Memory procedures, performance and processes in pigeons.

Short-term memory in pigeons is studied in the delayed matching-to-sample procedure where information is forgotten over short periods of time. Performance in this task reflects the separate influences of attention to the sample stimuli and memorial processes and is determined by a range of procedural variables. Forgetting functions can be obtained by varying the duration of the retention interval and can be quantified in terms of the parameters of a fitted function, such as the negative exponential. These parameters provide measures of initial discriminability and rate of forgetting and are sensitive to the effects of drugs known to influence the cholinergic, GABA and dopaminergic systems. The results of behavioral pharmacological studies suggest that the effects of a variety of drugs on initial discriminability and rate of forgetting are quite similar for pigeons and monkeys. We conclude that pigeons serve as an effective model to examine the effects of agonist and antagonist drugs on memory.