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Stimulus Control and Prompt Hierarchies FAQ

What is Stimulus Control?

Stimulus control is controlling the probability relationship between a specific stimulus or class of stimuli and the target or desired response. In other words, stimulus control is manipulating what you say or do (the stimulus) in order to elicit the desired response from the person you are teaching. For example, someone is learning to tell other people his/her name when asked. The stimulus would be the question, "What is your name?" The ultimate desired response would be, "My name is _________."

How is stimulus control developed?
Stimulus control can be developed through differential reinforcement (reinforcing the correct response and not reinforcing incorrect responses), extra-stimulus prompts/prompt hierarchy (information that the teacher adds to the learning interaction--pointing, verbal, modeling, etc.). You can also develop stimulus control by fading and shaping the stimulus. This is done by changing the stimulus to enhance its relevance for the child or by manipulating the number of distractors you present when you are teaching. For instance, when teaching  a student to identify 'car,' initially you would just present several different representations of cars (toy, real, different makes, etc.) When the student grasps the idea of 'car,' you would then present a car and a non-car (a 'distractor') side by side and the student would then be told to identify the car. You could increase the number of distractors to three or four items from which the student has to identify the car.
Why Should I Fade Additional Stimuli?
Students can become dependent on additional stimuli that is used to help you gain stimulus control. It is important that these added stimuli be faded out as soon as possible to avoid the student's becoming dependent on them. Fading allows the teacher to 'transfer' the control of the student's response from the prompt to the actual stimulus and/or natural cue in the environment. In order to preserve what the student has learned, the added stimuli should be faded in a systematic way.
What Is A Prompt Hierarchy?
A prompt hierarchy or using extra-stimulus prompts is a systematic method of assisting a student when he or she is learning a new skill. It is a way of gaining stimulus control (see above, How Is Stimulus Control Developed?).
What Is a Decreasing Prompt Hierarchy?
A decreasing prompt hierarchy (also known as "most-to-least" prompting) is simply beginning to teach the student using the highest or most intrusive level of prompt and systematically
fading the prompt down to a lower level prompt. When students are initially learning a concept, the use of a decreasing prompt hierarchy is superior.  You can blend prompts for more effectiveness (Gesture + Direct Verbal; Full Physical Assist + Direct Verbal, etc.) and easier fading. To implement a decreasing prompt strategies, develop a fading sequence before training begins; start with the prompt that will ensure a correct response; establish a criteria for when you will move from one level of prompt to the next (i.e. 8 out of 10 answers correct over 3 days.)
Levels of a Decreasing Prompt Hierarchy
FULL PHYSICAL ASSIST (FPA): Hand-over-hand assistance to complete the targeted response. This is usually used when the target response is motor in nature. For example, a full physical assist might entail putting your hand on the student's hand and moving the student's hand through the action of writing his or her name. If the student is learning to jump up and down, providing a full physical assist would mean physically lifting the student up and down in a jumping motion.

PARTIAL PHYSICAL ASSIST (PPA): As the name suggests, a partial physical assist is less intense or intrusive than a full physical assist. If full physical assist is hand-over-hand, the partial physical assist can be visualized as providing minimal supportive guidance--touching the wrist to stabilize handwriting and encouraging the student to jump without actually lifting his or her body off the ground are two examples of providing PPA. If the student doesn't need hand-over-hand assistance, start here.

MODELING: Modeling is simply showing the student what you want him or her to do. You do not physically touch the student. In order for modeling to work, the student must know how to imitate another person's actions. If a student has good imitation skills, start here.

GESTURE: Pointing, facial expression, mouthing words silently or otherwise indicating with a motion what you want the student to do.

DIRECT VERBAL (DV): This is a direct statement of what we expect the student to do or say. Example: "Come here." "Put the glass on the counter." This level of prompt requires that the student be able to follow your direction.

INDIRECT VERBAL (IV): An indirect verbal prompt tells the student that something is expected but not exactly what. Example: "What next?" "Now what?"

iNDEPENDENT: The student is able to perform the task on his or her own with no prompts or assistance from you.
 

What Is An Increasing Prompt Hierarchy?
An increasing prompt hierarchy (also known as "least-to-most" prompting) is the opposite of a decreasing prompt hierarchy. Instead of providing immediate direct assistance, in the increasing prompt hierarchy, the student attempts the task before you intervene with assistance. Following the response, the amount of information (prompts) increases until the student makes the correct response. Once a student has mastered a skill, use of an increasing prompt hierarchy is more effective in promoting maintenance of the skill (as compared to using a decreasing hierarchy.) To implement increasing prompt strategies establish a sequence of prompts to use before training begins; provide the level of assistance necessary to ensure a correct response before moving on to the next trial.
Levels of An Increasing Prompt Hierarchy
INDEPENDENT:  The student knows how to do this task without any help from you. Move on to the next task!

INDIRECT VERBAL (IV):  An indirect verbal prompt tells the student that something is expected but not exactly what. Example: "What next?" "Now what?" Start here when using the increasing hierarchy.

DIRECT VERBAL (DV): This is a direct statement of what we expect the student to do or say. Example: "Come here." "Put the glass on the counter." This level of prompt requires that the student be able to follow your direction. If the indirect verbal assist didn't work, move to this level.

GESTURE: Pointing, facial expression, mouthing words silently or otherwise indicating with a motion what you want the student to do.

MODELING: Modeling is simply showing the student what you want him or her to do. You do not physically touch the student. In order for modeling to work, the student must know how to imitate another person's actions.

PARTIAL PHYSICAL ASSIST (PPA): As the name suggests, a partial physical assist is less intense or intrusive than a full physical assist. If full physical assist is hand-over-hand, the partial physical assist can be visualized as providing minimal supportive guidance--touching the wrist to stabilize handwriting and encouraging the student to jump without actually lifting his or her body off the ground are two examples of providing PPA.

FULL PHYSICAL ASSIST (FPA): Hand-over-hand assistance to complete the targeted response. This is usually used when the target response is motor in nature. For example, a full physical assist might entail putting your hand on the student's hand and moving the student's hand through the action of writing his or her name. If the student is learning to jump up and down, providing a full physical assist would mean physically lifting the student up and down in a jumping motion. You will know before you start teaching if the student will need this type of assistance. If so, use the decreasing prompt hierarchy instead.
 
 

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