共查询到20条相似文献，搜索用时 15 毫秒
1.
D. J. Zerbolio 《Learning & behavior》1985,13(3):269-273
Goldfish, trained in the shuttlebox apparatus to avoid shock, acquired a color discrimination between two colors (red/green) and were tested in transfer with a new set of colors (yellow/blue). Transfer color shock-pairing was either consistent with (red=yellow, blue=green) or opposite to (red≠ yellow, green≠blue) categorical color coding seen in pigeons. Groups with transfer shock-pairing consistent with categorical color coding showed positive transfer, and groups with transfer shock-pairing opposite to categorical color coding showed negative transfer, similar to an attenuated reversal learning effect. These results indicate that goldfish, like pigeons, code different colors as behavioral equivalents even though they can easily learn to discriminate between them. As with pigeons, the finding of the categorical color coding phenomenon changes the conclusions drawn from earlier goldfish conditional-discrimination transfer studies using only signal color changes between acquisition and transfer testing, from evidence of concept learning to evidence for categorical color coding, on the grounds of parsimony. It is important to note that this finding affects only the explanation of conditional-discrimination transfer effects, and the fact remains that both pigeons and goldfish can learn to conditionally discriminate—pigeons for positive reinforcement, and goldfish to avoid shock. 相似文献
2.
Jacky Emmerton 《Learning & behavior》2001,29(1):21-35
Pigeons were trained to discriminate the proportion of red to green color in paired stimulus displays. Initially, the stimuli were horizontal bars composed of continuous blocks of color that varied from being all red versus all green to .5 proportions of these two colors. Discrimination accuracy decreased as a function of the disparity in the proportions of the two colors. This relationship was maintained when the stimulus configurations were altered in various ways. Tests with horizontal bars indicated that the pigeons could utilize differences in the lengths (or areas) of one of the colors when choosing between stimuli. They did not rely only on this type of cue to assess proportion disparities but rather on multiple stimulus parameters. Also, the form of the discrimination function suggests that the pigeons distinguished ratio differences, so that Weber’s law applies to this type of discrimination. 相似文献
3.
Four experiments were performed to determine the stimulus characteristics that favor the development of conditional stimulus control in the single reversal paradigm with pigeon subjects. In Experiment 1, pigeons were trained on a successive discrimination between tone frequencies ranging from 350 to 3500 Hz in a particular houselight context condition (houselight-on or -off). The subjects then were trained on the reversal of the tone discrimination in the alternative context. Subsequent tone-frequency generalization testing in the two contexts indicated that they had failed to gain conditional control over the pigeons’ discriminative performance. Such control was obtained in Experiment 2, in which the two problems were alternated daily for 32 sessions of training. The gradients then peaked at the appropriate S+ value in each context. In Experiment 3, the key colors (blue vs. red) served as contexts while pigeons learned a successive discrimination in which the discriminative cues were houselight-on versus houselight-off conditions. This was followed by a reversal of the discrimination in the alternative key-color context condition. The key colors were effective conditional cues in this situation. In a previous experiment (Thomas, McKelvie, & Mah, 1985), key color had been ineffective as a conditional cue when the discriminative cues were lines superimposed on the colored background. In Experiment 4, key color was effective when the color and lines were presented on a single key as in the earlier experiment, but were sequenced such that the onset of the key color preceded and then overlapped the presentation of the lines. We concluded that conditional discriminations are easiest for pigeons when visual cues are used, but the conditional and discriminative cues must be presented in such a way that they do not combine to form a psychological compound. 相似文献
4.
Pigeons served in two experiments in which responding on an observing key converted a two-component mixed schedule to the corresponding multiple schedule of reinforcement. Presentation of the stimulus correlated with the more valued component was faded out (probabilistically) over sessions, so that ultimately an observing response produced only the stimulus correlated with the less valued component. Observing was well maintained after a fading procedure when a stimulus was produced by a single response, regardless of whether the less valued stimulus was associated with food or with extinction (Experiment 1). However, observing was not well maintained after a fading procedure when a stimulus was produced according to an intermittent schedule (Experiment 2). Taken together, the results of the two experiments suggest that the absence of an exteroceptive stimulus change after a single response may become discriminative in its own right for the more valued component, and that the fading procedure is an effective means of promoting this discrimination. However, if observing responses produce a stimulus change according to an intermittent schedule, then the absence of a stimulus change after a response is correlated with both components. Under these conditions, the absence of stimulus change is not discriminative for either component, even with fading, and observing is not maintained. 相似文献
5.
Four colors (red, yellow, green, and blue) were arranged in all possible two-color sets to determine if goldfish can discriminate between color sets associated with shock and color sets associated with safety/shock omission in a one-phase (linear presentation) discrimination-learning procedure. The results showed that goldfish learned to discriminate between two-color sets if set colors were natural categorical color-code mates (red = yellow and green = blue). When natural code mates were not in the same set, and therefore were paired with different shock consequents, no discrimination learning occurred, suggesting that goldfish, unlike pigeons, are not able to code colors arbitrarily. The method also allowed a measure of preference between colors within sets associated with safety/shock omission. Original-learning preference measures between colors in sets so associated showed that goldfish chose red over any other color, yellow over blue or green, and green over blue, despite the fact that both colors in any set were procedurally identical, implying that goldfish do discriminate between colors in the absence of explicit discrimination training. The goldfish that failed to discriminate between red/blue and green/yellow sets in original learning were transferred to red/yellow and blue/green color sets. In transfer, the color paired with safety/shock omission in original learning was preferred over the color paired with shock in original learning, which resulted in a reversal of original-learning color preferences for half the goldfish. The transfer color-preference results imply that the goldfish had associated specific colors with specific shock consequents, but the associations were not robust enough to support discrimination learning in the face of categorical color coding. 相似文献
6.
Ben A. Williams 《Learning & behavior》1984,12(2):117-121
Pigeons were trained on a conditional discrimination involving form and color elements in an autoshaping procedure. When the colors were also illuminated during 50% of the ITIs (Experiment 1), or were presented alone on additional extinction trials (Experiment 2), the discrimination was not acquired, indicating a loss of salience for stimuli not temporally predictive of reinforcement. But when the colors and the forms were both similarly illuminated, the discrimination was acquired, indicating that relative stimulus validity, not the absolute temporal predictiveness per se, was the controlling variable. 相似文献
7.
We explored response rate as a possible mediator of learned stimulus equivalence. Five pigeons were trained to discriminate
four clip art pictures presented during a 10-sec discrete-trial fixed interval (FI) schedule: two paired with a one-pellet
reinforcer, which supported a low rate of responding, and two paired with a nine-pellet reinforcer, which supported a high
rate of responding. After subjects associated one stimulus from each of these pairs with a discriminative choice response,
researchers presented two new clip art stimuli during a 10-sec FI: one trained with a differential reinforcement of low rate
schedule (DRL) after the FI and the other trained with a differential reinforcement of high rate schedule (DRH) after the
FI. Each of the stimuli that were withheld during choice training was later shown to see if the choice responses would transfer
to these stimuli. The results suggest that response rate alone does not mediate learned stimulus equivalence. 相似文献
8.
We investigated whether pigeons are able to discriminate color photographs of male and female pigeons, using a categorical
discrimination procedure. In Experiments 1 and 2B, 10 out of 14 pigeons learned the discrimination. Of these, 5 pigeons showed
transfer to novel stimuli, demonstrating the categorical nature of the trained discrimination. Experiment 3 showed that the
discriminative behavior was based primarily on the body, as opposed to the head and the neck region. In 1 out of 3 pigeons,
the discriminative behavior was maintained by the black-and-white photographs. The results suggest that some pigeons have
the ability to discriminate the sex of conspecifics without behavioral cues. 相似文献
9.
Pigeons were given successive discrimination training in which pecking during a choice period when the key was white was either reinforced or not, depending upon the prior presence or absence of a discriminative stimulus, which was a two-element serial compound. The compound consisted of a keylight and food, with food presented second or first in a forward or backward pairing for different groups of pigeons. In Experiment 1, the sequence was an S+ indicating reinforced trials, while in Experiment 2, the sequence was an S? indicating nonreinforced trials. Following acquisition of discriminated operant behavior, a sequence generalization test was administered during which all possible orders of the two stimuli were presented on test trials prior to the onset of the choice period. The results showed that food overshadowed stimulus control by the color of the light on the key on the sequence-generalization test, independently of whether food was presented first or second during training and independently of whether food was associated with reinforcement or nonreinforcement. The similarity of results for the two experiments suggests that overshadowing occurs independently of whether the compound is a discriminative stimulus for reinforcement or nonreinforcement. Simultaneous presentation of elements of a compound stimulus is not necessary for overshadowing because the phenomenon was captured with sequentially presented stimuli. 相似文献
10.
Previous studies have shown that pigeons could learn a serial list of colors and to select each color in the proper order when presented with an array of colors. Errors of jumping forward in the required sequence (forward errors) were most probable, with jumps backward in the required sequence (backward errors) being relatively improbable. One proposed explanation for the higher probability of forward errors suggests that the pigeon pecks at the correct stimulus without activating the response switch and then pecks the next stimulus in the sequence closing the response switch. This “inadequate-peck” hypothesis suggests that forward errors are due to weak stimulus control and that increased feedback for correct pecks should therefore reduce forward error probability relative to a low-feedback condition. The present study compared responding under conditions of high and no experimenter-provided feedback for correct pecks. As the feedback did not affect the probability of forward errors, the inadequate-peck hypothesis was not supported. A short-term memory explanation is consistent with the data. 相似文献
11.
In two experiments, we examined the discrimination of photographs of individual pigeons by pigeons, using go/no-go discrimination procedures. In Experiments 1A and 1B, the pigeons were trained to discriminate 4 photographs of one pigeon from those of a number of pigeons. The subjects learned the discrimination, but their discriminative behavior did not transfer to new photographs taken from novel perspectives. When the pigeons were trained to discriminate between 20 photographs of five pigeons taken from four perspectives as the S+ and 20 photographs of five different pigeons as the S-, the subjects learned the discrimination, and this discriminative behavior partially transferred to new photographs taken from novel perspectives (Experiments 2A-2C). The results suggest that pigeons are able to discriminate among conspecific individuals, using stationary visual cues. This strengthens the assumption in evolutionary theory that animals can discriminate among individuals and encourages further investigation as to how this ability is used in various behaviors of animals. 相似文献
12.
Patricia B. Cronin 《Learning & behavior》1980,8(3):352-358
Delayed-reward learning in pigeons was examined using a simultaneous red-green visual discrimination task in which the conditions during the delay interval were varied between groups. The nondifferential group received training in which the stimulus present during the 1-min delay was the same following a peck on the correct and incorrect colors. The other three groups received 1-min delay training in which different stimuli occurred in the delay interval following correct and incorrect choices. The differential group received continuous, differential stimuli during the delay. The reinstatement group received the differential stimuli in the 10 sec immediately following the choice and during the last 10 sec of the delay. The reversedcue group was treated in the same way, except that the 10-sec delay stimulus immediately following an incorrect response was also presented for 10 sec prior to reward on correct choices, and the stimulus following a correct response also occurred 10 sec before nonreward on incorrect choices. Nondifferential birds failed to learn the discrimination, while differential and reinstatement birds learned it readily. The reversed-cue birds learned to choose the incorrect stimulus. Differential and reinstatement birds showed no decrement in performance when the delay was increased to 2 min. These findings suggest that similarity of prereward and postresponse delay stimuli controls choice responding in long-delay learning, a finding compatible with both memorial and conditioned reinforcement interpretations. 相似文献
13.
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
14.
An attempt was madeto manipulate the strength of internal stimulus representations by exposing pigeons to brief delays between sample offset and comparison onset in a delayed conditional discrimination. In Experiment 1, pigeons were first trained on delayed conditional discrimination with either short (0.5-sec) delays or no delays. When delays were increased by 2.0 sec, birds trained with a delay performed at a higher level than did birds trained with no delays. In Experiment 2, subjects were first trained on a delayed simple discrimination. Following a circle stimulus, responses to a white key were reinforced; however, following a dot stimulus, responses to the white key were not reinforced. The pigeons were then trained on a delayed conditional discrimination involving hue samples and line-orientation comparisons with differential outcomes. Choice of vertical following red yielded food; choice of horizontal following green yielded no food. Mixed delays were then introduced to birds in Group Delay, whereas birds in the control group received overtraining. When tested on a delayed simple discrimination with hue stimuli (red and green initial stimuli followed by white response stimulus), pigeons in Group Delay tended to perform at a higher level than did birds in the control group (i.e., although the birds in both groups responded more following red than following green, birds in Group Delay did this to a greater extent than did birds in the control group). Thus, experience with delays appears to strengthen stimulus representations established during training. 相似文献
15.
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
16.
Edward F. Meehan 《Learning & behavior》1979,7(4):473-476
Match-to-sample and oddity-from-sample problems with four colors were acquired by two pigeons under the supraordinate control of a line tilt superimposed on samples, Since the supraordinate stimulus terminated before the comparison stimuli were presented, accurate matching and oddity performance indicated trace stimulus control as well, The temporal extent of trace control was assessed in one subject by presenting probes—trials without a line tilt on the sample—in which the basis of correct responding was the supraordinate stimulus presented on the previous trial, Trace supraordinate control did not extend between trials, Subsequently, the delay between the termination of the supraordinate stimulus and the presentation of the comparison stimuli was gradually increased within a trial, Both subjects were able to perform matching and oddity over longer delays, and eventually on probe trials, although accuracy decreased, Results were discussed in terms of instructional stimulus control and memory. 相似文献
17.
E. J. Capaldi 《Learning & behavior》1979,7(1):63-68
In this investigation, which employed rats in a runway, discriminative responding consisted of faster running on the reinforced than on the nonreinforced trials of either the 4NR or R4N schedule, both schedules containing fixed, repeated sequences of nonreinforced and reinforced trials. Under the 4NR schedule, four nonreinforced trials preceded a reinforced trial each day, and under the R4N schedule, a reinforced trial was followed by four nonreinforced trials each day. The major finding obtained was that under the 4NR schedule, discriminative responding was improved very substantially by a shift to extinction. Rats maintained on the 4NR schedule did not show improved discriminative responding, nor did discriminative responding improve in extinction following training under either the R4N schedule or a schedule of consistent reinforcement. Latent discrimination learning was defined as discriminative responding which fails to reflect adequately the amount of discrimination learning accomplished. The present findings demonstrate latent discrimination learning for regular schedules of partial reinforcement, something already demonstrated for brightness differential conditioning and possibly DRL schedules, as well. 相似文献
18.
In Experiment 1, pigeons were trained to peck red or blue keys for food reinforcement at variable intervals, while food was contingent on withholding key pecks in the presence of a vertical line (omission training). When the line was briefly superimposed on red or blue in a compound test, responding was reduced. When the orientation of the line was varied during extinction, generalization gradients were variable but often had most responding at or near vertical. In Experiment 2, pigeons were trained in a discrete trials procedure that made food contingent upon pecking in the presence of triangle, and upon the absence of pecking in the presence of red (omission training). Food was never given on green-key trials (extinction). When red or green backgrounds were presented with the triangle in a compound test, responding was reduced similarly in the presence of both key colors. Subsequent resistance to auto-shaping was also similar for red and green. These data, taken together with reports in the literature, suggest that the inhibitory effects of omission training are quite similar to those of extinction. Thus, the crucial condition for obtaining inhibitory effects is not a negative stimulus-reinforcer correlation, as in extinction, but simply the establishment of low rates of responding to the inhibitory stimulus. 相似文献
19.
The present experiment demonstrated in a simultaneous discrete trial discrimination that the stimulus control of a rat’s leverpress response can be errorlessly transferred across stimulus modalities, i.e., from light to click location and from click to light location. Subsequent to acquisition of the original discrimination, the original and new discriminative stimuli were simultaneously presented for several sessions. Then the new discriminative stimulus was presented 3 sec prior to the onset of the original discriminative stimulus. Within the direction of transfer, e.g., from light to click location, the delay group emitted fewer trial and intertriai errors than the control group. As the new discriminative stimuli acquired control over responding, the response latency distributions were differentially affected. The results suggest that the transfer of control from the original to the new discriminative stimuli is mediated by the temporal aspects of the delay interval. 相似文献
20.
We report the first successful demonstration of a simultaneous, two-itemsame-different (S/D) discrimination by 6 pigeons, in which nonpictorial color and shape stimuli were used. This study was conducted because
the majority of recently successful demonstrations of S/D discrimination in pigeons have employed displays with more than
two items. Two pairs of stimulus items were simultaneously presented on a touch screen equipped computer monitor. Pigeons
were reinforced for consistently pecking at either thesame (i.e., identical) or thedifferent (i.e., nonidentical) pair of items. These pairs were created from combinations of simple colored shapes drawn from a pool
of six colors and six shapes. After acquiring the discrimination with item pairs that differed redundantly in both the shape
and the color dimensions, the pigeons were tested for transfer to items that varied in only one of these dimensions. Although
both dimensions contributed to the discrimination, greater control was exhibited by the color dimension. Most important, the
discrimination transferred in tests with novel colored, shaped, and sized items, suggesting that the mechanisms involved were
not stimulus specific but were more generalized in nature. These results suggest that the capacity to judge S/D relations
is present in pigeons even when only two stimuli are used to implement this contrast. 相似文献