Begin Transcript Welcome to Module 6. In this module, we will take a deeper look at how behavior comes under the control of different stimuli, and different types of generalized outcomes. This module will cover the following topics: B-11 Discrimination, Generalization and Maintenance, and B-15 Derived Stimulus Relations. First, let’s take a look at discrimination. Recall that during the last module, we talked about the principle of stimulus control. Stimulus control is when an SD evokes a response due to its association with the reinforcement that the response produces while the other stimulus conditions, s-deltas, abate the response. Therefore, this process requires reinforcing the response under one stimulus condition while not providing reinforcement for the response under other stimulus conditions. Stimulus control is established when an organism behaves differently in the presence of the SD and s-delta, or the organism can discriminate between stimuli. There are two types of discrimination, simple discrimination and conditional discrimination. In simple discrimination, an individual responds to an SD and does not respond to an s-delta. For example, when an instruction, “stand up,” is given, a student should stand up. The student should not stand up following other instructions. The instruction generally does not depend on context in order to evoke the response. The simple discrimination training relies on differential reinforcement. That is, reinforce the specific response only when the SD is present. For example, when an instruction, “stand up,” is given, deliver reinforcer as soon as the student stands up. In addition, no reinforcer should be delivered for the response when an s-delta is presented. For example, if the student stands up upon the instruction, “clap hands,” the teacher should not deliver any reinforcer. As such, the student will learn to respond only when the SD is given and not under other antecedent stimulus conditions.Another example of simple discrimination task is labeling items. The student’s response is under the control of the item presented. ASR 1 Now, let’s take a look at conditional discrimination. Imagine there are three items on the table in front of you: salt, bread, and cheese, and you hear a request, “give me salt.” You would then pass salt and probably receive social reinforcement. If you pass bread or cheese, you will not receive social reinforcement. However, if another request, “give me bread,” is made, you will pass bread instead of salt or cheese, even though the items in front of you hasn’t changed. This is an example of conditional discrimination. Your response is dependent on context. In conditional discrimination, responses to antecedents only produce reinforcement under certain conditional stimuli. In other words, discrimination is conditional, dependent on the context. Thus, the conditional stimulus is also called contextual stimulus. In the previous example, your selection of salt only produces social reinforcement when salt is requested. Thus, the request is a conditional stimulus, under which salt becomes an SD that evokes your response, while bread and cheese are s-deltas. If the request for bread is made, bread in this case has turned into an SD that evokes the selection while salt and cheese are s-deltas. If we compare conditional discrimination and simple discrimination, conditional discrimination consists of a four-term contingency: conditional stimulus – antecedent – behavior – consequence. Simple discrimination only has three terms: antecedent – behavior – consequence. Here is an example of the match-to-sample procedure used to teach conditional discrimination. This procedure is commonly seen in early behavioral intervention programs. A student may be presented with three choice items or comparison stimuli, and then the student is handed with a conditional stimulus. As you see in this example, under two different conditional stimuli, the function of the comparison stimuli changes. In the left figure, when a picture of a bicycle is presented, the word, “bicycle,” becomes the SD for the response. In the right figure, however, when the picture of an airplane is presented, the word, “airplane,” instead becomes the SD. As you can see, the response to the comparison stimuli should be dependent on distinctive conditional stimulus before reinforcement can be delivered. ASR 2 through 7 Since the match-to-sample procedure is often used to teach relations between stimuli, we will discuss B-15 Derived Stimulus Relations first. We will come back to B-11 later for topics on generalization and maintenance. To understand derived stimulus relations, let’s take a look at antecedent stimulus class first. Stimuli in the same stimulus class evoke the responses in the same operant response class or elicit the same respondent behavior. For example, a picture of a Boston Terrier, a Dalmatian, and a Beagle should all evoke the same operant response, “dog” or “puppy”. There are two types of stimulus classes: feature stimulus class and arbitrary stimulus class. A feature stimulus class comprises stimuli that share physical forms or relative relations. In the previous example, the Boston Terrier, the Dalmatian, and the Beagle all share similar physical form. They belong to the same feature stimulus class. An example of stimuli that share relative relations would be items that have the same spatial placement, such as being on the table. The other stimulus class is the arbitrary stimulus class. Stimuli in the arbitrary stimulus class do not share common features. In the below examples, a picture of a bicycle and the word, “bicycle,” would evoke the same verbal response, “bicycle.” Since they do not share common physical features or relative relations, they belong to the same arbitrary stimulus class. Likewise, a picture of an airplane and the word, “airplane,” do not share common physical features either. Therefore, they belong to the same arbitrary class because they can evoke the same response. ASR 8 In arbitrary stimulus class, stimulus generalization does not occur. It only emerges when the responses are evoked by stimuli that share similar physical features. In other words, stimulus generalization only occurs in feature stimulus class. It is not a characteristic of arbitrary stimulus class. As mentioned earlier, the relations among stimuli in arbitrary stimulus class is often taught through the match-to-sample procedure. For example, supposing a student is presented with three words, “bicycle,” “airplane,” and “car,” and he receives reinforcement for selecting the word, “bicycle,” upon being presented with a picture of a bicycle. The relation between the word and picture is therefore reinforced. Likewise, if the student receives reinforcement for selecting the word, “airplane,” upon being presented with an airplane picture, the relation between the word, “airplane,” and the picture is reinforced. As a result, equivalence between stimuli may be created through the match-to-sample procedure. The phenomenon, stimulus equivalence, is demonstrated when relations between stimuli within an arbitrary class are derived or untrained. These relations can be reflexivity, symmetry, and transitivity. Reflexivity occurs when an individual can select a stimulus that is matched to itself without training. For example, the individual can match the bicycle picture to the same bicycle picture without being taught. This is also called generalized identity matching. The second relation is symmetry. If an individual has been taught to select A upon being presented with B, symmetry is observed when the individual can complete the reversed relation: selecting B upon being presented with A without training. Transitivity emerges when the individual is able to select C upon being presented with A without instruction, after the individual has been taught the relations between A and B, as well as B and C. Please remember that if any of these specific relations have been taught, they are not derived relations. For example, for children with autism, explicit teaching of identity matching, or matching of the same item, may be necessary. If a child with autism has been taught and demonstrated that a car matches to itself after intervention has concluded, the relation between the same car cannot be called reflexivity. Likewise, if a child has been taught both the picture-to-word matching of bicycle, and word-topicture matching of bicycle, neither relation was derived. The derived relations are fundamental in developing verbal, reading, and math skills. This example shows the equivalence class of car. Within the class, we have a written word, a spoken word, and a picture of a car. As you see, after you have reinforced the relation between the car picture and the spoken word, if the reversed relation is derived, symmetry is demonstrated. Similarly, symmetry is also observed if the relation between the written word and the picture car is derived after the reversed relation has been reinforced. Last, transitivity is seen if the relation between the spoken word and the written word is derived. Acquisition, Generalization, and Maintenance of Behavior, Part 2 We just discussed simple and conditional discrimination and a related phenomenon of stimulus equivalence which can be taught through the match-to-sample procedure. They are all related to how responses come under the precise control of stimuli. Next, we will take a look at generalized outcomes. Let’s start with stimulus generalization. Recall the example with the three types of dogs. Supposing a student has learned that both the Boston Terrier and the Dalmatian are dogs, stimulus generalization is observed if the student also names the Beagle a dog without instruction. Stimulus generalization is defined as a tendency that a response may be evoked by stimulus conditions that share similar features as the initial stimulus condition in which the response was learned. Thus, it is a characteristic of feature stimulus class Discrimination, on the other hand, is the opposite to stimulus generalization because discrimination requires differential responding to different stimuli. In other words, discrimination represents precise stimulus control while stimulus generalization represents a relatively loose degree of stimulus control. Sometimes, stimulus generalization is preferred such as in the example with the three types of dogs. Other times, precise stimulus control is preferred. You would not want the student to start calling all dogs Boston Terriers. ASR 14, 15, and 16 To demonstrate the degree of stimulus generalization and discrimination, you may use a figure called stimulus generalization gradient. In general, stimulus generalization occurs when responding emitted for stimuli that are similar to the initial stimulus condition in which the response was learned. As the stimulus becomes more and more different from the initial stimulus condition, responses are expected to decrease. Below are three stimulus generalization gradients showing the responding patterns from an organism in relation to color wavelength. Supposing the organism has been trained to respond to the color, yellow. A relatively tight stimulus control is shown in the left figure in which responding is the highest under the yellow color and decreases quickly as the wavelength changes. That is, the greater the difference between the stimulus and the initial stimulus condition is, the fewer responses are made to them. Note that there are some responses under the wavelengths that are similar to Yellow. This means some stimulus generalization has occurred. A relatively less precise degree of stimulus control is shown in the middle figure when compared to the left figure because the responses decrease less drastically as the color changes from yellow. The right panel, on the other hand, shows a lack of discrimination as the responding is similar across wavelength, indicating a lack of stimulus control. Remember that generalization is the opposite of discrimination, and they are relative to each other, so the right figure may show the most amount of generalization, or overgeneralization, among the three figures, while the left figure shows the least amount of generalization. As demonstrated, you would be able to use a stimulus generalization gradient to demonstrate the degree of discrimination and stimulus Generalization. ASR 17 and 18 Setting generalization refers to when a learned behavior is emitted in a novel setting that is different from the setting in which the behavior was learned. For example, if a student learned to cross the street in the classroom and the student subsequently crossed the street on the street intersection without being taught, setting generalization has occurred. In this case, the classroom is the instructional setting while the street intersection is the generalized setting. A generalized setting is a novel setting where the response is desired. It differs from the instructional setting in some meaningful way. For example, if the student is asked to demonstrate street crossing in another classroom, the other classroom is generally not considered a generalized setting for this skill since it is not a setting where the response is desired, and it is not that different from the instructional setting. ASR 19 Response generalization, on the other hand, is observed when a learner demonstrates an untaught response that are functionally equivalent to the learned response. In other words, the novel response is emitted without instruction and it is in the same response class as the learned response. For example, if one learns to drink water from a glass, a generalized response would be sipping water through a straw without instruction. Both responses serve the same function, water ingestion. ASR 20, 21, and 22 Some issues with generalization may emerge during teaching. The first one is overgeneralization. Overgeneralization occurs when the response comes under the control of a stimulus class that is too broad. An example would be a child calling every man he sees, “dad.” In this case, the degree of stimulus control of the child’s response is too loose, even though there are commonalities in relevant physical features. Another issue is faulty stimulus control. It emerges when the response comes under the control of irrelevant stimulus. For example, if a student learned to name “table” after being presented with a white table, and then the student started labeling all white items, “table.” This is the case of faulty stimulus control because the controlling stimulus of the student’s response is the white color instead of the table. These two issues may be remedied by teaching nonexamples. Non Examples are those that do not share all relevant physical features. For example, teaching the child that pictures of other men are not “dad” should increase the control of the actual stimulus. Similarly, if nonexamples such as other white items are introduced, the student’s response would not be controlled by white color. As such, teaching of nonexamples would allow for a more precise stimulus control and more desirable degree of stimulus generalization. ASR 23 and 24 Response maintenance is the extent to which a learner continues to perform the learned response after some or all of the intervention has been terminated. Response maintenance is a form of generalized behavioral outcome across time. For example, if a student was taught to plan navigation routes using Google Maps, response maintenance is demonstrated when this student continues to independently plan routes after the instruction has been terminated. Response maintenance is relative to the passage of time. You may want to probe maintenance at different points of time. For example, even if a response has been maintained one week after the intervention was terminated, it does not mean that the individual will continue to emit the response over a longer period of time. Intermittent probing of maintenance would allow you to determine if the response has been continuously maintained and plan accordingly. While all previously discussed are forms of generalized behavioral outcomes, they are different phenomena. Stimulus and setting generalization is related to the same behavior across different novel stimuli or settings. For example, if a student learned a math strategy and applied this strategy to novel tasks or different settings such as a supermarket, stimulus or setting generalization is demonstrated. Response generalization refers to novel response forms that serve the same function. Using the same example, the same student came up with their own math strategy that solves similar problems. In this case, a new response form has emerged but serves the same function. On the other hand, response maintenance refers to the same response emitted as the time passes. That is, the same student is able to continuously use the same math strategy over time even when the instruction has been terminated. Because different generalized outcomes may occur to the same response at the same or different points of time, when you try to differentiate the forms of generalized outcomes, make sure that you determine the outcome based on the relevant definition. ASR 25 and 26 Unfortunately, generalization and maintenance do not emerge automatically, and planning is required. There are a number of procedures that can be used to promote generalization and maintenance, and I encourage you to refer to your textbooks for further information on these procedures. End of Transcript
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