Short-term retention of individual verbal items.

It is apparent that the acquisition of verbal habits depends on the effects of a given occasion being carried over into later repetitions of the situation. Nevertheless, textbooks separate acquisition and retention into distinct categories. The limitation of discussions of retention to long-term characteristics is necessary in large part by the scarcity of data on the course of retention over intervals of the order of magnitude of the time elapsing between successive repetitions in an acquisition study. The presence of a retentive function within the acquisition process was postulated by Hull (1940) in his use of the stimulus trace to explain serial phenomena. Again, Underwood (1949) has suggested that forgetting occurs during the acquisition process. But these theoretical considerations have not led to empirical investigation. Hull (1952) quantified the stimulus trace on data concerned with the CS-UCS interval in eyelid conditioning and it is not obvious that the construct so quantified can be readily transferred to verbal learning. One objection is that a verbal stimulus produces a strong predictable response prior to the experimental session and this is not true of the originally neutral stimulus in eyelid conditioning. Two studies have shown that the effects of verbal stimulation can decrease over intervals measured in seconds. Pillsbury and Sylvester (1940) found marked decrement with a list of items tested for recall 10 sec. after a single presentation. However, it seems unlikely that this traditional presentation of a list and later testing for recall of the list will be useful in studying intervals near or shorter than the time necessary to present the list. Of more interest is a recent study by Brown (1958) in which among other conditions a single pair of consonants was tested after a 5-sec, interval. Decrement was found at the one recall interval, but no systematic study of the course of retention over a variety of intervals was attempted. EXPERIMENT I The present investigation tests recall for individual items after several 1 The initial stages of this investigation