共查询到20条相似文献，搜索用时 46 毫秒
1.
Edson M. Huziwara Saulo M. Velasco Gerson Y. Tomanari Deisy G. de Souza Armando D. Machado 《Learning & behavior》2013,41(2):192-204
In two experiments, we investigated emergent conditional relations in pigeons using a symbolic matching-to-sample task with temporal stimuli as the samples and hues as the comparisons. Both experiments comprised three phases. In Phase I, pigeons learned to choose a red keylight (R) but not a green keylight (G) after a 1-s signal. They also learned to choose G but not R after a 4-s signal. In Phase II, correct responding consisted of choosing a blue keylight (B) after a 4-s signal and a yellow keylight (Y) after a 16-s signal. Comparisons G and B were both related to the same 4-s sample, whereas comparisons R and Y had no common sample. In Phase III, R and G were presented as samples, and B and Y were presented as the comparisons. The choice of B was correct following G, and the choice of Y was correct following R. If a relation between comparisons that shared a common sample were to emerge, then responding to B given G would be more likely than responding to Y given R. The results were generally consistent with this prediction, suggesting, for the first time in pigeons, the emergence of novel relations that involve temporal stimuli as nodal samples. 相似文献
2.
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
3.
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
4.
In Experiment 1, pigeons were trained to discriminate the duration (2 or 8 sec) of an empty interval separated by two 1325-Hz tone markers by responding to red and green comparison stimuli. During delay testing, a choose-short bias occurred at 1 sec, but a robust choose-long bias occurred at 9 sec. Responding in the absence of tone markers indicated that the pigeons were attending to the markers and not simply timing the total trial duration. The birds were then trained to match short (2-sec) or long (8-sec) empty intervals marked by light to blue/yellow comparisons. For both visual and auditory markers, delay testing produced a choose-short bias at 1 sec and a choose-long bias at 9 sec. In Experiment 2, the pigeons were shifted from a fixed to variable intertrial intervals (ITI) within sessions. On trials with tone markers, the duration of both the empty interval and the preceding ITI affected choice responding. On trials with light markers, only the duration of the empty interval influenced choice responding. Subsequent delay testing in the context of variable ITIs replicated the memory biases previously obtained. In Experiment 3, performance was assessed at various delay intervals on trials in which either the first or the second marker was omitted. The data from these omission tests indicated that the first marker initiated timing but that the second marker sometimes initiated the timing of a new interval. Explanations of these effects in terms of the internal clock model of timing are discussed, and a simple quantitative model of the delay interval data is tested. 相似文献
5.
Pigeons learned a series of reversals of a simultaneous red-green visual discrimination. Delay of reinforcement (0 vs. 2 sec)
and intertrial interval (ITI; 4 vs. 40 sec) were varied across blocks of reversals. Learning was faster with 0-sec than with
2-sec delays for both ITI values and faster with 4-sec ITIs than with 40-sec ITIs for both delays. Improvement in learning
across successive reversals was evident throughout the experiment, furthermore, even after more than 120 reversals. The potent
effects of small differences in reinforcement delay provide evidence for associative accounts and appear to be incompatible
with accounts of choice that attempt to encompass the effects of temporal parameters in terms of animals’ timing of temporal
intervals. 相似文献
6.
A discriminal distance analysis procedure similar to that used by Roitblat (1980) was employed to test the hypotheses that animals either retrospectively (Spetch & Wilkie, 1983) or prospectively (Kraemer, Mazmanian, & Roberts, 1985) encode durations of events. Pigeons were required to discriminate 2-, 8-, and 10-sec presentations of light. Choices of red, orange, and green keys were correct after 2, 8, and 10 sec, respectively. The key elements in this design were (1) that some samples (8 and 10 sec) and some choice stimuli (red and orange) were more difficult to discriminate than were others, and (2) that an easy sample discrimination (2 vs. 8 sec) was mapped onto a difficult choice discrimination (red vs. orange), and vice versa. An examination of raw error scores and calculated confusion indexes in three experiments supported the hypothesis that subjects retrospectively, rather than prospectively, encode event duration. 相似文献
7.
In the present experiment, we compared directly pigeons’ short-term memory of temporal and visual stimuli in a delayed matching-to-sample task. The sample stimuli consisted of red and green lights presented for 5 and 30 sec, followed by a retention interval and blue and yellow comparisons. For subjects in the visual group, duration was irrelevant and the color of the sample was the conditional cue. For animals in the temporal group, color was irrelevant and duration of the sample was the conditional stimulus. The results showed that acquisition of the matching task was faster and accuracy was higher in the visual than in the temporal group. More importantly, memory of either sample generally declined at a similar rate when the duration of the retention interval was increased and when the intertrial interval was reduced. Taken together, the results indicate that with 1–8-sec retention intervals, short-term memory for temporal stimuli is similar to that found with color-visual samples. The findings are discussed in terms of retrospective and prospective processing. 相似文献
8.
In two experiments, pigeons' responding on an extraneous task was explicitly reinforced during delayed matching-to-sample
trials. In Experiment 1, red or green sample stimuli were followed by retention intervals of 0.2, 1, 4, or 12 sec, during
which pecks to a white center key were reinforced with 2.5-sec access to wheat according to extinction, variable-interval
30-sec, and variable-interval 15-sec schedules in different conditions. A proportion of .2, .5, .7, or .9 of subsequent red
or green choice responses that matched the sample were reinforced with 3-sec access to wheat. The result was that increasing
center key reinforcement, or reducing reinforcer probability, lowered overall accuracy. Initial discriminability fell, but
with no change in the rate of forgetting. In Experiment 2, initial discriminability was affected by extraneous reinforcers
that were contingent on center key pecking, but not by noncontingent reinforcers. A plausible conclusion is that initial discriminability
decreases when reinforcers strengthen competing behaviors. 相似文献
9.
The ability of pigeons to use event durations as remember (R) and forget (F) cues for temporal samples was examined. Pigeons were required to indicate whether a houselight sample stimulus was short (2 sec) or long (6 sec) by pecking a red or a green comparison stimulus. After training with a constant 10-sec delay interval, temporal cues (illumination of the center key) were presented 2 sec after the offset of the temporal samples. For one group, a short (2-sec) temporal cue served as the R cue and a long (6-3ec) temporal cue served as the F cue. This was reversed for a second group of birds. During training, comparison stimuli were always presented following the temporal R cue, but never following the temporal F cue. Tests for the effectiveness of the temporal R and F cues showed that F cues were equally effective in reducing matching accuracy in both groups of birds. It was concluded that pigeons used the duration of the cue to determine whether or not to rehearse the memory code for the temporal sample. 相似文献
10.
Kelling AS Snyder RJ Marr MJ Bloomsmith MA Gardner W Maple TL 《Learning & behavior》2006,34(2):154-161
Hue discrimination abilities of giant pandas were tested, controlling for brightness. Subjects were 2 adult giant pandas (1
male and 1 female). A simultaneous discrimination procedure without correction was used. In five tasks, white, black, and
five saturations each of green, blue, and red served as positive stimuli that were paired with one or two comparison stimuli
consisting of 16 saturations of gray. To demonstrate discrimination, the subjects were required to choose the positive stimulus
in 16 of 20 trials (80% correct) for three consecutive sessions. Both subjects reached criterion for green and red. The female
subject also reached criterion for blue. The male was not tested for blue. This study is a systematic replication of Bacon
and Burghardt’s (1976) color discrimination experiment on black bears. The results suggest that color vision in the giant
panda is comparable to that of black bears and other carnivores that are not strictly nocturnal. 相似文献
11.
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
12.
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
13.
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
14.
Pigeons were trained on two independent tasks. One involved red and yellow hues, the other involved blue and green hues. For half of the birds, the two tasks were the same (i.e., both tasks were either matching-to-sample, or oddity-from-sample). For the remaining birds, the two tasks were different (i.e., one task was matching-to-sample; the other task was oddity-from-sample). Following acquisition, the pigeons were exposed to test trials on which either the correct or the incorrect comparison hue was replaced with one of the hues from the other task. On yellow-sample trials and on green-sample trials, the pigeons performed as if they had a common code for yellow and green. When there was one comparison available that was appropriate to the “yellow/green” code, performance remained high; but when either both comparisons or neither comparison was appropriate to the “yellow/green” code, performance dropped. The pigeons also tended to code red samples as green and to code blue samples as yellow. The results indicate that pigeons can categorically code colors under conditions that rule out a failure to discriminate among the colors. 相似文献
15.
Pigeons were exposed to differentially cued autoshaping trials in which conditioned stimuli were followed by food after 6 or 14 sec. Average and momentary rates of keypecking were examined on two types of unreinforced test trials: single-stimulus probe trials and simultaneous choice trials, each 40 sec in duration. Rates averaged over the 40-sec test trials did not favor the cue associated with the shorter delay to food (the short-delay cue) on either type of test trial; however, average rates prior to the scheduled time of food delivery were reliably higher for the short-delay cue on choice trials. Momentary rates of keypecking during choice trials varied as a function of both cue and elapsed time from trial onset. At short elapsed trial times, rate of pecking was higher for the short-delay cue, with this difference reversing at longer times. A reversal of the programmed relation between key color and delay to food presentation for 5 birds confirmed the generality of these findings. Implications of these data for models of Pavlovian conditioning and for methods of assessing conditioned response strength are discussed. 相似文献
16.
In Experiment 1, pigeons were trained to discriminate short (2 sec) and long (8 sec) durations of tone by responding to red and green comparison stimuli. During delay testing, a systematic response bias to the comparison stimulus correct for the long duration occurred. Tests of responding without the tone reduced accuracy on long-sample trials but not on short-sample trials suggesting that the pigeons were attending to the tone and not simply timing the total trial duration. The pigeons were then trained to match short (2 sec) and long (8 sec) durations of light to blue/yellow comparisons. During delay testing, “choose-long errors” occurred following tone durations, but “choose-short errors” occurred following light durations. In Experiment 2, accuracy was assessed on test trials in which the tone and the light signals were simultaneously presented for the same duration or for different durations. Pigeons responded accurately to durations of light, but were unable to accurately respond to durations of tone simultaneously presented with the light. The data from Experiment 1 suggest that there are important differences between light and tone signals with respect to the events that control the termination of timing. The data from Experiment 2 indicate that pigeons cannot simultaneously time visual and auditory signals independently and without interference. Consequently, they are inconsistent with the idea that there is a single internal clock that times both tone and light durations. 相似文献
17.
Pigeons were trained initially with 2- and 8-sec empty or filled intervals as sample stimuli. Interval onset and termination
was signaled by 1-sec start and stop markers. Following retention and psychophysical testing, both groups were trained with
the alternative type of interval, and the tests were repeated. Group empty-first demonstrated a choose-long effect with both
empty and filled intervals. Group filled-first demonstrated a weak (and nonsignificant) choose-short effect with filled intervals
and a robust choose-long effect with empty intervals. Both groups tended to time the markers and to add that duration to the
sample duration only on filled-interval trials. Initial training with empty intervals alters the way pigeons process temporal
information on filled-interval trials, whereas initial training with filled intervals has little effect on the processing
of temporal information on empty-interval trials. 相似文献
18.
The effect of differential outcome expectancies on memory for temporal and nontemporal information was examined. Pigeons were trained to match short (2-sec) and long (8-sec) sample durations to red and green comparison stimuli, and vertical and horizontal lines to vertical and horizontal comparison stimuli. In Experiment 1, one differential outcome (DO) group received food for correct choices on short-sample trials, whereas another received food for correct choices on long-sample trials. On line-orientation trials, half of each DO group received food for correct responses following vertical samples, whereas the other half received food for correct responses following horizontal samples. Overall retention was greater in the DO groups than in a nondifferential (NDO) group that received either food or no food for correct responses on a random half of all trials. Furthermore, although the NDO group displayed a choose-short bias for temporal samples, both DO groups displayed equivalent biases to select the comparison stimulus associated with food. In Experiment 2, differential outcome expectancies were extinguished off-baseline. Subsequently, in the first nondifferential outcome test session, the. DO groups performed less, accurately than the NDO group. These findings indicate that temporal samples are not retrospectively and analogically coded when they are differentially associated with food and no food. Instead, they are remembered in terms of the corresponding outcome expectancies. 相似文献
19.
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
20.
European starlings (Sturnuis vulgaris) were trained to discriminate between pulses of sound presented at rates (tempos), for different birds, of 4/sec and 8/sec or 8/sec and 16/sec in a two-alternative choice task. Once the discrimination was learned, psychometric functions and bisection points were determined for tempos between the standards. Then the starlings were transferred to a new discrimination, which either maintained or changed the relationship between response keys and tempo (relational or nonrelational transfer). The results showed that the starlings generated psychometric functions for tempo with properties much like those found for discrimination of single time intervals. Also, the starlings transferred the tempo discrimination faster under the relational than the nonrelational condition. In general, starlings-like human and other nonhuman animals-perceive temporal structures as invariant over proportional changes in the duration of structural elements. 相似文献