opponent processes in HABITUATION	opponent processes in EXTINCTION
A-PROCESS:	EXCITATORY ASSOCIATION:
- innate	- learned during acquisition phase
- response to a stimulus	- response to CS when it predicts appearance of US, leading to tendency to produce CR
- always occurs at full strength	- starts from nothing, reaches full strength and is thereafter permanent (consider evidence of spontaneous recovery, disinhibition, and rapid reacquisition)
B-PROCESS:	INHIBITORY ASSOCIATION:
- innate	- learned during extinction phase
- response to a-process, working in opposite direction	- response to CS when it predicts absence of US, leading to tendency not to produce CR
- starts weak and lags behind a-process, but over repeated presentations of a stimulus, automatically increases in strength and decreases in lag-time after the a-process	- starts from nothing, reaches full strength over the course of extinction to cancel out excitatory association
- weakens over rest period, so habituation is not permanent	- dissipates during rest period leaving only a slight "residue" of inhibition behind (acounting for spontaneous recovery and eventual permanent inhibitory association)
- requires a-process to occur first	- requires prior excitation as a context, since without prior expectation of something occurring, the absence of something occurring is not specifiable (but note apparent contradiction of this point in latent inhibition / CS pre-exposure effect)