Stimulus Competition Between a Discrete Cue and a Training Context: Cue Competition Does Not Result From the Division of a Limited Resource

摘要

Several associative learning theories explain cue competition as resulting from the division of a limited resource among competing cues. This leads to an assumption that behavioral control by 2 cues competing with each other should always reflect a tradeoff, resulting in apparent conservation of total reinforcer value across all competing cues. This assumption was tested in 3 conditioned lick suppression experiments with rats, investigating the effects of changing the conditioned stimulus (CS) duration (Experiment 1), administering pretraining exposures to the CS (Experiment 2), and presenting nonreinforced CSs during the intertrial interval (Experiment 3) on Pavlovian conditioned responding to both the CS and the conditioning context. Fear conditioned to the context and to the CS decreased when the CS was of longer duration, massively preexposed before being paired with the reinforcer, or presented alone during the intertrial interval. These observations are problematic for the theories that explain cue competition as the division of a limited resource and suggest that the total reinforcer value across competing cues is not always fixed for a given reinforcer.