Stimulus Control Justin Daigle, BCBA, LBA

Stimulus“An energy change that affects an organism through is receptor cells” (Michael, 2004, p.7)

Note: Stimulus is singular. Stimuli is plural.

StimulusStimuli is a part of an organism’s environment. Includes both overt and covert events.

Overt – Able to be seen by an observerCovert- Private Events

StimulusAn stimulus is considered arbitrary when there is no connection between the stimuli and the behavior.

SD

Discriminative Stimulus –A stimulus in the presence of

which responses of some type have been reinforced and in the absence of which the same type of responses have occurred and not been reinforced

S∆

Stimulus Delta –A stimulus in the

presence of which a given behavior has not produced reinforcement in the past.

Natural ExampleArbitrary Stimulus

No “Ring”

“Ring”

None

“Hello”

S∆

SD

Target Behavior

StimulusThe only stimulus that controlled the behavior was the “ring”

We can say that the phone ringing has stimulus control over the behavior of answering the phone.

Stimulus ControlA situation in which the frequency, latency, duration, or amplitude of a behavior is altered by the presence or absence of an antecedent stimulus.

In Other WordsIf an SD can accurately elicit a target behavior, that SD has stimulus control over the target behavior.

Examples• I only smoke when I’m at a bar.• I only drink when I’m sad.• I jam Alanis Morrissette when

I’m angry.• Just seeing Jim makes me

angry.

PunishmentA behavior can come under stimulus control both by reinforcement (as our previous definition suggested) or by punishment.

Nat’l Ex - PunishmentStimulus

Go

Stop Absence of Ticket

PostcedentBehavior

Stimulus Control GameInstructions:On a piece of paper, write the numbers 1-5 vertically. In each example a behavior and with two consequences will be given. Write down what you image to be the stimuli that control the behavior.

1) DanielleStimulus

Go

Stop Absence of Ticket

PostcedentBehavior

?

2) JimmyStimulus

Talking Loud

Outside Absence of Trouble

PostcedentBehavior

? Got in Trouble

Talking Loud

3) DanielStimulus

“Suck My Dick”Pretty Girl

Laughed

PostcedentBehavior

?

Slapped in Face

“Suck My Dick”

4) AlexStimulus

15 minutes late

Job Interview

Positive Social Impact

PostcedentBehavior

?

Negative Social Impact

15 minutes late

5) StephenStimulus

Joke about 9/11

Yesterday around buddies

NegativeSocial Impact

PostcedentBehavior

?

Positive Social Impact

Joke about 9/11

Stimulus Control The same behavior, elicited by a stimuli, can have different consequences.

Often times we have to train or re-train stimuli to elicit specific behaviors.

Real Life ExampleStudent: EionAge: 7Target Behavior: StereotypyIn Sessions: A “Red” card was placed on a specified spot on a visual schedule when stereotypy would be blocked (or punished)

Real Life ExampleBecause of the need for school: Eion was taught only to engage in stereotypy in the presence of a green card on his desk.

Real Life ExampleThis was later generalized to be a rubber band or rubber bracelet on his wrist. During P.E. or recess, he was given the green bracelet and stereotypy was not interfered with.

Real Life ExampleWhile wearing the red bracelet, Eoin never engaged in the target behavior.

He was allowed to wear the green bracelet less and less over the years until it was not needed.

Real Life ExampleEoin is now 25 and will occasionally wear a red bracelet when he feels like it going to be a “bad day”.

Concept FormationIn Behavior Analysis, words like “concept” is a hypothetical construction; however, during teaching, we observe our clients understanding the concept behind the trial.

Concept FormationIn Behavior Analysis, we do accept concept formation. It is a complex example of stimulus control. The stimuli is generalized across a stimulus class.

Stimulus ClassA group of stimuli that share specified common elements:

- Form (e.g. size, color)- Function (e.g. SD)

“Touch” and “Point to” both elicit the same behavior. Both phrases are in a stimulus class.

Feature Stimulus ClassWhen members of a stimulus class share a common physical form or common relative relations.

Ex. Black lab and a blood hound have similar features – both are dogs.

Arbitrary Stimulus ClassWhen members of a stimulus class do not share a common stimulus feature

Ex. Seeing 50%, ½, divided evenly, or .5 will elicit the same target behavior – halving.

Stimulus Equivalence Justin Daigle, BCBA, LBA

Stimulus EquivalenceThe emergence of accurate responding to untrained and non-reinforced stimulus-stimulus relations following the reinforcement of responses to some stimulus-stimulus relations.

Stimulus EquivalenceDeveloped by Murray Sidman in a landmark 1971 study.

Based on mathematical statements

Stimulus Equivalence1) If A=B, 2) And B=C,3) Then A=C

Stimulus EquivalenceA, B, and C are all variables.So for our examples, let’s define them:

A = Spoken Word “Bicycle”B = Picture of Bicycle

C = Written word Bicycle

Stimulus EquivalenceA- Spoken Word, B – Picture,

C – Written Word

Key

Bicycle

Teach A=B

Stimulus EquivalenceA- Spoken Word, B – Picture,

C – Written Word

Key

Bicycle

Teach B=C

Stimulus EquivalenceA- Spoken Word, B – Picture,

C – Written Word

Key

Bicycle

Equivalence A=C

Bicycle

ReflexivityThe teaching of A=A

(Matching to Sample)

SymmetryThe understanding that if A=B, then B=A

TransitivityUnderstanding the final “jump” without training.

A=C and C=A

ConclusionThe learner must exhibit Reflexivity, Symmetry, and Transitivity in order to prove Stimulus Equivalence.

Further ReadingSidman, M. (1971). Reading and auditory-visual equivalences. Journal of Speech and Hearing Research, 14, 5-13.