A Primer of Covert Sensitization

Covert sensitization is the first of a family of behavior therapy procedures called covert conditioning initially developed by Joseph Cautela in the 1960s and 1970s. The covert conditioning procedures involve the use of visualized imagery and are designed to work according to operant conditioning principles. When working with cooperative clients to treat maladaptive approach behaviors, covert sensitization has been found to be a humane and effective alternative to in vivo aversion therapy procedures that employ aversive stimuli such as chemicals and electric shock. This primer describes covert sensitization, provides examples and notes representative research. Guidelines for use and suggestions for further readings are also included.     

Visual discrimination in an orangutan (Pongo pygmaeus): measuring visual preference

Although previous studies have confirmed that trained orangutans visually discriminate between mammals and artificial objects, whether orangutans without operant conditioning can discriminate remains unknown. The visual discrimination ability in an orangutan (Pongo pygmaeus) with no experience in operant learning was examined using measures of visual preference. Sixteen color photographs of inanimate objects and of mammals with four legs were randomly presented to an orangutan. The results showed that the mean looking time at photographs of mammals with four legs was longer than that for inanimate objects, suggesting that the orangutan discriminated mammals with four legs from inanimate objects. The results implied that orangutans who have not experienced operant conditioning may possess the ability to discriminate visually.     

Taste preconditioning augments odor-aversion learning

On the basis of previous work that has shown a taste can potentiate odor-aversion conditioning in AX+ conditioning, 6 experiments used rats to examine the effects of pairing a preconditioned taste (A) with a novel odor cue (X) in an A+/AX+ aversion conditioning design. Experiments 1A and 1B demonstrated that a preconditioned taste produced a robust odor aversion that was significantly stronger than a potentiated odor aversion. The results of Experiment 2 showed that the robust odor aversion produced by A+/AX+ conditioning was not the result of the potentiated odor aversion summating with generalization from the taste aversion. The augmented odor aversion was produced only when the taste and odor stimuli were presented simultaneously (Experiment 3) and the preconditioned taste aversion was intact at compound conditioning (Experiment 4). Pairing a novel odor with a preconditioned taste was not sufficient to condition an aversion to odor (Experiment 5), although other results implicated a role for an association between odor and taste in the odor augmentation effect (Experiment 6). The present results have implications for current models of taste + odor interactions in flavor-aversion conditioning.     

ENURESIS CONTROL THROUGH FADING,ESCAPE, AND AVOIDANCE TRAINING

A twin-signal device that provides both escape and avoidance conditioning in enuresis control is described involving a procedure documented by two case studies. In addition, a technique of fading as an adjunct to the process is utilized with one subject. The results indicate that a combination of operant and respondent conditioning involving escape and avoidance training may be an improvement over the more traditional conditioning procedure.     

Overshadowing of a context aversion by a novel incentive in operant conditioning

Two experiments examined the processes underlying the suppression of instrumental behaviours by lithium in rats, as reported by Meachum (1988 and this issue). Experiment 1 examined whether presenting a novel sucrose solution prior to lithium chloride administration would overshadow aversion learning to either the stimuli of the operant chamber or to familiar food pellets. After lever pressing had been established, and in the absence of responding, animals received free deliveries of a novel sucrose solution, familiar food pellets, or both, or they were exposed to only the cues of the operant chamber, prior to lithium injections. Lever pressing for food pellets was then assessed. It was found that the animals receiving the novel sucrose, either alone or with the familiar food pellets, pressed more for pellets than either the group receiving only food pellets or the group exposed to only the context. In addition, there was no appreciable difference in the response rates between the context-only group and the group that received the familiar food pellets. These outcomes were interpreted in terms of the novel sucrose overshadowing aversion learning to the context. Experiment 2 investigated whether in fact aversive contextual conditioning could be obtained using the present parameters. This was accomplished by directly manipulating the contexts. In this experiment animals were trained to lever press in two distinctive contexts. Subsequently, one context was paired with the novel sucrose, and the second was experienced in the absence of reinforcement prior to toxicosis. During a subsequent non-reinforced test it was found that responding in the context paired with the novel sucrose was considerably higher than responding in the context that was experienced alone. These findings stand in contrast to the taste-mediated contextual potentiation observed when a consumatory response is used to assess aversive contextual conditioning.     

The operant and the classical in conditioned orientation of Drosophila melanogaster at the flight simulator

Ever since learning and memory have been studied experimentally, the relationship between operant and classical conditioning has been controversial. Operant conditioning is any form of conditioning that essentially depends on the animal's behavior. It relies on operant behavior. A motor output is called operant if it controls a sensory variable. The Drosophila flight simulator, in which the relevant behavior is a single motor variable (yaw torque), fully separates the operant and classical components of a complex conditioning task. In this paradigm a tethered fly learns, operantly or classically, to prefer and avoid certain flight orientations in relation to the surrounding panorama. Yaw torque is recorded and, in the operant mode, controls the panorama. Using a yoked control, we show that classical pattern learning necessitates more extensive training than operant pattern learning. We compare in detail the microstructure of yaw torque after classical and operant training but find no evidence for acquired behavioral traits after operant conditioning that might explain this difference. We therefore conclude that the operant behavior has a facilitating effect on the classical training. In addition, we show that an operantly learned stimulus is successfully transferred from the behavior of the training to a different behavior. This result unequivocally demonstrates that during operant conditioning classical associations can be formed.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

Evaluating the relative effectiveness of three aversion therapies designed to reduce craving among cocaine abusers

Crack cocaine use and dependence has been steadily increasing since the mid‐1980s. Treatment approaches vary from simple psychotherapy to intensive medication regimens. One clear phenomenon that has been implicated in the continued use and abuse of crack cocaine is craving. Craving is believed to be a response that has been conditioned with previous drug using episodes, and is elicited by environmental cues. The current study investigated the use of three aversion therapies (chemical, covert sensitization, and faradic) designed to eliminate craving for cocaine. Seventy subjects were randomly assigned to one of three aversion treatments or a relaxation control condition. Results indicate that aversion therapy reduces crack cocaine craving. The use of aversion therapy as an adjunct to traditional treatment programs for reducing craving is discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Elicited versus emitted behavior: Time to abandon the distinction

The concept of emitted behavior was formulated as a part of the original argument for the validity of a new kind of learning called operant conditioning. The rationale for operant conditioning contrasted it with Pavlovian or classical conditioning, which was (and remains) fundamentally based on responses to conditioned and unconditioned stimuli. Classical conditioned responses were said to be elicited. In contrast, operant behavior was viewed as emitted and controlled primarily by response consequences rather than antecedents. I argue that the distinction between emitted and elicited behavior is no longer warranted for three major reasons. First, the distinction was based on a view of Pavlovian conditioning that is no longer viable. Second, the distinction is incompatible with both empirical data and contemporary conceptualizations of operant behavior. Third, the only way to overcome these problems is to define emitted and elicited in terms of the type of conditioning (operant and classical) that produces these behaviors, but that approach makes the definitions circular and does not avoid implications of the terms that are misleading and counterproductive in light of contemporary research and thinking.     

Identification of a reinforcement pathway necessary for operant conditioning of head waving in Aplysia californica

The marine mollusc Aplysia californica exhibits a wide range of nonassociative and associative forms of learning. Recently, we found that the learning repertoire of Aplysia includes operant conditioning (Cook & Carew, 1986, 1989b). The behavior we examined is a naturally occurring, side-to-side head-waving response used by Aplysia in seeking food, obtaining a foothold, and egg laying. Aplysia can be operantly conditioned to reduce head-waving to one side of their body if such a response results in exposure to bright uniform-field illumination, which the animals find aversive. An essential step toward achieving a mechanistic understanding of operant conditioning is to identify and characterize the reinforcement pathway used during the learning. Toward this end, we wished to determine which of the peripheral visual pathways in Aplysia are critical for performance of the operant task. Previous experiments indicated that photic input from the optic and rhinophore nerves functionally inhibited motor neurons that participate in the operant response (head-waving), while photic input from the oral veil nerves excited these same motor neurons (Cook & Carew, 1989c). These findings suggested the hypothesis that one or both of these pathways could play an important role in mediating reinforcement during training. To explore this possibility we operantly trained animals that had received chronic bilateral transections of either the optic and rhinophore nerves or the oral veil nerves C1-C3 (in conjunction with transection of the optic and rhinophore nerves). We found that operant conditioning was not disrupted by ablation of input from the eyes and rhinophores. By contrast, ablation of input from the oral veil (together with that from the eyes and rhinophores) abolished operant conditioning. Thus, the oral veil nerves play a critical modulatory role in operant conditioning of head-waving. This observation further suggested that photic input from the oral veil is conveyed to the CNS via the oral veil nerves. In a final experiment we confirmed that stimulation of the oral veil with light evokes increased afferent activity in the oral veil nerves C1-C2. These results support the idea that the oral veil nerves contain processes that are critical components of the reinforcement pathway for operant conditioning of head-waving.     

Further evidence for the summation of latent inhibition and overshadowing in rats’ conditioned taste aversion

Repeated exposures to a target taste (X) attenuated subsequent development of rats’ conditioned aversion to X (latent inhibition effect). Presentation of another taste (A) after X in conditioning (serial X-A compound conditioning) also attenuated conditioned X aversion compared with conditioning without A (overshadowing). Furthermore, the latent inhibition and overshadowing effects summed to show the least conditioned aversion in the rats given both the target preexposures and the serial X-A compound conditioning treatment. These results question the validity of the comparator hypothesis as an explanation for Pavlovian conditioning of rats’ conditioned taste aversion.     

Extending in vitro conditioning in Aplysia to analyze operant and classical processes in the same preparation

Operant and classical conditioning are major processes shaping behavioral responses in all animals. Although the understanding of the mechanisms of classical conditioning has expanded significantly, the understanding of the mechanisms of operant conditioning is more limited. Recent developments in Aplysia are helping to narrow the gap in the level of understanding between operant and classical conditioning, and have raised the possibility of studying the neuronal processes underlying the interaction of operant and classical components in a relatively complex learning task. In the present study, we describe a first step toward realizing this goal, by developing a single in vitro preparation in which both operant and classical conditioning can be studied concurrently. The new paradigm reproduced previously published results, even under more conservative and homogenous selection criteria and tonic stimulation regime. Moreover, the observed learning was resistant to delay, shortening, and signaling of reinforcement.     

Exteroceptive context in tasteaversion conditioning and extinction: odour, cage, and bottle stimuli

Five experiments investigated the extent to which the exteroceptive context, present on a saccharin aversion conditioning trial with rats, controlled the resulting aversion on one-bottle extinction tests and subsequent preference tests. The presence or absence of the specific odour which had been present on the conditioning trial was found not to influence saccharin intake on extinction tests, whereas the presence of the particular compartment in which, and the bottle from which, the saccharin had been consumed greatly suppressed saccharin intake as compared to the absence of these elements. Preference tests, performed in the respective conditioning contexts, showed extinction to be specific to the compartment + bottle context: groups that had extinguished their saccharin aversion in a context different from the conditioning context, retained their aversion in the conditioning context. No such specificity was found for the odour context. However, in the absence of the taste stimulus during the extinction phase, the odour that had been present on the conditioning trial did control the amount of water consumed, whereas the compartment+bottle context did not. Moreover, on preference tests, groups that had consumed water during extinction in the presence of the odour context, evidenced a lesser saccharin aversion than groups not exposed to the odour. The results are interpreted as demonstrating that rats learn about taste, odour, cage and bottle stimuli on a taste-aversion conditioning trial, and that taste and bottle stimuli seem to be the most salient.     

Augmentation of taste conditioning by a preconditioned odor.

Five experiments explored facilitated taste-aversion conditioning (odor-mediated taste augmentation), using rats that experienced odor (A) and taste (X) in an A+/AX+ design. Augmentation occurred when the stimuli were presented simultaneously during AX+ conditioning, and significantly weaker conditioning occurred after a sequential presentation (Experiment 1). Experiments 2 and 3 demonstrated that augmented conditioning decreased if the odor aversion was reduced through preexposure or extinction following A+ conditioning. A second-order conditioning explanation was not supported by the results of Experiment 4. Experiment 5 showed that extinction of the odor aversion after AX+ conditioning did not alter the strength of the augmented taste aversion. Odor-mediated taste augmentation is similar to potentiation, in which odor and taste cues operate in a synergistic, not competitive, manner.     

The Wandering IQ: A Continuation

The hypothesis addressed in this study was that for every experimental condition, learning with awareness would occur. An experiment was conducted with use of a collating task that incorporated the awareness question into the design investigating the change in performance quality and quantity. Statistical evaluation of Dulany's awareness questionnaire suggested general unawareness of attempted verbal operant conditioning. There is some evidence suggesting that an actual change in performance quality and quantity is accompanied by awareness with use of operant conditioning procedures.     

Taste aversions conditioned by the aversiveness of insulin and formalin: role of CS specificity

Experimenters in the past have reported that when insulin is used as the unconditioned stimulus (US), rats will learn an aversion to a sodium chloride but not a sucrose solution, whereas with formalin as the US, they will learn an aversion to a sucrose but not a saline solution. The present experiments failed to confirm these findings. Aversions to sucrose were conditioned with insulin and aversions to sodium chloride were conditioned with formalin. The use of a more concentrated sucrose solution in the present study may have been responsible for the successful sucrose-aversion conditioning with insulin. Although the source of the discrepancy in findings concerning aversion conditioning with formalin remains unclear, experiments ruled out numerous possibilities. These experiments also showed that sodium chloride aversion conditioning with formalin is a highly robust phenomenon that occurs with a variety of conditioned stimulus durations and formalin doses, with distributed and massed training, in male and female rats, and even if saline is not the only novel solution presented during conditioning. Furthermore, the aversion can be detected with both single-stimulus and choice test procedures.     

Operant techniques used in stuttering therapy: A review

This article reviews research concerning the use of operant conditioning in stuttering therapy, and discusses the clinical implications of this literature. In order to be considered for this review, a report had to treat the findings of research specifically designed to use operant conditioning in the manipulation of speech disfluency. This body of experimental literature clearly indicates that operant management techniques can effectively reduce stuttering with punishment of disfluencies producing more notable results than reinforcement of fluent responses. Operant conditioning is an effective means of modifying stuttering behavior and should be more visible in terms of procedures used by speech therapists.     

Amplitude measures of operant response: Implementation with Apple Pascal

Because operant conditioning studies involving force of response as a dependent variable require high-speed A/D conversion, conventional operant software, which treats the input datum as a dimensionless event, is generally unsuited for this kind of work. The author describes a complete Apple-based hardware-software ensemble that measures and records on diskette the peak force, duration, time integral of force, and interresponse time for individual operant responses. Data acquisition and control programs were written in Apple Pascal linked to selected assembly language modules. The real-time base was derived from an inexpensive crystal clock interfaced     

The effectiveness of electric shock and foul odor as unconditioned stimuli in classical aversive conditioning

In a partial replication of an earlier study, eighty undergraduate volunteers were assigned to the eight cells of a three between- and two within-group experimental design. One factor was the nature of the UCS—faradic shock or a carefully-timed blast of pyridine vapor; the second factor was the UCS contingency—the UCS being contingent upon the CS or randomly interspersed; the third factor was the nature of the CS—all CSs were compounds of colored, flavored liquids, with the discriminable dimension being either color or taste. The two within-subjects factors were the successive presentation of either the CS+ of the CS? over trials in a standard classical conditioning format. The outcome measures were sip-size, order of preference, and semantic differential ratings. It was found that the foul odor UCS resulted in no aversive conditioning with either color or taste cues. Where shock was the UCS, color, but not taste, became aversive. While lending no direct support to cue-appropriateness concepts, the results reveal the complexity of cue utilization in human aversive conditioning.     

Chemical aversion conditioning as a treatment for alcoholism: A re-analysis

The literature on chemical aversion conditioning is characterized by the lack of controlled clinical research. The existing data derive primarily from methodologically inadequate studies. Although short-term conditioned aversion reactions to alcohol have been demonstrated, the independent efficacy of this technique in clinical treatment remains to be shown. Beyond the failure to demonstrate the value of adding chemical aversion conditioning to more standard treatments for alcoholism, evaluation in terms of broader outcome criteria (e.g. safety, intrusiveness, acceptability, the availability of alternative methods, and cost-effectiveness) indicates that chemical aversion conditioning cannot be recommended as a standard form of treatment for alcoholism.