Learning with no US
• Classical conditioning would be limited if direct exposure to the US was required for learning
to occur ( differnet association occurs in NON US and then CS manner in the real world). There
are situations where learning (i.e., associations) occur without a US, per se such as:
1. Higherorder conditioning
2. Sensory preconditioning
Higher order conditioning:
• CS may serve as a US, once conditioned.
• Key is to have few CSno US pairings CS1 and CS2 pairing should be small) to avoid
• CS1 and US paired up▯leads to CR response. Later give CS2+ CS1 ( which now acts as US) ▯
produces CR same as the previous one.
• Associations learned between two stimuli, each of which only elicits a mild orienting response
before conditioning (CS1▯CS2 are associated. Then after conditioning CS1 and US▯CR1 and
after then if you give them CS2 ▯ it creates the same CR1 response because CS1 and CS2 are the
What shapes the CR?
Stimulus Substitution Model
• After training the CS comes to act as a US and produces are CR.
• New functional neural pathways become established after this training.
• The CS becomes a substitute for the US (StimulusStimulus or SS relationship).
The Role of the US on the form of the CR
• Procedure: Compared conditioning in pigeons with either food or water as the US
• CR food pecked response key as if eating grains; rapid pecks with beak open
• CR = pecked response key as if drinking water ; slower pecking with beak closed, often with
• Results: There is a shifting of a response from one to the other as the US is changed or
depending on the animals used. Different CRs for water and grain
• Food used as USàfood response and when Water used as USàwaterdrinking response. Also
there was difference force used if water was given (high force initially then slows down) or if
grain was used as US (increase and rapid force)
Learning and Homeostasis
• Conditioned homeostatic responses can cause compensation in anticipation of physiological
changes (i.e. learning can cause change in our physiological response. e.g., condition rats to
cold US; anticipatory shivering so they can get through the cold and keep him in good shape
(shivering produces heat)
– Studied intensely using reactions to psychoactive drugs
What are the players in drug taking behaviour?
• CS = cues related to drugtaking (e.g., location, paraphernalia)
• US = pharmacological/chemical stimulation of the drug
• UR = physiological effects of drug (e.g., analgesia in morphine)
• CR = physiological effects (like or opposite of drug) following exposure to stronglyassociated
• Drug tolerance = repeated administrations of a drug have progressively less effect ( not
physiological but actually learnt)
Procedure: Users with history of concubine or no drugs
1) cocaine, 2) heroine, 3: nondrugs movies was shown.
And Beat per minutes in your heart rate was measured. Results: When you watch the film about the cocaine, the HR goes up. BUT NOT when heroine or
the neutral film was watched. When the particular CS (cocaine in this case) is presented there is a
change in the physiology in body
Naïve drugs users did not show any increased in HR.
Conditioning Model of Drug Tolerance
• Primary reaction before conditioning – initial effects of the drug ( is usually high)
• Reaction to the CS after experience/conditioning (usually now negative effect like after
effect of drinking)
• Response to the CS plus the drug after conditioning (now not as much of effect)
See the rate study:
Main point: Learning can modulate/change the physiological response
Observed effects/what did they find: rats the ones who were morphine injected while they had CS
around them, their response to morphine was much lower then the other ones not paired.
Procedures: 4 different conditions (see above) with 3 session of tolerance developing or 9 tolerance
develop tolerance sessions.
Results: reuduction in the effectiveness of the morphone because of the learning that had happen that
causes condition compulsatory reaction and lead to less analgesia ( drug is less effective)
CS as a determinant for the CR (see slides notes as well)
Rat: shown another moving rat as a CS for a particular CR.
Mainpoint Paw and groom are behavior they could use as food
But they Not doing is that like eating behaviors like the pigeon did when they were showing the
water or the food. Thus the CS effects the behaviors.
A Systems Approach to Conditioning
• Conditioning treated in a broader, systemsbased approach e.g., feeding system;