Generality: Many different paradigms have been used in different species (mostly rats, pigeons, rabbits) to study Pavlovian learning. These illustrate the different types of response systems (reflexive, hedonic, motivational/emotional, whole body locomotion, etc) that can be influenced by Pavlovian processes.
Different paradigms
There is a great deal of specificity in the eyeblink response system. Shock to the right eye primarily evokes right eyeblink responses, and shock to the left eye primarily evokes left eyblink responses. CSs associated with shocks to the different eyes will also evoke eyeblink CRs that are specific in their location.
Rats hedonic reactions to tastes paired with illness, but not shock are decreased as a result of this form of learning.
Measured with suppression ratio (responding during CS/(responding during CS + responding prior to CS)).
Since the CS associated with shock will suppress food-reinforced lever pressing, but increase shock avoidance-reinforced lever pressing, it looks like what gets conditioned to the CS is a central motivational state (like fear) and not a specific response (like freezing) that is incompatible with lever pressing.
Pigeons peck the keylight paired with an appetitive reinforcer. Their CRs are affected by whether the US is grain or water or access to a female pigeon.
The male Japanese quail will display interesting CRs to a taxidermically-prepared model of a female quail when tested in the context (the arena) in which prior sexual encounters with a live female quail have taken place.
Siegel has proposed that Pavlovian conditioning participates in the development of drug tolerance. Drug-opposite CRs are assumed to get conditioned to the contextual stimuli that accompany the drug administration. These drug-opposite CRs are assumed to counteract the actual effect of the drug. Thus, according to this view, tolerance should be context specific and it should be possible to directly observe the conditioning of these drug-opposite CRs.
1. Procedures used to generate excitatory conditioning include the following: Delay, Inhibition of Delay, Trace, Simultaneous, and Backward conditioning. Conditioning of CRs is a function of the interstimulus interval (i.e., the CS-US interval). In particular, there is relatively little conditioning with very short ISIs, optimal conditioning with longer ISIs, but with conditioning tapering off with very long ISIs.
2. Measurement techniques. The CR can be taken as a direct measure of excitatory conditioning. However, in cases where the CS does not produce a CR, one can use the Second Order Conditioning test to see if excitatory learning occurred to the CS. In the Second Order Conditioning test we ask if the CS can support learning (e.g., after CS1-US pairings) to another stimulus that is paired with it (e.g., CS2 Ð CS1).
3. Control Groups. In order to know that excitatory conditioning has occurred we need to assess learning in a group receiving CS-US pairings with a control group of some kind. Different control groups that have been used include (CS alone, US alone, CS | US explicitly unpaired (EUP)). Of these three control groups the best one is the EUP group because it differs from the experimental group (i.e., the group receiving CS-US pairings) only in the temporal relationship between CS & US. If a difference between the pairing and EUP groups emerge in the experiment then we can confidently conclude that this is due to the different temporal arrangement in the two cases. Excitatory conditioning is thought to be pairing dependent. So more CRs in response to the CS in the group receiving pairings vs the EUP control would indicate that excitatory learning has occurred in the pairing group. Unlike the EUP group, the other control groups leave open the possibility that more responding in the pairing group can be understood in terms of sensitization.
B. Extinction: Is it due to Unlearning or New learning?
1. Extinction refers to a procedure and a process. Procedurally, following CS-US pairings and the emergence of CRs to the CS, the CS is repeatedly presented without the US with the result being that CRs decline. The extinction process refers to whatever goes on psychologically to result in a loss of CRs to the CS during repeated nonreinforcement.
2. The phenomena of Spontaneous Recovery, Disinhibition, and Renewal (p. 109-110 in the text) all suggest that extinction is not entirely due to unlearning. Instead, Pavlov believed that there was new learning going on to the CS during extinction. He characterized this new learning in terms of inhibition.
C. Inhibitory conditioning (p. 103-107 in your text): CS acquires an ability to oppose excitation.
1. Procedures used to produce inhibitory conditioning include Pavlovian conditioned inhibition, Backward Conditioning, EUP conditioning, differential conditioning.
2. Methods of measuring inhibitory conditioning include the summation test, the retardation of learning test, and the approach/withdrawal test (in autoshaping only).
3. Control groups. How does one assess when a CS has acquired inhibitory conditioning? Since the EUP procedure, itself, has been found to result in inhibitory learning, then this suggests that this procedure is not ideal as a control group to assess excitatory conditioning. More on this later. But back to the question of control groups for inhibitory learning, the appropriate answer depends on our understanding of what is responsible for inhibitory learning in the first place. Current wisdom is that inhibitory learning will occur to a stimulus when it is ÒpairedÓ with the omission of an expected US. This being the case, you can see how the Pavlovian inhibitory conditioning procedure is ideal and the differential conditioning procedure would provide for a suitable control.