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1.
Whereas rats exposed to a series of progressively decreasing shock durations show deficits in shuttle-escape performance 24 h later, the same number and intensity of shocks in the reverse (increasing) order of durations does not produce the “learned helplessness” effect (Balleine & Job, 1991). We conducted two experiments to establish the generality of this shock-duration order effect on other measures of distress and helplessness in rats. In Experiment 1, rats exposed to decreasing durations of inescapable shock showed reduced consumption of quinine-adulterated water (finickiness), whereas increasing durations produced no finickiness. By contrast, increasing shock durations produced greater conditioned fear to the shock context than did decreasing shock durations in Experiment 2. The differential effects of shock-duration order on finickiness and fear are explicated in terms of the specificity of fear conditioning during exposure to increasing versus decreasing series of shock duration orders. 相似文献
2.
R. F. S. Job 《Learning & behavior》1988,16(4):451-460
The results of experiments on learned helplessness in the appetitive situation have varied from facilitation to debilitating effects produced by exposure to uncontrollable food. The conditions under which the interference effect (debilitation) may occur were examined in the first three experiments, employing the triadic design. Sixteen sets of conditions were examined. The results suggested that the effect occurs when (1) subjects are preexposed to the manipulandum to be used in the test stage, by having it present during pretreatment with uncontrollable food, and (2) the manipulandum employed during pretreatment is absent during the test stage. Furthermore, under the reverse conditions (test manipulandum absent during pretreatment, and pretreatment manipulandum present during testing) and partial reinforcement of the response contingent subjects during pretreatment, the test performance of rats exposed to uncontrollability was facilitated. Experiment 4 confirmed the occurrence of the interference effect under the suggested conditions. Apparently inconsistent results of previous studies may be interpreted in the light of these findings. 相似文献
3.
Le Bourg E 《Learning & behavior》2005,33(3):265-276
The learned suppression of photopositive tendencies was studied at the individual level in young flies of both sexes. In a
T-maze, flies had to choose between an arm leading to a lighted vial associated with an aversive stimulus (i.e., a solution
of quinine chlorhydrate deposited on a filter paper in the vial) and another arm leading to a darkened vial free of quinine.
The present experiments were carried out to determine the roles of quinine and relative humidity in the maze. The flies avoided
the lighted vial containing quinine even if they had no tarsal contact with quinine, and this result was not due to any odor
of quinine. Subsequent experiments showed that relative humidity in the lighted vial, and probably in the arm leading to it,
was an aversive stimulus, which partly explains why the flies avoided the lighted vial. However, in conditions in which the
flies had tarsal contact with water or quinine it was confirmed that flies trained with quinine have higher avoidance scores
than those trained with water only. Moreover, individual aversion to humidity was not correlated with the individual avoidance
score: At similar levels of motivation (i.e., similar levels of aversion to humidity), some flies learn to avoid the lighted
vial containing quinine whereas others do not. All these results show that, in addition to quinine, humidity is an unconditioned
aversive stimulus in our paradigm and thus needs to be tightly controlled in experiments of conditioned avoidance. 相似文献
4.
We examined immunization against learned helplessness in 36 dogs. The experiment consisted of five phases: (1) appetitive contingent training, (2) immunization training, (3) inescapable noise training, (4) recovery, and (5) an appetitive noncontingent test. There were six groups: (1) a group immunized by controllable and predictable noise, (2) a group immunized by controllable but unpredictable noise, (3) a group immunized by uncontrollable but predictable noise, (4) a group given uncontrollable and unpredictable noise during immunization training, (5) a group not submitted to any treatment during the immunization phase, followed by uncontrollable noise, and (6) a group not submitted to any treatment. The immunization effect was assessed by measuring the acquisition of an appetitive response when food was not contingent upon responding. Our results demonstrate that the immunization effect can be observed in a noncontingent appetitive context. The effects of escapable noises that ensure immunization against the motivational deficit and predictable noises that immunize against the associative deficit seem to be additive. 相似文献
5.
Three experiments are reported assessing whether rats prefer controllable over uncontrollable aversive shock. In Experiment 1, subjects chose between escapable and inescapable shock while relative shock duration varied parametrically. In Experiment 2, subjects again chose between escapable and inescapable shock, but duration was held constant and equal. The final experiment gave subjects a choice between avoidable and unavoidable shock under several signaling conditions. Choice behavior proved sensitive to relative shock duration and to predictability of shock but not to controllability of shock. 相似文献
6.
Rick A. Bevins Heather C. Jensen Todd S. Hinze Joyce Besheer 《Learning & behavior》1999,27(3):358-366
Rats (Rattus norvegicus) that received a taste cue (saccharin, saline, quinine, or sucrose) paired with a lithium chloride (LiCl) injection displayed
a robust decrease in consumption of that taste, relative to controls that had the taste unpaired with LiCl. Consumption of
the paired taste increased with each nonreinforced presentation (i.e., extinction). After asymptotic extinction, rats that
had had a 0.1% saccharin cue paired with LiCl consumed less of the saccharin solution than did controls. A similar data pattern
was observed with a 10% sucrose solution. These results are consistent with the view that some aspect of the excitatory CS-US
association remains after extinction. On the other hand, rats that had a bitter (0.005% or 0.001% quinine) or salty (1% or
0.5% saline) solution paired with LiCl drank similar amounts of the fluid as controls after asymptotic extinction treatment.
Together, these experiments suggest that a taste that is either sweet or preferred is required in order to demonstrate the
chronic decrease in fluid consumption after extinction treatment. The data suggest that the conditioning experience prevents
the later development of a preference for the sweet taste, rather than there being a retained aversion that suppresses fluid
consumption. 相似文献
7.
Dennis A. Vanderweele 《Learning & behavior》1974,2(4):309-312
Mongolian gerbils (Meriones unguiculatus) were examined for components of thirst in the laboratory. The gerbil, reputed to be a desert-adapted rodent, was tested for its response to quinine adulterations of water, hypertonic solutions (1 M sodium chloride, NaCl), and hyperoncotic solutions (40% W/V polyethylene glycol in isotonic saline, PG). Both NaCl and PG were administered intraperitoneally. Gerbils accepted quinine when it was the only solution available and food was ad lib, but preferred distilled water to quinine if both were available. Both PG and NaCl produced increased water intakes in gerbils within the first 2 h, postinjection. PG, however, produced the most reliable and largest increase in water consumption, illustrating that extracellular dehydration is probably a more significant thirst stimulus in gerbils. 相似文献
8.
A task was designed to teach individual flies to avoid a lighted area after they had displayed an initial preference for it. The flies walked in a T-maze and chose between a lighted and a darkened alley leading, respectively, to a lighted and a darkened vial. Flies that were photopositive on a first trial were subjected to an aversive stimulus (a filter paper inserted into the lighted vial and wetted with a quinine solution), and they performed 16 training trials; they learned to avoid the lighted vial. The flies trained with water instead of quinine in the lighted vial still displayed avoidance of the lighted vial, but to a lesser extent. The flies trained with a dry filter paper in the lighted vial did not show any increase in avoidance during training. Like the flies trained with no quinine at all, those trained to avoid the lighted vial under a partial reinforcement condition (one half of the trials with quinine, the other half with a dry vial) did not master the task. Finally, removal of the quinine after an avoidance acquisition criterion was reached resulted in an extinction process. 相似文献
9.
Two experiments allowed rats to drink freely two neutral flavors (almond and vanilla) in simultaneous compound with two hedonically valued flavors (quinine and saccharin). The neutral flavor previously paired with saccharin was subsequently preferred. The neutral flavor that had been paired with quinine was subsequently avoided. Experiment 3 found similar results when the animals were hand-fed a preset amount of the solution. Preference shifts were not obtained when differential amounts of the neutral flavors were consumed in isolation. The data indicate that flavor-flavor associations can shift taste preferences. 相似文献
10.
R. F. S. Job 《Learning & behavior》1987,15(3):342-346
Four groups of rats were exposed to response-contingent, yoked noncontingent, or en masse food deliveries in a Skinner box or to no experimental pretreatment. All groups were subsequently tested for transfer of the learned-helplessness effect to an appetitive discrete-trial T-maze discrimination employing experimenter-blind procedures. The yoked group showed retarded discrimination learning in comparison with the response-contingent and naive control groups but not in comparison with the en masse control group. This nonsignificant difference between the yoked group and the en masse group may reflect the effect of limited exposure to uncontrollability in the en masse group. The groups did not differ in terms of the speed of maze traversal. The latter result suggests that the learned-helplessness effect observed in discrimination was not due to a competing response. 相似文献
11.
Previous research has demonstrated that running in a rotating wheel functions as a reinforcer for leverpressing in rats. In these studies, the pattern of responding was similar to the pattern of responding maintained by consummatory reinforcers, such as food and water. The present study investigated quantitative features of responding maintained by running. In previous experiments in which responses were reinforced according to variable-interval (VI) schedules and food and water served as the reinforcer, the equation for a rectangular hyperbola described the relationship between response rate and reinforcement rate. This experiment tested whether this quantitative regularity also applies to leverpressing maintained by the opportunity to run in a wheel. Fourteen male Wistar rats responded on levers for the opportunity to run. In each session, subjects were exposed to a series of VI schedules. An opportunity to run for 60 sec was the reinforcing consequence. Results showed that response rate was a negatively accelerated function of reinforcement rate, and the relationship between these two variables was described well by the equation for a rectangular hyperbola. To further test the similarity between running and consummatory reinforcers, the response requirement and access were manipulated. In previous experiments with food and water, these types of manipulations differentially changed the two parameters of the hyperbola. A similar pattern of results was obtained with wheel running. Thus, the equation appears to apply to running about as well as it does to consummatory reinforcers. 相似文献
12.
选用192只28±2d实验用清洁级SD大鼠,分为6组,每组32只,雌雄各半,分别饮用添加硼0、40、80、160、320和640mg/L的蒸馏水,试验期60d,分别于试验第30天(65日龄)和60天(95日龄)每组随机取鼠16只,雌雄各8只,10%水合氯醛腹腔麻醉,立即解剖取胰腺,称重,制作石蜡切片,HE染色,光镜观察并显微摄影。结果表明,与对照组比较,65d试验Ⅰ~Ⅳ雄鼠胰腺重量与器官指数降低,雌鼠胰腺重量与器官指数升高,95d试验Ⅰ~Ⅳ雄鼠和试验Ⅰ、Ⅱ组雌鼠胰腺重量升高,但均无统计学意义(P>0.05)。试验Ⅴ组大鼠的胰腺重量多显著或极显著低于对照组(P<0.05或P<0.01)。95d试验Ⅰ、Ⅱ组大鼠的胰腺的腺泡和胰岛结构较对照组有较明显地改善;试验Ⅲ~Ⅳ组胰腺的组织结构则呈现不同程度病理组织学变化;试验Ⅴ组胰腺腺泡细胞肿胀、顶部胞质酶原颗粒明显减少,胰岛体积变小,胰岛周边细胞萎缩,中央细胞肿胀。试验结果表明,饮水添加40、80mg/L硼对大鼠胰腺发育及组织结构有较明显地促进和改善作用;添加160~640mg/L硼对大鼠胰腺的发育及组织结构与功能则有较明显的不良影响甚至毒性作用;结果提示,微量元素硼对大鼠的胰腺发育及组织结构与功能的影响可能存在性别和日龄差异。 相似文献
13.
In two experiments, behavioral stereotypies elicited by scheduled presentations of food and water were compared. In Experiment 1, pigeons were exposed to a fixed-time 30-sec (FT 30-sec) schedule of food or water deliveries with a brightening keylight stimulus signaling time to the unconditioned stimulus (UCS) on each trial. Food and water presentations both produced terminal autoshaped keypecking that was similarly distributed in the trial but differed in response topography and persistence. Locomotor interim behavior was different in the two motivational conditions: With food presentations, it consisted of a “retreat” to the rear of the chamber after UCS termination, followed by “pacing” in the midportion of trials. The water schedule produced very little locomotor activity with no regular distribution in the trial. Experiment 2, using a random-time 30-sec (RT 30-sec) schedule, showed that the differences in interim locomotor behavior persisted in the absence of temporal predictability of the UCS and the keypecking terminal response. The results are taken to support Timberlake’s (1983a) behavior-system theory. 相似文献
14.
In two experiments with goldfish patterned after work with rats, consummatory responding for a less preferred food (adulterated with quinine) was measured in subjects that did or did not have previous experience of a preferred (unadulterated) food. The result in each case was not the negative contrast found in rats, but the opposite—more responding in subjects with experience of both foods. The experiments are in accord with a variety of others that have failed to show control of performance by remembered reward in goldfish. 相似文献
15.
Food-deprived rats that receive intermittent delivery of small amounts of food develop excessive drinking--specifically, schedule-induced polydipsia (SIP). A main characteristic of SIP is its occurrence at the beginning of interfood intervals. The purpose of this study was to demonstrate that SIP can be developed toward the end of interfood intervals, in closer proximity to upcoming than to preceding food delivery. In Experiment 1, two groups were exposed to a fixed-time (FT) 30-sec food schedule with water available during the first or the last 15 sec of each interfood interval. Two additional groups, which had access to water throughout, were exposed to FT 30-sec or FT 15-sec schedules of food presentation. The FT 30-sec group with free access to water developed the highest level of intake; similar and intermediate levels were induced in all the remaining groups. In Experiment 2, three groups of rats were exposed to an FT 90-sec food schedule with water available during the first, the second, or the last 30 sec of each interfood interval. One additional group with access to water throughout was exposed to the FT 90-sec schedule of food presentation. The group with free access to water developed a higher level of consumption than did the other groups, but by the end of training none of the four groups showed statistical differences in polydipsic drinking. Results show that adjunctive drinking can be developed in proximity to upcoming food delivery even with long interfood intervals. 相似文献
16.
Anthony L. Riley Richard L. Hyson Cory S. Baker Paul J. Kulkosky 《Learning & behavior》1980,8(2):211-217
In Experiment 1, rats poisoned following schedule-induced saccharin consumption showed a moderate reduction in the schedule-induced consumption of saccharin. With repeated poisoning, schedule-induced saccharin polydipsia was markedly reduced. Acquisition of conditioned aversion under the schedule-induced procedure was significantly slower than acquisition under water deprivation. In addition, recovery of consumption of the previously poisoned solution during extinction was more rapid under schedule-induced polydipsia. Experiment 2 revealed that schedule-induced polydipsia was less sensitive to suppression by conditioned aversions than a prandial drinking condition in which subjects were equally food deprived but were given a mass feeding instead of spaced pellet deliveries, suggesting that the relative insensitivity of schedule-induced polydipsia to conditioned taste aversions is not simply a function of different levels of food deprivation. This relative insensitivity is offered as a partial basis for the occurrence and maintenance of schedule-induced alcohol polydipsia. 相似文献
17.
In one experiment, the rate and pattern of responding (head entry into the food cup) under different distributions of intervals
between food deliveries were examined. Separate groups of rats received fixed-time (45, 90, 180, or 360 sec), random-time
(45, 90, 180, or 360 sec), or tandem fixed-time (45 or 90 sec) random-time (45 or 90 sec) schedules of reinforcement. Schedule
type affected the pattern of responding as a function of time, whereas mean interval duration affected the mean rate of responding.
Responses occurred in bouts with characteristics that were invariant across conditions. Packet theory, which assumes that
the momentary probability of bout occurrence is negatively related to the conditional expected time remaining until the next
reinforcer, accurately predicted global and local measures of responding. The success of the model advances the prediction
of multiple measures of responding across different types of time-based schedules. 相似文献
18.
Experiment 1 sought to determine whether schedule-induced drinking could be abolished by means of a taste aversion. Polydipsic rats were given access to a .4% saccharin solution while they were exposed to an intermittent food schedule. Immediately after the session, they received an intraperitoneal injection of either lithium chloride or sodium chloride. Following a recovery day with water in the experimental chamber, the animals were again exposed to the saccharin solution. The poisoned animals (lithium chloride) drank very little saccharin compared to the control animals (sodium chloride), indicating that they had learned a taste aversion in only one conditioning trial. Experiment 2 established that polydipsic rats can learn a taste aversion despite a long delay between schedule-induced saccharin consumption and poisoning, and that the delay gradient displayed by polydipsic rats is similar to that observed in thirst-motivated rats. 相似文献
19.
In Experiment 1, 12 rats were exposed to an FT 60 schedule of food reinforcement, followed either by extinction or by a massed-food control condition, in the presence of a wood block. In 9 rats, wood-chewing behavior increased systematically during the FT 60 condition and declined again during extinction or massed food, while the other 3 rats showed virtually no chewing behavior at any stage of the experiment. In Experiment 2, frequency and bout duration of wood-chewing under an FT 60 schedule of food reinforcement declined as body weight increased, in 7 rats. We conclude that wood-chewing qualifies as a schedule-induced behavior, and that it resembles schedule-induced drinking in its dependence on body weight. Unlike drinking, however, induced chewing occupied the middle region of the 60-sec interreinforcement interval, declined markedly within the session, and showed considerable within- and between-subject variability. 相似文献
20.
Rats were selectively bred for high versus low saccharin ingestion, a putative measure of enhanced stress and emotionality (Dess, 1991). In Experiment 1, third-generation Occidental high-saccharin (HiS) and low-saccharin (LoS) rats were tested for saccharin ingestion and emotionality. The saccharin test confirmed that the lines differed on the selection phenotype. In addition, LoS rats were more emotional, as evidenced by longer emergence latencies and more defecation in a modified open-field test. In Experiment 2, LoS rats had lower quinine preference scores and drank saccharin-adulterated glucose less avidly. These outcomes are reminiscent of the behavior shown by inescapably shocked rats. Unlike helpless rats, however, LoS rats drank less avidly during a dilute sucrose test, an effect more reminiscent of chronic mild stress. The lines did not differ reliably on intake of concentrated glucose or Polycose, even when the latter was mixed with saccharin. In Experiment 3, LoS rats preferred saccharin less strongly than did HiS rats at concentrations of 0.05% to 0.7% and had an aversion to a 1.0% solution. In Experiment 4, LoS rats were affected more by shock, as assessed by stress-induced anorexia. These and other recent findings support the notion of shared mechanisms for taste, emotionality, and stress vulnerability. 相似文献