a poorer schedule—VI 20 sec vs. VI 40 sec and VI 40 sec vs. VI 80 sec), the stimulus originally paired with the poorer schedule was preferred. But Belke’s results may have been obtained because the pigeons had been trained to peck the VI 40 sec paired with the poorer schedule and they had been trained not to peck the VI 40 sec paired with the richer schedule. In the present experiment, we avoided this bias by training pigeons on two concurrent schedules in which the tested stimuli both had been associated with the poorer schedule of the pair [A(VI 20 sec) vs. B(VI 80 sec) and C(VI 40 sec) vs. D(VI 80 sec)]. Evidence for value transfer was demonstrated when on probe trials pigeons preferred B over D. 相似文献
8.
Control of beak opening (gape) and peck location was examined in pigeons. Feeding pecks showed accurate guidance that positioned the seed between the beaks. At the moment of contact with the seed, gape was proportional to seed diameter, although pecks with gape less than seed diameter were more frequent following an increase in seed size during a meal. There were no substantial differences between pigeons trained to keypeck with autoshaping and those trained with operant conditioning procedures. With either procedure, water reinforcement produced keypecks with the beak closed; seed reinforcers of different sizes produced means for gape proportional to the seed diameters. Black or white circular stimuli of different sizes projected as conditioning signals had little influence upon gape, but a greater percentage of responses was directed to white stimuli. These results indicate that visual stimuli elicit and orient the peck, whereas the adjustment of gape also involves the somatosensory stimuli provided during previous experience with a particular reinforcer or food type. 相似文献
9.
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
10.
Willson and Wilkie (1993) developed a novel procedure for assessing pigeons’ memory for the spatial location of food. Only one of four locations (consisting of an illuminated pecking key and grain feeder) provided food each day. Over days, different locations provided food. The pigeons’ tendency to revisit the location that was profitable on the previous day demonstrated memory for food-spatiallocation associations over a period of 24 h, retention longer than previously reported for this species. This basic finding was replicated and extended in three experiments. Experiment 1 demonstrated that location-food discriminations were also remembered well when established with successive rather than concurrent procedures. Experiment 2 demonstrated that pigeons can remember two location-food associations over 24 h. Experiment 3 showed that the discrimination training inherent in this paradigm is important for retention; retention was impaired when only the rewarded location was presented. Overall, this research suggests that cross-species differences in spatial memory performance may be due to quantitative rather than qualitative differences in the memory system underlying performance. 相似文献
11.
Barry Schwartz 《Learning & behavior》1985,13(3):261-268
When pigeons are required to peck each of two keys in any order for reinforcement, stereotyped response sequences develop that are resistant to disruption by extinction, schedules of reinforcement, or contingencies requiring sequence variability. To test the hypothesis that stereotyped response sequences become integrated behavioral units, two experiments introduced within-sequence temporal delays of varying duration. Experiment 1 found that when a delay followed each peck in a sequence, there was substantial disruption of sequence performance that was independent of delay duration. However, such disruption was only temporary. Experiment 2 found that when the location of a delay within a sequence was varied, sequence disruption was a function of when, in a sequence, the delay occurred. Delays that occurred within sequence subunits had large effects, whereas delays that occurred between such subunits had small effects. The data indicate that pigeons can learn to bridge within-sequence delays, and suggest that response sequences are organized into “phrases.” 相似文献
12.
Kelly J. Stanhope 《Learning & behavior》1989,17(3):311-321
A dissociation between the effect of reinforcer type and response strength on the force of the pigeon’s keypeck response was shown in three experiments. In Experiment 1, pigeons were trained to peck two conditioned stimuli, one paired with water and another paired with grain. The pigeons made more forceful pecks for grain than for water and also showed a tendency, albeit an unreliable one, to respond on a higher percentage of food trials than water trials. In Experiment 2, the pigeons from Experiment 1 were satiated with either food or water and were then presented with the two conditioned stimuli in an extinction test. It was found that, regardless of the drive state, the pigeons made more forceful pecks to the stimulus that predicted food than to the stimulus that predicted water. In the thirsty group, however, this difference in force was not accompanied by a difference in the percentage of trials with a response. In Experiment 3, pigeons trained with a single reinforcer pecked more often on instrumentally reinforced trials than on Pavlovian conditioning trials, but there was no difference in the force of the pecks. Taken together, these results imply that differences in response strength cannot account for the difference between the force of food- and water-reinforced pecks. Instead, stimulus-substitution theory may provide the best account of the topography of the two types of pecks. 相似文献
13.
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
14.
The present research tested the generality of the “work ethic“ effect described by Clement, Feltus, Kaiser, and Zentall (2000).
In Experiment 1, we trained 10 pigeons on a pair of either simultaneous or successive discriminations. One discrimination
followed a high-effort requirement (20 pecks to the center key) and the other followed a low-effort requirement (1 peck).
Contrary to Clement et al.’s results, we found that preferences between the S+ and S− stimuli in transfer tests depended on the event that initiated the trial: Pigeons preferred the stimulus from the baseline
discrimination whose initiating event was most dissimilar from that preceding the test trial. Preferences were similar but
less extreme in the successive condition. In Experiment 2, we investigated whether test preferences depended on the amount
of training. A total of 12 pigeons were trained on a pair of simultaneous discriminations, except that test sessions were
scheduled after every three baseline sessions. Preferences increased across test sessions but were similar to those in Experiment
1. Together with Vasconcelos, Urcuioli, and Lionello-DeNolf (2007a), our study represents a second failure to replicate Clement
et al.’s work ethic effect. The finding that preference depends on the event that initiates the test trial suggests that choice
probes may not provide unambiguous assessments of stimulus value. 相似文献
15.
Three experiments were performed to address factors contributing to the Ponzo illusion. In Experiment 1, pigeons learned to peck at the longer of two bars in varying line contexts. When these lines converged, the birds had difficulty in learning several patterns in which a Ponzo illusion would reduce the perceived difference. In Experiment 2, the subjects chose one response if a stimulus bar was longer than a predetermined length and a second response for shorter bars. The subjects were more likely to choose “long” as the stimulus bar approached the apex of converging lines. These results suggested that pigeons experience the Ponzo illusion. In Experiment 3, the effects of contexts that did and did not form a texture gradient were compared. The magnitude of the illusion did not differ according to context lines. This result failed to support a perspective theory of the Ponzo illusion. 相似文献
16.
Pigeons were trained to discriminate between arrays containing equal numbers of two different elements as S+, and arrays which contained more elements of one kind than the other as S?. They were then tested with the full range of the proportions of the two elements. This resulted in behavioral contrast and peak shift, as the pigeons responded more to arrays containing more positive than negative elements than they did to the positive training arrays. These findings were obtained with elements that differed in color (blue vs. red dots) and with elements that differed in orientation (horizontal vs. vertical rectangles). The results indicate that the stimulus control exerted by the derived dimension of relative numerosity involves the same processes as the fundamental dimensions that characterize simple stimulus elements. 相似文献
17.
A symbolic delayed matching procedure may be used to study memory for stimulus duration in pigeons. Short and long presentations of a light sample stimulus are mapped onto the choke of visually differentiated comparison keys. When delay is varied in such a symbolic delayed matching procedure, pigeons show increasing preference for the short-sample key as the delay becomes longer (choose-short effect), even after a long sample stimulus has been presented. Two theoretical explanations of the choose-short effect are suggested. A subjective shortening model holds that the choose-short effect arises from progressive shortening of the memory of stimulus duration as the delay proceeds. An alternative coding model suggests that the choose-short effect arises from stimulus generalization after an initial response instruction to peck the long-sample key has been forgotten. These two models were tested by training pigeons to peck a third comparison key after no sample stimulus had been presented. Shifts in key preferences over delays ranging from 0 to 21 sec clearly supported the coding model. 相似文献
18.
Sequence learning in pigeons was studied in asimultaneous chaining paradigm: all stimuli and the opportunity to respond to each stimulus were available simultaneously. In contrast to the traditionalsuccessive chaining paradigm, a simultaneous chaining paradigm provides no differential feedback following each response (except the last). Subjects were first trained to perform on sequences of two (AB), then three (ABC), and then four colors (ABCD). Performance greatly exceeded that predicted by models of random choice. Generalization to novel arrays of three and four colors was complete. After training with a four-color sequence, the subjects were tested with subsequences consisting of all possible combinations of two and three of the four training colors (e.g., BD, AD, BC, ACD, BCD, etc.). The successful completion of these subsequences showed that the organization of the original sequence did not entail overt pecks to successive elements of that sequence. That subjects can respond accurately on nonadjacent subsets is not readily explained by a chaining theory, or by any theory that assumes that responding to element n provides a cue for responding to element n+1. 相似文献
19.
Numerical competence has been studied in animals under a variety of conditions, but only a few experiments have reported animals’
ability to detect absolute number. Capaldi and Miller (1988) tested rats’ ability to detect absolute number by using biologically
important events—the number of reinforced runs followed by a nonreinforced run—and found that the rats ran significantly slower
on the nonreinforced run. In the present experiments, we used a similar procedure. Pigeons were given a sequence of trials
in which responding on the first three trials ended in reinforcement but responding on the fourth trial did not (RRRN). When
the response requirement on each trial was a single peck (Experiment 1), we found no significant increase in latency to peck
on the fourth trial. When the response requirement was increased to 10 pecks (Experiment 2), however, the time to complete
the peck requirement was significantly longer on the nonreinforced trial than on the reinforced trials. Tests for control
by time, number of responses, and amount of food consumed indicated that the pigeons were using primarily the number of reinforcements
obtained in each sequence as a cue for nonreinforcement. This procedure represents a sensitive and efficient method for studying
numerical competence in animals. 相似文献
20.
Adult pigeons with one eye covered were trained to peck a response key using grain as a reinforcer. In subsequent tests, with the trained eye covered and the control eye open, the birds failed to peck the key. The subjects were then divided into two groups for a second experiment. The first group was trained on a single-key, peck/no-peck color discrimination task with the original control eye covered. When tested for interocular transfer of discrimination performance, these birds failed to respond at all. They were then trained to peck a blank response key with the training eye covered and the control eye open. Control-eye tests after this motor response training resulted in excellent transfer of color discrimination performance. The second group of subjects was trained to peck a blank key with first one eye covered and then the other, before monocular discrimination training was begun. These birds showed excellent transfer of discrimination performance during control-eye tests. These results show that, at least in the operant paradigm, motor response training does not transfer interocularly and this lack of transfer may interfere with transfer of discrimination performance. 相似文献