Basic Stimulus Control
Thus Far in Operant…
• Emphasis on the events following behavior
– Differentiation from Pavlovian?
• But control from antecedent stimuli also
very important
– “All behavior is under the exquisitely detailed
control of surrounding stimuli, some impinging
from outside the organism, others arising from
within its boundaries” Dinsmoor (1995)
STIMULUS CONTROL
Examples: Basic discrimination and
generalization, psychophysics, attentional
control, conceptual and relational behavior,
verbal behavior, remembering, applications
to the physiology of perception, learning,
and memory.
Three-term Contingency
SD
SR
SD: discriminative
stimulus
Ro
Ro: operant class
SR: reinforcer
What is the
D
S ?
• Tracking behavior in time
• Control from the past vs. control by the
present
• Bringing history to bear on current behavior
• The power of the SD
– How do you get the salt?
Discrimination Training
• Basic definition
– Rf in the presence of one stimulus (S+)
– And not in its absence (S-)
– Discrimination is acquired
• Morse code training in the military (Keller,
1943)
• Examples from Pavlovian conditioning
Remember generalization tests from Pavlovian?
What is generalization and discrimination?
Theories of Generalization
• Spread of activation
• Discrimination hypothesis
– Lack of discrimination
– Lack of training
• The deafened pigeon
• Discrimination/Generalization is learned
– How would we show that?
Compare to This:
350
300
NUMBER OF RESPONSES
Have we disproved
the hypothesis?
G U T T M A N & K A L IS H (1 9 5 6 )
250
200
150
100
50
0
520
540
560
580
600
W A V E L E N G T H (n m )
620
640
Is Discrimination “Observation”?
• Dinsmoor’s hypothesis
– Observation increases discrimination
No differential reinforcement
Observing Positive and Negative Stimuli
Inhibitory Gradients
Combined Gradients
Attention
• Another one of those things we possess
• Controlling relation between stimuli and
behavior