4.1 The Conditions of Conditioning Flashcards
What is temporal contiguity?
Two stimuli closely related in time; they co-occur together
What was previously thought about TC?
If the US and CS occurred close together in time = good effective learning
What is the general rule for TC?
Amount and speed of conditioning decreases as temporal separation of CS and US increases
Give an example of the effect of TC on conditioned suppression
When shock occurs 10s after noise, the learning of association is strong - show high freezing behaviour
When shock occurs 90s after noise, the learning of association is much weaker - show low freezing behaviour
What happens to learning when you present the CS and US v close in time together?
Learning is not very good
Why is small TC not always effective in learning? Give an example in your explanation.
The brain is trying to discount what is implausible
eg. flavour aversion - think about it biologically
- Learning that a flavour makes you sick - takes time for the digestive process to take place
- Something you ate a few mins ago isn’t what is making you sick, more likely to be something you ate hours ago
- The brain is factoring in the biological properties of what is going on
What is the spacing of trials and is it effective for learning?
The space between the US’s and it affects learning
Is TC the only factor important for learning?
No - trial spacing has a separate effect
What do we use to measure whether learning is effective due to the diff factors involved?
Interval between US’s : CS duration
What ratio shows best learning and how do we attain it?
A large ratio signals the best learning
We get a large ration when the interval between US’s is big and small CS duration
Who came up with the unconfounding control experiment to test whether TC is sufficient enough for learning?
Rescorla
Discuss the confounding control experiment looking at sufficiency of TC
Researchers would compare 2 conditions: paired or unpaired
Paired is experimental condition, unpaired = control
Unpaired condition: Tone present = no shock
- Shock occurred when the tone was absent
There is something that confounds the control condition -confounds the correlations of the CS and US in time
There is a strong +ve correlation in time in paired condition
In unpaired condition, there is a strong -ve condition
What did Rescorla do to the experiment to make it unconfounding?
Made it so the US occurred randomly - here there is no +ve or -ve correlation, it just equals 0
The CS would sometimes come on when the US was on
Under these conditions, there is still contiguity:
- There are still instances where the US follows the CS
- US = shock, CS = tone
- The randomness does break the correlation and resulted in no conditioning
What did Rescorla’s truly random experiment show?
Although there is perfect TC between the CS and US it was not enough to produce conditioning when the contingency is 0
What are the 2 demonstrations that show TC isn’t sufficient enough for learning to take place?
Overshadowing
Blocking
Discuss overshadowing experiment.
Rats learn that whenever the signal comes on they receive a sucrose pellet
- The more they poke their nose in, the more they have learnt about something
If you condition the CS’s alone, the rat learns well that both tone 1 and green light predicts sucrose pellet
What happens when 2 CS’s conditioned together (bottom group) to result in sucrose pellet but at test only present 1 CS?
The responding is lower for both CS’s when presented alone
Call this overshadowing - presenting the CS’s together in training detracts from learning about them individually
What is saliency?
Refers to how noticeable a stimulus is
Intrinsically related to the property of the CS but not quite right in all cases
Discuss the saliency and overshadowing experiment
Group 1 = light predicting shock
Group 2 = light and noise predicting shock
Group 3 = light and more salient noise predicting shock
Light is the same in all conditions - what happens when present the light alone at test?
The results show if the light is presented in isolation with the shock, you learn a lot = There is a small supp ratio
With a soft noise (group 2) still learn a lot about the light as there is a small supp ratio = The soft noise does not overshadow the light
The loud noise (group 3) overshadows the light a lot and has reduced the amount of learning = There is a high supp ratio
What is a suppression ratio?
Quantifies the amount of learning taking place
0 suppression ratio = a lot of learning
Max suppression ratio = 0.5 (i.e. no learning has taken place)
What did Kamin show in 1968?
Conditioning to a CS could be “blocked” by the presence of a 2nd CS that already signalled the US
What were the control conditions in the blocking experiment?
Overshadowing conditions = control conditions
- Only things happen in conditioning phase, no pre-condition
- Testing asymmetries in the stimuli that are being presented and together they are the control
Group 1: TL+shock, test L
Group 2: TL + shock, test T
What were the critical groups of interest in the blocking experiment?
The blocked groups = critical group of interest
Get the exact same pairings in the conditioning phase as the overshadowed group
Critical thing is the preconditioning phase in the blocked condition
He paired one of the stimuli with the shocks
Group 1 = noise shock pairing before light is introduced
Group 2 = light shock pairing before noise is presented
What did the blocking experiment results show?
Overshadowed groups on average show good suppression
The learning to the light is v bad in Group 1 blocked
The learning to the noise is v bad in Group 2 blocked
Why do the blocking experiment results occur?
This happens because you already know which CS predicts the shock due to the pre-conditioning phase
