A Postsample Cue to Forget Does Initiate An Active Forgetting Process in Pigeons

 Douglas S. Grant and Alexander S. Soldat

 University of Alberta

Remember (R)- and forget (F)-cued training trials differed in whether the sample stimulus was or was not relevant to predicting trial outcome. Delayed matching-to-sample (DMTS) accuracy was lower on trials in which the F, rather than the R, cue followed sample presentation (F-cue effect). Because both types of training trials involved the same (a) probability of end-of-trial reinforcement and (b) pattern of discriminated test responding, the F-cue effect could not result from the F cue triggering (a) negative affect, (b) indiscriminate responding, (c) failure to attend to test stimuli, or (d) a pattern of responding incompatible with accurate DMTS performance. Results also revealed that the F-cue effect was not solely caused by presentation of an unexpected test stimulus. It was concluded that reduced accuracy on F-cued DMTS trials reflected the operation of an active forgetting process.