Chapter 4 - Classical Conditioning Methods Flashcards
What are some explanations of Pavlovian conditioning?
- conditioning results in activation of “US centre” in the brain (representation of the US) by the CS= S-S learning
- conditioning establishes a new stimulus-response connection between the CS and the CR =S-R learning
(option 1 - S-S Learning: CS substitutes for US; option 2 - S-R Learning: a connection is formed between the CS and the new CR)
What evidence is out there that supports S-S Learning?
If the CS serves as a substitute for the US then the nature of the conditioned response should be determined by the US
prediction: CS’s conditioned with different US’s should elicit different types of conditioned responses (ex. autoshaping with grain vs. water- Jenkins and Moore, 1973 - light elicited two different responses)
Describe the study performed by Timberlake and Grant (1975) on the nature of the conditioned stimulus?
- rat paired with presentation of another rat + food
- conditional responses of a participant rat was dependent on the CS (therefore, the US was forgotten)
Describe the experiment performed by Rescorla (1975) in determining whether S-S Learning or S-R Learning was occurring?
Controlled experiment to test this: devalue the US
group 1: light = food (give lots of food)
group 2: light = food (restrict food) normal response to US
** the US still matters**
Describe how learning can occur without a US?
- higher order conditioning
a) first order conditioning (CS1—> US)
ex. donut store + donuts = happy
donut store = happy
traffic light + donut store = happy
traffic light = happy (but weaker response)
b) second order conditioning (CS2—>CS1) - sensory preconditioning: we learn associations between CS1 and CS2 right away
What are the implications of learning without a US?
- S-S associations may occur in the absence of a UR
2. Evidence for latent learning
What four factors influence the strength and time required for classical conditioning?
- # of pairings of the CS (ex. bell) and the US (ex. meat)
- more pairings = stronger CR
- the intensity of the US
- ex. a squeak vs. a roar (more intense = faster conditioning) - how reliably the CS predicts the US
- the more reliable the better - the temporal relationship between the CS and the US
- less time = better (best at 0.5 seconds)
What things make for an effective CS and US?
- initial response to the stimuli
- CS does not initially elicit the conditioned response
- US elicits target response without prior training - significance and discriminability
a) intensity/salience
- give more > make the US more relevant to the biological needs of the organism
- make it naturalistic > make the CS more similar to the kinds of stimuli that an animal will encounter in its natural environment
b) novelty of the stimuli
- CS pre-exposure effect (latent learning - delaying learning because a previous association has been learned)
- US pre-exposure effect (doesn’t allow association to form) - CS-US relevance (belongingness)
Describe the study performed by Garcia and Koelling (1966) on belongingness?
2 CSs: 1 audiovisual and saccharin
2 USs: 1 sickness or shock
test: audiovisual or saccharin (only one)
results: taste without audiovisual + sickness = more fear
audiovisual without taste aversion + shock = more fear
** more likely to condition things that belong together**
What needs to happen for conditioning to occur?
The US needs to be surprising or unexpected for conditioning to occur
Describe Kamin’s blocking study
group 1: tone –> US (paired)
group 2: tone –> no US (not paired)
conclusions:
1. temporal contiguity (pairing of a CS with a US) is not sufficient for Pavlovian conditioning
2. for learning to occur, the US must be surprising
What is the Rescorla-Wagner model?
A mathematical model of Pavlovian conditioning
- surprisingness of the US determines how much conditioning will occur
What are the assumptions of the Rescorla-Wagner model?
- when a CS and a US are paired, an association is formed
- The learning of this association is a curvilinear function
- the effectiveness of the US in conditioning a CS is determined by how different the US is from what is expected
- the expectation of the US is related to the conditioned properties of all the stimuli that precede the US
Describe the Rescorla-Wagner model
- associative strength of a CS increases with the conditioning until the CS perfectly predicts the US
- associative strength of the CS/expectation of the US is denoted by V - US is denoted by lamda, thus, lamda is determined by the magnitude of the US
- when the CS perfectly predicts the US then V is at its maximum (V=lamda)
- lamda - V = amount of surprise (V approaches lamda with conditioning)
- deltaV = lamda -V: V increases by deltaV until V=lamda - with each conditioning trial the US becomes less surprising, therefore the value of deltaV will decrease across trials
- to quantify surprise
What does the Rescorla-Wagner look like?
DeltaV = K(lamda-V)
- most learning occurs within the first experience
