Discrimination & Complex Stimulus Control Chs12 & 13

Reinforcement-Based Discrimination Before SS SDSD After Behavior

Discriminative Stimulus (S D ) 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 S D 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 StimulusTwo 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 S D 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 S D 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

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 S D but not in the presence of S . This is ______________ Responds at similar rates in presence of S D and S . This is __________________

Stimulus Generalization

Stimulus Discrimination

Stimulus-Generalization Gradient

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 (S D ) 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 S D and the S   differ along at least two stimulus dimensions (green & white, new & old). The difference between the S D and the S   along all but one dimension is reduced until there is no difference along the reduced dimensions. The the S D and the S   differ 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

Susan

Jimmy

Susan Jimmy

Susan Jimmy

Reinforcement-Based Discrimination Before Jimmy has no raisin S  Susan on a black card S D 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 ProcedureArea of Application Purpose ShapingResponse 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 FadingStimulus 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” S D 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.