Yas- CM
Lecture 1 Overview
Reminder of Pavlovian conditioning.
Demonstrating Pavlovian conditioning.
Prediction Error reminder.
Inhibition: when it happens, what it is, how to test for it
Second-order conditioning vs. inhibition.
Pavlovian conditioning is often good, sometimes bad: omission schedules.
Applications of Associative Learning
Learning cause-effect relationships (Lecture 1).
Attention and addiction (Lecture 2).
Anxiety, phobia, and exposure therapy (Lecture 2).
Pavlovian Conditioning Components
NS: Neutral Stimulus
CS: Conditioned Stimulus
US: Unconditioned Stimulus
CR: Conditioned Response
UR: Unconditioned Response
Example of Pavlovian Conditioning
Initial Stage:
Metronome (NS) -> No salivation
Food (US) -> Salivation (UR)
Conditioning Process:
Metronome (NS) followed by Food (US) -> Salivation (UR)
After Conditioning:
Metronome (CS) -> Salivation (CR)
Control Conditions for Pavlovian Conditioning
Purpose: To determine if CS-US pairings are crucial.
Control setups:
CS with no US
US then CS
CS/US presented randomly
Key aspect: keep all conditions identical to the CS-US experimental condition, except for the CS-US pairings.
What is Learned in Pavlovian Conditioning?
An 'association' between the CS and the UR: S-R link
An association between the CS and US
Often conceptualized as a link in memory between the CS and US 'representations'.
S-R Link
Bell (CS) -> Salivation (CR)
Food (US) -> Salivation (UR)
S-S Link
Bell (CS) -> Food (US)
Food (US) -> Salivation (UR)
Bell (CS) -> Salivation (CR)
Learned Fears
Teddy (CS) -> Stab (US)
Stab (US) -> Pain (UR)
Teddy (CS) -> Fear (CR)
Example: Pleyers et al (2007) Experiment
Procedure:
Participants see a brand followed by a picture.
Participants say ‘ahh’ for nice pictures and ‘yuck’ for nasty pictures.
Participants reflect on their expectations during each trial.
Learning Curves
A graph showing the strength of the conditioned response (CR) over time.
The y-axis represents the strength of the CR.
The x-axis represents the number of conditioning trials.
Asymptote \, of \, conditioning: The plateau where further training yields minimal increase in CR strength.
Prediction Error Model of Learning
Learning happens when predictions are incorrect.
A discrepancy exists between expectation and outcome (surprise).
Early Learning:
Predictions often incorrect due to unfamiliarity.
Results in fast learning early in the learning curve.
Late Learning:
Predictions largely correct.
Minimal learning occurs late in the learning curve.
Five Effects of Prediction Error
Learning curves: A+ (Lecture 1)
Inhibition: A+/AX- (Lecture 1)
Blocking: A+ then AB+ (Lecture 2)
Extinction: A+ then A- (Lecture 2)
Protection from extinction: A+/AX-/B+ then XB- (Lecture 2)
They all follow the principle of ‘prediction error’.
Causal Learning Example
Scenario: A doctor trying to identify which foods cause migraines in a patient.
Method:
The patient consumes particular foods each day.
The patient predicts whether a migraine will occur ('yes' or 'no').
Example Days
Day 17: Food eaten - Apple. Migraine? Yes.
Day 18: Food eaten - Pineapple. Migraine? Yes.
Day 19: Food eaten - Nectarine. Migraine? No.
Day 20: Food eaten - Pineapple and Banana. Migraine? No.
Prediction Error Example
Pineapple -> Migraine
Pineapple + Banana -> No Migraine
Expectation: Migraine
Experience: No Migraine
Result: Negative prediction error leading Banana to acquire negative associative strength.
Summation Test
Testing the inhibitory properties of a cue by combining it with an excitatory cue.
Banana and Apple - Migraine?
Nectarine and Apple - Migraine?
Summation Test Explained
Apple causes migraine.
Pineapple causes migraine.
Banana inhibits the migraine caused by Pineapple.
Inhibition by Banana transfers to the Apple.
Inhibition in the Associative Model (1)
Apple -> Migraine
Banana -> No Migraine
Inhibition in the Associative Model (2)
Apple -> Migraine
Banana -> No Migraine
Terms for Similar Things
Excitatory CS-US association (e.g., Pineapple -> migraine)
The Pineapple CS has positive associative strength
The Pineapple CS causes the migraine outcome (US)
Inhibitory CS-US association (e.g., Banana)
The Banana CS has negative associative strength
The Banana CS prevents the migraine outcome (US)
Alternative Inhibition Training
Migraines occur almost every day.
Migraines do not occur on days when the patient eats Pears.
Conclusion: Pears prevent migraines, leading to an inhibitory association (Pears have negative associative strength).
Summation and Retardation Tests
Summation Test: Apple -> Migraine, but Bananas reduce US expectation.
Retardation Test: Pairing Bananas with Migraine leads to slower learning compared to Nectarine-Migraine pairing.
Nectarine is a neutral control cue.
Second Order Conditioning
Conditioning where a CS is paired with another CS, rather than a US.
Cue A = Pineapple (excitatory stimulus)
Cue X = Banana (inhibitory stimulus)
Within-Compound Associations
Two kinds of trial:
Pineapple = migraine (A+ trials)
Pineapple + Banana = no reaction (AX- trials).
Two Opposite Things Occur
Inhibition
Second-order conditioning
When Inhibition and When 2nd Order Conditioning
Non-humans (Yin, Barnett & Miller, 1994):
Large number of training trials = inhibition.
Small number of training trials = 2nd order conditioning.
Humans (Karazinov & Boakes, 2007):
Lots of time to think = inhibition.
Little time to think = 2nd order conditioning.
Inhibition requires some time and thought.
2nd order conditioning is just remembering what went with what?
Karazinov & Boakes (2007) Results
X is an inhibitor (PX-/P+).
M followed by no outcome (M-).
T followed by outcome (T+).
Summary of Inhibition and 2nd Order Conditioning
Banana -> no migraine US when the US is expected (due to pineapple).
Inhibition: Banana predicts 'no US'. An inhibitory association can form with the US (negative associative strength).
2nd order conditioning: banana can bring to mind pineapple, which brings to mind the migraine US.
Both processes happen. Second-order conditioning requires less training (less thought). Inhibition requires more training (more thought).
Usefulness of Pavlovian Conditioning
Fear conditioning:
CR is freezing – less likely to be spotted.
CR is flight (increased adrenalin) – more likely to be able to escape.
Conditioning with nausea: CR is a taste aversion – less likely to eat this in the future.
Predicting the delivery of food: CR is salivation and other preparation for digestion.
Pavlovian Conditioning Can Be Unhelpful (Hearst and Jenkins 1974)
Pavlovian conditioning can be unhelpful
Light
60+cm
Food hopper
Omission Schedule (Williams and Williams, 1969)
Light -> food delivery
If the pigeon pecks the light, the light goes off, and food is not delivered.
What should the pigeon do? What does the pigeon do?
Lecture Summary
Excitatory conditioning often results in links between representations: CS can activate US representation via this link.
Inhibition training results in a CS-US inhibitory link or CS-no US link.
Learning of both kinds requires a prediction error (positive or negative).
Initially, before inhibition develops, 2nd order conditioning is seen in the A+/AX- design, possibly due to associations between cues A and X.
Pavlovian conditioning allows the organism to prepare for the US.
Sometimes, the CR is unhelpful.
Reading
Pearce (2008) Animal Learning and Cognition: An introduction, Chapter 2. In particular pages: 39-43; 46-55.
Additional Yin, H., Barnet, R. C., & Miller, R. R. (1994). Second-order conditioning and Pavlovian conditioned inhibition: operational similarities and differences. Journal of Experimental Psychology: Animal Behavior Processes, 20(4), 419.
Karazinov, D. M., & Boakes, R. A. (2007). Second-order conditioning in human predictive judgements when there is little time to think. Quarterly Journal of Experimental Psychology, 60(3), 448-460.