Effects of prior and interpolated learning on retention in pigeons.

Abstract

A discrimination situation was developed for pigeons which would permit the investigation of retention problems in the animal laboratory. Changes in Retroactive and Proactive Inhibition (RI and PI) were studied as a function of the length of the retention interval (1, 10, or 30 days). A S-key discrete-trial situation was employed in which a task was denned by the key color that was associated with reinforcement.Comparison of the number of correct responses made by the various groups on Day 1 of relearning permits the following conclusions: (a) Retroactive Inhibition was very prominent at all retention intervals, (b) The RI Ss relearning after a 30-day interval performed better than those relearning after a 1-or 10-day interval, (c) Ss learning an additional task prior to the task to be recalled made as many correct responses during the retention test as did control Ss. That is, no Proactive Inhibition was evident, (d) Both PI and control Ss relearning after a 30-day interval performed more poorly at recall than did those Ss relearning after a 1-or 10-day interval-a trend opposite to that shown by the Ss in the RI condition. A supplementary experiment showed that even when the number of prior tasks was increased from 1 to 2, no PI was evident after a 30-day interval-the only interval tested under this special interference condition.

Role of proactive interference in infantile forgetting

“…The finding that PI was not manifested for the spatial discrimination in adult rats is consistent with a number of experiments (Crowder, 1967;Kehoe, 1963;Rickard, 1965;Zentall, 1970; also see Gleitman, 1971, andSpear, 1971, for reviews). Worth mentioning is the experiment by Crowder (1967), which reported that, although a retention control group exhibited reliable forgetting of an appetitive spatial discrimination after 7 days, there was no evidence of PI in experimental animals.…”

“…Maier and Gleitman (1967), however, suggested that the failure of animal experiments to observe PI for a spatial discrimination was because the vast majority failed to sample sufficiently long retention intervals. This interpretation may now be questioned in light of Kehoe's failure to observePI after 30 days (Kehoe, 1963), Zentall's failure to observe PI after 40 days, and the failure of Experiment 1B to demonstrate PI after 65 days even though sufficient time had passed for the observation of extensive forgetting. While it is possible that, had retention been tested at an interval intermediate between 30 and 65 days, PI may have been found among adults, the consistent failure to demonstrate PI for a simple spatial discrimination in adult rats, in contrast with the present finding of three cases of PI in infant rats, lends credence to the conclusion that infant rats are more susceptible to proactive interfering events than are adults.…”

FORGETTING AND CONDITIONED SUPPRESSION: ROLE OF A TEMPORAL DISCRIMINATION1

“…On the other hand, a number of reports describe sizable retention decrements of foodreinforced instrumental behavior (Gleitman and Bernheim, 1963;Steinman, 1963, 1964;Cleitman, Steinman, and Bernheim, 1965;Kehoe, 1963). It is difficult to abstract any one common dimension from these studies that might be responsible for the retention decrements.…”

Reversal and nonreversal learning in the goldfish

“…It is possible, for example, that when a goldfish is trained with red positive after training with green positive, the red preference simply gives way to a green preference, with no residual of the training to red remaining to interfere with the retention of the new preference for green. It should be noted, however, that a more conventional experiment on retention in the pigeon has failed to give evidence of proactive interference (Kehoe, 1963). Further experiments of the same kind are required with both animals.…”