Pigeons prefer a positive discriminative (S+) stimulus that follows a less preferred event (a large number of required responses, a longer delay, or the absence of food) over a different S+ with a similar history of reinforcement that follows a more preferred event (a single required response, no delay, or food). We proposed that this phenomenon…

Pigeons show a preference for an alternative that provides them with discriminative stimuli (sometimes a stimulus that predicts reinforcement and at other times a stimulus that predicts the absence of reinforcement) over an alternative that provides them with nondiscriminative stimuli, even if the nondiscriminative stimulus alternative is…

Spatial pattern separation (SPS) and spatial pattern completion (SPC) have played an increasingly important role in computational and rodent literatures as processes underlying associative memory. SPS and SPC are complementary processes, allowing the formation of unique representations and the reconstruction of complete spatial environments based…

Recent studies have demonstrated that the expectation of reward delivery has an inverse relationship with operant behavioral variation (e.g., Stahlman, Roberts, & Blaisdell, 2010). Research thus far has largely focused on one aspect of reinforcement--the likelihood of food delivery. In two experiments with pigeons, we examined the effect of two…

Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task--a computer game measuring learning of Pavlovian associations through conditioned suppression--for assessing context conditioning in humans. One between-subjects and one within-subjects study are reported.…

Experiments 1 and 2 involved independent groups that received primary reinforcement after a correct match with a probability of 1.0, 0.50 or 0.25. Correct matches that did not produce primary reinforcement produced a conditioned reinforcer. Both experiments revealed little evidence that acquisition or retention was adversely affected by use of…

Four experiments explored the role of contexts in information retrieval after different levels of acquisition training in human predictive learning. Participants were trained where cue (X) was followed by an outcome in context A while a different cue (Y) was followed by the absence of the outcome in context B. When 4 training trials with each cue…

The ABA renewal procedure involves pairing a conditional stimulus (CS) and an unconditional stimulus (US) in one context (A), presenting extinction trials of the CS alone in a second context (B), and nonreinforced test trials of the CS in the acquisition context (A). The renewal of extinguished conditioned behaviour is observed during test. The…

Earlier studies on human avoidance learning showed that an avoidance response reduces the expectancy that a warning stimulus (WS) will be followed by an unconditioned stimulus (US). This modulation can transfer to WSs with which the avoidance response did not occur in the past. Recent studies suggest that transfer of modulation is selective in…

This paper presents evidence of extinction, spontaneous recovery and renewal in a conditioned preferences paradigm based on taste-taste associations. More specifically, in three experiments rats exposed to a simultaneous compound of citric acid-saccharin solution showed a preference for the citric solution when the preference was measured with a…

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…

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…

Truly flower-naive bumblebees, with no prior rewarded experience for visits on any visual patterns outside the colony, were tested for their choice of bilaterally symmetric over asymmetric patterns in a radial-arm maze. No preference for symmetry was found. Prior training with rewarded black and white disks did, however, lead to a significant…

In three experiments, rats received exposure to a sucrose solution followed by conditioning with a neutral flavor as the conditioned stimulus (CS) and sucrose as the unconditioned stimulus (US). In Experiments 1 and 2, some rats were given both the preexposure and the conditioning phases in a highly familiar context (the homecage), whereas other…

Two experiments examined temporally based changes in the conditioned magazine-entries of rats when a target food pellet arrived at a fixed time before the termination of a conditioned stimulus. Both experiments found that increasing the rate of intertrial pellets systematically interfered with the rate of acquisition. When intertrial pellets were…