Which of the following is the major theme of characteristics of the operant approach?

VI. Summary

“Operant conditioning” does not refer to a single therapeutic technique. Instead, the term refers to an important form of learning, or conditioning, in which behavior is primarily controlled by its consequences. The consequences of a particular kind of behavior in one setting can either increase or decrease the probability of such behavior occurring in similar settings in the future. Descriptions of the consequences of behavior, called rules, can have similar effects. A great deal is known concerning how consequences affect behavior, and this knowledge has been put to good use in designing interventions shown to be effective across a wide range of client populations, behavior problems, and settings.

Applications

The principles and methods of operant conditioning have been put to important use in several applied settings, notably clinical (especially in the treatment of autism and phobias) and educational settings. The application to the enhancement of self-control has already been noted, though the range of techniques has not. The methodology of operant conditioning has been exploited with great success in research on psychopharmacology and on brain mechanisms. In addition, cognitive phenomena have been better understood with the application of operant theory and methodology. References and suggested readings appear in the endnotes. While the applications of operant conditioning may constitute the field's most celebrated contributions (and there are far more applied than basic practitioners), these contributions rest firmly on the theoretical and empirical underpinnings provided by the at least 60 years of research inspired initially by the canonical writings of B.F. Skinner.

b. Operant Conditioning

Operant conditioning, which occurs all day every day in all types of situations, causes behavior change by building in consequences to behaviors. In other words, everyone from parents and teachers to employers and spouses use it to either reward or punish particular behaviors of others and thus increase or decrease the probability of those behaviors being repeated. Operant conditioning takes many forms but the reward and/or punishment theme is common to all of them.

A specialized form of operant conditioning is contingency contracting. Contingency contracts are behavioral contracts between individuals (often parents or teachers) who wish to see changes in behavior and those (children or students) whose behavior is to be changed. The contracts, usually written out and signed by those involved, allow the rewards and punishments of various behaviors to be negotiated by both parties.

Abstract

Operant conditioning is a form of associative learning that allows animals, both vertebrates and invertebrates, to establish a predictive relationship between the expression of a specific action and its positive or negative outcome. The behaviors of invertebrates can be modified by operant conditioning procedures similar to those used in vertebrates, and because their simpler nervous systems are amenable to detailed cellular analysis, invertebrates have been successfully used to analyze the behavioral adaptations and associated neuronal changes induced by this learning paradigm. This article will summarize operant learning procedures, behavioral changes, and the underlying neuronal and network plasticity that have been described in several invertebrate animal models, including molluscs (the sea slug Aplysia and the pond snail Lymnaea) and insects (the fruit fly Drosophila and the honey bee Apis). This description will draw out fundamental concepts on behavioral and neuronal processes implicated in learning and memory that may be shared by vertebrates.

1 Targeted Neuroplasticity Induced Through Operant Conditioning

Operant conditioning is a powerful method to induce behavioral learning; through operant conditioning, modification of a behavior is induced by the consequence of that behavior. In 1983, Wolpaw et al. (1983) showed for the first time that a properly designed operant-conditioning protocol could change the spinal stretch reflex (SSR), a large monosynaptic behavior arising from the excitation of muscle spindle afferents. Variations of this protocol have been applied to condition the SSR or its electrical analog, the H-reflex, in monkeys, rats, humans, and mice; they have confirmed that a specific change (i.e., up- or down-regulation) can be induced in the targeted reflex through operant conditioning (for review: Thompson and Wolpaw, 2014a; Wolpaw, 2010).

All the different versions of this conditioning protocol have three key features: (1) they require maintenance of a certain level of background (prestimulus) electromyographic (EMG) activity in the target muscle, (2) the reward is based on the size of the reflex measured as EMG activity, and (3) the reward contingency (i.e., whether larger or smaller reflexes are rewarded) remains the same over days and weeks. These protocols are designed to induce and maintain a long-term change in descending influence over the spinal reflex pathway, and to thereby produce targeted neuroplasticity in that pathway (Wolpaw, 1997). A comparable operant-conditioning protocol for the motor-evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS) has recently been developed to induce targeted neuroplasticity in a corticospinal pathway (Brangaccio et al., 2014; Favale et al., 2014).

Because these protocols can change the function of specific neural pathways, they can be designed to address the specific functional deficits of an individual with a spinal cord injury (SCI) or other CNS disorder. In a study of people with spastic hyperreflexia due to incomplete SCI, the soleus H-reflex was down-conditioned because hyperactivity in this reflex pathway impaired their locomotion (Thompson and Wolpaw, 2014c; Thompson et al., 2013). In contrast, in a study of rats with limping due to partial SCI, the soleus H-reflex was up-conditioned because soleus weakness impaired the stance phase of locomotion (Chen et al., 2006). In both cases, the intervention was effective; both the humans and the rats walked better. Because it can focus on an individual's particular deficits, the targeted neuroplasticity that can be induced and guided by operant-conditioning protocols is distinguished from less-focused interventions such as botulinum toxin or baclofen, which simply weaken muscles or reflexes and may have undesirable side effects (Dario and Tomei, 2004; Dario et al., 2004; Sheean, 2006; Thomas and Simpson, 2012; Ward, 2008).

Operant/instrumental conditioning

Operant conditioning was clearly demonstrated by Skinner, working a little before Pavlov, through his work with rats in mazes. He was the first behaviourist to make a distinction between respondent behaviour (that which is triggered automatically) and operant behaviour (that which occurs voluntarily). Skinner believed that most animal or human behaviour is not elicited by a specific stimulus, but is a voluntary, active process. He argued that people ‘operate’ on their environment and that behaviour is ‘instrumental’ in leading to certain ‘consequences’, which lead to the behaviour being repeated. Contingent upon the consequences of the action, responses that bring pleasure or satisfaction are likely to be repeated; those that bring discomfort or pain, are not (Skinner 1938).

Delayed matching to sample tests (short-term memory and attention)

Operant conditioning is a powerful technique for studying behavior under well-controlled conditions. The animal obtains food reward or avoids punishment by pressing on a lever. Operant techniques make it possible to quantify, in an automated manner, a wide range of psychopharmacological effects, such as those associated with antipsychotics, anxiolytics, antidepressants, and analgesics Roux et al (1994). Operant techniques can also be used to study memory function by using delayed responding procedures. In delayed responding the animal is required to retain information (which lever or stimulus was previously presented) over a short period (usually seconds) and then to show, by pressing on an appropriate lever, whether it has correctly remembered the information Dunnett et al (1988).

Operant delayed matching techniques possess a considerable advantage over most other cognitive models in that parallel procedures can be set up in rodents, primates and even man, thereby increasing the translational validity of the data obtained Bartus and Dean (2009).

Scopolamine or MK-801in rats or in primates are frequently used as amnesic reference substances. (Figure 3).

Operant conditioning

Operant conditioning differs from classical conditioning in that it is dependent on voluntary actions performed by the subject. Such learning obeys Thorndike's law of effect, which states that a voluntary behaviour that produces a rewarding outcome is more likely to be repeated. If the reward is a positive outcome (such as food when hungry) the process is referred to as positive reinforcement. If in contrast the reward is the prevention of an unpleasant outcome, the process is referred to as negative reinforcement. It should be noted that both positive and negative reinforcement lead to an increase in the probability that the voluntary action will be performed. This contrasts with punishment, where the outcome of a voluntary action is unpleasant (such as an electric shock), leading to a decrease in the probability of the voluntary action being performed.

Operant conditioning can be conducted under a range of different schedules of reinforcement. If every action is rewarded conditioning is said to be under a continuous schedule of reinforcement. However if only some of the responses are reinforced a partial schedule of reinforcement is established. Partial reinforcement schedules can be delivered on ratio schedules, in which the reinforcer is provided after a set number of responses, or on interval schedules, in which the first response after a given time period leads to reinforcement. Both ratio and interval schedules can be either fixed or variable. In fixed schedules the ratio or interval between reinforcers is constant. In contrast in variable schedules the ratio or interval is allowed to vary within a set range. Such partial schedules of reinforcement, once established, can maintain very high response rates. This is of importance in relation to gambling, where a partial reinforcement schedule such as that used in slot machines leads vulnerable individuals to continue gambling at a high rate. A further property of partial reinforcement schedules is that the behaviour is more resistant to extinction (the partial reinforcement extinction effect); thus, if reinforcement is no longer presented, an individual who has been rewarded on a continuous schedule of reinforcement will normally stop responding sooner than someone who has received partial reinforcement.

Operant Conditioning

Operant conditioning is another type of associative learning in which an animal learns to associate a behavior with its consequences. Reinforcement and punishment are the core tools of operant conditioning. The former causes a behavior to occur with greater frequency, whereas the latter causes a behavior to occur with lower frequency, sometimes even until its complete inhibition (cf. the PT procedure). Darmaillacq et al.66 designed a paradigm of aversion learning. In this experiment, cuttlefish were trained not to attack their preferred prey. This prey was rendered distasteful with a coating made of quinine (a substance that tastes bitter to humans) and presented to the cuttlefish every 15 min until they stopped attacking the prey twice in a row. In such condition, cuttlefish inhibit their predatory behavior within a few trials (<10), whereas control cuttlefish that tried to catch the prey but did not get it (removed before it is seized) kept on trying to get it. Indeed, after the cuttlefish inhibited their predatory behavior, a choice between the preferred prey and another prey was presented 24 or 72 hr later. For each retention delay, significantly more cuttlefish chose the other prey than their preferred one, although control cuttlefish still chose their preferred food. Beyond the demonstration that cuttlefish are capable of instrumental learning, these results showed for the first time 72-hr retention capabilities in cuttlefish. In an ecological perspective, this learning appears adaptive. Prey choice may be affected by prey defense mechanisms, such as the presence of toxins, escape strategies, and the availability of prey.65 Quinine is a natural and widespread chemical. Thus, it makes sense that cuttlefish avoid prey that is distasteful, particularly when they experience it several times. Furthermore, cuttlefish are able to store for a long time information that is crucial to their survival and welfare. Unpublished data obtained using CO histochemistry24 showed that taste aversion learning induced changes in CO staining with a pattern in the cuttlefish brain that depended on the delay after learning. Immediately after training, CO staining was decreased in the posterior superior frontal lobe; after 24 hr, it was increased in the inferior frontal lobe; and after 72 hr, significant changes in CO activity were observed in the VL and the superior frontal lobe (unpublished data). Like previous studies in cuttlefish and vertebrates,24,67 these results suggest a differential temporal evolution of post-training changes in regional brain activity supporting an evolution of the neural substrate of memory. They also confirm the involvement of the VL system in learning and memory processes. Unlike in the study by Agin et al.,24 the superior frontal lobe is not the only brain region involved in these processes. This difference can be explained because the learning procedures in the two studies are different in terms of learning length, reinforcements, and control groups. However, the results presented here were obtained with a small number of animals and need further investigation.