1. Chapter 3: Pavlovian Conditioning: Foundations
Pavlovian Conditioning or Classical Conditioning
Ivan Pavlov
Early 1900s
A Russian physiologist
digestive system
Nobel prize
 Interested in the Salivary reflex.
The reflex seemed to depend on the nature of the stimulus.
marble = little saliva
sand = quite a lot.

2. Sometimes dogs would salivate prior to receiving food
Puzzling to Pavlov
Reflex in the absence of stimulus presentation
Psychic secretions
How was it possible that experience could alter the salivary reflex?

3. Pavlov carefully examined the development of psychic secretions
Eliciting factors?
sight and smell of food
food bowl
lab coats
footsteps
Dog had associated these visual and auditory stimuli with taste?

4. Pavlov began to put together a theory Two distinct kinds of reflexes.
1) Unconditional Reflex
inborn and unlearned (innate)
usually permanent reflex
Found in virtually all members of a species
varies little from individual to individual.
salivary reflex
patellar reflex
2) Conditional Reflex
must be acquired through experience (not innate)
not permanent.
varies considerably from species to species
Varies from individual to individual.
salivating to footsteps.

5. Elements of Pavlovian Conditioning.
First let’s distinguish between excitatory and inhibitory conditioning.
Excitatory Conditioning
Learning that a stimulus predicts the presence of another stimulus
Pavlov’s initial studies
Inhibitory Conditioning
Learning that the stimulus predicts the absence of another stimulus
We will discuss this more later
Back to Excitatory Conditioning 
First Pavlov described the basic reflex
e.g., Food elicits salivation
Pavlov named the stimuli
Unconditioned Stimulus (US) elicits Unconditioned Response (UR)

6. Conditioned Stimulus (CS)
a previously neutral stimulus
Pavlov’s bell
Normally doesn’t elicit salivation
What response would it elicit?
Known as orienting response
Pair the Conditioned Stimulus with an Unconditioned Stimulus 
tone  food = salivation.
CS  US = UR
After several CS  US pairings
Test to see if learning occurred
How?
Test with CS alone
Look for Conditioned Responding (CR)
CS now elicits CR

7. Let’s go through an example in more detail Saliency
consider Empiricists rules of association (chapter 1)
Saliency CS
Tone
10 seconds
500Hz
70 db US
5.0 gm meat powder
Contiguity
CS-US interval = 20 seconds (from offset of the CS to the onset of the US)
Intertrial Interval = 10 minutes (also can have effects on contiguity)
Frequency
trials: = 60 (frequency of associations or number of trials can affect strength of conditioning
Test every 10th trial
How do we test?

8. Let’s look at how the findings might have come out
Graph
Y axis?
X axis?
Baseline

10. Typically a learning experiment uses control groups.
In the hypothetical Pavlovian experiment we have been discussing thus far, we already have a control condition.
Baseline measurement
Is that enough?
What other controls would be important?
 A group that receives the tone alone.
CS alone control -
A group that receives the meat powder in the absence of the tone.
US alone control
Any increase in salivation in these control groups can be viewed as non-contingent learning.
Sensitization?
The US (meat powder) alone group may be particularly important to rule out any unintended cues that indicate reinforcement is about to occur.
Confounds

11. What other controls might be appropriate?
Maybe just experiencing bells and food sensitizes the animal and gets them drooling.
Either one alone is not enough, but both creates sensitization
Remember 12 checks vs. 4 checks in infant study (chapter 2)
How can we control for this?
Three ways
1) Backward Conditioning control
USCS
may cause conditioning (learning).
What kind?
Known as inhibitory (we will discuss this more later)

12. 3) Explicitly unpaired control
2) Random control
The CS and US occur randomly
Sometimes the CS will precede the US
equally often the US will precede the CS.
Also the temporal relationship between the CS and US varies
Seems it should prevent association of tone and food
Nevertheless sometimes the animals still associate
3) Explicitly unpaired control
Present CS and US on separate trials
Length of ITI necessary - varies depending on task
Must be long (i.e., 24 hours for CTA)
There is some debate about whether random or explicitly unpaired controls are best
Some form of learning seems to occur in all situations

13. conditioning a patellar reflex?
E. B. Twitmeyer (1902)
PhD thesis at University of Pennsylvania
Zeitgeist
CS?
Tone
US?
Tap knee
UR?
Kick
When?
CR?

14. An introduction to contemporary conditioning methods
There are many ways to examine Classical Conditioning
It’s not all slobbering dogs
Fear Conditioning
Little Albert
Watson and Raynor
Conditioned Emotional Response
Aversive Conditioning vs. Appetitive Conditioning

15. Fear Conditioning in animals?
How do we measure fear?
Freezing behavior?
How do you quantify it?
Would be nice to have initial activity to serve as a baseline
Conditioned Suppression procedures
lick suppression procedure
Water deprived
Measure licks on water bottle
Present fear stimulus
slows licking
Conditioned Emotional Response procedure
Phase 1
Train rat to press lever to receive food.
Phase 2
Pair tone with shock
Test
Introduce tone while rat is lever pressing for food

16. Often use Suppression Ratio as Dependent Variable
CS responding / (CS responding + pre-CS responding)
Suppression ratios vary from 0 (complete fear) to .50 (no fear at all)
Lower suppression ratio = more fear
0/(0+10) = 0  complete fear
1/(1 + 10) = .09  almost complete fear
10/(10+10) = .50  no fear at all

17. Conditioned eye-blink procedure.
Often rabbits
but has also been shown in rats and humans.
also aversive conditioning.
CS, US, UR, CR?

18. Taste Aversion Conditioning
novel flavor (CS; often saccharin or chocolate milk)
CS?
Taste
US?
LiCl
UR?
Illness
CR?
How do you measure this?

19. Conditioned Taste Aversion
one-trial learning
long-delay learning
Eye-blink takes many many trials to learn
Why the large difference?
Preparedness to learn?

20. Sign Tracking (AKA – autoshaping)
Brown and Jenkins (1968)
Key light reliably predicts food – Operant Chamber
8 second Key light then Food
How do you think the pigeons behaved?
Pigeons pecked the key
remember pecking was not required
The Long Box Study = Hearst and Jenkins (1974)
Three feet long
Key at one end
Food at the other
Video

21. Temporal factors in conditioning
Short Delayed Conditioning
CS onset shortly precedes (less than a minute) US onset.
Trace conditioning
a lag between CS offset and US onset.
closer = stronger the conditioning will be
too long = no conditioning
Long delayed Conditioning
CS onset occurs 5-10 minutes before US onset

22. Figure 3.7 - Five common classical conditioning procedures

23. Simultaneous conditioning Backward Conditioning
CS and US occur simultaneously
ultimate in contiguity.
weaker conditioning than above
Backward Conditioning
US offset occurs simultaneously with CS onset.
Another example of contiguity of stimuli,
Excitatory Conditioning?
often results in inhibitory conditioning.
What if CS = tone and US =shock?
How would you recognize inhibitory conditioning?
Safety behaviors
Increased activity during CS

24. Figure 3.7 - Five common classical conditioning procedures

25. Inhibitory Conditioning
Backward US-CS pairings tend to cause inhibitory conditioning.
less-than-normal salivation if food precedes the bell
activity “safety” if the shock precedes the bell

26. Can be examined using the conditioned suppression procedure
Induction Method for producing conditioned inhibition (Pavlov’s Procedure)
Can be examined using the conditioned suppression procedure
After training the rats to barpress for food you could introduce Pavlov’s induction method.
Half of trials are excitatory conditioning trials (type A)
CS+(tone)US (shock)
Other half of trials are inhibitory conditioning trials (type B)
CS+(tone) and CS-(light)  nothing
Each day they receive both types in a random order (say 30 of each)
What should responding be like
During CS+ alone presentations?
During CS+ and CS- presentations?
During CS- alone?

27. Figure 3. 10 – Pavlov’s procedure for conditioned inhibition
Figure 3.10 – Pavlov’s procedure for conditioned inhibition. On some trials (Type A), the CS+ is paired with the US. On other trials (Type B), the CS+ is presented with the CS- and the US is omitted. The procedure is effective in conditioning inhibitory properties to the CS-.

28. The negative contingencies procedure (aka - explicitly unpaired)
Another way of producing conditioned inhibition
This time there is only one CS though
Presentations are organized such that the US never follows the CS closely in time

29. Figure 3.11 – A negative CS-US contingency procedure for conditioning inhibitory properties to the CS. Notice that the CS is always followed by a period without the US.

30. Heth (1976) examined negative contingencies
conditioned suppression procedure
trained rats to barpress for food.
Then 60 negative contingency pairings.
Tone and shock
This procedure resulted in the rats first fearing the tone in early trials.
How would he know?
SR = close to 0
Later as the animal had more experience with the tone and shock, he found a safety response in the presence of the tone.
SR = close to .50

31.  The induction method (Pavlov’s procedure) and negative contingencies are good ways to examine Conditioned inhibition
if you are measuring behaviors that can be both increased and decreased
Bar Pressing
Sometimes, however, there is such a small amount of initial behavior that it cannot be decreased.
Under these circumstances special procedures are needed to examine conditioned inhibition.

32. Indirect methods for measuring conditioned inhibition.
Lets say that you have been running an experiment where you repeatedly present food (US) followed by a bell (CS) to dogs.
backward conditioning.
What behavior would you expect from the dog toward the bell?
no salivation.
Dogs, however do not salivate to bells normally anyway.
how would you know that the bell was inhibiting responding, rather than just being ignored?
Two procedures
Summation test
Retardation test.

33. In the summation test an animal is trained in two ways.
1) they are trained that one (CS-) is a conditioned inhibitor using backward conditioning.
US(food) CS1- (bell)
2) they are trained that a second (CS+) is a conditioned excitor
CS2+( light)US(food).
summation group
train US (food)CS1- (bell)
CS2+(light)US(food)
test CS1- and CS2+
Salivation to CS1?
Salivation to CS2?
Salivation to CS1- and CS2+?
Note – increasing the baseline (by conditioning salivation) allows us to see this
It is also interesting in its own right
independent learning about CS+s and CS-s can summate

34. Retardation test this is a simple idea
it should be more difficult to train an excitatory response to a stimulus that has become a conditioned inhibitor than it would be to one that has not become a conditioned inhibitor
retardation gp control
phase US(food)CS(bell)
phase 2 (10 tr) CS(bell)(food) CS(bell)(food)
test CS alone CS alone