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1.
In three experiments, we examined how matching-to-sample by pigeons is affected by discrimination versus nondifferential training between the matching stimuli. In Experiment 1A, pigeons responding differentially to the sample stimuli off-baseline acquired accurate matching performances more rapidly than did pigeons responding nondifferentially to those same stimuli. In Experiment 1B, tests involving reversal of the off-baseline requirements demonstrated that the birds were primarily controlled in their matching choices by the sample stimuli. The results of Experiment 2 showed that off-baseline nondifferential training did not retard acquisition relative to comparable training between stimuli unrelated to the matching task. Together, these results suggest that discrimination training can facilitate matching acquisition by enhancing attention to the sample stimuli. 相似文献
2.
L. Caitlin Elmore Anthony A. Wright Jacquelyne J. Rivera Jeffrey S. Katz 《Learning & behavior》2009,37(2):204-213
Three pigeons were trained in a three-item simultaneous same/different task. Three of six stimulus combinations were not trained (untrained set) and were tested later. Following acquisition, the
subjects were tested with novel stimuli, the untrained set, training-stimulus inversions, and object shape and color manipulations.
There was no novel-stimulus transfer—that is, no abstract-concept learning. Two pigeons showed partial transfer to untrained
pairs and good transfer to stimulus inversions, suggesting that they had learned the relationship between the stimuli. Lack
of transfer by the third pigeon suggests item-specific learning. The somewhat surprising finding of relational learning by
2 pigeons with only six training pairs suggests restricted-domain relational learning that was controlled more by color than
by shape features. Individual differences of item-specific learning by 1 pigeon and relational learning by 2 others demonstrate
that this task can be learned in different ways and that relational learning can occur in the absence of novel-stimulus transfer. 相似文献
3.
Pigeons were trained to depress a treadle in the presence of a discriminative stimulus, either a tone or illumination of red houselights, in order to obtain access to grain or avoid electric shock. In avoidance training, the auditory discriminative stimulus yielded faster acquisition than did the visual one. In appetitive training, the visual discriminative stimulus yielded faster acquisition than the auditory one. Experiments 2 and 3 used these stimuli in Kamin’s (1969) blocking design. In Experiment 2, when the pigeons were trained to depress a treadle in the presence of tone to obtain grain and then red light was added as the redundant stimulus, the light acquired stimulus control over treadlepressing; blocking was not observed. In Experiment 3, when the pigeons were trained to depress a treadle in the presence of red light to avoid electric shock and then tone was added as the redundant stimulus, the tone acquired stimulus control over treadle-pressing. Again, blocking was not observed. The implications of these results for several models of stimulus control are discussed. 相似文献
4.
Within-trial contrast has been proposed as a mechanism underlying preferences for stimuli that follow relatively more aversive
events over stimuli that follow less aversive events. In this study, we manipulated deprivation level to test within-trial
contrast predictions. In Experiment 1, pigeons encountered two discriminative stimuli, one presented when they were deprived
and the other when they were prefed. When later given a choice between the two stimuli, pigeons strongly preferred the stimulus
encountered when deprived, independently of their deprivation level at test. In Experiment 2, pigeons learned two simultaneous
discriminations, one when deprived and the other when prefed. Here, subsequent tests between the two S+ or the two S− stimuli revealed no consistent preferences. These contrasting findings suggest that differential aversiveness is necessary
but not sufficient to induce preferences via within-trial contrast. 相似文献
5.
We trained 7 pigeons to discriminate visual displays of 16same items from displays of 16different items. The specific stimulus features of the items and the relations among the items could serve as discriminative stimuli.
Unlike in most studies of same-different discrimination behavior, we gave a small number of probe tests during each session
of acquisition to measure the time-course of control by the learning of specific stimulus features and relational cues. Both
the specific stimulus features and relational cues exerted reliable stimulus control, with the specific stimulus features
exerting more control during the final three fourths of same-different learning. These findings replicate research suggesting
that pigeons encode both the specific stimulus features and relational cues, and for the first time document the time-course
of control by each kind of cue. 相似文献
6.
In three experiments, we examined pigeons’ recognition of video images of human faces. In Experiment 1, pigeons were trained
to discriminate between frontal views of human faces in a go/no-go discrimination procedure. They then showed substantial
generalization to novel views, even though human faces change radically as viewpoint changes. In Experiment 2, the pigeons
tested in Experiment 1 failed to transfer to the faces dynamically rotating in depth. In Experiment 3, the pigeons trained
to discriminate the dynamic stimuli showed excellent transfer to the corresponding static views, but responses to the positive
faces decreased at novel viewpoints outside the range spanned by the dynamic stimuli. These results suggest that pigeons are
insensitive to the three-dimensional properties of video images. Consideration is given to the nature of the task, relating
to the identification of three-dimensional objects and to perceptual classifications based on similarity judgments. 相似文献
7.
Response summation in pigeons was examined in four experiments. In Experiment 1, summation was not found with a compound of two visual stimuli on a television screen after they had individually been used for instrumental conditioning. In this experiment, the training and test trials were separated by an interval during which the television screen was dark. Summation was found in Experiment 2 for which the television screen was permanently white during the interval between trials and in the region that was not occupied by the experimental stimuli. These results were replicated using a within-subject design (Experiment 3) and autoshaping (Experiment 4). Experiment 2 also revealed summation with compounds of auditory and visual stimuli, but not with compounds of two auditory stimuli or two diffuse lights. The results can be explained by a variety of theories of learning, if they take account of generalization between the stimuli. 相似文献
8.
Second-order conditioning (SOC) in pigeons, but not rats, appears to involve an association between the second-order stimulus (S2) and the first-order stimulus (SI). Nairne and Rescorla (1981) suggested it was the use of stimuli from the same modality that promoted an association between S2 and SI in pigeon SOC studies. In support of their hypothesis, they demonstrated that pigeons, like rats, did not form an association between S2 and SI when these stimuli were from different modalities. In this study, we sought to determine whether rats, like pigeons, would associate S2 with SI when these stimuli shared the same modality. Female Lister rats injected with LiCl after consuming .12M saline solution (SI) showed an aversion to a 15% sucrose solution (S2) that was subsequently paired with the saline. This was so regardless of whether S2 and SI had been presented sequentially (Experiment 1) or simultaneously (Experiment 2). Only in Experiment 2, however, did extinction of the aversion to saline diminish the aversion to sucrose; that is, employing stimuli from the same modality was not a sufficient condition, of itself, to allow rats to associate S2 with SI. 相似文献
9.
Thomas R. Zentall Lou M. Sherburne Janice N. Steirn Christopher K. Randall Karen L. Roper Peter J. Urcuioli 《Learning & behavior》1992,20(4):373-381
Common coding in pigeons was examined using a delayed conditional discrimination in which each sample stimulus was associated with two different comparison stimuli (one-to-many mapping). In Experiment 1, pigeons matched circle and dot samples to red and green hues and vertical and horizontal line orientations. In Experiment 2, the samples were red and green and the comparisons were vertical and horizontal spatial positions (up vs. down and left vs. right). Following acquisition to high levels of accuracy in each experiment, the associations between the samples and either both sets or only one set of comparisons were reversed. Pigeons learned the total reversals faster than the partial reversals. These results suggest that when different comparisons are associated with a common sample, they may become functionally equivalent. 相似文献
10.
Past research has shown that when given a simultaneous visual-discrimination midsession reversal task, pigeons typically anticipate the reversal well before it occurs and perseverate after it occurs. It appears that they use the estimation of time (or trial number) into the session, rather than (or in addition to) the more reliable cue, the outcome from the previous trial (i.e., a win–stay/lose–shift response rule), to determine which stimulus they should choose. In the present research, we investigated several variables that we thought might encourage pigeons to use a more efficient response strategy. In Experiment 1, we used a treadle-stepping response, rather than key pecking, to test the hypothesis that reflexive key pecking may have biased pigeons to estimate the time (or trial number) into the session at which the reversal would occur. In Experiment 2, we attempted to make the point of reversal in the session more salient by inserting irrelevant trials with stimuli different from the original discriminative stimuli, and for a separate group, we added a 5-s time-out penalty following incorrect choices. The use of a treadle-stepping response did not improve reversal performance, and although we found some improvement in reversal performance when the reversal was signaled and when errors resulted in a time-out, we found little evidence for performance that approached the win–stay/lose–shift accuracy shown by rats. 相似文献
11.
Discrimination performance was investigated with pigeons using feature negative (FN) discrimination procedures which differed in the temporal arrangement of the stimuli on S? trials. In both procedures, a single common element was presented on reinforced (S+) trials. In thesimultaneous FN procedure, a distinguishing element was presented simultaneously with the common element of S? trials. In thesequential FN procedure, the distinguishing element preceded onset of the common element on S? trials. In two experiments, the sequential FN procedure yielded better discrimination performance. In Experiment 1, a summation test designed to separate learning and performance variables indicated that sequential FN subjects had learned the negative relationship between the distinguishing element and reinforcement while simultaneous FN subjects had not. In Experiment 2, summation and acquisition tests indicated that the distinguishing element developed inhibitory properties in the sequential FN procedure but not in the simultaneous FN procedure. 相似文献
12.
Random presentations of keylights and food retarded acquisition and suppressed asymptotic rates of keypecking in autoshaping. Sequences of 10 sessions of random training alternated with 10 sessions of autoshaping resulted in poor performance (in terms of both the acquisition and asymptotic indices) relative to a group that received sequences of CS-only (rather than random) training alternating with autoshaping. When the birds that previously were trained with the random sequence were exposed to CS-alone extinction, retardation of acquisition was alleviated but the asymptotic suppression was not (Experiment 1). Pigeons with a history of autoshaping without prior random training showed no asymptotic suppression when exposed to the random procedure. These birds, when switched between two-session sequences of random training alternating with two-session sequences of autoshaping, were able to (1) surpass pigeons that received CS-only rather than random treatment in terms of asymptotic levels of responding in autoshaping, and (2) showed improvement in extinction performance with repeated random/autoshaping sequences (Experiment 2). Detailed observations of pigeons in random training showed that stereotypic activity behaviors were acquired, and these generally persisted in autoshaping; the degree of change in these behaviors was related to asymptotic rates of keypecking in autoshaping (Experiment 3). The same kinds of behaviors were observed when pigeons initially were autoshaped, and these persisted in subsequent random and fixed-interval 10-sec training. We suggest that the suppression effect is reflected in activity, conditioned in random training, which persists in autoshaping (especially if the activity is compatible with the kinds of behaviors elicited by the autoshaping contingency itself), and that the effect may be a deficit due to performance factors rather than to associative learning. 相似文献
13.
Visual illusions are objects that are made up of elements that are arranged in such a way as to result in erroneous perception of the objects’ physical properties. Visual illusions are used to study visual perception in humans and nonhuman animals, since they provide insight into the psychological and cognitive processes underlying the perceptual system. In a set of three experiments, we examined whether dogs were able to learn a relational discrimination and to perceive the Müller-Lyer illusion. In Experiment 1, dogs were trained to discriminate line lengths using a two-alternative forced choice procedure on a touchscreen. Upon learning the discrimination, dogs’ generalization to novel exemplars and the threshold of their abilities were tested. In the second experiment, dogs were presented with the Müller-Lyer illusion as test trials, alongside additional test trials that controlled for overall stimulus size. Dogs appeared to perceive the illusion; however, control trials revealed that they were using global size to solve the task. Experiment 3 presented modified stimuli that have been known to enhance perception of the illusion in other species. However, the dogs’ performance remained the same. These findings reveal evidence of relational learning in dogs. However, their failure to perceive the illusion emphasizes the importance of using a full array of control trials when examining these paradigms, and it suggests that visual acuity may play a crucial role in this perceptual phenomenon. 相似文献
14.
Pigeons learned to respond at one spatial position when a pair of stimuli matched and at a different spatial position when they mismatched. All birds were then transferred to novel stimuli on an orthogonal dimension. For the positive-transfer group, the correct positions for matching and mismatching stimuli remained as they were during training. For the negative-transfer group, the correct positions were reversed. In Experiment 1, the birds were trained with shape stimuli and transferred to hue stimuli. Significant group differences were found, in spite of considerable stimulus-specific learning. In Experiment 2, when the same birds (counterbalanced for Experiment 1 transfer group) were transferred to steady-intermittent stimuli, even larger group differences were found. The data indicate that pigeons have some capacity for representing the concepts “same” and “different” with arbitrary stimuli (i.e., symbols). The data further suggest that distinctions that have been made between matching/oddity transfer tasks and same/different tasks may be procedural rather than conceptual. 相似文献
15.
The influence of dimensional organization on pigeon texture perception was examined in a simultaneous conditional discrimination procedure. Six experienced pigeons were reinforced for pecking at a small block oftarget elements randomly located within a larger array ofdistractor elements in each texture stimulus. Target/distractor differences in color, size, orientation, and combinations of these dimensions were examined. In Experiment 1, the influence of target/distractor similarity on performance was investigated by using different forms of unidimensional and conjunctively organized texture stimuli made of two and three dimensions. Targets infeature displays, in which the two regions consistently differed along a single dimension, were located more accurately than targets inconjunctive displays, where a combination of values from all dimensions defined each region. In Experiment 2, a tradeoff between response speed and accuracy was found in the pigeons’ processing of conjunctive displays. In Experiment 3, the number of distractors differentially influenced the localization of feature and conjunctive targets. Overall, the pigeons’ reactions to these feature and conjunctive stimuli paralleled those of humans, suggesting that functionally equivalent mechanisms may mediate the perceptual grouping, search, and discrimination of textured multidimensional stimuli in both species. 相似文献
16.
In simultaneous matching-to-sample and oddity-from-sample tasks, briefly delaying the offset of trial stimuli following an incorrect choice response was found to facilitate task acquisition (Experiment 1). Because thispenalty-time procedure also resulted in longer choice-response latencies, it was hypothesized that any procedure that increased response latency would facilitate task acquisition. However, in Experiment 2, no evidence of facilitation was found when a 2-sec pause was imposed prior to the choice response. The results of Experiment 3 suggest that penalty-time facilitation of acquisition was not due to either the added differential outcome on correct versus incorrect trials (i.e., incorrect choice responses do not darken the keys as do correct choice responses) or the aversive effects associated with trial prolongation (i.e., incorrect responses not only result in the absence of reinforcement but also delay the start of the next trial). Instead, results suggest that birds trained with the penalty-time procedure review the trial stimuli following an incorrect choice. 相似文献
17.
Compared with their performance with localized (on-key) visual stimuli, pigeons are notoriously poor at performing go/no-go discriminations when keypecking for food in the presence of auditory discriminative stimuli. The difference might reflect the fact that an aversive visual onkey stimulus signaling nonreward can be escaped by looking away and not pecking, which contributes to the measure of good discriminative performance, while an auditory stimulus cannot be escaped. In Experiment 1, discriminative performance was significantly improved by providing pigeons with a response incompatible with keypecking by which they could escape a tone S+ and a tone S?. However, the pattern, frequency, and duration of escape responses were found to be insufficient to explain the improvement. In Experiment 2, it was found that the capacity to escape only S+ or only S? enhanced discriminative performance as much as the capacity to escape both. It is theorized that the Pavlovian relationship between the absence of the discriminative stimuli and the nonoccurrence of food might transfer to the instrumental relationships learned in a go/no-go discrimination. The possibility that intermittent stimuli command more attention than continuous stimuli is also considered. 相似文献
18.
Two groups of pigeons were trained with a go/no-go procedure to discriminate video images of conspecifics based on the individuals or else on their actions. Both groups showed rapid acquisition, and the discrimination transferred to new scenes in Experiment 1 and to static scenes in Experiment 2. In Experiment 3, experimentally naive pigeons were trained to discriminate video images of particular birds showing different actions. Transfer to novel scenes, including a new bird and a new motion, revealed the dominance of motion as a cue to discriminate video images. In Experiment 4, the pigeons trained to discriminate video scenes of 2 pigeons showing a variety of activities successfully recognized these stimuli regardless of whether the video was played forward or backward, and transferred the discrimination to still scenes. The findings suggest that pigeons’ discrimination of video images is primarily based on information that is invariant across static and dynamic conditions. 相似文献
19.
Donald M. Wilkie 《Learning & behavior》1986,14(3):257-266
In the delayed matching of key location procedure, pigeons must remember the location of the sample key in order to choose correctly between two comparison keys. The deleterious effect of short intertrial intervals on key location matching found in previous studies suggested that pigeons’ short-term spatial memory is affected by proactive interference. However, because a reward expectancy mechanism may account for the intertriai interval effect, additional research aimed at demonstrating proactive interference was warranted. In Experiment 1, matching accuracy did not decline from early to late trials within a session, a finding inconsistent with a proactive interference effect. In Experiment 2, evidence suggestive of proactive interference was found: Matching was more accurate when the locations that served as distractors and as samples were chosen from different sets. However, this effect could have been due to differences in task difficulty, and the results of the two subsequent experiments provided no evidence of proactive interference. In Experiment 3, the distractor on Trialn was either the location that had served as the sample on Trialn ? 1 or one that had been a sample on earlier trials. Matching accuracy was not inferior on the former type of trial. In Experiment 4, the stimuli that served as samples and distractors were taken from sets containing 2, 3, 5, or 9 locations. Matching accuracy was no worse, actually slightly better, with smaller memory set sizes. Overall, these findings suggested that pigeons’ memory for spatial location may be immune to proactive interference. However, when, in Experiment 5, an intratrial manipulation was used, clear evidence of proactive interference was found: Matching accuracy was considerably lower when the sample was preceded by the distractor for that trial than when it was preceded by the sample or by nothing. Possible reasons why interference was produced by intratrial but not intertrial manipulations are discussed, as are implications of these data for models of pigeons’ short-term spatial memory. 相似文献
20.
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