Conditioning

Situation Versus Intermittent Stimulus

Wanda Wyrwicka

• Publisher: Routledge
• Year: 2017
• eBook ISBN: 9781351289344
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

In laboratory research, the process of conditioning is traditionally initiated with a single intermittent stimulus (such as a tone or flash of light). This is true of both classical and instrumental research. Because of its role in evoking conditioned behavior, the use of an intermittent stimulus has become an indispensable part of laboratory research on conditioned behavior. The question arises whether the same scheme of conditioning may be applied to behaviors occurring in real life.

In Conditioning, Wanda Wyrwicka analyzes evidence of the influence of situations on behavior in laboratory studies. She looks at cases in which the subject's reaction was dependent on complex situations rather than a single stimulus. Wyrwicka suggests that beyond external situations there exists internal factors located in the brain that consist of previous and present experiences that may influence behavior. In Chapter 1, Wyrwicka summarizes Ivan Pavlov's concept of the conditioned reflex using intermittent stimuli. Chapter 2 deals with the mechanisms of motor conditioned behavior and the results of instrumental conditioning studies. Chapter 3 covers the phenomenon called "switching," which is the appearance of a conditioned reaction different than the original conditioned stimulus. In Chapter 4, Wyrwicka describes various studies in which situation becomes a potent factor in conditioned reactions. Chapter 5 describes research pertaining to defensive and alimentary behaviors. Chapter 6 analyzes three examples of complex conditioning: detour, feeding, and presleep behaviors. Chapters 7 and 8 focus on the functions of various internal organs, and the conditioning of electrical brain activity leading to inhibition of epileptic seizures. In her concluding chapter, Wyrwicka discusses theoretically the data mentioned previously.

Conditioning opens up rich possibilities for continued exploration. This revealing work will interest scientists specializing in behavioral sciences, psychologists, neuroscientists, educators, as well as students of biology.

1

Classical Conditioned Reflexes

Ivan Pavlov’s historic discovery of the principle of the conditioned reflex was an enormous break in the scientific approach to the understanding of brain functions.

One of Pavlov’s first observations in this area was made during a study on the secretion of saliva in dogs. Namely, Pavlov found that the animals salivated not only when they were eating food offered by a caretaker, but also when they saw the caretaker approaching or heard his footsteps. This simple observation indicated that the inborn reaction of salivation to food (or other objects) in the mouth may also appear to originally neutral stimuli which accompanied or immediately preceded the food intake.

As a physiologist, Pavlov chose a physiological interpretation of this phenomenon (Pavlov 1926, 1960). He accepted the concept of the reflex introduced by Descartes (1764) that “an external or internal stimulus falls on some one or another nervous receptor and gives rise to a nervous impulse; this nervous impulse is transmitted along nerve fibers to the central nervous system. There, due to the existence of nervous connections, it gives rise to a fresh impulse which passes along outgoing nerve fibers to the active organ where it excites a specific activity of the cellular structures” (Pavlov 1960, p.7). Pavlov considered the secretion of saliva to the presence of food in the mouth (and specifically to the tactile and taste stimuli produced by the morsel) an inborn reflex and called it an unconditioned reflex (UCR) while the salivation observed to the stimuli previously neutral (such as e.g., sounds of the caretaker’s footsteps) he called a conditioned reflex (CR). The stimulus that produced unconditioned reflex was called an unconditioned stimulus (USC). The previously neutral stimulus that produced conditioned reflex was called conditioned stimulus (CS) (e.g., a definite sound or a visual object). This terminology has been widely accepted by researchers.

Pavlov emphasized that the establishment of a conditioned reflex is dependent on the application of the unconditioned stimulus (which is also called the reinforcing stimulus or simply reinforcement) during or following the action of the conditioned stimulus; it is necessary that the conditioned stimulus starts to operate before the application of the reinforcing stimulus. If the conditioned stimulus is not followed by the unconditioned stimulus, the conditioned reflex cannot be established.

According to Pavlov, “conditioned reflexes are phenomena of common and widespread occurrence: their establishment is an integral function in everyday life. We recognize them in ourselves and in other people or animals under such general names as ‘education’, ‘habits’ or ‘training’; all of these are really nothing more than the results of an establishment of new nervous connections during the post-natal existence of the organism. They are, in actual fact, links connecting the extraneous stimuli with their definite response reactions” (Pavlov 1960, p. 26).

In Pavlov’s laboratory a great variety of conditioned stimuli were used. These included various sounds (called by Pavlov “stimuli of the acoustic analyzer”), visual objects (“stimuli of the visual analyzer”), touch (“stimuli of the tactile analyzer”), various smells (“stimuli of the olfactory analyzer”), changes in environmental temperature (“stimuli of the thermal analyzer”), and even the sensory feedback produced by performance of a passive movements (“stimuli of the motor analyzer”). Practically each change in the environment could become a conditioned stimulus on condition that it could be noticeable by the corresponding receptor. For instance, a thermal stimulus of 45°C applied to the dog’s skin could be made into a conditioned stimulus, whereas a stimulus of 38–39°C, similar to the usual temperature of the dog’s skin, was ineffective in spite of the fact that food reinforcement was offered after each application of this stimulus.

Manipulations with a variety of conditioned and unconditioned stimuli resulted in an accumulation of a great amount of experimental data that served as constant enrichment of the Pavlovian theory. Let us reminiscence with some topics of study in Pavlov’s laboratory (Pavlov 1960).

One of these topics was the process of inhibition of the previously acquired behavior. Inhibition could be either external or internal. External inhibition could be caused by an appearance of an extraneous stimulus, not involved in the conditioned reflex arc. For instance, such extraneous stimulus could be a sudden noise, not used previously, an unknown person who appeared suddenly during the presentation of the conditioned stimulus, etc.

Internal inhibition is strictly related to the already formed conditioned reflex and occurs inside the arc of this reflex. A simple example of internal inhibition is a case when the reinforcing stimulus (e.g., food) has been withheld. When this procedure occurs repeatedly in the following trials, the conditioned reflex (e.g., salivation) gradually diminishes and finally stops appearing to the conditioned stimulus. This phenomenon was called by Pavlov the extinction of the conditioned reflex (Pavlov 1960, p. 49). It could be obtained even during a single session when successive presentations of the stimulus remained nonreinfored. However, the conditioned reflex to this stimulus recovered as soon as the reinforcement was given again.

Internal inhibition observed in Pavlov’s laboratory included a form called the conditioned inhibition. This type of inhibition was obtained when the conditioned stimulus was preceded by a new stimulus and, in this case, the reinforcement was not given. After several repetitions of this manipulation, the conditioned stimulus, preceded by the new stimulus, never produced the conditioned salivation whereas the conditioned stimulus applied alone did (Pavlov 1960, Ch.V.).

Another case of internal inhibition studied in Pavlov’s laboratory was the “inhibition of delay.” This kind of inhibition consisted of extending the time interval between the beginning of the action of the conditioned stimulus and the reinforcement. The prolongation of the period of the delay could be achieved gradually when (after establishment of a conditioned reflex with a usual reinforcement given 1–3 seconds after the beginning of the action of CS) the reinforcement was delayed by an additional, e.g., 5 seconds, in each consecutive session, until the delay reached several minutes. As a result of such procedure, the conditioned salivation did not start immediately after the onset of the conditioned stimulus, but only 30–60 seconds or longer after the beginning of action of the CS. The same result could be achieved when after the establishment of the conditioned reflex the delay in reinforcement was prolonged to the desired length rapidly, without any gradual steps. However, in this case, some complications in the dog’s behavior could appear during the training period (Pavlov, p.89).

Finally, a form of internal inhibition was obtained when two similar conditioned stimuli were used and one of them was always reinforced by food whereas the other was not. As a result of this manipulation, the conditioned salivation was present only to the CS which was reinforced each time, whereas it was absent to the other stimulus. This form of internal inhibition has been called differential inhibition or differentiation (Pavlov 1960, pp. 117–125 and following).

It should be mentioned, however, that the above described differential inhibition does not mean a complete disappearance of the reflex. In some circumstances such as, for instance, the entrance of a new person into the experimental chamber, the previously inhibited reflex may be disinhibited and the conditioned salivation may reappear (Pavlov 1960, p. 115).

Generalization of Stimuli

An important phenomenon observed mainly during the initial phase of establishing the conditioned reflex is the tendency to react not only to one particular stimulus but to all stimuli similar to it. For instance, when a conditioned reflex has been established to a tone of specific frequency by reinforcing it with food, many other tones will also produce salivation in spite of the fact that they were never reinforced. The value of the conditioned reflex produced by these similar stimuli depends, however, on the degree of similarity to the original tone. The same can be said about stimuli of other sensory systems (i.e., other analyzers). This phenomenon was called generalization of stimuli (Pavlov 1960, p. 113). It is often observed both in the laboratory and in natural life.

The research on conditioned reflexes not only consisted of compiling more and more experimental material supporting Pavlov’s concept, but also involved some new topics and experimental techniques. Studies performed in the laboratory of Bykov (1957) may serve as an example of such extension of research on conditioned reflexes. The results of these studies showed that it is possible to establish a conditioned reflex not only in relation to salivation but also to secretion of other glands of the alimentary system. It was demonstrated in a child provided with a stomach fistula that when the food reinforcement was always given after the sound of a trumpet, the stomach secretion started to flow to the sound of the trumpet before the food was given (experiments of Bogen, described by Bykov 1941).

The ability of conditioning was also observed on the gall bladder; namely, the contractions of the gall bladder increased when food was shown to a hungry dog (experiments of Kurtsin and Gorshkova, described by Bykov 1957).

The extension of the research on conditioned reflexes also included some new methods. An example of such novelty were experiments conducted by W.H.Gantt who also was one of Pavlov’s pupils. Gantt chose the functions of the heart and the circulatory system as the object of research and demonstrated that the rules of conditioning also extended to this area (Gantt 1944, 1960, Gantt and Hoffman 1940).

All the above described experimental results, which represent only a small part of the pioneer achievements of Pavlov and his pupils, were obtained with the use of single intermittent stimuli. In their research there was no problem of the situational background. However, Pavlov was aware of the existence of a great number of various stimuli in the environment which could influence the experimental results. In order to avoid interference of external stimuli during experiments with conditioned reflexes, a special building (known also as a “tower of silence”) was constructed (see fig. 3 at the beginning of Lecture 3, Pavlov 1960). This building consisted of four chambers on each of three floors. Each chamber was fully isolated from the external environment, securing stable conditions for the experiment. This allowed the investigator to concentrate on the effects of the intermittent stimuli and not pay attention to the situational background against which these stimuli were applied.

This led to an almost complete neglect of the problem of the situation in Pavlov’s laboratory and later in the laboratories of Pavlov’s followers. In fact, by using special training methods, the problem of the environmental background was removed from most experimental studies on conditioning.

Nevertheless, the problem of the situation exists. It will be discussed in further chapters of this book.

2

Instrumental Conditioned Reflexes

As usually happens in science, new theories develop by the addition of previously unknown facts or by different interpretations of the known facts. Although Pavlov’s concept and theories of the conditioned reflexes seemed to encompass the whole problem of behavior, one of its mechanisms still remained unclear. That was the mechanism of the motor conditioned reflexes.

According to Pavlov (1951), the general rule of the conditioned reflex also included the motor conditioned reflexes. When a movement is performed, it produces a sensory input of impulses from the muscle. When this input is each time followed by the reinforcement (e.g., food), the conditioned salivation appears to the movement (such as a flexion of the dog’s leg) before the food has been offered. This was demonstrated by Krasnogorski (1911; cit. by Pavlov 1951), who used a special device to produce a passive lifting of the dog’s leg. In this case, therefore, the motor conditioned stimulus was indeed analogical to the acoustic, visual, or tactile conditioned stimuli (see a scheme of this conditioned reflex in fig. 2.1).

An important question remained unanswered. In order to get the motor sensory input, the movement must be performed first. In the laboratory it was produced through the use of a special device. But how is the movement initiated and performed in natural conditions? This question was not answered by Pavlov’s concept (see Windholz and Wyrwicka 1996).

The problem of the motor conditioned reflexes was experimentally analyzed by two medical students of Warsaw (Poland) University, Jerzy Konorski and Stefan Miller. After reading Pavlov’s just published book on conditioned reflexes, they became enthusiasts of Pavlov’s concept of conditioned reflexes. They found, however, that there was an area in the behavior of the organism that was not included in Pavlov’s concept. This area was the conditioned motor behavior (occasionally also called by them “voluntary motor behavior”). Konorski and Miller, therefore, started their own experiments in the provisional laboratory space offered to them by a friendly professor of psychology.

FIGURE 2.1

A diagram of motor conditioned reflex in experiments of Krasnogortski according to the explanation of LP. Pavlov (see Ch. 2).

Movement, a passive movement of the dog, evoked by a special devise (provided by the experimenter).

Impulses, nervous impulses deriving from the performed movement to the brain sensory system.

Salivation, conditioned reflex of salivation.

As shown on the diagram, the conditioned reflex of salivation appears only after the performance of the movement by the dog. In the laboratory, the movement appears due to the use of a technique producing the passive movement. However, there is no explanation of origin of the active movement of the animal in free conditions (without provoking any passive motor activity).

The design of their first study was very simple. Using a mechanical device which could be controlled by them from a distance, they produced a flexion of the dog’s leg to an acoustic stimulus which was immediately followed by food. After several repetitions of this procedure, the dog started to perform the leg flexion actively (i.e., without any help of the mechanical device) to the acoustic stimulus. Using various kinds of reinforcement (positive reinforcement such as food, or negative reinforcement as a puff of air to the ear, as well as the presence of the reinforcement in some cases and its absence in other cases), they found that four varieties of the motor conditioned reflexes exist. Let us briefly describe each of these varieties.

First variety. When a specific movement (e.g., flexing the leg) is performed to a conditioned stimulus (e.g., a tone) and is always followed by obtaining a reward (e.g., food), then this movement will always spontaneously appear to this stimulus.

Second variety. When a specific movement (e.g., leg flexion) appearing to a conditioned stimulus (e.g., a tone) is never rewarded (e.g., by food), whereas the reward is offered only to the conditioned stimulus alone (without the movement), then the leg’s flexion stops being performed, and in its place an antagonistic movement (usually an extension of the leg) will appear to the conditioned stimulus.

Third variety. When a specific movement (e.g., leg flexion) appearing to a conditioned stimulus (e.g., a tone), is always rewarded by withholding a punishing stimulus (e.g., an airpuff to the ear), then the specific movement will always appear to the conditioned stimulus. This variety is often referred to as an “avoidance reaction.”

Fourth variety. When a specific movement (e.g., leg flexion) appearing to the conditioned stimulus (e.g., a tone), is always followed by a punishing unconditioned stimulus (e.g., an air puff to the ear), then this movement will cease to appear and an antagonistic movement (e.g., leg extension) will be performed instead.

Each variety was experimentally documented. The young investigators, however, needed to hear an opinion about their research and discuss the results. Therefore, they wrote to Pavlov informing him about their study. In answer, Pavlov invited Konorski and Miller to his laboratory in Leningrad, where they had an opportunity to repeat and confirm their previous experimental results on a greater number of dogs and under better ...

Table of contents

• Cover Page
• Half Title
• Title Page
• Copyright Page
• Content Page
• Acknowledgments
• Introduction
• 1. Classical Conditioned Reflexes
• 2. Instrumental Conditioned Reflexes
• 3. The Phenomenon of Switching
• 4. Cases of Dependence of Conditioned Behavior on Situational Factors
• 5. Studies on the Role of the Situation and the Intermittent Stimulus in Conditioning
• 6. Examples of Complex Conditioned Reflexes to the Situation
• 7. Conditioning of the Activity of the Internal Organs
• 8. Therapeutic Role of the EEG Feedback in Epilepsy
• 9. Theoretical Comments
• 10. Summary and Conclusions
• References
• Name Index
• Subject Index