"Surprisingness" and short-term retention in pigeons.

Trained 14 Silver King pigeons in a symbolic matching-to-sample task in which food (access to grain) and no-food (blackout) samples were used. Responding to red test stimuli was reinforced on food sample trials, and responding to green test stimuli was reinforced on no-food sample trials. Samples of food and no food were rendered "expected" or "surprising" during subsequent testing by preceding samples with a previously established signal for either food (CS+) or no food (CS–). CS+ preceded food samples and CS– preceded no-food samples on surprising trials. Findings suggest that enhanced retention on surprising trials was apparent from the outset of testing to the extent that (a) surprising and expected trials were not markedly dissimilar to the trials of training, and (b) control over test responding by the CSs presented on expected and surprising trials was minimized. Results are discussed with regard to generalization decrement and directed remembering. It is concluded that surprising samples receive enhanced postperceptual processing and that the mechanism involved is that of retrieval-generated priming of short-term memory. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)