A concurrent-chains procedure was used to examine choice between segmented (two-component chained schedules) and unsegmented schedules (simple schedules) in terminal links with equal inter-reinforcement intervals. Previous studies using this kind of experimental procedure showed preference for unsegmented schedules for both pigeons and humans. In…

To better understand short-term memory for temporal intervals, we re-examined the choose-short effect. In Experiment 1, to contrast the predictions of two models of this effect, the subjective shortening and the coding models, pigeons were exposed to a delayed matching-to-sample task with three sample durations (2, 6 and 18 s) and retention…

Rats in a Pavlovian situation were trained under three different reward schedules, at either a 30 s or a 90 s intertrial interval (ITI): Consistent reward (C), 50% irregular reward (I), and single alternation of reward and nonrewarded trials (SA). Activity was recorded to the conditioned stimulus (CS) and in all 10 s bins in each ITI except the…

Rats were given differential exposure to three distinct and novel foods. One of these foods was exposed for 7 days; another for 2 days, and the last was not exposed. Next, half of the rats received six daily sessions in which a compound of the three flavors was followed by opportunities to run in wheels. The other rats received the food compound…

Latent Inhibition (LI) attenuation when a long delay is introduced between acquisition and test phases has been repeatedly observed using aversive conditioning procedures (e.g., Aguado, Symonds, & Hall, 1994). This effect has been used as evidence to support those theories that consider LI to be the result of a retrieval failure. We designed three…