Lectures 6-15 Flashcards
Sometimes an instrumental procedure is employed however the animal learns a CS-US association. What is this called, and what is occuring?
Implicit classical - when animal learns that leaver is a stimulus that gets food. so animal will bite on leaver, and therefore food is delivered. Looks like instrumental conditioning but the rat is just learning the relationship between the leaver and food.
Describe the test used to determine if an instrumental response or CS-US association is learned.
Omission test - does the conditioned response persist even when it prevents or delays access to a positive US. IF it persists, then Classical conditioning, if the response stops this means that the animal has learnt that their behaviour controls the outcome, therefore instrumental learning has occurred.
Can conditioning occur when you prevent the UR
Yes, e.g. if you give a dog a drug which prevents salvation, it will still condition. i.e. when drug wears off will get salvation
Give an example of S-S learning and S-R learning. Is the distinction between these absolute? why or why not? How does this effect the rate at which a US is devalued.
S-S = bell associated with food S-R = bell associated with salivation
The distinction is not absolute as we can think of a stimulus as having multiple levels of experience. The animal can associate the CS with any type of process going on in the animals brain - depending on how early in the sequence the association is formed.
If the association forms up the top (S-S), then you will see a devaluation effect happen fast, however if the association forms with the response (S-R), then devaluation of US won’t effect response.
Describe the ratio that describes the rate of conditioning.
(US-US)/(CS-US) = interval between US’s/CS duration
conditioning occurs the fastest when ratio is larger
so greater conditioning when trials are far apart, and CS-US are paired closely*
*but very short CS-US intervals reduces conditioning
Is continuity enough? explain your answer.
No - Rescorla’s truly random schedule - demonstrates that even when you have continuity, don’t get conditioning.
Describe overshadowing
If A and B were individually paired with a US, and C+D were paired together with an US you would find greater conditioning when test A and B than C and D. C and D overshadowed each other and resulted in less learning.
Describe Blocking
Blocking is a phenomena originally described by Kamin, where pre-training of a cue (CS-US) impairs subsequent learning about another cue in a cue compound with the pre-trained cue. In a blocking paradigm, responding to cue B in a reinforced stimulus compound, AB, is reduced due to pre-training of cue A.
Is continuity necessary for learning. Explain your answer.
No! Rats learn about a CS associated with no US - inhibitory conditioning. e.g. leanring that a noise is a safety signal.
Is contingency necessary for learning?
No! e.g. when shock is sometimes presented with a noise - no conditioning to the noise, but conditioning/learning about the chamber. they are learning that the chamber is frightening.
Can the RW model explain Rescorla’s original demonstration of contingency (i.e. Rescora’s truly random schedule = no conditioning to the CS)?
Yes, extra CSs delivered are associated with the context, this blocks learning about the original CS
How does the RW model explain extinction? What does this suggest?
Lambda = 0 since no US, sigma V > 0 since the CS has already acquired an associative strength, usually 1. Therefore 0-1=-1, V decreases, gradual reduction to 0. This suggests that extinction is unlearning, which we know is not true.
If extinction is not unlearning, what is extinction?
Extinction is new learning about the CS that masks the original learning. The animal acquires memories of the CS:
- after conditioning, only memory is CS-US association
- after extinction, animal have two different conflicting memories. memory of CS-US and memory of CS alone.
CR is determined by which type of memory received upon testing. If an animal has recent and extreme experience with the Cs alone, then does not show CR to CS (ie. extinction)
How is extinction influenced by the context.
The animal uses the environment to tell it which type of memory it should be retrieving. Extinction now means the CS is ambiguous, the way you can resolve this is you encapsulate that ambiguity with the context. therefore renewal of CRs if animal is tested in different context and spontaneous recovery of CRs over time.
Describe what is meant by extinction as inhibition
This describes the notion that extinction is a CS-noUS memory, which is essentially inhibitory learning.
