Stimulus Control in Behavioral Psychology
Stimulus Control
Stimulus Control of Behavior
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Having stimulus control means that the
probability of the
behavior varies depending upon the stimuli present.
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If a behavior is under stimulus control then
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The behavior happens when the stimulus is present
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The behavior doesn’t happen when the stimulus is absent
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Most of our behavior is under stimulus control
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A person that contributes to charity generously while in church
may watch every penny spent while at work
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Definition
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Degree to which antecedent stimuli set the
occasion for particular responses
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Precise degree of stimulus controlling responding
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E.g., Man has beard and is Daddy; Man has beard and is
Uncle Eddie: Child only responds to bearded Daddy as
Daddy
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Stimulus discrimination is taught by using discrimination
training procedures such as differential reinforcement
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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.
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Loose degree of stimulus controlling a response
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E.g., All men with beards are Daddy
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Stimulus generalization
is taught by using
generalization training procedures: Reinforce any
stimulus within the class of related stimuli.
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Stimulus discrimination training requires
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One behavior
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Two antecedent stimulus conditions: the S
D
and the S
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Or the S+ and the S-
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Responses that occur in the presence of the S
D
are reinforced
(thus, the response increases in the presence of the S
D
)
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Responses that occur in the presence of the S
are not
reinforced: The response decreases in the presence of the S
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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?”
Response:
“red”
Reinforcer:
“Super! You
said red!”
S
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“What’s your
favorite color?”
S
Δ
:
“What’s your
name?”
No praise
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When a child’s behavior comes under the control
of the S
D
,
the S
D
has acquired
stimulus control
over the child’s behavior
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So the verbal stimulus “What’s your favorite
color?” gains stimulus control over the response
“red” – why?
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And the child is
discriminating
or
responding
differentially
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When a response is reinforced in the presence of one
stimulus as well as similar stimuli
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The
same behavior response tends to be evoked by
stimuli that share similar physical properties with that
controlling antecedent stimulus
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Stimulus Generalization is more likely when stimuli that
are
highly similar
to the original stimulus are presented
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You stop at first traffic light you come upon in driver’s ed,
but you generalize your responding so you stop at any
red traffic light in any city or town.
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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)
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Respond to similar stimuli to the original
stimulus
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E.g., similar people, materials, or settings
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Generalization is more likely when the novel
stimulus is similar to the training stimulus
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Stimulus
Discrimination
Stimulus
Generalization
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Generally, as the training and test stimuli become more different
responding will decline
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Produces a
generalization gradient
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The gradient shows the degree to which discrimination or
generalization has occurred.
How to test generalization
Train
GeneralizationTest
T+
For example, train a
pigeon to detect T =
1000hz tone
No reinforcers
Present tones of varying
frequencies and
examine keypecking
rate in response to each
tone
Generalization Gradient
Guttman & Kalish (1956)
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pigeons reinforced for pecking a
580 nm lit key (orange-yellow)
(S+) on a VI schedule
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A test session was then given
where many different colored key
lights were presented in
extinction
S
+
Interpreting Generalization Gradients
Pigeons trained to peck
a moderately
bright light
(S+)
to get food.
(
S- = dim light
)
After asymptote is
reached, present
occasional non-
reinforced probe trials
at various wavelengths
or levels of brightness.
Excitatory and
inhibitory gradients
Excitatory gradients
form
around the CS+; show
where responding is MOST
likely
Inhibitory gradients
also
form; show where
responding is least likely
e.g., Pigeons trained to peck
at a 800 hz tone (S+), with a
500 nm light S-.
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Phenomena where
the peak of the generalization curve
shifts AWAY from the S-
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Means that the most responding does not occur for
the S+,
but
slightly offset from the S+ and away from
the S-
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The peak of responding shifts AWAY from the S-
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Question is WHY!
Peak Shift Effect – Hanson (1959)
Let’s do an example of Discrimination Training
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Two choices:
1
4
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4
is the correct answer
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Using the last question and correct answer, which is
the “best” answer for each of the following?
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3.9
-1
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-1
5
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0.9
3
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4
16
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Again,
4 is the answer
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Now which is the best answer?
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Using your answer from the last slide: Which is the answer for each of
the following?
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16
48
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8
32
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100
400
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First set of slides: Tend to pick answer that is
closest to 4
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Second set of slides: Tend to pick the smaller (1/4
of the second answer)
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Why?
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Two theories may explain
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Spence’s Summation Theory
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Kohler’s Interdimensional Theory
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Peak shift occurs because of the summation of the
excitatory and inhibitory curves
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Result is that the
most responding is slightly in
favor of the S+
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Not as strong of suppression for S-; thus, get a
slight shift away from S- when sum the two curves
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Just a math phenomenon
Spence’s Theory to Account for Peak Shift
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The animal learns a conceptual rule: When given stimuli,
choose whichever fits the characteristics of S+ to S-
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E.g.: S+ is always larger
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E.g.: S+ is the most green
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Thus, when given generalization stimuli, look for whatever is
the most “S+” compared to what should be “S-”
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”.
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Shift away from S+ occurs because the organism
compensates for “not S-”, and overcompensate
PAST the S+ but away from the S-
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Learning a concept
: Always choose larger or greener,
etc.
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Given a large and small stimulus, choose large even if
it is too large
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If S+ is read and S- is green, choose the “reddest” but
the least “green”.
Inter
dimensional discrimination
Discrimination: S+ = 555nm Light; S- = Tone
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Choose between squares:
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S+
S-
Situation:
100
cm
2
50 cm
2
Original training
250 cm
2
150
cm
2
Test 1:
Spence’s test
500
cm
2
250 cm
2
Test 2
:
Kohler’s test
1000 cm
2
500 cm
2 ??????
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Spence's prediction
: Will choose closest to original S+
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Transposition or interdimensional
: choose larger
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Tests for summation yield evidence supporting Spence’s
theory
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When using
stimuli close to the original stimulus
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Animal tends to make errors towards the original stimulus
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Tests for transposition/interdiminensional yield
evidence supporting Kohler’s theory
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When using
stimuli highly different from original stimulus,
error towards original stimulus
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But show “concept” rule in that
keep the relation of the
difference constant (e.g., choose the smaller one)
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BOTH!
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When the test includes stimuli close to the original S+, animal
tends to choose the one closest to the S+
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As differences become increasingly larger, animal tends to choose
the stimulus consistent with the type of difference between the
S+ and S-
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E.g., larger or red-er
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Why?
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Discrimination is a fundamental process that controls behavior.
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Discrimination allows us to differentiate when reinforcement is
available for specific responses.
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Many essential tasks require discrimination skills
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Reading.
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Labeling Objects.
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Following directions.
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Following activity schedules.
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Greeting people.
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Self-care skills.
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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.
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Most stimuli are compound (they consist of different
elements)
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It may be difficult to control which element(s) of the
stimulus exert control over behavior
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We must be careful how we teach and what stimuli
we use!
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All stimuli are compound.
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They consist of many different elements.
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Modality (visual, auditory, tactile)
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Size, color, shape, etc.
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It is difficult to control which element or elements of the stimulus exert
control over behavior.
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Need to be careful how we teach and what stimuli we use.
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Have organism attend to critical aspects of the S+
2
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Simple Discriminations.
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Non-Conditional Discrimination.
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Simple association A = B
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Conditional Discriminations
.
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Matching-to-sample.
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Arbitrary Discrimination.
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Involves complex associations
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Stimulus is present or not present
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Simple association: If red then apple
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One picture on the table that’s a “cat” Say touch
“cat” and they do
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Cue dog to “sit”; sitting is the only correct response
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Not “real life” for most human tasks (or for dogs for
that matter).
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A response to a given stimulus is followed by a reinforcer if and only if
another stimulus is present
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Said another way…a stimulus is discriminative for reinforcement or no
reinforcement depending on (conditional on) the presence of another
particular antecedent
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Often taught via Match-to-Sample procedures
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If a picture of a dog, then say dog; if a picture of a cat, then say cat
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Vary the answer for the same reinforcement depending on conditional cue (dog or cat picture)
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Many programs consist of
Identity Matching
(matching identical
stimuli):
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Objects
Pictures
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Letters
Shapes
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Colors
Numbers
Match-to-Sample
Sample
Learner 1
st
responds to sample
(conditional stimulus)
Then responds to one of
the comparison stimuli
S
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/S+
S
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/S-
S
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Match-to-Sample
S
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/S
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Sample (Conditional Stimulus)
S
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/S
+
Sample (Conditional Stimulus)
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Identity matching (single mode)
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Visual: visual
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Auditory: auditory
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Arbitrary matching (multimodal)
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Visual: auditory
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Auditory: visual
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Auditory: tactile
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Stimuli are not physically identical
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Different modalities (visual/verbal)
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Different types of stimuli: story problem; number answer
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Examples
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Match non-identical visual stimuli
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Object to pic, printed word to picture, object to printed word
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Match auditory stimulus to visual stimulus (“Receptive
Identification”)
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Others?
Receptive Picture ID
“flower”
“baby”
SD/S+
Sample
SD/S+
Sample
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Complex stimulus control that results in:
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Generalization
within
a class of stimuli and
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Discrimination
between
classes of stimuli
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Two procedures for teaching concept formation:
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Simultaneous Discrimination
: The concurrent
presentation of multiple stimuli
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Successive Discrimination
:
The successive
presentation of multiple stimuli
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Teaching elements of a stimulus class!
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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
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Emergence of accurate responding to untrained and
nonreinforced stimulus-stimulus relations following the
reinforcement of responses to some stimulus-stimulus
relations
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3 aspects
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Reflexivity
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Symmetry
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Transitivity
DOG
“dog”
A
B
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In the absence of training, person selects an
identical stimulus (AKA Generalized identity
matching)
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Logic
is…
A = A
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For example: W
ithout specific training, the person
matches
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After being taught to match A to B, person can
match B to A (without training)
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Logic is…If
A = B
, then
B = A
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For example
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After being taught to match
to
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Person can match to
DOG
DOG
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Critical test for stimulus equivalence – if you get transitivity, the
stimuli are members of an
equivalence class
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After being taught to match A to B and B to C, person can match
A to C (without training)
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Logic is…If A = B and B = C, then A = C
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For example…
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After being taught to match to
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AND being taught to match to
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The subject can match to
dog
DOG
DOG
Factors Affecting the Development of Stimulus Control
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Reinforcement
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Differential reinforcement with rich schedules of
reinforcement
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Preattending Skills
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Looking at type of instructor or materials, sitting up tall, no
stereotypy or other misbehavior
Factors Affecting the Development of Stimulus Control
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Specificity of directions
for responding to stimuli
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Should relate to discrimination
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Touch the correct response; say the correct word
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If ask for response unrelated to setting, get more errors
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Opportunity to respond
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Frequent, active opportunities to respond leads to higher rates of correct responses
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More opportunities for making conditional responses
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Pacing of response opportunities
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Higher pace often leads to superior performance and less off-task behavior
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Not lose attention during/between trials
Factors Affecting the Development of Stimulus Control
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Salience of the stimuli
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Influences attention and ultimately the development of
stimulus control
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Dependent on the capabilities of an individual, the past
history of reinforcement, and the situation
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Be aware of modality of presentation:
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E,g, Visual vs. auditory animals
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The more modalities the stimuli are presented, the better the
concept formation.
Factors Affecting the Development of
Stimulus Control
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Masking and overshadowing
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Masking
–Even though one stimulus has control over behavior,
another stimulus blocks that control from being expressed
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E.g., Student knows answer but won’t answer in front of peers
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Dog will only respond if there is a treat
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Overshadowing
–The presence of one stimulus condition interferes
with the acquisition of control by another stimulus
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E.g., hallway may be more interesting that teacher’s presentation in the front
of the classroom
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Ways to overcome include
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Make changes to physical environment
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Make instructional stimuli as intense and centrally located as possible
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Reinforce behavior in the presence of the relevant stimuli
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Behavior
occurs immediately
upon presentation of the cue
stimulus
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Behavior
never occurs in absence
of stimulus
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Behavior
never occurs in response to another stimulus
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No other behavior
occurs in response to the stimulus
Marchal, Bregeras, Puaux, Gervais & Ferry, 2016
Human Scent Matching to Sample Detection
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Scent detection (drug detection, human identification, location, etc.) by
canines used commonly in law enforcement
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Results of dog detection often not admissible in courts because of lack of
rigor and standardization of training for scent with the dogs
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Does seem to be a reliable training method- matching to sample- that is
readily available and easily used, but few law enforcement agencies use it
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Study wanted to demonstrate effectiveness of this approach
Methods
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Dogs: 13 Shepherd dogs, all out of Hungarian
breeding program and French training program
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Dogs started at about 10 mos of age
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Trained for about a year each
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Dogs trained 5x per week in special work room
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Rubber floors
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Five jars on metal tripods
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Human scent collected by qualified tech and collection method
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Body scent
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Trace scent
MTS Training Methods
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Steps 1 to 3:
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Dog given jar with scent to sniff
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Dog brought to line and shown jars along line
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Match scent to original jar
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Given food treat if correct
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Had to place nose in jar; later trained an alert behavior
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Started with 1 jar; increased up to 5
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Step 4:
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Tech puts out scent in one of jars; blind to dog and handler
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Dog must identify; handler must call alert
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Step 5:
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Target person scent plus DISTRACTOR scents
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Dog must identify scent of the identified person
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Criterion: Hits, misses, correct rejections and false alarms calculated
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Had to get 100% correct for 100 successive trials!
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Only dogs meeting 100% correct for 200 trials moved to step 5, or remained in training
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Then continue in continued training until judicial cases
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Judicial cases: actual court cases (minimum of 3 dogs detected on each case)
Results
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Initial training
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Took longer to train as task grew more complex
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Dogs learned the task: NO dog has a false alert in last 100
trials of level 5!
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Dogs were consistently good at all types of tasks/scents
when trained to criterion and remained at high detection
rate through continuous training
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100% accuracy in judicial cases (as judged by other dogs
getting same result)
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More confessions by the defendant when dog identified!
WHY is this study important
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Currently, scent detection not admissible in court
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Too much inconsistency
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This shows that it is poor training, not poor dog ability
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HOW you train is critical!
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Also shows importance of having learning experts develop the
training!
Stimulus control plays a crucial role in determining behavior based on the presence or absence of stimuli. It influences responses through discrimination and generalization processes, shaping behavior patterns. By understanding stimulus control, we can explore how antecedent stimuli affect responses and how training procedures can enhance learning and behavioral outcomes.
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Presentation Transcript
Stimulus Control of Behavior Having stimulus control means that the probability of the behavior varies depending upon the stimuli present. If a behavior is under stimulus control then The behavior happens when the stimulus is present The behavior doesn t happen when the stimulus is absent Most of our behavior is under stimulus control A person that contributes to charity generously while in church may watch every penny spent while at work
Discrimination 1.2 CS+ CS- 1 Response Strength 0.8 0.6 0.4 0.2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Trials
Stimulus Control: Discrimination Stimulus Control: Discrimination Definition: Degree to which antecedent stimuli set the occasion for particular responses Precise degree of stimulus controlling responding E.g., Man has beard and is Daddy; Man has beard and is Uncle Eddie: Child only responds to bearded Daddy as Daddy Stimulus discrimination is taught by using discrimination training procedures such as differential reinforcement
Stimulus Control: Generalization Stimulus Control: 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 controlling a response E.g., All men with beards are Daddy Stimulus generalization is taught by using generalization training procedures: Reinforce any stimulus within the class of related stimuli.
Development of Stimulus Control Development of Stimulus Control Stimulus discrimination training requires One behavior Two antecedent stimulus conditions: the SDand the S Or the S+ and the S- Responses that occur in the presence of the SDare reinforced (thus, the response increases in the presence of the SD) Responses that occur in the presence of the S are not reinforced: The response decreases in the presence of the S ) 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?
SD: What s your favorite color? Response: red Reinforcer: Super! You said red! S : No praise What s your name?
Differential Responding Differential Responding When a child s behavior comes under the control of the SD, 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
Stimulus Generalization Stimulus Generalization When a response is reinforced in the presence of one stimulus as well as similar stimuli The same behavior response tends to be evoked by stimuli that share similar physical properties with that controlling antecedent stimulus Stimulus Generalization is more likely when stimuli that are highly similar to the original stimulus are presented You stop at first traffic light you come upon in driver s ed, but you generalize your responding so you stop at any red traffic light in any city or town.
Stimulus Generalization 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)
Stimulus Generalization Stimulus Generalization Respond to similar stimuli to the original stimulus E.g., similar people, materials, or settings Generalization is more likely when the novel stimulus is similar to the training stimulus
Stimulus Discrimination and Stimulus Generalization are Stimulus Discrimination and Stimulus Generalization are a Continuum a Continuum Stimulus Discrimination Stimulus Generalization Generally, as the training and test stimuli become more different responding will decline Produces a generalization gradient The gradient shows the degree to which discrimination or generalization has occurred.
Generalization Gradient Guttman & Kalish (1956) pigeons reinforced for pecking a 580 nm lit key (orange-yellow) (S+) on a VI schedule 350 300 250 Responses A test session was then given where many different colored key lights were presented in extinction 200 150 100 50 S+ 0 510 530 550 Wavelength (nanometers) 570 590 610 630
Interpreting Generalization Gradients Pigeons trained to peck a moderately bright light (S+) to get food. (S- = dim light) After asymptote is reached, present occasional non- reinforced probe trials at various wavelengths or levels of brightness.
Excitatory and inhibitory gradients Excitatory gradients form around the CS+; show where responding is MOST likely Inhibitory gradients also form; show where responding is least likely e.g., Pigeons trained to peck at a 800 hz tone (S+), with a 500 nm light S-.
Peak Shift Peak Shift Phenomena where the peak of the generalization curve shifts AWAY from the S- Means that the most responding does not occur for the S+, but slightly offset from the S+ and away from the S- The peak of responding shifts AWAY from the S- Question is WHY!
Lets do an example of Discrimination Training Two choices: 1 4 4 is the correct answer
Now what is the correct answer? Now what is the correct answer? Using the last question and correct answer, which is the best answer for each of the following? 3.9 -1 -1 5 0.9 3
Second problem: Think about it: Second problem: Think about it: 4 16 Again, 4 is the answer Now which is the best answer?
Now which is the best answer? Now which is the best answer? Using your answer from the last slide: Which is the answer for each of the following? 16 48 8 32 100 400
Examine your answers: Examine your answers: First set of slides: Tend to pick answer that is closest to 4 Second set of slides: Tend to pick the smaller (1/4 of the second answer) Why? Two theories may explain Spence s Summation Theory Kohler s Interdimensional Theory
Spences Theory Spence s Theory Peak shift occurs because of the summation of the excitatory and inhibitory curves Result is that the most responding is slightly in favor of the S+ Not as strong of suppression for S-; thus, get a slight shift away from S- when sum the two curves Just a math phenomenon
Spences Theory to Account for Peak Shift S+ 80 Inhibitory Excitatory Difference Inhibitory or Excitatory Strength 60 40 20 0 -20 S- -40 -60 490 510 530 550 570 590 610 630 650 670 Wavelength (nanometers)
Kohlers Kohler s Tranposition Tranposition Interdimensional theory Interdimensional theory The animal learns a conceptual rule: When given stimuli, choose whichever fits the characteristics of S+ to S- E.g.: S+ is always larger E.g.: S+ is the most green Thus, when given generalization stimuli, look for whatever is the most S+ compared to what should be S- .
Kohlers Kohler s Tranposition Tranposition Interdimensional theory Interdimensional theory Shift away from S+ occurs because the organism compensates for not S- , and overcompensate PAST the S+ but away from the S- Learning a concept: Always choose larger or greener, etc. Given a large and small stimulus, choose large even if it is too large If S+ is read and S- is green, choose the reddest but the least green .
Interdimensional discrimination 700 Pseudodiscrim Discrimination 600 500 # Responses 400 300 200 100 0 501 530 555 576 606 Wavelength Discrimination: S+ = 555nm Light; S- = Tone
Test of Theories Test of Theories Choose between squares: S+ 100 cm2 250 cm2 500 cm2 250 cm2 1000 cm2 500 cm2 ?????? S- 50 cm2 150 cm2 Situation: Original training Test 1: Spence s test Test 2:Kohler s test Spence's prediction: Will choose closest to original S+ Transposition or interdimensional: choose larger
Which is correct? Which is correct? Tests for summation yield evidence supporting Spence s theory When using stimuli close to the original stimulus Animal tends to make errors towards the original stimulus Tests for transposition/interdiminensional yield evidence supporting Kohler s theory When using stimuli highly different from original stimulus, error towards original stimulus But show concept rule in that keep the relation of the difference constant (e.g., choose the smaller one)
So, which theory is right? So, which theory is right ? BOTH! When the test includes stimuli close to the original S+, animal tends to choose the one closest to the S+ As differences become increasingly larger, animal tends to choose the stimulus consistent with the type of difference between the S+ and S- E.g., larger or red-er Why?
Teaching Stimulus Discrimination Teaching Stimulus Discrimination Discrimination is a fundamental process that controls behavior. Discrimination allows us to differentiate when reinforcement is available for specific responses. Many essential tasks require discrimination skills Reading. Labeling Objects. Following directions. Following activity schedules. Greeting people. Self-care skills.
Basic Problem of Discrimination Training 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. Most 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!
Stimulus Compounding Stimulus Compounding All stimuli are compound. They consist of many different elements. Modality (visual, auditory, tactile) Size, color, shape, etc. It is difficult to control which element or elements of the stimulus exert control over behavior. Need to be careful how we teach and what stimuli we use. Have organism attend to critical aspects of the S+
2 Types of Discriminations. 2 Types of Discriminations. Simple Discriminations. Non-Conditional Discrimination. Simple association A = B Conditional Discriminations. Matching-to-sample. Arbitrary Discrimination. Involves complex associations
Simple Discrimination Simple Discrimination Stimulus is present or not present Simple association: If red then apple One picture on the table that s a cat Say touch cat and they do Cue dog to sit ; sitting is the only correct response Not real life for most human tasks (or for dogs for that matter).
Conditional Discrimination 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 no reinforcement depending on (conditional on) the presence of another particular antecedent Often taught via Match-to-Sample procedures If a picture of a dog, then say dog; if a picture of a cat, then say cat Vary the answer for the same reinforcement depending on conditional cue (dog or cat picture) Many programs consist of Identity Matching (matching identical stimuli): Objects Letters Colors Pictures Shapes Numbers
Match-to-Sample Learner 1st responds to sample (conditional stimulus) Sample Then responds to one of the comparison stimuli S /S- SD/S+ S /S-
Match-to-Sample SD/S+ SD/S+ Sample (Conditional Stimulus) Sample (Conditional Stimulus)
Establishing New Forms of Establishing New Forms of Conditional Stimulus Control Conditional Stimulus Control Identity matching (single mode) Visual: visual Auditory: auditory Arbitrary matching (multimodal) Visual: auditory Auditory: visual Auditory: tactile
Arbitrary Matching Arbitrary Matching Stimuli are not physically identical Different modalities (visual/verbal) Different types of stimuli: story problem; number answer 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?
Receptive Picture ID SD/S+ SD/S+ baby flower Sample Sample
Concept Formation Concept Formation Complex stimulus control that results in: Generalization within a class of stimuli and Discrimination between classes of stimuli Two procedures for teaching concept formation: Simultaneous Discrimination: The concurrent presentation of multiple stimuli Successive Discrimination: The successive presentation of multiple stimuli Teaching elements of a stimulus class!
Stimulus Class 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
Stimulus Equivalence 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
Reflexivity 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
Symmetry 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 DOG to DOG Person can match to
Transitivity 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 DOG dog DOG AND being taught to match to The subject can match to
Factors Affecting the Development of Stimulus Control Reinforcement Differential reinforcement with rich schedules of reinforcement Preattending Skills Looking at type of instructor or materials, sitting up tall, no stereotypy or other misbehavior
Factors Affecting the Development of Stimulus Control Specificity of directions for responding to stimuli Should relate to discrimination Touch the correct response; say the correct word If ask for response unrelated to setting, get more errors Opportunity to respond Frequent, active opportunities to respond leads to higher rates of correct responses More opportunities for making conditional responses Pacing of response opportunities Higher pace often leads to superior performance and less off-task behavior Not lose attention during/between trials
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 Be aware of modality of presentation: E,g, Visual vs. auditory animals The more modalities the stimuli are presented, the better the concept formation.
