Prior experience of unsignaled food can interfere with subsequent acquisition by birds of autoshaped key-pecking at a signal light. This has been understood to indicate that unsignaled food results in context conditioning, which blocks subsequent learning about the keylight-food relationship. In the present experiment with rats lever insertion as…

Three Pavlovian fear conditioning experiments with rats as subjects explored the effect of extinction in the presence of a concurrent excitor. Our aim was to explore this particular treatment, documented in previous studies to deepen extinction, with novel control groups to shed light on the processes involved in extinction. Relative to subjects…

arrow]US associations also survived The memories of the unconditioned stimulus (US) and its absence (No US), symbolized as S[superscript R] and S[superscript N], respectively, may be retrieved on US or No US trials giving rise to four types of associations, S[superscript R][right arrow]US, S[superscript R][right arrow]No US, S[superscript N][right…

Two conditioned taste aversion experiments with rats were conducted to establish if a target taste that had received a prior pairing with illness could be subject to second-order conditioning during extinction treatment in compound with a flavor that also received prior conditioning. In these experiments, the occurrence of second-order…

In Experiment 1, rats were trained on a discrimination in which one occasion setter, A, signaled that one cue (conditioned stimulus, CS), x, would be followed by one outcome, p (unconditioned stimulus, US), and a second CS, y, by a different outcome, q (x [right arrow] p and y [right arrow] q); a second occasion setter, B signalled the reverse…

In two experiments, the evidence showed that 20 min of forced swimming by rats caused aversion to a taste solution consumed before swimming. When one of two taste solutions (sodium saccharin or sodium chloride, counterbalanced across rats) was paired with swimming and the other was not, the rats' intakes of these two solutions showed less…

McSweeney and Weatherly (1998) argued that differential habituation to the reinforcer contributes to the behavioral interactions observed during multiple schedules. The present experiment confirmed that introducing dishabituators into one component of a multiple schedule increases response rate in the other, constant, component. During baseline,…