Showing papers in "Animal Learning & Behavior in 1979"
TL;DR: It is suggested that rats’ memories for spatial locations are immune to retroactive interference, at least within the range of conditions reported, and that the rat can successfully segregate memories foratial locations established in different contexts.
Abstract: Treatments that interfere with animals’ short-term retention (e.g., in delayed matching-to-sample) were studied using a spatial memory task. Rats performed in an eight-arm radial maze in which choosing each arm without repetition was the optimal behavior. Performances were interrupted between fourth and fifth choices for a delay of 15 sec to 2 min. A variety of events occurring during the delay interval did not disrupt memories for prior choices (as assessed by the accuracy of postdelay choices). The ineffective treatments included variations in visual and auditory environments, removal from the maze, food consumed during the delay, a distinctive odor added to the maze, or combinations of these manipulations. Additionally, performance on another spatial task (a four-arm maze) during the delay between Choices 4 and 5 did not interfere with performance in the eight-arm maze. These findings suggest that rats’ memories for spatial locations are immune to retroactive interference, at least within the range of conditions reported, and that the rat can successfully segregate memories for spatial locations established in different contexts.
211 citations
TL;DR: Rats in the extramaze group performed almost perfectly during maze rotation, demonstrating that intramaze cues were not necessary to support accurate choice behavior, and other experiments describing the influence of “odor trails” or other olfactory stimuli on choice behavior in mazes are compared.
Abstract: The relative importance of intramaze cues and extramaze cues in directing choice behavior on a radial arm maze was examined using a discrimination procedure which selectively rewarded rats for following only one set of cues. Rats in the intramaze group obtained food from a food cup on the end of each arm. Rats in the extramaze group obtained food from a food cup on a small platform just beyond the end of each arm. All rats were first shaped to perform correctly with the maze in a constant position. Then the maze was rotated to a new position after every choice. For rats in the intramaze group, the food moved with the arms, making intramaze cues relevant. For rats in the extramaze group, the food remained on the platforms (in the same position in the room), making extramaze cues relevant. Rats in the extramaze group performed almost perfectly during maze rotation, demonstrating that intramaze cues were not necessary to support accurate choice behavior. Rats in the intramaze group never performed better than chance, demonstrating that intramaze cues (from the rats, the reinforcement, and the apparatus) were not adequate to control choice behavior. The results of the present experiment are compared to those of other experiments describing the influence of “odor trails” or other olfactory stimuli on choice behavior in mazes.
204 citations
TL;DR: In this article, a precise account of the relationship between the distribution of behavior and reinforcement rate on the standard concurrent schedule was given, and it was shown that matching and maximizing are different.
Abstract: The distribution of behavior between concurrently available schedules of reinforcement approximates the distribution of reinforcements between the schedules. This equality, called matching, has been explained as an instance of the principle that organisms maximize reinforcement rate. However, a precise account of the relationship between the distribution of behavior and reinforcement rate on the standard concurrent schedule shows that matching and maximizing are different.
165 citations
TL;DR: In this article, two experiments with rats tested independent predictions from cognitive theories of serial pattern learning and showed that learning rate and the qualitative response to the elements of the monotonie and non-monotonic patterns were independent of the value of the terminal element.
Abstract: Two experiments with rats tested independent predictions from cognitive theories of serial pattern learning. The animals learned to anticipate, as measured by running times in a straight alley, different quantities of food pellets organized into formally defined, five-element serial patterns. In Experiment 1, for some animals the patterns were all formally structured according to a monotonic “less than” relationship in which any quantity was always less than its predecessor. For others, no consistent formal rule was applied. Results of a transfer test with a new pattern showed positive transfer if the formal structure of the new pattern was identical to that used initially, but negative transfer if the new pattern was formally different. In Experiment 2, two groups learned the monotonic patterns 18-10-6-3-1 or 18-10-6-3-0 food pellets, while two others learned the nonmonotonic patterns 18-3-6-10-1 or 10-3-6-10-0 food pellets. We asked if the difference in value of the terminal element, 1 or 0 food pellets, would affect the facility with which the patterns were learned. The results showed that learning rate and the qualitative response to the elements of the monotonie and nonmonotonic patterns were independent of the value of the terminal element. Both experiments lend additional support to the utility of using cognitive models of human serial-pattern learning for an analysis of the sequential behavior of nonhuman animals.
151 citations
TL;DR: Hulse and Dorsky as mentioned in this paper found that rats were better able to track (run slowly to) 0 food pellets in a strongly monotonic (decreasing) serial pattern (14-7-3-1-0 food pellets) than in either a weakly-monotonic one (14.5-5-1/1/0) or a non-convex one(14-1,3,7-7/7/0), which was seen as inconsistent with associative approaches based on animal experiments.
Abstract: Hulse and Dorsky found that rats were better able to track (run slowly to) 0 food pellets in a strongly monotonic (decreasing) serial pattern (14-7-3-1-0 food pellets) than in either a weakly monotonic one (14-5-5-1-0) or a nonmonotonic one (14-1-3-7-0). These findings were seen as incompatible with associative approaches based on animal experiments. Instead, they were taken to be consistent with cognitive theories of human behavior that relate pattern difficulty to formally defined structural complexity. In Experiment 1, tracking was found to be poorer with a strongly monotonie series (15-10-5-0) than with either of two weakly monotonic series (15-15-0-0 or 14-14-2-0), and in Experiment 2 a nonmonotonic series (1-29-0) produced better tracking than a strongly monotonic one (20-10-0). Although these results are not necessarily incompatible with the structural complexity view, they do suggest that “element discriminability” is a factor in serial-pattern learning. They are, therefore, compatible with a memory approach that views tracking as a form of discrimination learning.
97 citations
TL;DR: In this paper, single paramecium caudatum were conditioned by pairing ac-generated electric shock (US) with a vibratory stimulus (CS) produced by an auditory speaker.
Abstract: SingleParamecium caudatum were conditioned by pairing ac-generated electric shock (US) with a vibratory stimulus (CS) produced by an auditory speaker. Naive paramecia subjected to shock reliably exhibited a backwards jerk and axial spinning similar to the avoiding reaction described by Jennings in 1904. Such responses did not occur initially to CS alone, but increasingly appeared during the CS period preceding shock pairing (delayed conditioning paradigm). Control subjects given the CS and UCS at the same intervals, but explicitly unpaired, did not show a sustained increase of responses to the CS alone. Short-term memory was demonstrated by subjects first conditioned and then presented CS alone during extinction. These subjects were readily reconditioned. Paramecia trained and stored for 24 h showed reliable memory savings as compared to stored control subjects. Other paramecia were differentially conditioned by training with two CSs. Following the recommendations of Rescorla (1967), a procedure was designed for truly random presentation of the CS and UCS as an additional control for pseudoconditioning. Single paramecia were conditioned with intervals between CSs randomly ranging from 8 to 32 sec. Control subjects received the same number of CSs and UCSs, which were administered independently and randomly during the same total session duration. Thus, CS and UCS were occasionally paired for control subjects. The responses to CS in the conditioned group were anticipatory conditional responses due to the pairing contingency and not wholly due to pseudoconditioning.
95 citations
TL;DR: This article found that the extinction of CER under the high alcohol dose was state dependent, that is, post-extinction tests after saline injection showed a reinstatement of suppression to the tone.
Abstract: A conditioned-emotional-response (CER) paradigm was used in two experiments to evaluate the effects of alcohol on extinction. In both experiments, rats received tone-shock pairings without alcohol and then received extinction trials either with or without alcohol (injections of saline, .75 or 1.5 g/kg ethanol). The high dose of alcohol suppressed baseline barpressing for food reward, but there was only weak evidence (Experiment 2) that it enhanced responding during the tone early in extinction. In both experiments, extinction of CER under the high alcohol dose was found to be state dependent, that is, post-extinction tests after saline injection showed a reinstatement of suppression to the tone. Experiment 2 indicated that this effect could be attributed to alcohol’s becoming a conditioned inhibitory stimulus as a result of its association with extinction. This supports the general suggestion that situational stimuli normally become inhibitory during the course of simple extinction and may have implications for the role that state-dependent learning plays in drug dependence.
88 citations
TL;DR: In two experiments, saccharin (CS) and lithium chloride (US) were paired in a context consisting of specific visual, auditory, tactual, and olfactory cues, indicating an important role played by the exteroceptive context in taste-aversion conditioning.
Abstract: In two experiments, saccharin (CS) and lithium chloride (US) were paired in a context consisting of specific visual, auditory, tactual, and olfactory cues. The saccharin aversion was then extinguished in a context free from conditioning-context cues. Later, saccharin preference tests were given in the presence and absence of these cues. The results indicated that the background cues of the conditioning trial controlled the amount of saccharin drunk on extinction trials, and, furthermore, that extinction of the taste aversion was context specific; i.e., groups given extinction trials in a different (from conditioning) context retained their saccharin aversion in the conditioning context only. The results indicate an important role played by the exteroceptive context in taste-aversion conditioning.
83 citations
TL;DR: A sex difference in both the degree and the form of affiliative behavior of rats was revealed, in general, males were more affiliative and more responsive to a second animal.
Abstract: Three experiments were conducted to investigate the influence of rearing and housing manipulations on the affiliative behavior of male and female rats. Animals were tested in same-sex pairs in an open field for time spent in contact and for socially facilitated activity. The results revealed a sex difference in both the degree and the form of affiliative behavior of rats. In general, males were more affiliative and more responsive to a second animal. Males engaged in more rough-and-tumble play, whereas females spent more time in social grooming. Housing conditions of adult animals and rearing conditions were found to influence the degree to which males engaged in male-like affiliative behaviors and females engaged in female-like affiliative behaviors. Social behavior appears to be a function of the interaction between the affiliative repertoire of the animals involved, the nature of the social stimulus, and the features of the environment.
78 citations
TL;DR: Rats shocked once by a stationary, wire-wrapped prod incorporated sand, wooden blocks, or commercial bedding material on the floor of the chamber into a defensive response, adapting the response topography to the particular demands of the available material.
Abstract: Rats shocked once by a stationary, wire-wrapped prod mounted on the wall of the test chamber incorporated sand, wooden blocks, or commercial bedding material on the floor of the chamber into a defensive response. They moved the available material toward and over the shock prod in all three conditions, adapting the response topography to the particular demands of the available material. In the sand and bedding conditions, the rats buried the prod by pushing and spraying piles of the material with snout and forepaws, whereas, in the blocks condition they picked up the blocks with their teeth and placed them individually around the prod. In Experiment 2, the rats buried the shock prod with blocks even when they had to first carry the blocks to the prod from the back of the chamber. Thus, conditioned defensive burying is not a simple, reflexive response to objects paired with a painful stimulus: it is a complex behavioral sequence that can vary as a function of the availability of burying materials.
67 citations
TL;DR: The results suggested that Pavlovian conditioned responding may involve two independent types of behavior—one appropriate to the US and another based on the original OR to the CS.
Abstract: The form of rats’ Pavlovian conditioned responses to visual and auditory conditioned stimuli (CSs) paired with a variety of unconditioned stimuli (USs) was examined in three experiments using direct behavioral observation techniques. In Experiment 1, the form of conditioned behavior occurring most frequently during later portions of the CS-US interval depended only on which of several appetitive USs was used, but the form of behavior occurring most frequently during early portions of the CS-US interval depended only on the nature of the CS. US-dependent behaviors resembled the response to the US, and CS-dependent behaviors resembled the original orienting response (OR) to the CS. In Experiment 2, the use of larger magnitude appetitive USs resulted in higher frequencies of US-dependent behaviors, but lower frequencies of CS-dependent behaviors in the presence of auditory and visual CSs. In Experiment 3, US-dependent conditioned behavior to auditory and visual CSs paired with shock was more frequent when high-intensity shocks were used, but CS-dependent behavior was more frequent when low-intensity shocks were used. These results suggested that Pavlovian conditioned responding may involve two independent types of behavior—one appropriate to the US and another based on the original OR to the CS.
TL;DR: The present findings of sex differences and deprivation effects were presented as examples of state-generated behavioral fields and provided evidence for the response-selection function rather than the energizing function of food deprivation.
Abstract: Male and female rats under different levels of food deprivation were observed in an enclosed chamber equipped with several manipulanda. Dependent variables included: time spent in immobility, grooming, exploration, and different types of manipulation (e.g., sand-digging); sequential dependencies between different kinds of behaviors; and ultrasonic activity counts. Results showed that deprivation generally increased exploration and manipulation and decreased immobility. Deprivation also increased the variability of bout lengths but had little effect on sequential dependencies or activity counts. These results provide evidence for the response-selection function rather than the energizing function of food deprivation. Various sex-related factors appearing in the data were also described. The present findings of sex differences and deprivation effects were presented as examples of state-generated behavioral fields.
TL;DR: In this paper, two-way avoidance trials were administered with either.3- or 1.6-mA shock and with either small or large reward (presence or absence of visual stimuli following the response).
Abstract: In Experiment 1, four groups of subjects (n = 16 each) were exposed to the situational stimuli of a shuttlebox apparatus for 4 h. Subsequently, 200 two-way avoidance trials were administered (100/day) with either .3- or 1.6-mA shock and with either small or large reward (presence or absence of visual stimuli following the response). Avoidance performance was directly related to shock intensity on both days and to magnitude of reward on the 2nd day. In Experiment 2, four groups of subjects (n = 24 each) were given 4 h of exposure either to the situational stimuli of the shuttlebox or to a neutral box. Then, 10 two-way avoidance trials were given with 1.6-mA shock. Subsequently, subjects were allowed to escape from one of the shuttlebox compartments to an adjacent safe box. Following preexposure to situational stimuli, avoidance performance was superior whereas escape-from-fear performance was inferior. This latter finding demonstrated that less fear of situational cues was present during avoidance training in the preexposed condition. All of these results support the effective reinforcement theory, an extension of two-factor theory, which emphasizes the importance for avoidance learning of the amount of fear of situational cues present following a response.
TL;DR: In an experiment designed to demonstrate the overshadowing of appetitive instrumental conditioning, three groups of rats were given 10 sessions of RI (random interval) training in which reinforcement was delivered 450 msec following the response, and subjects in the two control conditions increased their rate of responding significantly faster than Subjects in the correlated condition in both replications.
Abstract: In an experiment designed to demonstrate the overshadowing of appetitive instrumental conditioning, three groups of rats were given 10 sessions of RI (random interval) training in which reinforcement was delivered 450 msec following the response. The correlated group experienced a stimulus during the response-reinforcer delay interval, while an uncorrelated control group experienced a similar brief stimulus occasionally following responses, but these were not responses that typically produced reinforcement. A no-stimulus control group did not experience the brief response-produced stimulus. The experiment was run in two replications. The first employed a light as the critical stimulus, the second a tone. Over the 10 RI sessions, subjects in the two control conditions increased their rate of responding significantly faster than subjects in the correlated condition in both replications. This finding was interpreted as an instance of the overshadowing of the acquisition of signal value by a response because of the presence of the stimulus, which, in the correlated condition, was a more reliable predictor of reinforcement than the response. A subsequent conditioned reinforcement test confirmed that, in the correlated condition, the stimulus had, indeed, become a signal for reinforcement as a function of RI training.
TL;DR: Pigeons performed a delayed matching-to-sample task in which they matched red and green disks as comparison stimuli to samples of food and no food as discussed by the authors, and found that matching to surprising samples was more accurate than matching to expected samples.
Abstract: Pigeons performed a delayed matching-to-sample task in which they matched red and green disks as comparison stimuli to samples of food and no food. The birds were also taught a discrimination between two lines: vertical (S+) followed by food and horizontal (S−) followed by no food. The two kinds of trials were then chained in infrequent probes such that (a) S+ and S− preceded samples of food and no food, (b) a longer than usual delay occurred, and then, (c) the comparison stimuli were presented. Therefore, in probes when S+ preceded food and S− preceded no food, the samples were “expected. ” But in probes when S+ signaled no food and S− signaled food, the samples were “surprising. ” Matching to surprising samples was more accurate than matching to expected samples. This result completes a pattern of findings implying that surprising reinforcers enhance learning and also persist (are longer rehearsed) in short-term memory.
TL;DR: In the course of imprinting, chicks were regularly tested by brief exposure to a novel stimulus in successive choice tests, and their approach towards the novel stimulus relative to their approach to the familiar was used as a measure of preference.
Abstract: In the course of imprinting, chicks were regularly tested by brief exposure to a novel stimulus in successive choice tests. Their approach towards the novel stimulus relative to their approach towards the familiar was used as a measure of preference. The repeated tests with the novel stimulus were started at four different times after the beginning of imprinting: 21, 43, 65, and 87 min. The first test of each group showed the longer that chicks had been imprinted beforehand, the greater the preference for the familiar. However, chicks trained for 21 min before testing were influenced by the first test and continued to show a preference for the more novel stimulus throughout subsequent testing. By contrast, the other three groups showed a stable preference for the familiar stimulus.
TL;DR: The authors showed that simple exposure to the box reduced the vigor of instrumental performance in comparison with a condition in which food was made available during the exposure phase, while animals which received no exposure treatment also showed a relatively high rate of response.
Abstract: In each of two experiments, rats were trained to press the lever in a Skinner box, food reinforcement being available on a variable-interval 60-sec schedule (VI 60). There followed an “exposure phase” for which the levers were removed from the boxes, and then a final test with the levers replaced to assess the effects of the intervening treatment on instrumental responding. Experiment 1 showed that simple exposure to the box reduced the vigor of instrumental performance in comparison with a condition in which food was made available during the exposure phase. Animals which received no exposure treatment also showed a relatively high rate of response. Experiment 2 demonstrated that an exposure treatment in which the occurrence of food is signaled by a light stimulus also leads to a decline in instrumental responding. These results are held to support the notion that associations between the context and the reinforcer serve to energize appetitive instrumental behavior.
TL;DR: A clear and consistent preference emerged for the differentiated condition, i.e., for information about shock duration, and the relevance of this finding for theories which attempt to account for the preference-for-signaled-shock phenomenon was discussed.
Abstract: Rats were permitted to control, by means of a changeover response, the amount of time spent in either a “differentiated” or an “undifferentiated” condition. Shock occurred in both conditions on the same variable-time schedule, half of the shocks being short (.75 sec) in duration, the other half, long (5 sec). In the differentiated (informative) condition, all short shocks were preceded by one signal and all long shocks were preceded by a discriminatively different signal. No information about shock duration was available in the undifferentiated condition, as the same signal preceded short and long shocks. A clear and consistent preference emerged for the differentiated condition, i.e., for information about shock duration. The relevance of this finding for theories which attempt to account for the preference-for-signaled-shock phenomenon was discussed.
TL;DR: Of the three algebraic models used to predict noncontingent effects, the substitution model was most promising, but still not adequate, and the procedure of a between-subjects yoked control was also not effective.
Abstract: Separation of the contingent and noncontingent effects of a schedule on amount of instrumental responding is desirable but difficult in schedules that involve instrumental and contingent responses that are either highly probable or very similar. Three studies in which rats were required to lick a solution of .1% saccharin for access to a preferred solution of .4% saccharin showed that neither single nor paired operant baselines of the instrumental response allowed accurate separation of the contingent and noncontingent effects of a fixed-ratio schedule. Two within-subject yoking procedures provided the best baselines of noncontingent effects: the massed baseline measured amount of .1% licking when each subject received free access to the total amount of .4% licking it obtained at asymptote under the schedule; the matched baseline measured .1% licking when each subject received the same access to the .4% solution, but presented in the intermittent pattern obtained during the schedule. Of the three algebraic models used to predict noncontingent effects, the substitution model was most promising, but still not adequate. The procedure of a between-subjects yoked control was also not effective.
TL;DR: The results contradicted the hypothesis that reinforcement is produced by an overall or momentary probability differential between two responses and supported the condition of response deprivation as a key determinant of reinforcement.
Abstract: Rats increased eating that produced access to a running-wheel or increased running that produced access to food, depending on which response was potentially deprived, relative to baseline, by the scheduled ratio of responding. Under both schedules, instrumental responding significantly exceeded appropriate baselines of the noncontingent effects of the schedule. The results contradicted the hypothesis that reinforcement is produced by an overall or momentary probability differential between two responses; instead, they supported the condition of response deprivation as a key determinant of reinforcement. Of several recent quantitative models that predict reversibility of reinforcement by schedule changes, only the predictions of the relative response-deprivation model did not differ significantly from the data of either schedule.
TL;DR: Investigation of the retention of an attribute of a tonal CS that had been paired with shock and was thus capable of eliciting a conditioned emotional response (CER) in rats suggested that memory for specific attributes of the CS does diminish as a function of time.
Abstract: Although a number of studies have demonstrated nearly complete retention of fear in a conditioned suppression task, they provide little information about the nature of the memory for the CS. The purpose of the present experiment was to investigate the retention of an attribute of a tonal CS that had been paired with shock and was thus capable of eliciting a conditioned emotional response (CER) in rats. The Kamin blocking effect was utilized to detect changes in the memory of CS attributes. Either 1 or 21 days following conditioning to a tone, separate groups of rats received compound conditioning in which either the original or a novel tone was combined with a light. Subsequent measurement of suppression to the added element (light) indicated that only the original CS produced blocking at the short delay, but that both original and novel tones resulted in blocking at the 21-day interval. This increase in the extent of blocking suggests that memory for specific attributes of the CS does diminish as a function of time.
TL;DR: It is suggested that flight reactions are components of a rat’s defensive repertoire that appear very rapidly between 10 and 15 days of age.
Abstract: Ten- and 15-day-old rat pups were trained with two procedures to approach an anesthetized mother, and then were punished for approaching. Both ages of subjects exhibited increased latencies to reapproach the mother, indicating passive inhibitions, but only the older pups retreated. All but one of the younger pups eventually reached the mother within 3 min after the punishment, while only half of the older pups did so. In a second experiment examining the development of locomotor avoidance reactions, 5- to 20-day-old rats were shocked without the mother present. Fifteen- and 20-day-old rats significantly decreased their activity patterns in reaction to shock and spent significantly less time in the shock area than either of the younger aged pups. These results suggest that flight reactions are components of a rat’s defensive repertoire that appear very rapidly between 10 and 15 days of age.
TL;DR: The remarkably robust character of the proximal US-preexposure phenomenon is demonstrated, where the subjects are exposed to the unconditioned stimulus shortly before the conditioning trial but not if this single US preexposure treatment occurs 1 day or more before conditioning.
Abstract: Taste-aversion learning in rats is disrupted if the subjects are exposed to the unconditioned stimulus (US) shortly before the conditioning trial but not if this single US preexposure treatment occurs 1 day or more before conditioning. Several characteristics of this proximal US-preexposure phenomenon were explored. Experiment 1 showed that the time course of the interference with conditioning is directly related to the preexposure drug dose. Experiment 2 demonstrated that the interference effect is evident even if the test for aversion learning is conducted following a drug injection, thereby minimizing stimulus generalization decrement for the preexposed subjects. Finally, Experiment 3 showed that disruption of the contingent relationship between tastes and drug effects is probably not responsible for the proximal US-preexposure phenomenon because the interference with conditioning occurs regardless of whether or not the preexposure drug treatment is paired with a novel flavor. These findings, together with previous research, demonstrate the remarkably robust character of the proximal US-preexposure phenomenon.
TL;DR: It was suggested that schedule-induced polydipsia is insensitive to conditioned taste aversions and this conclusion was discussed in terms of schedule- induced alcohol consumption and its potential as an animal model of alcoholism.
Abstract: Conditioned taste aversions produced a moderate, but transient, suppression of schedule-induced polydipsia. This suppression was greater and longer lasting when rats were offered a choice between water and the previously poisoned solution on the polydipsia baseline. A final experiment demonstrated that taste aversions were more effective in suppressing schedule-induced consumption when superimposed on a developing schedule-induced drinking baseline as opposed to a stable pattern of schedule-induced drinking. It was suggested that schedule-induced polydipsia is insensitive to conditioned taste aversions. This conclusion was discussed in terms of schedule-induced alcohol consumption and its potential as an animal model of alcoholism.
TL;DR: In this paper, four groups of pigeons were exposed to an autoshaping procedure in which a 20sec key illumination preceded the presentation of response-independent grain, the groups differed according to the duration of feeder access and the intertriai intervals, if feeder durations are not included in the time between trials, two of the groups had identical inter triai intervals.
Abstract: Four groups of pigeons were exposed to an autoshaping procedure in which a 20-sec key illumination preceded the presentation of response-independent grain, The groups differed according to the duration of feeder access and the intertriai intervals, If feeder durations are not included in the time between trials, two of the groups had identical intertriai intervals. If feeder durations are included, each of the other two groups was identical to one of the first two in terms of the intertriai interval, The speed of acquisition and maintained measures of responding were directly related to the duration of the interval from food offset to signal onset, Groups exposed to equivalent intertriai intervals and different feeder durations did not differ from one another on these measures, The results were interpreted as evidence that feeder durations were not included in the functional intertrial interval and that feeder duration, per se, did not affect autoshaped responding.
TL;DR: The habituation of locomotor activity across repeated exposures to a novel maze was studied in a series of experiments using rats as subjects and the results were discussed in terms of theories of “priming” and encoding variability.
Abstract: The habituation of locomotor activity across repeated exposures to a novel maze was studied in a series of experiments using rats as subjects. Habituation, defined as a decrease in ambulation, was greater on a second trial occurring 5 min after a first trial than on one occurring 60 min after. This short-term decrement occurred only when the same maze was used on both trials, and could be dishabituated by intertriai detention in another novel environment. On a delayed test trial, habituation was, in one case, somewhat greater following initial spaced trials, and in another condition, comparable following both massed and spaced trials. The longer term habituation was maze specific, but was not affected by the presence of a dishabituator following either or both of the first two trials. The results were discussed in terms of theories of “priming” and encoding variability.
TL;DR: In this paper, the authors show that the degree of accustomed effort per reinforcer becomes a generalized component of instrumental behavior, and high effort increases the habituation of frustration-produced disruptive responses.
Abstract: Rats barpressed for food on a variable-interval schedule and then received food in a runway for one of three degrees of effort. Finally, all animals again barpressed for food. Requiring five runway shuttles per food pellet produced a greater subsequent rate of barpressing than reward for each shuttle, which, in turn, yielded more barpressing than free food. A follow-up study showed the five-shuttle treatment to produce more subsequent barpressing than a control condition which omitted any runway treatment. Another experiment indicated that the higher rate of barpressing following the five-shuttle treatment was not due to greater conditioned general activity, since the five-shuttle treatment failed to increase the number of grid crossings to the cue of food presentation and produced no more unconditioned barpressing than following free food in the runway. Two possible interpretations of the results were compared: (1) The degree of accustomed effort per reinforcer becomes a generalized component of instrumental behavior, (2) high effort increases the habituation of frustration-produced disruptive responses.
TL;DR: Results support the view that an associative (taste-nausea) component is superimposed on a neophobic avoidance of the novel taste stimulus, and raise doubts about the use of absolute saccharin intake as a measure of taste-aversion learning.
Abstract: Data from 36 groups of rats from a total of 12 taste-aversion (saccharin+lithium chloride) experiments were analyzed for (1) individual differences of absolute saccharin (sacc) intake on the first (conditioning) and second (test) presentations, and (2) the correlation between intakes on the two presentations. Large individual differences and strong positive correlations were found for sacc+LiCl, sacc+NaCl, sacc−LiCl unpaired, and “different context” conditions. In addition to raising doubts about the use of absolute saccharin intake as a measure of taste-aversion learning, these results support the view that an associative (taste-nausea) component is superimposed on a neophobic avoidance of the novel taste stimulus.
TL;DR: Feature-positive and feature-negative successive discrimination learning was investigated in the rat, finding that FP rats developed a tendency to direct their responding toward the differentiating feature in S+ while FN rats shifted their responding away from this element in S−.
Abstract: Feature-positive (FP) and feature-negative (FN) successive discrimination learning was investigated in the rat. When a discrete, visual element serving to differentiate the discriminanda belonged to S+ (FP), rats acquired the discrimination more rapidly than when it formed a part of S− (FN). During the course of training, FP rats developed a tendency to direct their responding toward the differentiating feature in S+ while FN rats shifted their responding away from this element in S−. These findings were discussed in terms of the conceptions of stimulus-reinforcer relations and “sign-tracking” behavior.