1. Stimulus Control

2. Stimulus Control is involved in…
When to talk to strangers
When to cross the street
When to say hi to someone
When to eat week-old food out of the refrigerator
When to say “reward” and
when to say “reinforcer”
When to hug vs. give hand shake to someone

3. Stimulus Control Stimulus control is everything!
Most children with autism have difficulty emitting social and verbal behavior under appropriate stimulus conditions.

4. Reinforcer:
Break from work
SD:
Teacher Joe
Response:
Scream
SΔ:
Teacher Jenny
No break

5. Reinforcer:
Door is opened
SD:
Teacher
Response:
“Open door”
SΔ:
Peer
Door is not opened

6. Reinforcer:
“ouch!”
SD:
Mom in room
Response:
pinch
SΔ:
Dad in room
No response

7. Hold out picture of spoon
Reinforcer:
spoon
SD:
Person in room
Response:
Hold out picture of spoon
SΔ:
No one in room
No spoon

8. Stimulus Control
Stimulus Discrimination
Stimulus Generalization

9. Stimulus Control Stimulus Discrimination
Definition: Degree to which antecedent stimuli set the occasion for particular responses
precise degree of stimulus control
E.g., Man has beard and is Daddy; Man has beard and is Uncle Eddie
Stimulus discrimination is taught by using discrimination training procedures such as differential reinforcement

10. Stimulus Control Stimulus Generalization
Definition: When a response is reinforced in the presence of one stimulus there is a general tendency to respond in the presence of new stimuli that have similar physical properties ore have been associated with the stimulus.
loose degree of stimulus control
E.g., All men with beards are Daddy
Cannot be taught –but can plan for it

11. Development of Stimulus Control
Stimulus discrimination training
Requires one behavior
Two antecedent stimulus conditions (the SD and the S)
Responses that occur in the presence of the SD are reinforced (thus, the response increases in the presence of the SD)
Responses that occur in the presence of the S are not reinforced (this, the response decreases in the presence of the S
Can also result in a lesser amount or quality of reinforcement

12. Development of Stimulus Control
Example: Reinforcing a child’s saying “red” when someone asks “What’s your favorite color?” and witholding reinforcement if they said “red” when asked “ What’s your name?”

13. “What’s your favorite color?”
SD:
“What’s your favorite color?”
Response:
“red”
Reinforcer:
“Super! You said red!”
SΔ:
“What’s your name?”
No praise

14. Differential Responding
When a child’s behavior comes under the control of the SD,
We say the SD has acquired stimulus control over the child’s behavior
So the verbal stimulus “What’s your favorite color?” gains stimulus control over the response “red” – why?
And the child is discriminating or responding differentially

15. Stimulus Generalization
When a response is reinforced in the presence of one stimulus,
That same type of behavior tends to be evoked by stimuli that share similar physical properties with that controlling antecedent stimulus

16. Stimulus Generalization
If you teach “green” using this color circle …
Student’s most likely to say “green”
Student’s less likely to say “green” (discrimination)
Student’s less likely to say “green” (discrimination)

17. Stimulus Generalization
So…when a response has been trained with a specific teacher, materials, or setting
It may occur with other, similar teachers, materials, or settings
The more similar the novel teacher, materials, and setting are to the training teacher, materials, and setting…
The more likely stimulus generalization will occur

18. Discrimination vs. Generalization
Essentially opposite processes
As one increases, the other decreases
Discrimination
Responding differently to 2 or more stimuli
Tight degree of stimulus control
Generalization
Responding similarly to 2 or more stimuli
Loose degree of stimulus control

19. Stimulus Discrimination and Stimulus Generalization are a Continuum

20. Why Teach Discriminations?
Discrimination is a fundamental process that controls behavior.
Discrimination allows us to differentiate when reinforcement is available for specific responses.
For example, saying the word book when the teacher points to a book will result in reinforcement. Saying car when the teacher points to a book will not result in reinforcement.
Also red light on the soda machine example.

21. Why Teach Discriminations?
Many essential tasks require discrimination skills
Reading.
Labeling Objects.
Following directions.
Following activity schedules.
Greeting people.
Self-care skills.

22. Basic Problem of Discrimination Training
Discrimination training teaches learners to perform a specific response in the presence of a specific stimulus and not to perform that response in the presence of other stimuli.

23. Discrimination Training
Many individuals with developmental disabilities have difficulty learning discriminations
Stimuli are compound (they consist of different elements)
It may be difficult to control which element(s) of the stimulus exert control over behavior
We must be careful how we teach and what stimuli we use!

24. Stimulus Compounding All stimuli are compound.
They consist of many different elements.
It is difficult to control which element or elements of the stimulus exert control over behavior.
We need to be careful how we teach and what stimuli we use.

25. 2 Types of Discriminations.
Simple Discriminations.
Non-Conditional Discrimination.
Conditional Discriminations.
Matching-to-sample.
Arbitrary Discrimination.

26. Simple Discrimination
Stimulus is present or not present
One picture on the table that’s a “cat” Say touch “cat” and they do
Not very useful for children with autism
That kind of trial becomes stimulus independent which is what you DON”T want to happen

27. Conditional Discrimination
A response to a given stimulus is followed by a reinforcer if and only if another stimulus is present
Said another way…a stimulus is discriminative for reinforcement or not, depending on (conditional on) the presence of another particular antecedent
Often taught via Match-to-Sample procedures
Many programs consist of Identity Matching (matching identical stimuli):
Objects
Pictures
Letters
Shapes
Colors
Numbers

28. Match-to-Sample Sample SD/S+ SΔ/S- SΔ/S-
Then responds to one of the comparison stimuli
Sample
Learner 1st responds to sample (conditional stimulus)

29. Match-to-Sample SD/S+ SD/S+ Sample (Conditional Stimulus)

30. Establishing New Forms of Conditional Stimulus Control
Identity matching (single mode)
Visual: visual
Auditory: auditory
Arbitrary matching (multimodal)
Visual: auditory
Auditory: visual
Auditory: tactile

31. Arbitrary Matching Stimuli are not physically identical Examples
Match non-identical visual stimuli
Object to pic, printed word to picture, object to printed word
Match auditory stimulus to visual stimulus (“Receptive Identification”)
Others?

32. Receptive Picture ID
SD/S+
SD/S+
“baby”
“flower”
Sample
Sample

33. Discrimination in the Laboratory.
Many laboratory discrimination procedures have focused on understanding exactly which stimuli or which aspects of stimuli control responding.
Several laboratory procedures have been developed that allow us to isolate these stimulus control factors.
Matching-to-Sample.
Equivalence Class Formation.

34. Concept Formation
Definition: Complex stimulus control that results in generalization within a class of stimuli and discrimination between classes of stimuli (Keller & Schoenfeld, 1950).

35. Two Procedures to Teach Concept Formation:
Simultaneous Discrimination:
Definition: The concurrent presentation of multiple stimuli
Successive Discrimination
Definition: The successive presentation of stimuli
In applied settings, simultaneous discrimination training should be used –why?
The individual has access to all relevant stimulus cues at one time
An on the spot comparison of choices is permitted
Produces better generalization (Schroeder & Baer, 1972)

36. Classroom Teaching Procedures.
Classroom teaching is more complex than the laboratory.
Suggestions for improving discrimination training
Evaluate stimuli carefully to promote control of relevant antecedent cues
Rotate stimulus placement randomly
Change auditory stimuli frequently
Be sure that the S+/S- functions of stimuli change randomly
Teach with a variety of stimuli to promote discrimination between categories (and generalization within categories)
Never, never teach in isolation!!

37. Classroom Teaching Procedures.
NEVER, NEVER, NEVER teach in isolation!!

38. Stimulus Class
Stimulus Class: set of stimuli that have a common effect on behavior (evoke the same response class)
These would probably be in the same stimulus class for most people

39. Concept Formation Complex stimulus control that results in:
Generalization within a class of stimuli and
Discrimination between classes of stimuli

40. Stimulus Equivalence
Emergence of accurate responding to untrained and nonreinforced stimulus-stimulus relations
Following the reinforcement of responses to some stimulus-stimulus relations
3 aspects
Reflexivity
Symmetry
Transitivity A B C
DOG
“dog”

41. Reflexivity
In the absence of training, person selects an identical stimulus (AKA Generalized identity matching)
Logic is…A = A
For example
Without specific training, the person matches

42. Symmetry
After being taught to match A to B, person can match B to A (without training)
Logic is…If A = B, then B = A
For example
After being taught to match to
Person can match to
DOG
DOG

43. Transitivity
Critical test for stimulus equivalence – if you get transitivity, the stimuli are members of an equivalence class
After being taught to match A to B and B to C, person can match A to C (without training)
Logic is…If A = B and B = C, then A = C
For example…
After being taught to match
to AND
to “dog”
Person can match to “dog”
DOG
DOG

44. Factors Affecting the Development of Stimulus Control
Reinforcement
Differential reinforcement with rich schedules of reinforcement
Preattending Skills
Looking at instructor or materials, sitting up tall, no stereotypy

45. Factors Affecting the Development of Stimulus Control
Stimulus Presentation
Specificity of directions
Should relate to response definition
Opportunity to response
Frequent, active opportunities to respond (active student learning) correctly leads to higher rates of academic achievement
Pacing of response opportunities
Higher pace often leads to superior performance and less off-task behavior

46. Factors Affecting the Development of Stimulus Control
Salience of the stimuli
Influences attention and ultimately the development of stimulus control
Dependent on the capabilities of an individual, the past history of reinforcement, and the situation
Multiple intelligences: some respond to instructional stimuli in the visual modality more than the oral.
This research has generated mixed results but it is important to rule out sensory deficits and assess modality strength

47. Factors Affecting the Development of Stimulus Control
Masking and overshadowing
Masking –even though one stimulus has control over behavior, another stimulus blocks that control from being expressed
E.g., Student knows answer but won’t answer in front of peers
Overshadowing –the presence of one stimulus condition interferes with the acquisition of control by another stimulus
E.g., hallway may be more interesting that teacher’s presentation in the front of the classroom
Ways to overcome include to make changes to physical environment, make instructional stimuli as intense and centrally located as possible, reinforce behavior in the presence of the instructionally relevant stimuli