OCCASION SETTING IN PAVLOVIAN CONDITIONING

This chapter describes Pavlovian conditioning as the transfer of control of reflexes (unconditioned responses or URs) from stimuli that elicit them unconditionally (USs) to other stimuli that normally are incapable of eliciting them. Although auditory cues seldom elicit substantial salivation spontaneously, a tone provokes that response if it consistently predicts food delivery. This new-found control of salivation by the tone is typically attributed to the acquisition of some association or potentiated connection between the CS and US pathways: by virtue of that association, the CS becomes a substitute elicitor of activity along some portion of the US-UR pathway. This is often described as the CS's “activating a representation of the US”. Another behavioral control function occasionally ascribed to Pavlovian CSsis modulation. Rather than acquiring its own ability to elicit behavior usually controlled by another reflex system, a Pavlovian CS influences the efficacy of the normal elicitor of a response. The chapter is concerned with a particular modulatory function of CSs in rats solutions of elementary conditional discriminations, in which one CS modifies the efficacy of Pavlovian associations between other cues and the US. This function is called as occasion setting, which is readily distinguished from elicitation both conceptually and empirically, and perhaps anatomically as well. Furthermore, this occasion-setting function involves a hierarchical, multilayered organization of representations of events and relations and thus may aid the expansion of the domain of Pavlovian accounts of behavior. © 1992, Academic Press Inc.