Transcript LECTURE_07_CLASSICAL_COND

IVAN PAVLOV
The Adventures of the Black Girl in Her
Search for God, George Bernard Shaw
(1933)
“What am I running away from? I’m not afraid of that dear
noisy old man.”
“Your fears and hopes are only fancies” said a voice close to
her, proceeding from a very shortsighted elderly man in
spectacles who was sitting on a gnarled log. “In running
away you were acting on a conditioned reflex. It is quite
simple. Having lived among lions you have from your
childhood associated the sound of a roar with deadly
danger. Hence your precipitate flight when that
superstitious old jackass brayed at you. This remarkable
discovery cost me twenty-five years of devoted research,
during which I cut out the brains of innumerable dogs, and
observed their spittle by making holes in their cheeks for
them to salivate through instead of through their tongues.
The whole scientific world is prostrate at my feet in
admiration of this colossal achievement and gratitude for
the light is has shed on the great problems of human
conduct.”
“Why didn’t you ask me?” said the black girl. “I could have told you
The Adventures of the Black Girl in Her
Search for God, George Bernard Shaw
(1933)
[cont’d.]
“Your ignorance and
presumption
are unspeakable” said the
old myop. “The fact was known of course to every child;
but it had never been proved experimentally in the
laboratory; and therefore it was not scientifically known at
all. It reached me as an unskilled conjecture: I handed it on
as science. Have you ever performed an experiment, may I
ask?”
“Several” said the black girl. “I will perform one now. Do you
know what you are sitting on?”
“I am sitting on a log grey with age, and covered with an
uncomfortable rugged bark” said the myop.
“You are mistaken” said the black girl. “You are sitting on a
sleepy crocodile.”
With a yell which Micah himself might have envied, the myop
rose and fled frantically to a neighboring tree, up which he
climbed catlike with an agility which in so elderly a
gentleman was quite superhuman.
“Come down” said the black girl. “You ought to know that
crocodiles are only to be found near rivers. I was only
trying an experiment. Come down.”
Pavlov's significance:
• First empirical model of associationism.
• Integrated traditions of reflexology and associationism
• Began as a reflexologist by studying reflexes - a skilled
surgeon
– studied digestive reflexes
– a skilled surgeon, notably for maintained chronic
preparations
• Recognized significance of psychic secretion.
• Provided basis for investigating neuroscience of
classical conditioning (Kandel)
• Defined modern concepts of conditioning.
Classical Conditioning
(Basic Phenomena)
• Acquisition
• Extinction
• Spontaneous recovery
• Higher order conditioning
• Discrimination
– Experimental neurosis
• Generalization
– Mediated generalization
CATEGORIES OF BEHAVIOR
Voluntary
or operant
Unconditioned
Conditioned
Looking
Reading
Babbling
Writing
Crawling
Fence
jumping
GSR when
telling a lie
Involuntary Pupil response
or
GSR response
respondent
PAVLOV'S APPARATUS FOR
STUDYING CONDITIONED
SALIVARY RESPONSE
CONDITIONING
Trial 1:
CS
Later Trials:
//
(Bell)
CR
//
(Salivation)
US
//
(Food)
UR
(Salivation)
//
Classical Conditioning (Type S)
Signal a reinforcing event (an unconditioned stimulus
“US”), e.g.,
sound a buzzer (a conditioned stimulus) before delivering food.
Buzzer  food
CS  US
Initially,
US  UR
food  salivation
CS  orienting (?)
buzzer  turning towards source
no salivation (or minimal salivation)
After multiple pairings of CS and US:
CS  CR
buzzer  salivation
Unconditional Stimulus (US)
•The stimulus in a classical conditioning experiment
that elicits the unconditional response.
Unconditional Response (UR)
•The response in a classical conditioning experiment
that is elicited by the unconditional stimulus.
Conditional Stimulus (CS)
•The stimulus in a classical conditioning experiment
that is neutral with respect to the unconditional
response.
Conditional Response (CR)
•The response in a classical conditioning experiment
that is elicited by the conditional stimulus.
Unconditional reflex:
UCS
UCR
Drilling
Pain
Conditional reflex:
CS
Sound of drill
CR
Pain
Taste Aversion
US (stomach flu)
(nausea)
 UR
CS (taste of sauce)
+
 UR (nausea)
US (flu)
CS (taste of sauce)  CR (nausea)
Advertising
US (popular tune)
feeling)
 UR (good
CS (product)
+
 UR (good
feeling)
US (popular tune)
CS (product)
 CR (good
Conditioned Fear
(Phobia)
US (noise)
 UR (fear)
CS (rabbit)
+
US (noise)
 UR (fear)
CS (rabbit)
 CR (fear)
Counterconditioning
(desensitization)
CS (rabbit)
US (milk)
feeling)
 UR (fear)
 UR (pleasant
CS (rabbit)
+
 UR (pleasant
feeling)
US (milk)
ACQUISITION OF CONDITIONED SALIVARY RESPONSE
70
DROPS OF SALIVA
60
50
40
30
20
(PAVLOV, 1927)
10
0
0
10
20
30
40
NUMBER OF PAIRINGS OF CS & US
50
ACQUISITION OF CONDITIONED RESPONSE
LATENCY OF CR (SEC.)
20
15
(PAVLOV, 1927)
10
5
0
10
20
30
40
NUMBER OF PAIRINGS OF CS AND US
50
EXTINCTION
Trial 1:
Later Trials:
CS
//
CR
//
US
//
EXTINCTION OF CONDITIONED SALIVARY RESPONSE
70
DROPS OF SALIVA
60
50
(PAVLOV, 1927)
40
30
20
10
0
0
10
20
30
40
NUMBER OF UNPAIRED PRESENTATIONS OF CS
50
Temporal Relationships Between
CS & US
Classical Conditioning
Before Training
US(food in mouth)
CS (bell)
response
UR (salivation)
No relevant
Training
CS (tone) + US (food in mouth)
After Training (conditioning)
CS (tone)
CR (salivation)
GENERALIZATION OF CR
90
% MAGNITUDE OF CR
80
70
60
50
40
30
20
(PAVLOV, 1927)
10
0
400
800
1200
FREQUENCY [Hz]
1800
200
DISCRIMINATION LEARNING:
CS+ alternates with CSe.g., Buzzer  Food (Acquisition)
Light  No Food (Extinction)
*Initial generalization from CS+ to CS*Gradual weakening of response to CS*Subject responds mainly to CS+ at the
end of discrimination training
Establishing am “EXPERIMENTAL NEUROSIS”
S+
S16:8
Initial
Discrimination
14:8
10:8
12:8
9:8
Final
Discrimination
Establishing Higher Order Conditioning
Stage 1
Bell (CS1)
Food (US)
Salivation (CR)
Salivation (CR)
Light (CS2)
Bell (CS1)
No Salivation
Salivation (CR)
Stage 2
Light (CS2)
Bell (CS1)
Stage 3
Buzzer (CS3)
Light (CS2)
Buzzer (CS3)
salivation (CR2)
salivation (CR1)
no salivation
salivation (CR2)
salivation