Module 4 - Chap. 17: Stimulus Control Flashcards
Stimulus control occurs when
The rate, latency, duration, or amplitude of a response is altered
In the presence of an antecedent stimulus
Stimulus control is acquired when
Responses are reinforced only in the presence of a specific stimulus (known as the discriminative stimulus (S^D)
& not in the presence of other stimuli (known as stimulus deltas)
The development of stimulus control
S^D —> Response —> S^R+
Telephone rings —> Pick up phone and say “hello” —> Friendly conversation
S ^ delta —> Response —> S^O
Doorbell rings —> Pick up phone & say “hello” —> Friendly conversation withheld
Not to be confused with respondent conditioning
UCS —> Response
Meat powder —> Dog salivates
Neutral S or UCS —> Response
Bell rings or Meat Powder —> Dog salivates
CS —> Response
Bell rings —> Dog salivates
Notice the absence of any consequence stimuli in this example
Salivating is a respondent behavior
Also notice that here control is established by pairing specific antecedent stimuli
Stimulus Control & Motivating Operations
Similarities: both events occur before the behavior of interest; both events have evocative functions
However they are different!
Motivating Operations
Remember, a motivating operation is something that changes the value of a stimulus as a reinforcer
Establishing operation (EO) makes the reinforcer more valuable
Abolishing operation (AO) makes the reinforcer less valuable
MOs & Stimulus Control
EO SD —> Response —> S^R-
Difficult worksheet Teacher 1 —> Student displays aggression —> Task break provided
EO S delta —> Response —> S^O
Difficult worksheet Teacher 2 —> Student displays aggression —> Task break withheld
Stimulus Generalization
Occurs when stimuli that share similar physical characteristics with the controlling stimulus evoke the same behavior as the controlling stimulus
Stimulus Discrimination
Occurs when new stimuli that are similar to the controlling stimulus do not evoke the same response as the controlling stimulus
Stimulus control & stimulus generalization are a…
Continuum
Development of stimulus control
Stimulus discrimination training
- requires one behavior
- two antecedent stimulus conditions (the S^D & the S^delta)
Responses that occur in the presence of the S^D are reinforced (thus, the response increases in the presence of the S^D)
Responses that occur in the presence of the S^delta are not reinforced (thus, the response decreases in the presence of the S^delta)
- can also result in a lesser amount or quality of reinforcement
Concept formation
Not a hypothetical construct or mental process
Complex example of stimulus control that requires
- stimulus generalization within a class of stimuli
- stimulus discrimination between classes of stimuli
Example: Concept of Red
Stimulus generalization across all red objects
- Light red to dark red
- Different objects (ball, car, pencil)
Stimulus discrimination between red & other colors
- Red ball vs. yellow ball
- Red dress vs. blue dress
Teaching concepts
Requires discrimination training
- antecedent stimuli representative of a group of stimuli sharing a common relationship (examples) are presented, along with…
- antecedent stimuli from other stimulus classes (nonexamples)
So that the examples form a stimulus class
Types of stimulus classes
FEATURE STIMULUS CLASS
- Stimuli share common physical forms (i.e., topographical structures)
- Stimuli share common relative relationship (i.e., spatial arrangements)
- Developed through stimulus generalization
ARBITRARY STIMULUS CLASS
- Do not share a common stimulus feature
- Limited # of stimuli
- Developed using stimulus equivalence
Stimulus equivalence
The emergence of accurate responding to untrained and nonreinforced stimulus-stimulus relations following the reinforcement of responses to some stimulus-stimulus relations
Useful for teaching complex verbal relations
- Reading
- Language arts
- Mathematics
Testing for stimulus equivalence
Must have a positive demonstration on 3 different behavioral tests that represent the following mathematical statement:
- If A = B, and B = C, THEN A = C
Tests for stimulus equivalence
Reflexivity: occurs when in the absence of training and reinforcement, a participant selects a stimulus that is matched to itself (A = A)
Symmetry: occurs with the reversibility of the sample stimulus & the comparison stimulus (if A = B then, B = A)
Transitivity: requires demonstration of three untrained stimulus-stimulus sequences
- A = B relation (spoken name = picture)
- “Bicycle” (spoken name presented) then the child selects the picture
- B = C relation (picture = written word)
- Picture of bicycle presented, then the child selects the written word
- A = C relation (spoken word = written word)
- “Bicycle” (spoken word presented) then the child selects the written word
Matching to sample
Participant observes the sample stimulus
The comparison stimuli are then presented
Participant makes a selection response
- Matches are reinforced
- Nonmatches are not reinforced
Conditional discrimination training
Same selection must be correct with one conditional stimulus, but incorrect with one or more other sample stimuli
Factors affecting stimulus control
Consistent use of reinforcers contingent upon correct responding in the presence of the S^D is critical
Also important are:
- Pre-attending skills
- Stimulus salience
- Masking & overshadowing
Pre-attending
A prerequisite skills for stimulus control
- Looking at instructional materials
- Looking at teacher when responses are modeled
- Listening to oral instructions
- Sitting quietly for short periods of time
These may need to be taught before stimulus control procedures are implemented
Stimulus salience
Prominence of the stimulus in the environment
Increased saliency facilitates efficiency of instruction
Masking & Overshadowing
Increase or decrease salience of stimuli
Competing stimuli may block the evocative function of an S^D
To limit the negative effects of these:
- Rearrange the environment
- Make instructional stimuli more intense
- Consistently reinforce behavior in the presence of instructionally-relevant stimuli
Using prompts
Supplementary antecedent stimuli used to occasion a correct response in the presence of an S^D (that will eventually control behavior
- Response prompts operate directly on the response
- Stimulus prompts operate directly on the antecedent task stimuli
Response prompts
Verbal instructions
- Vocal
- Non-vocal (e.g., written)
Modeling
- A demonstration of the desired behavior
Physical guidance
- partially physically guide the student’s movement
As you move down, the intrusiveness increases
Stimulus prompts
Movement cues
- Pointing, tapping, touching, looking at
Position cues
- Place one stimulus closer to the student
Redundance
- Stimulus or response dimensions are paired with correct choice
Transfer of stimulus control
Prompts should be used only during acquisition
Transfer stimulus control from prompt to naturally-existing stimuli quickly using fading
Transferring from response prompts
Most-to-least prompts
- Physically guide participant through entire performance
- Gradually reduce amount of physical assistance
- Modeling
- Verbal instruction
- Natural stimulus
Graduated guidance
Immediately fade physical prompts
Follow participant closely with hands
Gradually increase distance between hands & participant
Least to most prompts
Provide participant with an opportunity to perform the response with the least amount of assistance on each trial
Participant receives greater degrees of assistance with each successive trial without a correct response
Time delay
Varying the time interval between presentation of a natural stimulus & the presentation of a response prompt
CONSTANT TIME DELAY
- Begin with a 0 second delay
- Then use a fixed delay (3 sec)
PROGRESSIVE TIME DELAY
- Begin with a 0 second delay
- Gradually & systematically increase delay (in 1 sec intervals) according to some rule
Stimulus fading
Highlighting a physical dimension of a stimulus & then gradually fading that exaggerated dimension
Superimposing one stimulus on top of another & gradually fading it out
Stimulus shape transformations
Use an initial stimulus shape that will prompt a correct response
This shape is gradually changed to form the natural stimulus, while maintaining correct responding
