discrimination & complex stimulus control chs12 & 13
TRANSCRIPT
Discrimination & Complex Stimulus Control
Chs12 & 13
Reinforcement-Based Discrimination
Before
S
SD
After
After
Behavior
Discriminative Stimulus (SD)
• A stimulus in the presence of which a particular response will be reinforced or punished
S-delta (S)
• A stimulus in the presence of which a particular response will not be reinforced or punished
Reinforcement-Based Discrimination
Before
Chicken has no food
S
Breland
SD
Brelandlesss target
After
Chicken has no food
After
Chicken has food
Behavior
Chicken pulls the trigger
Discrimination Training Procedure
• Reinforcing or punishing a response in the presence of one stimulus and extinguishing it or allowing it to recover in the presence of another stimulus.
Stimulus discrimination(stimulus control)
• The occurrence of a response more frequently in the presence of one stimulus than in the presence of another, usually as a result of a discrimination training procedure
Differential Reinforcement vs. Stimulus Discrimination
One Stimulus Two Stimuli
One Response Class
No differentiation or discrimination
Stimulus discrimination
Two Response Classes
Response differentiation
Combined differentiation & discrimination
Concept training
• Intuition?– Control by a concept or set of contingencies the
person or organism does not define or describe
• Concept of PERSON is complex
Herrnstein & Loveland
• Concept training procedure with nonverbal animal
Concept Training
Before
No grain
Sdelta
Various pictures with no people
SD
Various pictures of people
After
Pigeon has no grain
After
Pigeon has grain
Behavior
Pigeon pecks key
Concept Training
Before
No grain
Sdelta
Various painting by others
SD
Various Picasso paintings
After
Pigeon has no grain
After
Pigeon has grain
Behavior
Pigeon pecks key
Complex Stimulus Control
• Conceptual stimulus control
Stimulus class (concept)
• A set of stimuli all of which have some common physical property
• A stimulus class is the same thing as a concept
Stimulus generalization
• The behavioral contingencies in the presence of one stimulus affects the frequency of the response in the presence of another stimulus
• E.g. – reinforcement for pecking in presence of 1 Picasso painting affects likelihood of pecking in presence of another Picasso painting (more likely)
Concept Training
• Reinforcing or punishing a response in the the presence of one stimulus class and extinguishing it or allowing it to recover in the presence of another stimulus class
Concept training
Vs.
Conceptual stimulus control
Conceptual stimulus control
• Responding occurs more often in the presence of one stimulus class and less often in the presence of another stimulus class because of concept training
Testing for stimulus generalization
• Test for stimulus generalization using novel stimuli
• If respond correctly to novel stimuli, can say the behavior is under the stimulus control of concepts.
Stimulus generalization vs. stimulus discrimination
• Responds in presence of SD but not in the presence of S. This is ______________
• Responds at similar rates in presence of SD and S. This is __________________
Stimulus Generalization
0
10
20
30
40
50
60
Num
ber
of R
espo
nses
red green blue yellow
Stimulus Discrimination
0
5
10
15
20
25
30
35
40
45
Num
ber
of R
espo
nses
red green blue yellow
Stimulus-Generalization Gradient
0
50
100
150
200
250
300
350
Blue Yellow-green
Red
TEST COLORS
Num
ber
of K
ey P
ecks
Generalization vs. Discrimination
• Amount of generalization is the opposite of the amount of stimulus discrimination (stimulus control)
Fading, Errorless Learning, Imitation
Chapter 13 & 14, Part 2
Fading
• Stimulus dimensions– The physical properties of stimuli
Stimulus Dimensions
• Stimuli differ from each other– House vs. car
• Obvious dimensions– Size, weight, shape, material, etc.
vs.
Stimulus Dimensions
• The more dimensions along which objects differ, the easier to establish a discriminative stimulus control
• The fewer dimensions along which objects differ, the harder it is to establish discriminative stimulus control
Example
• Good golf balls (SD) vs. bad golf balls (S)
• This is a discrimination that is difficult
• How can the discrimination be established?
• The 2 golf balls are similar in so many dimensions….and differ in only a few– Roundness, resiliency, hardness of cover
Make stimulus dimensions more salient, then use fading
• Color the bad golf ball green
• Leave the good golf ball alone
• Reinforce picking out good golf balls
• Don’t reinforcer picking bad (green) golf balls
Fading
• Gradually fade out the difference between good balls and bad balls by reducing the “green”
Fading procedure
• At first, the SD and the Sdiffer along at least two stimulus dimensions (green & white, new & old).
• The difference between the SD and the Salong all but one dimension is reduced until there is no difference along the reduced dimensions.
• The the SD and the Sdiffer along only one dimension
Errorless Discrimination Procedure
• The use of a fading procedure to establish a discrimination, with no errors during training.
Jimmy
Susan
Jimmy
Susan
Jimmy
Jimmy
Susan
Susan
Jimmy
Susan
Jimmy
Susan
Jimmy
Reinforcement-Based Discrimination
Before
Jimmy has no raisin
S
Susan on a black card
SD
Jimmy on a white black card
After
Jimmy has no raisin
After
Jimmy has a raisin
Behavior
Jimmy picks card
Stimulus Dimensions
• Lettering
• Shading
• At first, choice of cards was under the control of the dimension of ________
• Then, after fading, responding was under the control of the dimension of _______
Techniques of Gradual Change
Procedure Area of Application
Purpose
Shaping Response differentiation
To bring about a response not made by the organism
Reinforcer Reduction
Type & amount of reinforcer
To maintain responses already made or to establish a particular pattern of responses
Fading Stimulus discrimination
To bring the response under the control of stimuli that didn’t exert control initially
Reinforcer Reduction
• Move from primary to secondary reinforcers
• Change from 3 pellets to 1 pellet
Imitation
• The form of the behavior of the imitator is controlled by similar behavior of the model
Imitation Training: Stimulus Discrimination
Before
Marilla has no food & praise
S
No arm raised or no “do this”
SD
Raised arm and “do this”
After
Marilla has no food & praise
After
Marilla has food & praise
Behavior
Marilla raises arm
Imitation Training: Differential Reinforcement
Before
Marilla has no food & praise
After
Marilla has no food & praise
After
Marilla has food & praise
Behavior
Marilla raises arm
Behavior
Marilla raises arm
Training Imitation
• Train imitation with a partner– Touch nose– Touch toes– Raise hand– Etc……
Generalized Imitation
• Imitation of the response of a model without previous reinforcement of imitation of that specific response.