Directed forgetting in animals.

Abstract

Directed-forgetting research with animals suggests that animals show disrupted test performance only under certain conditions. Important variables are (a) whether during training, the cue to forget (F cue) signals nonreward (i.e., that the trial is over) versus reward (i.e., that reinforcement can be obtained) and (b) given that reinforcement can be obtained on F-cue trials, whether the post-F-cue response pattern is compatible with the baseline memory task. It is proposed that some findings of directed forgetting can be attributed to trained response biases, whereas others may be attributable perhaps to frustration-produced interference. It is suggested that directed forgetting in animals should be studied using procedures similar to those used to study directed forgetting in humans. This can be accomplished by presenting, within a trial, both to-be-remembered and to-be-forgotten material.

True directed forgetting in pigeons may occur only when alternative working memory is required on forget-cue trials

“…After substantial experience with the R and F cues, one can assess memory on F-cue trials by presenting infrequent "probe" trials involving the presentation of comparison stimuli following the F cue. Poor performance on F-cue-probe trials has been taken as evidence that animals can be "directed to forget" the sample stimulus or, more generally, that animals show a kind of flexibility in the maintenance of memory that is similar to that of humans.In a review of the animal directed-forgetting literature, Roper and Zentall (1993) noted that the effectiveness ofF cues in producing a consistent decrement in DMTS probetrial performance seems to depend on the use ofthe "omission" procedure. With this procedure, the F cue, which signals the absence ofa memory test, is followed immediately by the intertrial interval (ITI).…”

“…In a review of the animal directed-forgetting literature, Roper and Zentall (1993) noted that the effectiveness ofF cues in producing a consistent decrement in DMTS probetrial performance seems to depend on the use ofthe "omission" procedure. With this procedure, the F cue, which signals the absence ofa memory test, is followed immediately by the intertrial interval (ITI).…”

“…In those experiments involving substitution procedures in which directed forgetting has been reported, Roper and Zentall (1993) proposed that, on F-cue-probe trials, the pattern of responding required following the F cue was different from what was established following the F cue during training. According to this notion of response compatibility, the end-of-trial behavior pattern on F-cue trials (relative to that on R-cue trials) determines whether or not performance will be disrupted on the unexpected memory test that occurs on F-cue-probe trials.…”

“…Furthermore, it is not clear that Grant's (1989) use ofsingle-sample . probe trials avoids the problems inherent in the doublesample procedure (see Roper & Zentall, 1993). Whenever two samples representing conflicting instructions are presented on a trial, there is a reasonable likelihood that an instructional deficit will occur on probe trials.…”

Transfer of directed-forgetting cues across discrimination tasks with pigeons

“…Roper and Zentall (1993) suggested that the absence of a delay interval cue could come to serve as an implicit R-cue. Grant's pigeons had never been trained to forget the sample stimuli within the transfer task discrimination and, therefore, may have had difficulties abandoning this default remember strategy when F-cue stimuli from the cue-training task were later inserted at test.…”