Classical Conditioning

1
Classical Conditioning
2
Ivan Pavlov

• Medical physiologist
• Digestion
• Reflexes
• Fistula

en.wikipedia.org/wiki/FileIvan_Pavlov_(Nobel).png
en.wikipedia.org/wiki/FileOne_of_Pavlov27s_dogs
.jpg
3
Stimuli Responses

• Unconditional
• Stimuli and responses whose properties are not
  dependent upon prior training
• Conditional (i.e., dependent)
• Stimuli and responses whose properties occur only
  after training
• US, UR, CS, CR

4
Classical Learning Features

• Reflex
• Subjects behaviour does not cause delivery of US
• Association of stimuli

5
Temporal Arrangement
6
Terms

• Conditioning trial
• Each CS-US pairing
• Intertrial interval
• Time from end of one trial to start of next trial
• Inter stimulus interval
• Time from the start of the first stimulus in pair
  to second stimulus in trial

7
CS
US
8
Measuring Learning

• Test (probe) trial
• Present CS by itself (no US)
• Magnitude
• How much CR occurs
• Probability
• How often CS produces CR
• Latency
• How soon CR occurs after CS

9
Pseudoconditioning

• Increase in response due to just the US
• Sensitization

10
Controls

• Random control
• Exp. Gr. CS-US pairings
• Control Gr. same number of CS US, but
  randomized
• Explicitly unpaired control
• Exp. Gr. CS-US pairings
• Control Gr. same number of CS US, but
  presented far enough apart (even separate
  sessions) to prevent association

11
CS Types

• Excitatory CS (CS)
• CS predicts the occurrence of US
• Activates behaviour related to US
• Inhibitory CS (CS-)
• CS predicts the non-occurrence of US
• Suppresses behaviour related to US

12
Inhibitory Conditioning

• Why predict non-event?
• Unpredictable aversive events more stressful
• Craske et al. (1995) measured general anxiety in
  subjects with panic disorder
• Predictable and unpredictable attacks
• Before and after anxiety ratings

13
Results

• Similar anxiety before
• Post attack anxiety significantly lower if attack
  predictable and higher if attack unpredictable

14

• Ability to predict aversive event also allows
  prediction of lack of aversive event
• Application stress management techniques
• Cant eliminate all stressors
• Introduce periods of predictable safety
• Reduces overall stress

15
Producing CS-

• Can produce CS- for either appetitive or aversive
  US
• Most research done with aversives
• Inhibitory conditioning (and inhibitory control
  of behaviour) only if there is also an excitatory
  context for US delivery
• Cant have CS- without CS
• But, can have CS without CS-

16
Pavlovs Protocol
Trial Type A
Trial Type B
CS
CS-
US

• Randomize trial type presentation

17
Negative Contingency Protocol

• Context cues serve as CS

18
Testing for CS-

• CS- produces absence of CR
• No CR
• Youve produced CS-
• Havent learned anything
• How to measure nothing

19
Techniques

• Bidirectional response
• Utilizes opposing responses
• Do one with CS, opposite with CS-
• Summation test
• Measure CR with CS
• Compound stimulus of CS CS- measure CR
• Retardation of acquisition
• Trained CS- and novel stimulus pair both with
  novel US for same number of trials
• Measure CR for both
• Prior learning of CS- inhibits learning new
  association

20
Backwards Conditioning

• Inconsistent results across studies
• Little learning at all, CS-, CS
• Keith-Lucas Guttman (1975)
• Backward conditioning and biological plausibility
• Predator attacks prey
• Antelope grazing
• Lion attacks
• Antelope clawed, but escapes
• Pain (US) proceeds sight of lion (CS)

21
Experimental Procedure

• Rats fed sugar pellets
• Give one-time electric shock (US)
• Lights go out
• 1, 5, 10, or 40 seconds
• Toy hedgehog added (CS)
• Observe rat one day later

22
Model

• Sugar pellets grazing
• Shock pain of attack
• Hedgehog lion

23
Control Groups

• Saw hedgehog, but no shock
• Shocked, but didnt see hedgehog

24
Results

• Backward conditioning not seen in controls
• In 1, 5, and 10 sec delay groups, got backward
  conditioning
• Avoid hedgehog
• Dont eat much when hedgehog present
• Fear induced by hedgehog is CR

25
Conclusion

• Biologically relevant CSs can cause backward
  conditioning

26
Emotional Conditioning

• Wide range of emotional responses
• Emotions universal
• Positive and negative
• Emotional response to stimulus reflexive
• Conditioned Emotional Responses (CERs)

27
John Broadus Watson

• Hard-line Behaviorism
• British Empiricism (nurture over nature)
• Early work with rats
• Shift to infant research
• Opposed Introspectionism and Freudian theories

28
Conditioning of Fear

• Watson Raynor (1920)
• Albert B.
• Mother a wet nurse at Harriet Lane Home (attached
  to Johns Hopkins University)
• Albert first assessed at about 8 months
• Emotionally stable, healthy

29
Method

• Present white rat
• No fear
• Present white rat and bang metal bar
• Produces CER of fear, avoidance, withdrawl
• US noise, UR startle
• CS rat CR fear
• CER generalizes to other furry objects
• Video

30

• Study went for several months
• Intended to reverse CER conditioning, but Albert
  Bs mother ended her job at hospital
• Research led directly to Mary Cover-Jones
  counter-conditioning with Peter

31
What Happened to Albert

• Beck, Levinson Irons (2009)
• Historical detective work
• Albert B.s mother probably Arvilla Irons
  Merritte
• Douglas Merritte, born 9 March 1919
• Arvilla Merritte left Johns Hopkins
• Worked as assistant for ill wife of farmer
• Douglas Merritte died 10 May 1925, probably from
  meningitis

32
Name

• Why Albert B.?
• Ethical concerns with confidentiality not firmly
  established
• Watson may have played name games
• His sons William and James
• His name from John Albert Broadus, Baptist
  minister Albert B.

33
What Happened to Watson

• Affair with Rosalie Raynor, his grad student
• Divorce, fired, resigned as president of APA
• Worked for J. Walter Thompson advertising agency
  vice-president within two years
• Ponds cold ream, Maxwell House coffee
• Published books and articles on childcare
• Psychological care of infant and child (1928)
• Criticized by many modern child
  experts/advocates, but not any more extreme than
  other childcare texts of the time
• Strongly advocated against spanking and corporal
  punishment

34
Nonhuman Studies of Fear

• Typically use shock as US
• Rats freeze
• SSDS
• Conditioned suppression ratio
• Train operant response train CS for aversive
  US, test suppression of operant response in
  presence and absence of CS
• Suppression video

35
Suppression Ratio

• 0 if behaviour entirely suppressed
• 0.5 if no suppression

Pre-CS CS Calculation S.R.
25 25 25/(2525)25/50 0.5
25 0 0/(025)0/25 0
25 15 15/(1525)15/40 0.375
36
Sign Tracking

• Also now called autoshaping (Brown Jenkins
  (1968)
• Response not required
• US often food
• Stimulus (CS) indicates US availability
• Subject tracks the sign more and more
• CS takes on properties of US
• Pigeon autoshaping
• Longbox autoshaping

37
Biological Predispositions
Burns Domjan (2000)
Timberlake Grant (1975)
38
Taste Aversion

• US stimulus producing illness
• UR illness, nausea, etc.
• CS (generally) novel taste
• CR nausea
• Long delay or trace conditioning

39
Theory of Interest

• Contiguity
• Equipotentiality Premise
• Pavlov
• Doesnt matter what you use as CS
• Any stimulus can be conditioned to any US

40
Initial Studies

• Garcia Koelling (1966)
• Garcia, Ervin Koelling (1966)
• Difficulty getting published
• Finally, accepted in Psychonomic Science

41
Results

• US poison, CS novel flavour
• Delay between CS and US 5 - 22 minutes produced
  very strong CR
• Weaker, but significant CR (avoidance of flavour)
  with up to 24 hour ISI!
• Violation of contiguity

42
Results
USX-ray
USshock
Flavoured water
Water Consumed
Water Consumed
Bright-noisy water
Pre-cond.
Post-cond.
Pre-cond.
Post-cond.

• Violation of equipotentiality
• Some CS-US combinations more easily learned
• Biological predispositions

43
Scientific Pardigms

• If evidence contradicts fundamental
  premisereject the evidence
• But sometimes unexpected results are correct

44
Eye Blink

• US air puff UR blink
• CS noise, light, vibration, etc. CR blink
• Straight-forward classical conditioning
• Vehicle for examining neurobiology of learning
  and memory

45
Brain Circuitry
Cerebral cortex
Climbing fibres
Mossy fibres
CS
US
Interpositus nucleus
Inferior olive
Pontine nuclei
CR
Red nucleus
Corneal air puff US
CS
US
Trigeminal nucleus
Auditory nuclei
Tone CS
CR
reflex paths
Cranial motor nuclei
UR
Reticular formation
Eyeblink UR CR
46
Eyeblink Exercise

• We can do science to it!
• Yes, real science with nothing more than a turkey
  baster, a pencil, and paper.