Independent effects of stimulus and cycle duration in conditioning: The role of timing processes     

Kimberly Kirkpatrick  Russell M. Church 《Learning & behavior》2000,28(4):373-388

Rats received delay conditioning procedures with a white-noise conditioned stimulus (CS), a food unconditioned stimulus (US), and head entries into the food cup as the conditioned response. The stimulus duration (S) and the interval between food deliveries (C) were varied between groups:S=15, 30, 60, and 120 sec;C=90, 180, and 360 sec. The stimulus/cycle duration ratio was negatively related to the asymptotic level of conditioning but had no effect on the rate of acquisition. Conditioning and timing of responses emerged together in training. Timing occurred during the CS-US interval (ISI) and the US-US interval (ITI), as evidenced by increasing response rate gradients that were steeper for shorter intervals. The effects of the stimulus/cycle ratio on conditioning were attributed to independent timing of theS andC durations. Serial-, parallel-, and single-process accounts of conditioning and timing are compared.  相似文献   

Control of pecking response form in the pigeon: Topography of ingestive behaviors and conditioned keypecks with food and water reinforcers     

Brent LaMon  H. Philip Zeigler 《Learning & behavior》1988,16(3):256-267

In Experiment 1, the form of keypecks produced in an autoshaping procedure with food or water reinforcers was compared with that of eating and drinking responses. Because the responses involve a number of different effector systems, several elements of response form were measured, including peck force and duration, gape, and eye closure. Gape was the only measure to reliably distinguish between both ingestive responses and between conditioned keypecks reinforced with food or water. With either reinforcer, keypecks had greater force than did ingestive behaviors. In Experiment 2, a transition between two forms of keypeck was produced by manipulating deprivation and reinforcer conditions. Some measures appeared to vary in a dichotomous manner between two discrete response forms; gape showed a gradual and continuous change involving the production of intermediate forms of the response. It was concluded that the control of conditioned response form involves theconstruction of the response from movements produced by several effector systems, each with potentially different sources of control.  相似文献   

Pavlovian aversive to instrumental appetitive transfer: Evidence for across-reinforcement blocking effects     

H. Fowler  J. H. Goodman  M. L. Zanich 《Learning & behavior》1977,5(2):129-134

Rats received Pavlovian aversive (shock) conditioning in which white noise was established for different groups as a CS+, CSO, or CS?. Then, in an appetitive T-maze discrimination, the CSs were presented contingent upon a designated correct response for which food reinforcement was factorially varied at 0, 1, 2, or 4 pellets. Although the CS+ suppressed and the CS? facilitated speed of running in the correct arm at the start of discrimination training, these effects extinguished rapidly and did not interact with reward magnitude. Furthermore, choice learning was faciltated by the CS+ and retarded by the CS?, with these effects being comparable for the 1- to 4-pellet reinforcement conditions, but absent for the 0-pellet condition. These findings are difficult to reconcile with a transfer interpretation positing a general signaling property of the CS and are better interpreted as across-reinforcement blocking effects: By predicting a preferred outcome (safety) comparable to the preferred outcome of food reinforcement, the CS? blocks (retards) the association of reinforcement and the S^D; conversely, by predicting a nonpreferred (shock) outcome discrepant from the preferred food outcome, the CS+ “counterblocks” (enhances) the association of reinforcement and the S^D.  相似文献   

Effects of partial vs consistent reward in noncontingent pairings of stimuli with reward: A noncontingently produced positive contrast effect     

Elizabeth D. Capaldi  John R. Hovancik 《Learning & behavior》1974,2(1):39-42

Rats received pairings of two stimuli with reward noncontingently in the Skinner box. During noncontingent pairings, the bar was immobilized. For Group CC 100% of the presentations of both stimuli were rewarded (S₁ ±, S₂ ±), for Group PP 50% of the presentations of each stimulus were rewarded (S₁, ±, S₂±), and for Group PC one stimulus was followed by reward on 50% of its presentations, while the second stimulus was followed by reward on 100% of its presentations (S₁ ±, S₂ ±). A fourth group received the stimuli and reward nonpaired. In a subsequent rewarded test phase, the response facilitating effects of the stimuli were evaluated. In the test phase all groups that received reward paired with S₁, and S₂ performed better in the presence of S₁ and S₂ than the group for which the stimuli were not paired with reward. For groups that received the stimuli paired with reward, a difference due to schedule of reward occurred when schedule of reward was varied within Ss (Group PC), but not when varied between Ss (Group PP vs Group CC). The specific form of this finding was that Group PC’s performance in the presence of S₂ ± was more vigorous than its performance in the presence of S₁ ± and was more vigorous than the performance of Groups PP and CC to S₂. Group PC’s performance to S₁ ± did not differ from that of Groups PP and CC to S₁.  相似文献   

Effects of CSs for food and water upon rats barpressing for different magnitudes of food reinforcement     

Richard M. Wielkiewicz 《Learning & behavior》1979,7(2):246-250

Forty-eight albino rats were first exposed to randomly intermixed, noncontingent presentations of one pellet, six pellets, and water. For each of three groups, a CS+ was paired with one of the reinforcers, while the other two reinforcers and a CS? were presented alone. Then half the subjects experienced a six-pellet reward and half experienced a one-pellet reward for leverpresses during a light S^D. Finally, on test trials, the CS+ or CS? was compounded with the light. Latencies on test trials indicated that responding for the one-pellet reward was significantly more disrupted by a CS+ for six pellets than by the CS+ for one pellet or the CS+ for water. Responding for the six-pellet reward was disrupted by the CS+ for one pellet somewhat more than by the CS+ for six pellets or water, but not significantly so. This pattern of results is partially consistent with an associative model of transfer and appears to contradict a motivational account of such effects.  相似文献   

Integrating control generated by positive and negative reinforcement on an operant baseline: Appetitive-aversive interactions     

Stanley J. Weiss  Charles W. Schindler 《Learning & behavior》1989,17(4):433-446

The interaction of opposing motivational states was measured within a design in which rats barpressed for food in one stimulus and to avoid shock in another. Tone and light discriminative stimuli (Sds) were counterbalanced over incentive conditions. Extinction eliminated responding when neither Sd was present. To minimize the influence of competing peripheral operants or reinforcer-elicited behaviors during appetitive-aversive interactions, contingency parameters were manipulated to generate similar rates and patterns of barpressing in both Sds and stimulus-compounding tests were administered in extinction. On these tests, rates in tone, light, and tone plus light (T+L) were equivalent. In contrast, when the same reinforcer (i.e., food or shock avoidance) maintained comparable training rates in tone and in light, in testing, T+L controlled double the rates of the single stimuli—strong additive summation. These results were strikingly similar to those of single-incentive experiments concerned with the contribution of excitatory and inhibitory incentive states to the results of stimulus compounding. Simultaneously presenting two Sds whose implicit stimulus-reinforcer (S-S^r) contingencies were arranged to make them, respectively, conditioned appetitive and aversive exciters (present experiment) produced test results comparable to those of two Sds whose implicit S-S^r contingencies were arranged to make them both conditioned inhibitors. Reciprocal antagonism between these two motive states more than neutralizes them. It appears to produce a negative (i.e., an inhibitory) motive state.  相似文献   

Replacement of event-generated memories of nonreinforcement with signal-generated memories of reinforcement during partial reinforcement training: Effect on resistance to extinction     

Steven J. Haggbloom  LaNeel Lovelace  Vickie R. Brewer  Shelia M. Levins  James D. Owens 《Learning & behavior》1990,18(3):315-322

Event-generated memory refers to the memory of a reinforcement (R) or nonreinforcement (N) event from an immediately preceding trial;signal-generated memory refers to the memory of a temporally remote R or N, retrieval of which is generated by presentation of a signal with which the memory is associated (Haggbloom, 1988). In each of three experiments, Group Signal-R received runway discrimination training in Phase 1 to establish a stimulus as a signal for R, and partial reinforcement training in Phase 2. An extinction test measured learning about the memory of nonreward (S^N)—learning that occurs when S^N is retrieved on R trials that follow N trials. In Group Signal-H, those R trials were accompanied by the signal for R, a treatment we hypothesized would generate retrieval of the memory of reinforcement (S^R) so that signal-generated S^R would replace event-generated S^N as the operative memory, thereby eliminating the increased resistance to extinction normally produced by PRF training. In each experiment, Group Signal-R was less resistant to extinction than was a control group conditioned to respond to-event-generated S^N. Extinction was as rapid in Group Signal-R as it was in a consistent reinforcement control group (Experiment 1) and in a group given intertrial reinforcements to interfere with learning about S^N (Experiment 3). Experiment 2 tested two alternative interpretations of the failure to learn about S^N in Group Signal-R. Those alternatives were found to be less viable than the hypothesis that the signal for R actively recruited retrieval of a competing memory.  相似文献   

Stimuli associated with the cancellation of food and its cues enhance eating but display negative incentive value     

Peter C. Holland 《Learning & behavior》2014,42(4):365-382

Initially neutral conditioned stimuli paired with food often acquire motivating properties, including serving as secondary reinforcers, enhancing instrumental responding in Pavlovian-instrumental transfer procedures, and potentiating food consumption under conditions of food satiation. Interestingly, cues associated with the cancellation of food and food cues may also potentiate food consumption (e.g., Galarce and Holland, 2009), despite their apparent negative correlations with food delivery. In three experiments with rats, we investigated conditions under which potentiation of feeding by such “interruption stimuIi” (ISs) develops, and some aspects of the content of that learning. Although in all three experiments ISs enhanced food consumption beyond control levels, they were found to act as conditioned inhibitors for anticipatory food cup entry (Experiment 1), to serve as conditioned punishers of instrumental responding (Experiment 2), and to suppress instrumental lever press responding in a Pavlovian instrumental transfer procedure (Experiment 3). Furthermore, when given concurrent choice between different foods, an IS enhanced consumption of the food whose interruption it had previously signaled, but when given a choice between performing two instrumental responses, the IS shifted rats’ choice away from the response that had previously yielded the food whose interruption had been signaled by IS (Experiment 3). Thus, the effects of an IS on appetitive responses were opposite to its effects on consummatory responding. Implications for our understanding of learned incentive motivation and the control of overeating are discussed.  相似文献   

Effects of reinforcement-paired stimuli on general activity     

Thomas S. Hyde  Milton A. Trapold 《Learning & behavior》1975,3(4):282-286

Two experiments were performed to explore the mechanisms responsible for the increase in activity that occurs in response to stimuli which have been paired with reinforcement (S^R. The first experiment showed a sharp increase in activity to S^R-paired stimuli under conditions in which subjects were not required to perform any instrumental response to obtain the S^R. This result seemed to rule out reinforcement of instrumental “food getting” behavior as the mechanism responsible for the learned activity increases. A second experiment used an “omission training” procedure to further explore the mechanisms underlying the activity increase. In this experiment, S^R was omitted on those trials on which activity increases were present during the stimulus. In this condition, no increases in activity were observed during the stimulus. There was, however, the characteristic increase in activity in a yoked-control group which received the same number and distribution of stimulus-paired S^Rs. The results of the second experiment open the possibility that increases in activity to S^R -paired stimuli could be due to the adventitious reinforcement of motor behavior rather than the Pavlovian conditioning of a motivational state.  相似文献   

Rats’ responses to a moving object related to food or water: A behavior-systems analysis     

William Timberlake 《Learning & behavior》1983,11(3):309-320

The present experiments compared rats’ responses to a moving object (a rolling ball bearing) related to either food or water under both Pavlovian and operant contingencies. In Experiment 1, food-restricted rats contacted food-related bearings more frequently and with more complex response patterns than water-restricted rats contacted water-related bearings. Food-related contacts occurred with shorter latency, longer average duration, and increased likelihood of dig, carry, and chew. Experiment 2 revealed that once contact with the bearing had been established, its form persisted despite changes in the type of reward and restriction. In Experiment 3, rats that were simultaneously food and water restricted learned to discriminate between painted and unpainted bearings related to food versus no food, water versus no water, and food versus water. Again, food-related bearings produced more complex, although not more frequent, interactions than did water-related bearings. In none of the experiments did rats lick the ball bearing related to water. The results supported a behavior-system approach, but not the stimulus-substitution or arbitrary-operant accounts of conditioned-response topography.  相似文献   

Operant variability when reinforcement is delayed     

Wagner K  Neuringer A 《Learning & behavior》2006,34(2):111-123

Operant responses are often weakened when delays are imposed between the responses and reinforcers. We examined what happens when delayed reinforcers were contingent upon operant responsevariability. Three groups of rats were rewarded for varying their response sequences, with one group rewarded for high variability, another for middle, and the third for low levels. Consistent with many reports in the literature, responding slowed significantly in all groups as delays were lengthened. Consistent with other reports, large differences in variability were maintained across the three groups despite the delays. Reinforced variability appears to be relatively immune to disruption by such things as delays, response slowing, prefeeding, and noncontingent reinforcement. Furthermore, the small effects on variability depended on baseline levels: As delays lengthened, variability increased in the low group, was statistically unchanged in the middle group, and decreased in the high group, an interaction similar to that reported previously when reinforcement frequencies were lowered. Thus, variable operant responding is controlled by reinforcement contingencies, but sometimes differently than more commonly studied repetitive responding.  相似文献   

Memories of reward events and expectancies of reward events may work in tandem     

E. J. Capaldi  Kimberly M. Birmingham  Suzan Alptekin 《Learning & behavior》1995,23(1):40-48

A common assumption is that expectancies of reward events in instrumental tasks are established on the basis of Pavlovian conditioning. According to the tandem hypothesis, tested in the four runway investigations reported here employing rats, memories of reward events may serve as the conditioned stimuli eliciting expectancies. In Experiments 1–3, rats were trained under a schedule of partial reward (P), which did not produce increased resistance to extinction, and subsequently shifted to consistent reward (C). According to the tandem hypothesis, the shift to the C schedule should result in increased resistance to extinction if, as hypothesized, under the P schedule the memory of reward, S^R, came to elicit the expectancy of nonreward,_EN. This hypothesis was confirmed under a variety of conditions. It was shown that increased resistance to extinction could not be attributed to the P schedule alone, to the rats receiving two schedules, P and C, to stimuli other than S^R eliciting E_N, or to the rats forgetting reward-produced memories when expecting nonreward (Experiment 4). It was shown that the tandem hypothesis could explain the divergent findings obtained in prior studies employing a shift from P to C as well as in the present study.  相似文献   

Effects of interrun interval on serial learning     

Steven J. Haggbloom  Michael W. Ekdahl 《Learning & behavior》1985,13(1):98-102

Two groups of five rats each received a decreasing quantity of food reward, 14-7-3-1-0 .045-g food pellets, over successive runs in a runway. The interrun interval (IRI) separating runs within each of two daily pattern repetitions (trials) was 10 sec (short, S) or 4–5 min (long, L) and varied over four successive phases of training in the order indicated by the group names, that is, Groups SLSS and LLLS. Anticipation of the 0-pellet element developed more rapidly in Group SLSS than in Group LLLS, but did eventually occur at the long IRI. Anticipation was eliminated by the increase in IRI experienced by Group SLSS in Phase 2 and by the decrease in IRI experienced by Group LLLS in Phase 4. The results are discussed with reference to the effects of changes in stimulus context accompanying IRI shifts on retrieval of task-specific knowledge and with reference to the possible signal value established to IRI-specific stimuli.  相似文献   

Cross-stimulus transfer of timing in pigeons     

Douglas S. Grant  Tim C. Robinson 《Learning & behavior》1993,21(2):106-112

Pigeons were trained in a delayed matching task in which the samples were short (2 sec) and long (10 sec) presentations of either a houselight or a keylight. Transfer trials involved short and long presentations of the nontrained signal as the sample. In the intermittent transfer test, infrequent transfer trials were intermixed with more frequent training trials; in the sustained transfer test, all trials were transfer trials. The intermittent test revealed only weak transfer. The sustained test revealed transfer in Session 1 only in birds that had received pairings of the transfer signal and food prior to testing. However, regardless of whether the transfer signal had been previously paired with food, birds exposed to consistent contingencies between duration and choice across training and testing learned the transfer task more rapidly than did birds exposed to inconsistent contingencies. It was concluded that some training in which the transfer signal serves as the sample is required before the durations of a transfer signal are related to the rules associating duration and responding  相似文献   

Samples of stimuli,responses, and reinforcers: Effect of incongruent sample type,serial position,and mode of presentation     

Douglas S. Grant 《Learning & behavior》1982,10(1):7-14

In two matching-to-sample experiments, pigeons’ performance with samples of stimuli (red and green), number of responses (1 and 20), and reinforcers (food and no food) was assessed. Samples of red, 20 responses, and food were associated with the red comparison stimulus, and samples of green, 1 response, and no food were associated with the green comparison stimulus. On interference trials, three sample types were presented on each trial, and two of the samples (congruent) were associated with the correct comparison and the third sample (incongruent), with the incorrect comparison. Performance on interference trials was compared with that on control trials in which either two (Experiment 1) or three (Experiment 2) congruent samples were presented. It was found that presentation of an incongruent sample reduced matching accuracy markedly, and about equally, whether samples were presented successively or in compound. Although the type of sample that was incongruent was without effect, matching accuracy declined strongly as the recency of the incongruent sample increased. Serial position of the incongruent sample also influenced the shape of the retention function on interference trials. Presentation of the incongruent sample either first or second resulted in accuracy decreasing across the retention interval, whereas presentation of the incongruent sample last in the input sequence resulted in increasing accuracy across the retention interval. The theoretical implications of the findings are considered.  相似文献   

Differential conditionability: Reinforcing grooming in golden hamsters     

Samuel G. Charlton 《Learning & behavior》1983,11(1):27-34

Differential conditionability is the empirical finding that not all responses are equally amenable to the same conditioning paradigm. One phenomenon associated with the conditioning of grooming behavior (a difficult-to-condition response) is a decrease in its average duration when followed by food reinforcement. The first experiment investigated this phenomenon by reinforcing golden hamsters (Mesocricetus auratus) with food for grooming or open rearing (a readily conditionable response) under three duration-dependent reinforcement schedules. The obtained data showed that different densities of food delivery had no differential effects on the average durations of grooming responses, indicating that the decreases were not the result of reinforcement-produced interruption. In the second experiment, golden hamsters were reinforced with food for grooming or for open rearing or received free food, under three interval reinforcement schedules. This experiment demonstrated that decreases in the average duration of grooming are independent of grooming behavior’s resistance to conditioning. Furthermore, although duration-dependent reinforcement schedules are largely ineffective in conditioning grooming behavior, interval schedules are shown to be quite effective in increasing rates of grooming.  相似文献   

Spatiotemporal characteristics of serial CSs and their relation to search modes and response form     

Francisco J. Silva  William Timberlake  Rory S. Gont 《Learning & behavior》1998,26(3):299-312

In four experiments, we examined how the spatiotemporal proximity to food of the two elements of a serial conditioned stimulus (CS) influenced the pattern of CS-directed versus food-site-directed behavior in rats. Experiment 1 showed that only temporal proximity affected responding when the serial CS consisted of two successive 4-sec presentations of either a spatially near or a spatially far lever (NN or FF). However, Experiment 2 showed that behavior depended markedly on whether rats received a near followed by a far lever (NF) or a far followed by a near lever (FN). Experiment 3 showed that the effects of Experiment 2 could be changed by increasing the duration of the second CS element, and Experiment 4 showed that these changes were not related to previous training. We concluded that behavior produced by the spatiotemporal qualities of the lever elements can be attributed to a mapping between the temporal qualities of the CS elements and an underlying sequence of search modes related to finding food.  相似文献   

Pavlovian appetitive discriminative conditioning inAplysia californica     

Ruth M. Colwill  Kevin Goodrum  Andre Martin 《Learning & behavior》1997,25(3):268-276

Three experiments demonstrated Pavlovian appetitive discrimination learning in the marine mollusc,Aplysia californica. In each experiment, subjects were exposed to two conditioned stimuli; one stimulus (CS+) was paired with food presentations and the other stimulus (CS?) was never followed by food. In Experiments 1 and 3 different chemosensory stimuli were used, and in Experiment 2 different tactile stimuli were used. For both types of conditioned stimuli, bite responses occurred significantly more often to the CS+ than to the CS?. Experiment 2 also showed thatAplysia could learn a reversal of this discrimination. Experiment 3 showed that nonreinforced presentations of CS+ resulted in a decline in the frequency of conditioned biting. The implications of these results for neurobiological analyses of learning are discussed.  相似文献   

The organization and temporal properties of appetitive behavior in rats     

Kathleen M. Silva  William Timberlake 《Learning & behavior》1998,26(2):182-195

In the presence and absence of an externalinterfood clock stimulus (a sequence of flashing lights), rats showed a multimodal behavior pattern during successive quarters of interfood intervals (IFI) ranging from 12 to 192 sec. Responses near the feeder peaked before and just after food presentations, whereas locomotion remote from the feeder peaked toward the middle of the IFI. The temporal patterns of nosing in the feeder and remote locomotion were scalar (the time at which a response peaked in the IFI was proportional to the IFI length), whereas the patterns of postfood feeder-directed behavior, rearing, and pawgrooming were time bound (peaking at a fixed time after food, regardless of IFI length). Responses varied in their control by the external clock stimulus. During the last half of the IFI, rats nosed in the feeder more with an external clock, but only at intermediate IFIs. During the first quarter of the IFI, rats pawgroomed more with an external clock, but only at the longest IFI. The general sequence of responses during the interfood clock was consistent with the view that food delivery engages an organized sequence of search states that are expressed through a variety of responses.  相似文献   

Prediction of concurrent keypeck treadle-press responding from simple schedule performance     

Frances K. McSweeney 《Learning & behavior》1978,6(4):444-450

Four pigeons pecked keys and pressed treadles for food reinforcers delivered by several variable-interval schedules of reinforcement. Then the subjects responded on several concurrent schedules. Keypecking produced reinforcers in one component, and treadle-pressing produced reinforcers in the other. The changeover delay, which prevented reinforcement after all switches from one response to the other, was 0, 5, or 20 sec long. An equation proposed by Kerrnstein (1970) described the rates of treadle-pressing and keypecking emitted during the variable-interval schedules. The k parameter of this equation was larger for keypecking than for treadle-pressing. The R₀ parameters were not systematically different for the two responses. The rates of keypecking and treadle-pressing emitted during the components of the concurrent schedules correlated with, but were not equal to, the rates of responding predicted by Herrnstein’s equation and the subject’s simple schedule responding. The ratios of the rates of responding emitted during, and the ratios of the time spent responding on, the components of the concurrent schedules conformed to an equation proposed by Baum (1974), but not to Herrnstein’s equation.  相似文献