Lecture 2 Flashcards
Explain associative learning
Basics of Ivan Pavlov’s discovery of conditioned reflexes serve as historical backdrop for current learning theories
- classical or “pavlovian” conditioning
Most popular form of classical conditioning?
Looking at dog digestion: US = food UR = salivation CS = bell CR = salivation
What becomes an executor of the behaviour in classical conditioning?
the CS
Unconditioned response
natural reaction, not a learned behaviour
e. g. fear caused by a loud explosion
e. g. salivation to the smell of food
What is conditioned inhibition?
two procedures to induce conditioned inhibition
- differential inhibition
- conditioned inhibition
In both procedures, CS#2 becomes an inhibitor of behaviour
Explain differential inhibition
CS#1 –> US
CS#2 –> no US
Explain conditioned inhibition
Step 1. CS#1 –> US
Step 2. CS#1 + CS#2 –> no US
- when presented together, CS#2 acts as an inhibitor
What are two tests to test conditioned inhibition?
- Summation
2. retardation of acquisition
Explain summation
CS#3 (a CS+) is presented with CS#2 = no CR
Explain retardation of acquisition
CS#2 –> US = the CR will develop very slowly
Drugs of abuse would be considered?
the unconditioned stimuli
- activation of the reward pathway
Effects of physiology due to the injection of drugs of abuse would be considered?
unconditioned response
Drug predictive stimuli would be considered?
Conditioned stimuli
- S-S learning
Alternative S-S* learning
- pseudo-conditioning
2. sensitization
Explain pseudo-conditioning
increased responding to the CS that occurs because of mere exposure to the US
Explain sensitization (S-S* learning)
increased responding tot he CS that occurs because of mere exposure to the CS
Explain post-conditioning devaluation (US devaluation)
- Associates CS with US –> response
- direct link between CS and UR
- change value of US as result of test
- during test, take food and pair with something nasty
- devaluate = make dog sick - redo test the next day - what does the animal do?
- if it salivates, no concept of food
- if it doesn’t salivate = bell reminds animal of food (usually CR goes away when US is devaluated)
–> Supports Pavlov’s S-S theory
Explain second order conditioning
First order CS = tone
First order conditioning = tone –> food (conditioning)
TEST: tone induces salivation
Second order CS = light
Second order conditioning = light –> tone
TEST: light induces salivation (even though light was never directly paired with food)
Explain sensory pre-conditioning
similar to second order conditioning but CS-CS association done before US is introduced
1. sensory pre-conditioning: tone light
2. conditioning: tone –> food
TEST: tone induces salivation, so does light
Important characteristic of CS?
Don’t choose a CS, that by itself can produce a strong response
Components of eye blink conditioning
US = puff of air to the eye CS = tone UR = eye blink CR = eye blink
Components of fear conditioning
US = foot shock CS = tone UR = jumping CR = automatic/somatic responses
Example of contextual conditioning
rat in a two sided box - alternating shots of heroin/saline
- rat chooses side in which it was previously injected with heroin
3 types of conditioned responses
- automatic - increase in heart rate, salivation, sweating
- motivational - emotions, change in affect
- somatic - movement toward/away stimulus
Measure of fear can be done by?
amount of decrease in behaviour
Explain the suppression ratio
An index used to measure the reduction in responding for food during the presentation of a CS associated with an aversive US (ratio of presence/absence of elver pressing)
What is the suppression ratio index?
= B/(A+B)
where:
B = # of responses during the CS
A = # of responses before the presentation of the CS
Suppression ratio index criteria
If there is no fear, A=B and S.R. = 0.5
If there is much fear, B=0 and S.R. = 0 (no response when CS is presented)
What is the purpose of the suppression index ratio?
To give number to an emotion
Strength of conditioning depends on?
Law of Association
What factors make up law of association?
- frequency of CS-US association
- the more CS-US association = the stronger conditioning will be - intensity and novelty of CS and US
- use of novel US and CS –> strong conditioning (motivated to learn) - contiguity (CS-US sequence/timing)
- occurring together in time/location–> strong conditioning
4 types of conditioning pertaining to contiguity
- delay
- trace
- simultaneous
- backward
Explain delay conditioning
- strongest level of conditioning
- CS turned on before US and they stop at the same time
Explain trace conditioning
- more difficult for subject because stuff happens in between
- test of memory
Explain simultaneous conditioning
- CS and US are presented at the same time
Problems:
- distracting
- essence of classical conditioning = learning predictors (which this lacks) - how valuable is a predictor if the food already exists?
Explain backward conditioning
US presented and CS comes after
- CS isn’t a predictor of anything
In order to obtain and observe strong conditioning:
the CS should precede the US and remain on until the US occurs
Who explained contingency?
Robert Rescorla
What is contingency?
The CS must not only be contiguous with a US, it must also be an accurate predictor of the occurrence of the US
- to explain the notion of predictability
- CS must be contiguous and an accurate predictor
How can contingency be calculated?
- probability that a US will occur in the presence of the CS = p(USICS) = good probability
- probability that a US will occur in the absence of the CS = p(USInoCS) = bad probability
Calculating Phi for contingency involves?
Phi = p(USICS) - p(USInoCS)
Value between 0 and 1:
0 = really poor
0.5 = some conditioning
1 = maximum level of conditioning
What does a positive contingency mean?
US is more predictable when CS is on
What does a negative contingency mean?
US is less predictable when CS is on
Which of the following could be an example of Pavlovian unconditioned response?
a sense of fear caused by a loud explosion
Which of the following could be an example of a Pavlovian conditioned response?
enjoying a familiar song
US devaluation experiments:
supports the S-S theory
Sensory pre-conditioning:
- is an example of S-S learning
- involves associating two CSs
- is conceptually similar to second order conditioning
During fear conditioning in rats, the foot shock is the?
unconditioned stimulus
Presentation of a CS+ associated with an incentive US will ? an instrumental action motivated by an incentive stimulus
increase
IN general, the most effective procedure for producing most classically conditioned association is the ? conditioning procedure?
delay
