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1.
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
2.
Pigeons were trained to match temporal (2 and 8 sec of keylight) and color (red and green) samples to vertical and horizontal comparison stimuli. In Experiment 1, samples that were associated with the same correct comparison stimulus displayed similar retention functions; and there was no significant choose-short effect following temporal samples. This finding was replicated in Phase 1 of Experiment 2 for birds maintained on the many-to-one mapping, and it was also obtained in birds that had been switched to a one-to-one mapping by changing the comparison stimuli following color samples. However, in Phase 2 of Experiment 2, when the one-to-one mapping was produced by changing the comparison stimuli following temporal samples, a significant choose-short effect was observed. In Experiment 3, intratrial interference tests gave evidence of temporal summation effects when either temporal presamples or color presamples preceded temporal targets. This occurred even though these interference tests followed delay tests that failed to reveal significant choose-short effects. The absence of significant choose-short effects in Experiment 1 and in Phase 1 of Experiment 2 indicates that temporal samples are not retrospectively and analogically coded when temporal and nontemporal samples are mapped onto the same set of comparisons The interference test results suggest that the temporal summation effect arises from nonmemorial properties of the timing system and is independent of the memory code being used 相似文献
3.
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
4.
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
5.
The research reported herein is designed to test a signal detection account of thechoose-short effect, which is the tendency of birds to report (after a long delay) that a short-duration sample was presented, regardless of whether a short or long sample initiated the trial. According to the detection account, the choose-short effect arises because birds learn to selectively search memory for evidence that the long sample appeared on a given trial. This idea is tested, in part, by replacing short-sample trials with nosample trials and showing that performance is unaffected by this manipulation for birds exhibiting a choose-short effect. In addition, when no samples and long samples were associated with the same choice alternative (and the short sample was associated with the other alternative), birds were flexible enough to learn to respond on the basis of the presence versus the absence of the short sample (and, as a result, a choose-long effect was observed). 相似文献
6.
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
7.
Systematic errors in pigeons’ memory for event duration: Interaction between training and test delay
Marcia L. Spetch 《Learning & behavior》1987,15(1):1-5
Pigeons trained to choose different stimuli following short- and long-duration signals make disproportionately more “short” choices (i.e., “choose-short errors”) following an increase in the retention interval and more “choose-long errors” following a decrease in this delay. The present experiment provided a systematic investigation of how these selective errors depend on the relationship between the training delay and the test delay. Pigeons were first trained with a 0-sec delay between the signal (2- or 8-sec food presentations) and the choice stimuli (red- and blue-lit keys). On subsequent test trials with 5- and 10-sec delays, choose-short errors predominated. Next, the birds were trained with a constant 10-sec delay and then tested with shorter or longer delays on some trials. The birds now responded accurately and without selective errors at the 10-sec training delay, but made choose-long errors at shorter delays and choose-short errors at longer delays. Finally, the birds were trained with a constant 20-sec delay and then tested with shorter and longer delays. Choose-long errors again appeared at shorter test delays, choose-short errors at longer test delays, and no differential errors at the 20-sec training delay. The selectivity of these errors generally increased with the absolute difference between the training and test delay. Theoretical implications of these results are discussed. 相似文献
8.
Philipp J. Kraemer 《Learning & behavior》1991,19(3):276-282
Two experiments examined the performance of pigeons on symbolic-matching-to sample in which the relevant sample dimension consisted of duration. Each pigeon was trained on two problems that had the same two sample durations, 2 and 10 sec, but were different with respect to other physical properties of the samples. Durations of light and tone were used in Experiment 1; durations of two different color-location compounds were used in Experiment 2. In each experiment, a unique choice stimulus was associated with each of the four possible combinations of duration and signal type. Test sessions contained probe trials in which the choice stimuli were these appropriate for a long and a short duration of the signal type opposite to that actually presented. Pigeons in both experiments displayed asymmetrical performance deficits. Accuracy on long durations dropped to chance or below, whereas accuracy on short durations remained high. This pattern is similar to the choose-short effect that is obtained when animals are tested with long retention intervals. The implications of these results for duration memory, coding, and transfer of training are discussed. 相似文献
9.
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
10.
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
11.
In seven experiments, an effect of the intertriai interval (ITI) duration on barpressing by rats was studied. A stimulus signaled a 15-sec variable-interval trial. The first response after the interval elapsed turned the stimulus off and was rewarded with food. Trials were separated by long (about 300 sec) or short (about 10 sec) ITIs. A within-subjects design established that response rate on trials after long ITIs was lower than that after short ITIs (Experiments 1 and 3–7). The effect was not cumulative (the effect of one and five consecutive short ITIs was the same). Response rate after short and long ITIs was the same when a between-subjects design was used (Experiment 2). Response rate was higher after 160-sec ITIs than after 300-sec ITIs, suggesting that the ITI duration at which all longer ITIs are treated the same (i.e., the upper limit) is greater than 160 sec (Experiment 3). When food, the trial stimulus, a novel stimulus, or a familiar stimulus never paired with food, was presented 10 sec before the next trial during some of the long ITIs, response rate on the next trial was similar to that found after 10-sec ITIs (Experiments 4–6). This similarity suggested that these events could mark the start of the ITI. However, the familiar stimulus did so only when it reliably predicted that the next trial would occur after a short interval. The effect of ITI duration on responding was apparently attributable to response latency. Response latency was greater after long ITIs, but once responding began, it was similar after long and short ITIs (Experiment 7). 相似文献
12.
The present experiment examined the effects of several disruptors on temporal discrimination. Pigeons responded under a 0-delay
symbolic matching-to-sample procedure in which responses to one key color were reinforced following the presentation of four
shorter sample durations, and responses to another key color were reinforced following the presentation of four longer sample
durations. Steady-state performance was disrupted by presession feeding, intertrial-interval food, visual distraction, and
extinction. All disruptors decreased temporal-discrimination accuracy. Analyses of the fitted cumulative normal functions
indicated that decreases in accuracy were produced mainly by decreases in overall stimulus control rather than specific effects
on timing. In addition, all disruptors selectively decreased accuracy on long-sample trials—a choose-short effect. This effect
is interpreted in terms of decreased attention to the samples under disruption. Current theories of the choose-short effect
do not appear to easily account for these results. 相似文献
13.
Pigeons were trained on duration matching-to-sample in which each of four combinations of signal type (red or white light) and duration (2 or 10 see) was mapped onto a different choice stimulus. Probe trials in Experiments 1 and 2 involved a successive presentation of two duration samples. In each experiment, birds tended to summate two durations when the same signal was presented twice, but not when two different signals appeared. These results contrast with those reported by Spetch and Sinha (1989), who found a summation effect with both same-signal and different-signal compounds. In Experiment 3, pigeons chose among two alternatives which were both associated with the duration of the sample but of which only one was also associated with the signal type of the sample. Pigeons systematically chose the stimulus that matched both sample duration and signal type. The implications of these findings are discussed in terms of transfer of training and coding of event duration. 相似文献
14.
J. Gregor Fetterman 《Learning & behavior》1995,23(1):49-62
Pigeons were trained on a psychophysical choice task to make one response after a 2-sec signal and a different response after a 10-sec signal. Delayed dimensional control was assessed by presenting durations intermediate to the short and long signals and by introducing delays between the signals and choice opportunities. In Experiment 1, choices after intermediate durations were not reinforced; in Experiment 2, one choice was reinforced after the three shortest durations and another was reinforced after the three longest durations. In Experiment 1, the slopes of the psychophysical functions decreased with increases in delays, but the decrease in stimulus control was not unbiased; choice probabilities decreased for longer durations, but did not increase for shorter durations. Experiment 2 revealed the same generalized loss of stimulus control on the temporal dimension, but not the same pattern of bias; temporal control was relinquished equally for shorter and longer durations. These results are evaluated in the context of the subjective shortening model of remembered duration (Spetch & Wilkie, 1983) and Staddon’s theory of timing and remembering (Staddon, 1984). 相似文献
15.
Ben A. Williams 《Learning & behavior》1989,17(2):223-233
Previous research has produced conflicting results regarding the effects of component duration on interactions in multiple schedules. In Experiment 1, potential sources of this conflict were evaluated. Both the effects of absolute reinforcement rate and carry-over effects (hysteresis) from a preceding condition were isolated. When 10-sec components were used, the sensitivity of relative response rate to relative reinforcement rate was affected very little by hysteresis effects and absolute reinforcement rate, but it was systematically reduced as a function of the number of prior conditions. Sensitivity to relative reinforcement rate was also substantially higher with the 10-sec components than with 2-min components. In Experiment 2, this effect of component duration was decomposed into two separate effects. Contrast effects during presentation of a target component with a constant reinforcement rate were greater the shorter the target component was itself; but they were smaller the shorter the alternative component in which reinforcement rate was varied. The latter effect was smaller and more unreliable across subjects. The existence of these two separate effects demonstrates that the usual method of studying component duration—that is, holding all components equal in duration—systematically causes underestimation of the effects of the component duration, and obscures the different processes controlling the two effects. 相似文献
16.
The effect of pattern of stimulus presentation on habituation of the cardiac component of the orienting response to an auditory stimulus was investigated in four experiments. The duration of stimulus presentation was held constant, but some animals were given six 10-sec stimulus presentations and others were given a single 60-sec stimulus. During the first 10 sec of the auditory stimulus, heart rate (HR) decreased approximately 40 beats per minute (bpm) in both groups, but during subsequent 10-sec epochs, the changes in HR were markedly different in the two groups. For those animals given a single 60-sec stimulus, the cardiac orienting response did not habituate; that is, HR either continued to decrease or remained approximately 40 bpm below baseline. In contrast, those animals given six 10-sec stimulus presentations showed smaller decreases in HR with each successive stimulus presentation, and after approximately four presentations, no detectable change in HR was observed. Despite these dramatic differences in habituation of the cardiac component of the orienting response, neither group oriented to the auditory stimulus when it was presented again following a short retention interval. Moreover, with increasing retention intervals, both groups showed the same forgetting function (reappearance of the orienting response). The implications of these findings for theories of the orienting response as well as theories of habituation are discussed. 相似文献
17.
Initial-link response allocation in concurrent chains becomes less extreme as the absolute duration of the initial links increases
(Fantino, 1969). The present study asked whether initial-link duration affected how quickly response allocation reached asymptote
(i.e., acquisition of preference). Six pigeons were trained on a concurrent-chains procedure in which the terminal links were
fixed-interval (FI) 8 sec FI 16 sec or FI 16 sec FI 8 sec and were reversed every 20 sessions. Across conditions, all possible
combinations of transitions between variable-interval (VI) 8-sec (short) and VI 24-sec (long) initial-link schedules were
studied. Overall, the rate of acquisition was faster when the durations of the initial links preceding the reversal were short
rather than long, and when the durations of the initial links following the reversal were long rather than short. By contrast,
initial-link duration had no effect on acquisition or asymptotic measures of temporal control of terminal-link responding.
These results support the core principle of delay-reduction theory (Fantino, 1969) that the impact of a conditioned reinforcer
varies directly with initial-link duration, but also suggest that temporal learning during the terminal links proceeds independently
of initial-link duration. nt]mis|These data were presented at the annual meeting of the Association for Behavior Analysis,
Boston, May 2004. 相似文献
18.
Louis M. Herman 《Learning & behavior》1975,3(1):43-48
Interference in auditory short-term memory in the bottlenosed dolphin,Tursiops truncatus (Montagu), was studied using a delayed matching-to-sample task. At each trial, one of two sample sounds, chosen randomly, was projected underwater for 4 sec and then, after a variable delay interval, both sounds were presented. A response to the sound matching the initial sample was reinforced. Correct matching was significantly reduced following short intervals between trials in combination with long delays after the sample (proactive interference), or when a near continuous irrelevant sound was inserted into the delay interval (retroactive interference). There was rapid habituation to interference if the irrelevant sound was short in duration relative to the delay interval. For both proactive and retroactive interference, the errors were predominantly responses to the sample sound appropriate to the prior trial rather than to the current trial, indicating that memory for the relative recency of events (temporal memory) was degraded by interference. When interference was deleted or minimized, temporal memory remained nearly perfect over 30-sec delay intervals, the longest tested. The importance of distinguishing between temporal memory and nontemporal, or event, memory in different forms of the delayed matching task was emphasized. 相似文献
19.
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
20.
Pigeons trained on a conditional event-duration discrimination typically “choose short” when retention intervals are inserted between samples and comparisons. In two experiments, we tested the hypothesis that this effect results from ambiguity produced by the similarity of the novel retention intervals and the familiar intertrial interval by training pigeons with retention intervals from the outset and, for one group, in addition, making retention intervals distinctive from the intertrial intervals. In Experiment 1, when the retention intervals (0–4 sec) were not distinctive from the intertrial intervals, the pigeons did not show a clear choose-short effect even when extended retention intervals (8 sec) were introduced. When the retention intervals were distinctive, the pigeons showed a choose-long effect (they appeared to time through the retention interval), but it was relatively weak until the retention intervals were extended to 8 sec. In Experiment 2, when pigeons were discouraged from timing through the retention intervals by making the intertrial intervals and retention intervals salient distinct events and using long (up to 16-sec) retention intervals in training, parallel retention functions were found. It appears that when ambiguity is removed, forgetting by pigeons does not occur by the process of subjective shortening. These experiments suggest that the accurate interpretation of results of animal memory research using differential-duration samples must consider the novelty of the retention intervals on test trials as well as their similarity to other trial events. 相似文献