The S-R information stream: where's the filter?

Pavlovian conditioning procedures, in which events such as tastes, lights, and sounds become predictors of food, water, and shocks, have been used for studying the role of the information filter in the selection of conditioned responses. Different models posit the filter at different locations in the S-R stream, but most models suggest either a pre-encoding filter, in which much information is discarded at an early stage of processing, or a post-encoding filter, in which the information is stored but not subsequently expressed in behavior. A selective review of the literature on cue-competition effects reveals a plethora of phenomena that support a post-encoding, but not a pre-encoding filter in Pavlovian processes.