Pavlovian-instrumental transfer

An example of specific PIT, as described by a neuroscience review on Pavlovian-instrumental transfer from 2013, is as follows:

In a typical experimental scenario a rat is trained to associate a sound (CS) with the delivery of food. Later, the rat undergoes an instrumental training where it learns to press a lever to get some food (without the sound being present). Finally, the rat is presented again with the opportunity to press the lever, this time both in the presence and absence of the sound. The results show that the rat will press the lever more in the presence of the sound than without, even if the sound has not been previously paired with lever pressing. The Pavlovian sound-food association learned in the first phase has somehow transferred to the instrumental situation, hence the name 'Pavlovian-instrumental transfer'.

Specific and general transfer

In relation to rewarding stimuli, specific PIT occurs when a CS is associated with a specific rewarding stimulus through classical conditioning and subsequent exposure to the CS enhances an operant response that is directed toward the same reward with which it was paired (i.e., it promotes approach behavior). General PIT occurs when a CS is paired with one reward and it enhances an operant response that is directed toward a different rewarding stimulus. Neurobiological state factors (e.g., appetite and satiety states, stress level, drug states such as intoxication and withdrawal, etc.), and particularly the motivational state of an animal, strongly affect the amount of appetitive motivational salience (i.e., incentive salience) that a reward cue confers to an associated rewarding stimulus via Pavlovian-instrumental transfer. Acute stress amplifies the motivational salience that reward cues confer to rewarding stimuli through both specific and general PIT; however, chronic stress reduces the motivational impact reward cues.

Specific PIT and general PIT also occur with aversive stimuli and are defined analogously. Specific PIT with an aversive stimulus occurs when a CS is paired with an aversive stimulus and subsequent exposure to the CS enhances an operant response that is directed away from the aversive stimulus with which it was paired (i.e., it promotes escape and avoidance behavior). General PIT with an aversive stimulus occurs when a CS is paired with one aversive stimulus and it enhances an operant response that is directed away from a different aversive stimulus.