Enhanced Pavlovian conditioning with a change in appetitive reinforcer

Abstract

In three experiments, rats received appetitive conditioning with two unconditioned stimuli (US+ and US*) that supported a similar conditioned response. Stimulus A was first paired with US+, and then, for a second stage of training, the compound AB was paired with US*. Subsequent test trials with A revealed an abnormally strong conditioned response. The findings from additional groups indicated that such enhanced conditioning with A depended on the presence of B in the second stage and on the use of US+ and US* for the two training stages. A modification to a configural theory of conditioning is proposed in order to explain the results.