Massed and spaced training build up different components of long-term habituation in the crabChasmagnathus

The crabChasmagnathus granulatus reacts to a shadow passing overhead with an escape response that habituates after 30 trials and for 5 days at least. The effect of a wide range of different intertrial intervals (ITIs) (0, 9, 27, 45, 81, 135, and 171 sec) on theChasmagnathus long-term habituation (LTH) was evaluated at 24 h. Memory retention was estimated separately at two phases of a six-trial testing session: at first trial (the initial testing phase) and at the subsequent block of five trials (the retraining phase). A training of 30 trials with an ITI equal to or longer than 27 sec induced LTH at both testing phases, however, with a 0- or a 9-sec ITI, training wholly failed to build up LTH. When the number of trials was increased, a massed training (ITI=0 or 9 sec) induced LTH at retraining but not at initial testing. Thus, massed training produces LTH only at retraining, whereas spaced training (ITI ≥ 27 sec) produces LTH at both initial phase and retraining. An ITI shift from training to testing diminished or abolished retention at retraining regardless of the direction of the shift, thus suggesting that crabs acquire a memory of the trial-spacing at training. According to these results, it is postulated that LTH consists of two memory components: one produced by spaced training and expressed at both initial testing and retraining, and one yielded by massed training and expressed only at retraining. The possibility that the two components of LTH were differentially affected by cycloxemide and context shift is discussed.     

Long-term habituation is produced by distributed training at long ISIs and not by massed training or short ISIs inCaenorhabditis elegans

To begin an investigation of the cellular processes that underlie long-term memory in the nematodeCaenorhabditis elegans, it is first necessary to determine thatC. elegans is capable of retention over 24 h, and to investigate the factors that may influence the expression of long-term memory. In the present study, the effects of stimuli number, interstimulus interval (ISI), and training procedure on long-term retention of habituation were tested inC. elegans. At a long (60-sec) ISI, distributed training sessions produced long-term habituation retained for 24 h, whereas massed training sessions or training with few stimuli did not. When training was performed at a short (10-sec) ISI, long-term habituation was not detectable with testing at either a 10- or a 60-sec ISI. The long-term habituation observed after distributed training sessions at a 60-sec ISI was consistently expressed when the training procedures were varied. Thus it is clear thatC. elegans can reliably express long-term retention for distributed training sessions at a 60-sec ISI, making the system a candidate for further investigations into the cellular processes supporting memory.     

The dual role of the context in postpeak performance decrements resulting from extended training

The context??s role in Pavlovian conditioning depends on the trial spacing during training, with massed trials revealing a function akin to that of discrete stimuli, and spaced trials revealing a modulatory function (Urcelay & Miller, Journal of Experimental Psychology. Animal Behavior Processes, 36, 268?C280, 2010). Here we examined the contextual determinants of a common but largely ignored effect: attenuated conditioned responding with extended reinforced training (i.e., a postpeak performance deficit [PPD]). Contextual sources of PPDs were investigated in four fear-conditioning experiments with rats. In Experiment 1, as the number of reinforced trials increased, conditioned responding decreased, even when testing occurred outside the training context. Experiment 2 revealed opposing influences of context on the PPD based on trial spacing, which interacted with whether testing occurred in the training context. This finding reconciles Experiment 1??s results with previous data (Bouton, Frohardt, Sunsay, Waddell, & Morris, Journal of Experimental Psychology. Animal Behavior Processes, 34, 223?C236, 2008). Experiment 3 suggested that extended training with these parameters did not lead to habituation to conditioned or unconditioned stimuli. In Experiment 4, few or many massed training trials were followed orthogonally by context extinction or no context extinction. After many pairings, context extinction reduced the PPD (i.e., enhanced responding), suggesting a competitive role of the context. These results, together with prior data suggesting that context modulates expressions of the PPD, are consistent with the view that contexts can play two distinctly different roles.     

Effect of number of trials,interstimulus interval,and dishabituation during CS habituation on subsequent conditioning in a CER paradigm

Three experiments were conducted to investigate the influence of variables during habituation of a CS on a subsequent conditioning to that CS in a conditioned emotional response paradigm. Experiment I varied the number of habituation trials received before conditioning, and it was found that additional habituation trials resulted in a further attenuation of conditioning. Experiment II varied the interstimulus interval of the habituating stimulus, and it was found that the longer intervals produced the greater attenuation in conditioning. Experiment III examined the effect of interpolating another stimulus between habituation and conditioning (dishabituation), and it was found that the dishabituating stimulus augmented subsequent conditioning. It was concluded that manipulations during habituation training that produce the greatest decrement in response to a stimulus, when assessed under equivalent conditions for all animals, have the greatest attenuating effect on subsequent conditioning to that stimulus.     

Habituation and recovery of orienting in rats as a function of stimulus significance

Three experiments measured orienting of rats to stimuli varying in intrinsic significance. In the first, rats showed greater reactivity to a recording of a conspecific’s distress squeal than to a simulated mimic squeal when the stimuli were presented at 100 dB but not at 80 dB, and orienting to all stimuli habituated rapidly with repeated stimulus exposures. Experiment 2 showed that, following several stimulus exposures, recovery of orienting after rest periods of 1 and 7 days was a function of the stimulus: Orienting to the distress squeal presented at 100 dB recovered more rapidly than did orienting to the mimic squeal at 100 dB or to either the mimic or the distress squeal presented at 80 dB. Experiment 3 showed that habituation to the most significant stimulus, the distress squeal presented at 100 dB, was retarded at long (24-h) interstimulus intervals, presumably a consequence of less stimulus-to-stimulus transfer of habituation with this stimulus. The results are discussed in terms of biological constraints on habituation of orienting and on recovery of orienting following habituation.     

Persistent effect of noise on the acoustic startle reflex in the rat

Continuous noise facilitates acoustic startle reflexes in the rat. Rats were exposed to noise for 23 h (Experiment 1) or to 23 h of startle eliciting stimuli at the rate of 1/min (Experiment 2). Facilitation was reduced following habituation in Experiment 2, but was unaffected by prolonged noise exposure in Experiment 1. Reflex inhibition produced by a brief noise was not altered by habituation. Prior experiments show that increases in intensity of continuous noise engage two disparate processes which affect the acoustic startle reflex, one facilitatory (arousal) and one inhibitory (masking). The present data reveal that arousal is not diminished by prolonged noise exposure. The loss of facilitation following reflex habituation may be attributed to its increased susceptibility to masking, or to a direct effect of stimulus repetition on the arousal process normally associated with the noise background.     

Differential effects of several retrieval cues over time: Evidence for time-dependent reorganization of memory

The retention performance following partial training (15 trials) of a brightness-discrimination avoidance task has been shown to fluctuate over time, with a drop in performance 1 h after training (Kamin effect), a long-term spontaneous improvement (LTSI) after 3 days, and long-term spontaneous forgetting after 21 days. The purpose of this paper was to determine if these time-dependent modulations of retention performance reflect time-dependent modifications in the organization of the attributes that constitute the memory trace. We studied the relative effectiveness of several pretest cuings on retention performance when they were delivered just before a retention test occurring 1 h, 3 days, or 21 days following initial training. Some cuing treatments were related to a particular training event (conditioned or unconditioned stimulus, experimental context). Compound cuings, composed of two or more training events, were also studied to test a possible additive effect between retrieval cues. To demonstrate time-dependent modifications in the memory trace, a differential effectiveness over time was expected for at least some retrieval cues. The results show that cuing may compensate for performance deficits (1 h or 21 days), but does not further enhance performance when spontaneously improved (3 days). No detectable additive effects of retrieval cues were obtained. However, these results provide information that suggests a time-dependent effectiveness for some cuing treatments. In the last experiment, we investigated this possibility by studying the effects of each of these treatments when delivered after either a 1-h or a 21-day retention interval. The results confirm a time-dependent decrease in effectiveness of a pretest exposure to the CS and an increase in effectiveness over time of a pretest exposure to the experimental context or to a well-ordered sequence of events. Such differential retrievability of a partially learned episode according to both the nature of the cues and the length of the retention interval suggests a time-dependent reorganization of memory attributes.     

Renewal of Pavlovian conditioned inhibition

Prior research has demonstrated renewal, which is the ability of contextual cues to modulate excitatory responding to a Pavlovian conditioned stimulus (CS). In the present research, conditioned lick suppression in rats was used to examine similar contextual modulation of Pavlovian conditioned inhibition. After Pavlovian conditioned inhibition training with a CS in one context, subjects were exposed to pairings of the CS with an unconditioned stimulus (US) either in the same or in a second context. Results indicated that, when the CS was paired with the US in the second context, the CS retained its inhibitory control over behavior, provided that testing occurred in the context used for inhibition training. However, when the CS-US pairings occurred in the inhibition training context, the CS subsequently proved to be excitatory regardless of where testing occurred. These observations indicate that conditioned inhibition is subject to renewal.     

Effects of tactile stimulation on the initiation and maintenance of the following response in Japanese quail (Coturnix coturnix japonica)

Effects of tactile contact with an imprinting stimulus object on the initiation and maintenance of the following response in neonatal Japanese quail,Coturnix coturnix japonica, were examined. Tactile contact with an imprinting stimulus object was permitted during a preexposure period and/or during a following test. Results indicated that following was stronger when tactile contact was permitted during either the preexposure or test periods than when such contact was not given. Following occurred sooner when contact was permitted during the preexposure period than during following only, or when no contact was permitted. The greatest strength of following occurred when tactile stimulation was permitted during both preexposure and testing periods. It was concluded that the results support the hypothesis that tactile stimulation can facilitate both the initiation and maintenance of following behavior, and this is interpreted as being consistent with Schneirla’s (1965) theory.     

Cross-modality contrast: Exteroceptive context habituation enhances taste neophobia and conditioned taste aversions

The relationship between absolute and relative stimulus novelty was examined within the context of the conditioned taste aversion paradigm in which the relative novelty of the conditioned interoceptive stimulus was manipulated by differential exteroceptive context habituation. Rats received similar isolation histories but either 5 or 30 days of habituation to the test environment prior to treatment. One group was administered lithium chloride following saccharin consumption, a second group was administered isotonic saline following saccharin consumption, and a third group was administered saline after water consumption. The animals habituated for 30 days exhibited greater conditioned avoidance and greater neophobic avoidance of saccharin than did animals habituated for only 5 days. The results are interpreted in terms of a cross-modality stimulus contrast effect which implicates context habituation as an important parameter of both taste neophobia and taste aversion learning.     

Chemosensory-based contextual conditioning inHermissenda crassicornis

In two experiments, the marine molluskHermissenda crassicornis was exposed to context discrimination training. In one context, defined by the presence of a diffuse chemosensory stimulus (shellfish extract A), brief, unsignaled, unconditioned stimuli (USs; high-speed rotation) were presented; in a second context, defined by the presence of shellfish extract B, no USs were presented. Animals were then tested (at both 1.5 and 24 h) by exposing them to small pieces of the shellfish meat used to define the two contexts. The latency to strike at the meat served as an index of the context-US association. In Experiment 1, the latency to strike at the cue associated with rotation was reduced relative to both preconditioning strike latencies and the associatively neutral cue. However, in a two-choice test where the animals could approach the conditioned or neutral stimulus, the animals regularly avoided the stimulus paired with rotation. Moreover, if, following conditioning, the animals were presented with an unsignaled rotation in the conditioned context or the neutral context, the animals exhibited more effective defensive clinging (an unconditioned reflex normally elicited by rotation) in the conditioned context, suggesting that it “prepared” the animal for the aversive US. In total, these results demonstrate thatHermissenda is capable of making associations to diffuse background (contextual) stimuli. Moreover, the results suggest that pairing the chemosensory cue with an aversive US elicits a strike response inHermissenda when the animal is placed in forced contact with the cue and an active avoidance response when the animal can choose between that cue and a neutral cue.     

Latent habituation of the orienting response in the preweanling rat

The effect of inhibiting the orienting response on information processing was examined in four experiments. A nonsignal auditory stimulus was presented four times to preweanhng rats either 30 sec or 15 min after they had been placed in an unfamiliar environment (Experiments 1A and 2), shocked (Experiment 1B)5 or experienced a shift in environmental context (Experiment 1C). Both an autonomic (heart rate) and a behavioral componentx of the orienting response to the novel stimulus were recorded. In the 15-min condition, the auditory stimulus elicited a consistent orienting response on the first trial that habituated rapidly with successive trials. In contrast, the auditory stimulus did not elicit a detectable orienting response in the 30-sec condition on any of the four trials. However, when the auditory stimulus was re-presented after a brief retention interval, a comparable level of habituation was seen in both groups. These results demonstrate that animals in the 30-sec condition detected, attended to, and encoded the auditory stimulus even though they did not orient, either autonomically or behaviorally, to that stimulus when it was first presented. This process of response-independent habituation is best described as latent habituation. Like latent learning, latent habituation took place in the absence of any observable change in behavior. The implications of this effect for current theories of habituation and of the orienting response are discussed.     

The effect of nonreinforced stimulus exposure on the strength of a conditioned taste aversion as a function of retention interval: Do latent inhibition and extinction involve a shared process?

Two experiments examined the effects of nonreinforced flavor exposure on the strength of a conditioned taste aversion. Rats were conditioned by pairing maple flavor with LiC1. Prior to or subsequent to this pairing, some animals received nonreinforced exposure to either maple or saccharin. In separate subjects, preference for maple was tested 1 or 21 days after the last training episode. In the first experiment, the nonreinforced stimulus exposure occurred before conditioning (latent inhibition, or LI, procedure); in the second experiment, the nonreinforced exposure occurred after conditioning (extinction, or EXT, training). In both experiments, nonreinforced exposure to maple or saccharin reduced the magnitude of a conditioned maple aversion when testing occurred soon after conditioning. When testing was delayed, however, the attenuation due to nonreinforced saccharin exposure dissipated, both with the LI procedure and with EXT. In contrast, the nonreinforced exposure to maple was found to attenuate conditioned reactions at both short and long retention intervals. The release from generalized LI and spontaneous recovery following generalized EXT training are discussed in terms of retrieval processing. The possibility that the same mechanism may underlie LI and EXT is considered.     

A Pavlovian analysis of food-attraction conditioning in the snailHelix aspersa

Following brief pairing of an odor with a feeding experience (food-attraction conditioning), snails will lower their tentacles when subsequently presented with that odor alone. Three experiments investigated the possible behavioral mechanism mediating food-attraction conditioning in the snailHelix aspersa. It is suggested that food-attraction conditioning is an example of Pavlovian conditioning. In this case, the odor (conditioned stimulus) is paired with oral stimulation (unconditioned stimulus), which elicits lowering of the tentacles (unconditioned response). Following conditioning, the odor comes to elicit lowering of the tentacles (conditioned response). Experiment 1 ruled out nonassociative effects, such as habituation and sensitization, using an unpaired control group. Experiment 2 provided further evidence against a role for habituation of neophobia, through the demonstration of extinction following conditioning. In Experiment 3, an omission procedure was used to rule out the possible role of instrumental contingencies.     

Examining the Effects of Problem‐solving Training on the Acquisition of Interpersonal Problem‐solving Skills by 5‐Year‐old Children in Turkey

This study was designed and carried out to examine the effect of problem‐solving training on the acquisition of interpersonal problem‐solving skills by 5 year‐old children. The subjects consisted of 74 5 year‐olds (34 girls and 40 boys) attending a kindergarten in Ankara, Turkey. Of these children 38 were assigned to the experimental group and 36 to the control group. The procedure consisted of pre‐testing, training and post‐testing activities. The training phase involved a programme of activities that required working with children for a certain period of time every day for 14 weeks. In the statistical analysis of the data collected ‘Chi‐Square (x²) test for significance’ was used for the evaluation of the differences between the experimental and control groups. The results were also evaluated on the basis of ‘the significance test for the difference between two means’. This was used to study the relationship between variables. The results showed that problem‐solving training was effective in helping 5 year‐old kindergarten children acquire interpersonal problem‐solving skills.     

Poetry education research as an anchorage of thought: using poetry as interview stimulus material

Interviews in qualitative research may sometimes employ stimulus material as a means of eliciting richer data. However, scant consideration has been given to the use of poetry for this purpose, especially within the field of poetry education research. This article seeks to address the gap in the literature by illustrating how the use of poetry as interview stimulus material can help poetry education research to clarify the connection between teachers’ and students’ beliefs and practices in relation to poetry and pedagogy. Depending on the nature of their inquiry and context, poetry education researchers can choose relevant poems that have the potential to stimulate a discussion about specific beliefs and practices.     

Stimulus preexposure speeds or slows subsequent acquisition of associative learning depending on learning test procedures and response measure

Prior exposure to a conditioned stimulus (CS) typically results in latent inhibition—slower acquisition of associative learning about that stimulus in subsequent training. Here, we found that CS preexposure had different effects on the appetitive conditioning of rats with a sucrose unconditioned stimulus (US) depending on training test procedures, the similarity of preexposure and training procedures, and the choice of response measure. Preexposure to a visual or an auditory stimulus produced facilitation of acquisition of food-cup-directed responding when both of those cues were (separately) paired with sucrose delivery in the training test (Experiments 1 and 3). By contrast, the same preexposure procedure resulted in latent inhibition of food-cup learning if the second stimulus in the test phase was of the same modality as the preexposed stimulus (Experiment 2). In Experiment 3, latent inhibition was enhanced if both phases included a single CS or both phases included both auditory and visual CSs, compared to treatments in which only one CS was presented in one phase but two CSs were presented in the other phase. In Experiment 4, preexposure of an auditory cue slowed subsequent learning about it if the context was salient but enhanced learning if the context was of weaker salience. Finally, a measure of general activity revealed latent inhibition after preexposure in all conditions in all 4 experiments. We discuss the results within several classes of latent inhibition theories, none of which provides a comprehensive account.     

Trial spacing effects in pavlovian conditioning: A role for local context

Two conditioned lick-suppression experiments with rats were conducted in order to replicate and extend findings by Ewing, Larew, and Wagner (1985). Ewing et al. observed that excitatory responding to a CS paired with a footshock US was attenuated when the ITIs thatpreceded each CS-US trial were short (60 sec) relative to when they were long (600 sec). This effect was isolated in the influence of the preceding ITI because the preceding ITI was consistently short for one CS and consistently long for a different CS, while the following ITIs were equally often short and long for both CSs. Ewing et al. interpreted this finding in the framework of Wagner’s (1981) SOP model. Experiment 1 replicated this trial-spacing effect and demonstrated a similar effect under conditions in which thefollowing ITI was consistently short for one CS and consistently long for a different CS, while the durations of preceding ITIs were equally often short and long for both CSs. Experiment 2 revealed that the detrimental effect of a short preceding or a short following ITI could be alleviated by extinguishing the conditioning context after CS-US training. The latter observation indicates that the trial-spacing effect is not mediated by a failure of a CS trained with a short ITI to enter into excitatory associations with the US, a conclusion that is not wholly consistent with the SOP model. Finally, we suggest that short pretrial and short posttrial ITIs may enhance the excitatory value of local context cues that modulate responding to a CS.     

Conditioning-specific reflex modification of the rabbit (Oryctolagus cuniculus) nictitating membrane response is sensitive to context

Conditioning-specific reflex modification occurs when an unconditioned response is modified in theabsence of the conditioned stimulus as a result of pairings of the conditioned stimulus and an unconditioned stimulus. In two experiments, we assessed conditioning-specific reflex modification in either a novel context (Experiment 1) or a context different from, but equally familiar in relation to, the training context (Experiment 2). Conditioning-specific reflex modification did not demonstrate sensitivity to a novel context but did demonstrate sensitivity to a change in familiar context. The data cannot be explained by unconditioned stimulus preexposure, overtraining, or context insensitivity. The results suggest that conditioning-specific reflex modification models normal stress and may be used to evaluate theories of and treatments for posttraumatic stress disorder.     

Differential generalization of habituation across contexts as a function of stimulus significance

Orienting to one of two levels of stimulus significance (a distress squeal or a simulated mimic squeal) in female hooded rats was measured by suppression of ongoing drinking. Subsequent generalization tests with the same stimulus presented in different contexts showed that generalization of habituation across contexts was a function of stimulus significance: Habituation to the distress squeal was restricted to the context in which it first had been presented, whereas habituation to the mimic squeal generalized across the different contexts.