共查询到20条相似文献，搜索用时 46 毫秒
1.
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
2.
Midsession reversals with pigeons: visual versus spatial discriminations and the intertrial interval
Jennifer R. Laude Jessica P. Stagner Rebecca Rayburn-Reeves Thomas R. Zentall 《Learning & behavior》2014,42(1):40-46
Discrimination reversal learning has been used as a measure of species flexibility in dealing with changes in reinforcement contingency. In the simultaneous-discrimination, midsession-reversal task, one stimulus (S1) is correct for the first half of the session, and the other stimulus (S2) is correct for the second half. After training, pigeons show a curious pattern of choices: They begin to respond to S2 well before the reversal point (i.e., they make anticipatory errors), and they continue to respond to S1 well after the reversal (i.e., they make perseverative errors). That is, pigeons appear to be using the passage of time or the number of trials into the session as a cue to reverse, and are less sensitive to the feedback at the point of reversal. To determine whether the nature of the discrimination or a failure of memory for the stimulus chosen on the preceding trial contributed to the pigeons’ less-than-optimal performance, we manipulated the nature of the discrimination (spatial or visual) and the duration of the intertrial interval (5.0 or 1.5 s), in order to determine the conditions under which pigeons would show efficient reversal learning. The major finding was that only when the discrimination was spatial and the intertrial interval was short did the pigeons perform optimally. 相似文献
3.
Numerical competence has been studied in animals under a variety of conditions, but only a few experiments have reported animals’
ability to detect absolute number. Capaldi and Miller (1988) tested rats’ ability to detect absolute number by using biologically
important events—the number of reinforced runs followed by a nonreinforced run—and found that the rats ran significantly slower
on the nonreinforced run. In the present experiments, we used a similar procedure. Pigeons were given a sequence of trials
in which responding on the first three trials ended in reinforcement but responding on the fourth trial did not (RRRN). When
the response requirement on each trial was a single peck (Experiment 1), we found no significant increase in latency to peck
on the fourth trial. When the response requirement was increased to 10 pecks (Experiment 2), however, the time to complete
the peck requirement was significantly longer on the nonreinforced trial than on the reinforced trials. Tests for control
by time, number of responses, and amount of food consumed indicated that the pigeons were using primarily the number of reinforcements
obtained in each sequence as a cue for nonreinforcement. This procedure represents a sensitive and efficient method for studying
numerical competence in animals. 相似文献
4.
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
5.
Pigeons and adult humans searched for a 2-cm2 unmarked goal in digitized images of an outdoor scene presented on a touch-screen monitor. In Experiment 1, the scene contained three landmarks near the goal and a visually rich background. Six training images presented the scene from different viewing directions and distances. Subsequent unreinforced tests in which landmark or background cues were removed or shifted revealed that pigeons’ search was controlled by both proximal landmarks and background cues, whereas humans relied only on the proximal landmarks. Pigeons’ search accuracy dropped substantially when they were presented with novel views of the same scene, whereas humans showed perfect transfer to novel views. In Experiment 2, pigeons with previous outdoor experience and humans were trained with 28 views of an outdoor scene. Both pigeons and humans transferred well to novel views of the scene. This positive transfer suggests that, under some conditions, pigeons, like humans, may encode the three-dimensional spatial information in images of a scene. 相似文献
6.
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
7.
The midsession reversal task involves a simple simultaneous discrimination that predictably reverses midway through a session. Under various conditions, pigeons generally both anticipate the reversal and perseverate once it has occurred, whereas rats tend to make very few of either kind of error. In the present research, we investigated the hypothesis that the difference in performance between rats and pigeons is related to the nature of the responses made. We hypothesized that rats could have been better at bridging the intertrial interval by keeping the relevant paw close to the lever while eating, whereas the pigeons had to remove their beak from the response key and insert it into the feeder, thus making it difficult to mediate the response last made. In the present experiment, in successive phases, rats were trained to leverpress or nose-poke on a 40-trial midsession reversal, an 80-trial midsession reversal, and a variable-location reversal. The results showed that the leverpress group acquired the task faster than the nose-poke group, but that both groups reached comparable levels of performance. Thus, the difference in the natures of the responses cannot fully account for the differences in accuracy between rats and pigeons. Additionally, differences in the types of errors made by the two groups suggest that the nature of the response plays different roles in the performance of this task. 相似文献
8.
The present research tested the generality of the “work ethic“ effect described by Clement, Feltus, Kaiser, and Zentall (2000).
In Experiment 1, we trained 10 pigeons on a pair of either simultaneous or successive discriminations. One discrimination
followed a high-effort requirement (20 pecks to the center key) and the other followed a low-effort requirement (1 peck).
Contrary to Clement et al.’s results, we found that preferences between the S+ and S− stimuli in transfer tests depended on the event that initiated the trial: Pigeons preferred the stimulus from the baseline
discrimination whose initiating event was most dissimilar from that preceding the test trial. Preferences were similar but
less extreme in the successive condition. In Experiment 2, we investigated whether test preferences depended on the amount
of training. A total of 12 pigeons were trained on a pair of simultaneous discriminations, except that test sessions were
scheduled after every three baseline sessions. Preferences increased across test sessions but were similar to those in Experiment
1. Together with Vasconcelos, Urcuioli, and Lionello-DeNolf (2007a), our study represents a second failure to replicate Clement
et al.’s work ethic effect. The finding that preference depends on the event that initiates the test trial suggests that choice
probes may not provide unambiguous assessments of stimulus value. 相似文献
9.
Pigeons’ choices between larger, more delayed and smaller, less delayed reinforcers were examined while the pigeons lived in the experimental chamber for 23-h sessions. In Condition 1, 4 pigeons were food deprived prior to each session and exposed to one session every 4th day. Condition 2 was identical except that the pigeons began each session at their ad-lib weights. Condition 3 was identical to Condition 2 except that sessions were conducted on consecutive days. Condition 4 was identical to Condition 3 except that the subjects (2 pigeons from Conditions 1–3 plus a naive pigeon) could obtain reinforcers much less frequently. In all of the conditions, the pigeons consistently chose the smaller, less delayed reinforcers; the pigeons were impulsive. The restriction of food access caused a disruption in the diurnal pattern of feeding, but did not decrease impulsiveness even in this 23-h live-in procedure. 相似文献
10.
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
11.
Pigeons were trained on an operant procedure to discriminate between morning and afternoon when location did not vary (Experiment
1). The pigeons were placed on a fixed interval (FI) schedule in the morning and on a different FI schedule in the afternoon.
Probe trials that occurred at the beginning of the training sessions were examined. The pigeons responded differently, depending
on the time of day, reflecting the learning of a stable 24-h memory representation of the association between the FI schedules
and the time of day. The pigeons from Experiment 1 were then clock shifted and tested twice, to determine whether they were
relying on an endogenous circadian oscillator, an hourglass mechanism influenced by the photoperiod, or environmental noise
to make the time-of-day discrimination (Experiment 2). The results of the second experiment indicated a circadian mechanism
was most important for the observed time-of-day learning. 相似文献
12.
Delamater AR 《Learning & behavior》2011,39(3):259-270
Two experiments with thirsty rats explored the harmful effects of non-reinforced exposures to a flavor cue in the control
by sensory-specific flavor–sucrose associations in a conditioned flavor preference paradigm. Experiment 1 demonstrated that rats learned to prefer a flavor cue that was consistently paired with sucrose over one that was paired
with sucrose the same number of times but was also presented without sucrose on other occasions. However, rats for which sucrose
was devalued following the conditioning phase preferred the partially reinforced flavor cue over the consistently reinforced
flavor, suggesting that non-reinforcement weakened the ability of that flavor cue to evoke a specific representation of sucrose
during the preference test. Experiment 2 demonstrated comparable effects of non-reinforcement in a latent inhibition procedure, although relatively more non-reinforced
pre exposures to the flavor, in conjunction with fewer flavor–sucrose pairings, were required to see the effect. Together,
the results suggest, as is often found with more traditional learning paradigms, that non-reinforcement of a flavor cue has
deleterious effects on preference learning and/or performance. 相似文献
13.
Rats and pigeons responded for food delivered according to multiple schedules. The session length varied from 10 to 120 min, and the programmed rate of reinforcement varied from 15 to 240 reinforcers per hour. Response rates usually changed systematically within experimental sessions. For both rats and pigeons, responding reached a peak after an approximately constant amount of time since the beginning of the session, regardless of session length. When rats, but not pigeons, served as subjects, the peak rates of responding occurred later in the session and the within-session changes were smaller for lower than for higher rates of reinforcement. The similarities between the results for rats and for pigeons when session length varied suggest that at least one of the factors that produces the within-session changes in responding is shared by the present species, responses, and reinforcers. The differences in results when rate of reinforcement varied are more difficult to interpret. 相似文献
14.
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
15.
Sequential priming refers to speeded visual search when target identity or location is repeated within a trial sequence. In two experiments with pigeons, we addressed the relative contributions of stimulus-driven factors and learned expectancies to this effect. Pigeons pecked at targets during trialwise presentations of visual-search displays. Random-sequence conditions minimized the role of expectancy by introducing same-target or same-location trial sequences unpredictably. Blocked-sequence conditions added predictability by regular repetition of target and/or location over trials. Intertrial interval varied from 0.5 to 3 sec. The findings revealed significant reductions in reaction time during predictable target or location sequences compared with unpredictable repetitions within random contexts. Stimulus-driven factors do not seem to have an important role in many instances of sequential priming. Expectancy-based priming of target and location followed similar patterns. 相似文献
16.
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
17.
Pigeons were trained in a two-choice delayed matching-to-sample task with red and green hues. A brief postsample cue (a vertical or horizontal line) signaled whether the comparison stimuli would be presented or omitted on each trial. Comparison stimuli were always presented following the remember-cue (R-cue) trial, but never following the forget-cue (F-cue) and no-cue trials. In Experiment 1, matching accuracy on F-cue and no-cue trials was equivalent and was considerably inferior to accuracy on R-cue trials. In Experiment 2, the placement of the postsample cue was manipulated. Matching accuracy decreased as the R cue was delayed in the retention interval, but performance in the F-cue condition was not affected. These data indicate that the no-cue condition can function as an implicit F cue and that the R cue can function to initiate and maintain rehearsal. 相似文献
18.
Sample and comparison location as factors in matching acquisition,transfer, and acquired equivalence
Urcuioli PJ 《Learning & behavior》2007,35(4):252-261
Pigeons learned symbolic matching with samples appearing equally often on left and right keys. For a location-relevant group,
the reinforced comparison choice for each sample reversed across sample locations; for a location-irrelevant group, the reinforced
choices were the same. Consistent with the hypothesis that samples at different locations are functionally different for pigeons,
Experiment 1 showed that matching acquisition was comparable in these two groups. Nevertheless, the location-irrelevant group
eventually ignored sample location, given that their performances subsequently transferred to a novel (center-key) sample
location. This transfer was not simply due to sample familiarity at different training locations; rather, it required that
left- and right-key samples occasion the same reinforced choices in training. Acquired equivalence between those samples was
then assessed in Experiment 2. The location-irrelevant group showed the predicted equivalence effects, but the location-relevant
group did not—in fact, its results were the opposite of those predicted by equivalence. Their results indicate that the functional
comparison stimuli are also defined in terms of their locations. 相似文献
19.
We investigated the role of dynamic information in human and pigeon object recognition. Both species were trained to discriminate
between two objects that each had a characteristic motion, so that either cue could be used to perform the task successfully.
The objects were either easy or difficult to decompose into parts. At test, the learned objects could appear in their learned
motions, the reverse of the learned motions, or an entirely new motion, or a new object could appear in one of the learned
motions. For humans, any change in the learned motion produced a decrement in performance for both the decomposable and the
nondecomposable objects, but participants did not respond differentially to new objects that appeared in the learned motions.
Pigeons showed the same pattern of responding as did humans for the decomposable objects, except that pigeons responded differentially
to new objects in the learned motions. For the nondecomposable objects, pigeons used motion cues exclusively. We suggest that
for some types of objects, dynamic information may be weighted differently by pigeons and humans. 相似文献
20.
Barry Schwartz 《Learning & behavior》1985,13(3):261-268
When pigeons are required to peck each of two keys in any order for reinforcement, stereotyped response sequences develop that are resistant to disruption by extinction, schedules of reinforcement, or contingencies requiring sequence variability. To test the hypothesis that stereotyped response sequences become integrated behavioral units, two experiments introduced within-sequence temporal delays of varying duration. Experiment 1 found that when a delay followed each peck in a sequence, there was substantial disruption of sequence performance that was independent of delay duration. However, such disruption was only temporary. Experiment 2 found that when the location of a delay within a sequence was varied, sequence disruption was a function of when, in a sequence, the delay occurred. Delays that occurred within sequence subunits had large effects, whereas delays that occurred between such subunits had small effects. The data indicate that pigeons can learn to bridge within-sequence delays, and suggest that response sequences are organized into “phrases.” 相似文献