Associative and reinforcing properties of a stimulus element after compound conditioning.

This article investigates the nature and functional properties of elemental conditioned stimuli (CS) previously trained as part of an audiovisual compound CS in mice, focusing on their ability to activate unconditioned stimulus (US) representations and to serve as conditioned reinforcers. Experiment 1 used US devaluation via conditioned taste aversion to show that while the original compound CS elicited conditioned responses (CRs) sensitive to US devaluation, the elemental CSs—particularly the auditory element—elicited CRs that were insensitive to devaluation, suggesting these elements do not activate detailed sensory representations of the US. Experiment 2 assessed conditioned reinforcement and found that both the compound and elemental CSs could reinforce new instrumental responses, but this effect was modality-dependent: the visual element supported instrumental responding, whereas the auditory element did not, despite eliciting stronger magazine CRs. These findings indicate an asymmetry in how visual and auditory elements function after compound conditioning, with elemental CSs capable of eliciting generalized CRs and reinforcing behavior independently of detailed US representation, highlighting qualitative dimensions of stimulus generalization and the potential influence of stimulus modality on associative learning processes.