The 5s were shown 10 lists of words, and each list was either followed by an immediate free recall test or was not tested. The 5s then received either a final free recall test on the words from all 10 lists or a three-alternative forced-choice recognition test. Initial testing facilitated retrieval on the final recall test for all serial positions but had no overall effect on recognition performance. Nonpositive recency occurred on final testing of items from both tested and nontested lists whether the test was recall or recognition. A number of words presented on lists prior to immediately tested lists were incorrectly included in immediate recall for the tested lists. These prior list intrusions were largely items which had been presented in lists which received no immediate test. The frequency of these prior list intrusion errors decreased over their original serial input positions. Final recall performance was an increasing function of output position in initial recall, although there was an indication that items from final output positions were recalled less well on the final test than those from intermediate output positions. The main conclusion is that prior testing increases item accessibility but not availability.

A visual search orienting task and incidental free-recall test were used to examine the effects of "nonelaborative" rehearsal, as defined by Craik and Watkins, on recall from long-term store. Each of 16 40-wordi lists was to be searched for a different target item. To control the length of time targets remained in short-term store, the placement of targets in the search list was varied systematically. Performance on a free-recall test of all target items was a direct function of an item's search-list position, indicating that nonelaborative, "attending" rehearsal may increment an item's retrievability from long-term store. Recall was also dependent on a target's position in the series of target and search-list presentations with both primacy and recency effects present. Since neither differential rehearsal frequency nor differential depth of processing are adequate explanations for the primacy effect observed here, we propose that the search-or entry-set notions of Shiffrin and Anderson may explain the effect.

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lollowing presentation and immediate free recall testing of 10 2G-word lists, 48 Ss were divided into two groups, one of which received an oral dose of marihuana extract calibrated to 20 mg of .£ll -THC and one of which received placebo. One hour later. all Ss were administered delayed recall, recognition, and order tests on the first set of words, Presentation of another set of 10 lists followed. and there were immediate recall and delayed recall, recognition. and order t<:5!S on these words. Performance of drug and placebo Ss did not differ significantly for any of the first delayed tests. However. the performance of drug Ss was poorer than that of placebo Ss on immediate recall, delayed recall, and delayed recognition of the second set of lists. We concluded that retrieval of information relevant to the occurrence or nonoccurrence of an event was not affected by marihuana intoxication. Storage difficulties probably account for memory deficits due to the drug. and these difficulties appear to occur in the process of transferring information from short-term to long-term memory.Previous studies Melges et aI, 1970: Abel. 1971a have shown that marihuana intoxication causes decrements in the performance of certain memory tasks. Because many cognitive functions necessitate the reliable accessing of previously presented information. it is important to know precisely how marihuana influences memory processes. For information to be remembered. it must have been stored accurately in memory and it must be retrievable at the moment it is needed. The purpose of the present study was to determine whether the storage processes, the retrieval processes, or both are adversely affected by marihuana intoxication.The experimental paradigm used was a variation of a standard free recall task. The variation introduced for the purpose of separating drug effects upon storage and retrieval processes was the administration of a delayed free recall test: this procedure has been used by Craik (1970) and involves having Ss recall as many words as possible from a prior series of free recall lists, each of which had been followed by an immediate free recall test. Delayed free recall is useful for drug research, since a drug may be administered during the interval between. the immediate test on the final list and the presentation of the delayed test. The delayed recall performance of Ss receiving the active drug during that interval can be compared to the performance of Ss receiving placebo. The immediate recall scores provide a predrug measure *This research was supported by the van Ameringen Foundation and NIMH Grants 19918, 3030. and 21747.-;-Requests for reprints should be sent to R. of the equivalence of the two groups on word recall. In the present study, a delayed recognition test was also administered to determine if marihuana intoxication affects recognition and recall processes differently. In addition, for each item on the recognition test, Ss were asked to indicate in which list that item had appeared. Following the first set of...